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User`s Manual - Stanford Research Systems

1. Flow the Reference Gas until the measurements have completely settled This may take may take many minutes to remove any residual gas especially at low flow rates Evacuate the acoustic cell to vacuum prior to flowing the Reference Gas This takes only a few seconds but requires additional valves and pumps Caution The accuracy of readings after setting a REL depends on how well the REL was performed Be sure that the measurement has completely settled before performing the REL JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Application Guide 105 Procedure Use one of the techniques to purge the acoustic cell to ensure that the pure Reference Gas is all that is in the acoustic cell Set the number of averages N between 20 and 60 Allow the reading to completely Stabilize Remember that it takes about N 1 14 seconds for measurements to settle Refer to Averaging page 72 for details Select Use REL Press REL to 100 REL to 0 or enter the lt REL Value gt directly as described in REL page 59 Return to the Home page The reading should be very nearly the exact value that was selected on the REL page JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Application Guide 106 Converting Molar Fraction vs Mass Fraction The ratio of the two gases can be reported as either a mole fraction or a mass fraction These differ only by the atomic weights of the gases Mole fraction is the ra
2. HELP takes you to a Help screen for the particular page you are on Each Help page describes the parameters and settings for that page There may also be suggestions to resolve problems or errors found on that page Event Relay 1 amp 2 The Event Relays can be used to control external devices that depend on different conditions in the BGA244 These conditions can be individually enabled and include things like exceeded limits loss of the measurement signal and system faults There are two independent events relays Event Relay 1 and Event Relay 2 If any enabled conditions are true the Event Relay becomes active If the Industrial Control Option Option 1 is not installed or 24 Vp is not present the Event Relay buttons are greyed out and the Event Relays are not active The EVENT RELAY buttons are dual purpose controls Pressing them takes you to the Event 1 or Event 2 configuration page where the event conditions are set If an event is currently active that event button will turn red as an indicator If the Event Relay is in a Force On or Force Off state that button will turn yellow to indicate that condition Event Relay Configuration Pages Event 1 and Event 2 are set independently and have separate configuration pages Any of the enabled conditions can activate an event The following conditions can be selected Use the Page T and Page 4 keys to navigate the Event list Event Relay 1 Config Any active con
3. RS 422 Interface for Computer Control C4 24V Power Connector C5 Analog Measure Out and 24V Power C6 2 Analog Outputs 0 5 V 0 10 V 4 20 mA C7 2 Analog Inputs 0 10 V 4 20 mA 4 20 mA w loop power C7 2 Event Relay Contacts C8 Connector Pinouts TABLE 3 C3 RS 232 JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Installation Guide 20 TABLE 4 C4 RS 422 Chassis GND 4 JD TABLE 5 C5 24V 1 Center 2 Outside GND 24V Return TABLE 6 C6 MEASURE OUT Pin Signal 4 GND 24VReturn TABLE 7 C7 ANALOG I O Pin Signal 4 Analogin2 6 GND OutiReturn 8 GND Out2Return TABLE 8 C8 RELAY CONTACTS Relay 1 Normally Open Relay 1 Common 4 Relay 2 Normally Open 6 Relay 2 Normally Closed JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Installation Guide 21 Terminal Strip Connectors The BGA244 uses Phoenix Contact Combicon MC Series connectors for its terminal strips Each terminal strip is made up of two pieces a PCB soldered base strip and a detachable terminal block Each terminal strip connector in the BGA244 comes with its terminal block inserted into the base strip Tip It s usually easier to remove the terminal strip from the BGA244 before connecting wires Unplug the terminal strip by pulling straight back from the unit Loosen the screws before inserting the wires Make sure to observe t
4. If an External Power Supply occurs the POWER LED will flash at 4 Hz If a General or Self Test Fault occurs the ERROR LED will stay on continuously External Power Supply Faults If the BGA244 s power supply input voltages fall outside the specified range an external power supply fault will be generated The 5V USB power supply is monitored only when the unit is powered over USB no 24V Otherwise the External 24V power supply is monitored The following faults are displayed on the Faults page and are indicated by the Power LED blinking at about 4 Hz See Power page 21 for details on power supplies and cabling Note There must be a minimum voltage 3 3 V for USB 18 V for the External 24 for the BGA244 to control the display or LEDs TABLE 12 EXTERNAL POWER SUPPLY FAULTS Fault Name Meaning USB Undervoltage External USB Supply lt 4 45V USB Overvoltage External USB Supply gt 5 50V 24V Overvoltage External 24 Supply gt 28V USB Undervoltage Fault This is usually caused by a USB port that cannot provide sufficient current or a high resistance USB cable USB Overvoltage Fault This fault may be caused by a faulty USB supply 24V Overvoltage Fault This fault indicates a faulty or improper power supply Confirm that the 24V Power Supply is appropriately rated SRS Stanford Research Systems BGA244 Binary Gas Analyzer Operations Guide 83 General System Faults General System Faults are critical
5. The saturation vapor pressure of the gas is computed to warn that the system may be close to condensation which can impact the speed of sound or fill the chamber with liquid and to limit the range of composition computational results The Antoine equation Eq 9 is used to model the saturation vapor pressure over the operating temperature range B Px bar yoli re Eq 9 Values for A B and C are given in columns 41 43 of the Gas Table These values were found by fitting the Antoine equation to vapor pressure data points over the operating temperature range Vapor pressure data points were generated from multiple sources including NIST s REFPROP and correlation functions and parameters found in Perry PG amp L PPL amp G JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Gas Table 196 Vapor pressure data is omitted for fluids with critical temperatures below 265 K as these fluids cannot be liquids at the BGA244 operating temperatures In cases where no vapor pressure data is available the BGA244 will not provide condensation warnings and will not limit composition results to below the saturation vapor pressure Speed of sound offsets Columns 44 46 The BGA244 computes the theoretical speed of sound using accurate molar masses temperature corrected heat capacities virial corrections and translational vibrational relaxation corrections The speed of sound is measured using the thermo viscous corrected resonanc
6. Accessory BGA 5 is a5 watt USB power adapter The appropriate adapter will be shipped based on the country being shipped to North America Europe UK and Australia New Zealand Be sure to use an appropriate USB cable when powering the BGA244 over USB The cable that is included with the BGA244 is suitable See Power in the Installation Guide for information on suitable USB cables 24V Power Supply BGA 24 Accessory BGA 24 is a 50W universal input power supply that provides 24 V at 2 5 A Note that this accessory requires the Industrial Control Option Option 1 be installed Shield BGA S Accessory BGASS is an Acrylic shield used to protect the BGA244 Display This accessory is not needed for units without displays Option 2 Note that the display touch screen will not operate through the Acrylic shield It is necessary to first remove the shield before using the touch screen Replace the Acrylic shield when you are done using the touch screen JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Getting Started 5 BGA244E The standard BGA244 is designed for use in a relatively clean environment The BGA244E packages the standard BGA244 in a NEMA Type 6 6P enclosure for use in exposed locations See Appendix B for information on the BGA244E All options and accessories except the gas fittings Options A H are available on the BGA244E Pressure Transducer Option T Option T is a 0 150 psia pressure tran
7. Column 1 The CAS registry number is a unique identifier assigned by the Chemical Abstract Service CAS to every chemical substance described in reviewed scientific literature The CAS numbers are used by chemical suppliers governmental regulators safety data sheets MSDS chemical and thermodynamic databases Using the CAS number instead of a chemical name will assure that correct gas has been selected The CAS Registry Number is a Registered Trademark of the American Chemical Society Preferred name Column 2 Except for a few arcane cases for example carbon dioxide is used instead of methanedione and ozone is used instead of 2 trioxiden 2 ium 1 ide the preferred name is usually the IUPAC name International Union of Pure and Applied Chemistry First and second alternate names Column 3 amp 4 Many compounds are commonly called by more than one name For example difluoromethane CH F is also called methylene fluoride and is an ASHRAE registered refrigerant designated as R 32 The alternate name columns accommodate these other names and industry designations Formula Columns 5 Formulas for compounds may be written in several ways The BGA244 uses a simple non structural form called Hill notation The rules are simple For molecules containing carbon the carbons are listed first followed by the hydrogens followed by everything else in alphabetical order of the element symbols If the compound co
8. Dihydrogen Monoxide 20 006 7664 39 3 Hydrogen fluoride poe Heavy Water Deuterated Water He D2 H4 H3N H20 HF D20 HN O N2 2 C Hydrogencyanide oo Carbon monoxide carbonos Jo soom eooo Nogen A T AA eo rre aoyo S rozar 2896 asooo Nitrogenoxde Nitrogen monoxide Nircosde no 30006 10102439 Formaldehyde LO oo oo ooo CA A A A YE owen O O o os aar Methni _ Methylatcohol o oo 3204236 Jerse JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Gas Table 178 Preferred Name Alternate Name Alternate Name2 Formula Weight cass wran OO S fa aos ooa Eydrogen sulfide O s o aooe roa Hydrogen ehioide LO a aa aroo uorine O ars rezar gon as raza acetonie O on ao rose oprop Trimet o es faos fsa fthyleneimine LO es aos assen meade eo aos oo Eenes O eo aos pas Propane oimetnymetnane JO es faaoose2 74986 Formamide S S ano so SDT formicacid __ Methanoicacid fonoz fasors Jerse Enmamol ett caso aeoea 64175 Metsise O es asas aaa Ozone riatomicogen jos aros 0028 25 yang ena os os Vinylacetyiene O ea ars ora feryonitile O en os oa 1 3 Butadiene Butadiene O fome saoo 06980 CST Ethylacetylene But 1 yne C4H6 54 09 107 00 6 Dimethyl acetylene 17 C4H6 54 09 503 17 3 C4H6 54 09 590 19 2 So o i Proponi O sn soe ono moen O S eo eos oros Tewe feue fome 5e1032 106989 Cydobutane Tetrametyiene foams 56106 287230 Methylisocyanate LO i oo sos foao Metryivinyener o eso fe
9. It supports a single transmitter and single receiver pair Connections are made using a 5 pin terminal strip Tx and Rx connections between the BGA244 and host should be made as follows Note that the transmit pins on the BGA244 connect to the receive pins on the host and the receive pins of the BGA244 connect to the transmit pins of the host BGA244 BGA244 Host GND GND RS 422 PINOUT FIGURE 5 RS 422 SIGNAL PATH JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Installation Guide 25 Use twisted pair cabling with an impedance of 100 Q especially for longer cable runs and higher data rates Shielded Cat5 or Cat6 cable is a good choice A 100 Q terminating resistor R can be added to each receive end for long cable runs or high data rates to improve signal quality The resistor should be rated for at least watts The resistor can be connected along with the RxD lines at the BGA244 terminal strip In order to communicate properly over RS 422 both the BGA244 and the host computer must be set to the same configuration The RS 422 interface supports baud rates from 2400 to 115 2 k baud RS 422 can operate at cable lengths over 1000 m 3250 ft In general the highest baud rates will operate successfully for shorter cable lengths Communication errors can be caused by excessive cable length missing terminators overly high baud rates or electrical noise If errors occur adding a terminator and or operating at a lower baud
10. Name molecular weight specific heat expansion of specific heat over temperature Selecting a User Gas User gases show up in gas selection searches as User Gas Name See Selecting Gases in the Operations Guide for more information Adding a User Gas with BGAMon JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Application Guide 114 Determining Gas Coefficients All User gases must have a name molecular weight and some thermodynamic data The name is used when selecting the gas and to display on the Home page The molecular weight is the atomic weight of the gas Differing amounts of thermodynamic data can be entered ranging from a single parameter to complete specifications The following section describes the simplest model for a gas the molecular weight and a single thermodynamic property Cp specific heat at constant pressure This model assumes that the gas follows the ideal gas law This is a reasonable approximation of the behavior of many gases especially at constant temperature and pressure See Appendix A Gas Table for details on obtaining a more complete set of parameters for a gas Finally remember that repeatability is often more important than accuracy As long as you operate at a similar temperature and pressure the measured values won t change even if you don t have a precise value for Cp Using the REL function can compensate for less than perfect parameters Mass Finding the mass o
11. References Appendix B BGA244E Operation Environment Access Unpacking Installation Mounting Gas Fittings Conduit Electrical Pressure Gauge SRS Stanford Research Systems 170 171 172 173 173 174 174 175 177 177 188 197 199 199 199 200 201 202 202 203 203 203 205 BGA244 Binary Gas Analyzer Safety and Precautions vil Safety Procedures and Precautions Observe the following general safety precautions during all phases of operation of this instrument Failure to comply with these precautions or with other specific warnings elsewhere in this manual violates the safety standards of intended use of this instrument and may impair the protection provided by the equipment Stanford Research Systems Inc assumes no liability for the customer s failure to comply with these requirements DO NOT SUBSTITUTE PARTS OR MODIFY THE INSTRUMENT Do not install substitute parts or perform any unauthorized modification to the instrument Return the instrument to Stanford Research Systems or an authorized representative for service and repair to ensure all safety features are maintained SERVICE BY QUALIFIED PERSONNEL ONLY Operating personnel should not attempt any component replacement or internal adjustments Any service should be performed by qualified service personnel only USE CAUTION WHEN OPERATING WITH HAZARDOUS MATERIALS lf hazardous materials are used users must take responsibility to
12. The REL relative function can be used to zero the ratio measurement to a reference gas This can be either a pure gas or a gas blend with a known ratio See the REL page 59 for more information The REL indicator only appears when the REL function is active Dual Concentrations There are a few gas combinations where there are two valid molar ratios for a given speed of sound The ratio of these gases can be accurately determined for certain concentrations but there two ratio values for a portion of the range Both ratios are equally valid as far as the BGA244 can determine Home Binary Gas Analyzer If a dual concentration is detected the BGA244 reports both ratios Concentration 1 is the smaller value and is displayed on top Concentration 2 is the larger value and is displayed on the bottom JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Operations Guide 43 Gas Purity Analyzer This analyzer reports the purity of a gas as measured by the ratio of its measured speed of sound to its ideal speed of sound The gas species or its ideal speed of sound must be known This instrument mode is useful when measuring relatively pure gases Results are reported in percent parts per million ppm or fraction 0 1 0 Go to Setup Control Panel Units to change the units Refer to Units page 71 for details on selecting units Principle of Operation The speed of sound of a pure gas at a known temperat
13. 1 2 for Analog Out 1 2 Parameter j selects one of the following output types Output Type O 5V 0 10V 3 4 20mA Example AOTY1 3 Set Analog Out 1 to 40 20 mA N e HF Analog Out User Setting Set query Analog Out i User setting to d in volts or amps Parameter i 1 2 for Analog Out 1 2 Example AOUS 2 9 00 Set Analog Out 2 to 9 00 volts for Analog Out 2 set to volts AOUS 1 20e 3 Set Analog Out 1 to 20 mA for Analog Out 1 set to current Analog Out Value Query the present Analog Out i The returned value is in volts or amps determined by the Analog Out Type Parameter i 1 2 for Analog Out 1 2 An Error 18 No 24V Available will be generated if the 24V power supply is not available An Error 24 Output Error will be generated if the output is disabled If an over temperature or current alert is active the command will return an overload value 9 9E37 The controlling program should identify this and check the Analog Status Register if it occurs Refer to Instrument Status Registers page 164 for more information JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Remote Programming 158 Analog Inputs Commands Analog Inputs can be read directly or configured as a pressure meter Refer to Pressure Commands page 151 and Analog Inputs page 78 for more details Some Analog In commands set parameters that are not currently relevant depending on the unit s configuration These parameters will be a
14. 10 1 43 8 57 Scale Max 10 20 2 1 43 22 86 There are two alerts that can occur for the Analog Outputs They appear as red text at the bottom of each Analog Output page and on the Alert page These normally indicate a problem with whatever is connected to the Analog Output rather than a problem with the output itself Out Alert indicates that the current output can t output the required current This usually indicates a break in the 4 20 mA current loop or an overly large series resistor Temperature Alert indicates the output driver has overheated and is in thermal limit This usually indicates that the output is shorted These alerts self clear if the condition that caused them goes away See the Message Log for a history of transient events See Alerts page 84 later in this chapter for details on alert behavior Measu re Output r Measurement Output i i nam ENA Measure Out is always linked to the measured parameter set by the Instrument Mode as follows 4 20mA Binary Gas Analyzer Gas Concentration Ratio Gas Purity Analyzer Speeds of Sound Ratio Physical Measurements Normalized speed of sound The present Output Value voltage or current is displayed just below Scale Max Output Range Press ENABLE DISABLE to enable or disable the output Press lt Type gt to open the selection list The currently selected type will be highlighted in yellow Press the desired value to select it En
15. 188 x 1074 should read 2 188 x 1071 per original published papers Second virial coefficient parameters Column 23 25 The second virial coefficient B T is parameterized as a function of temperature as shown in Eq 4 See Zuckerwar 4 30 4 32b B T a b e Eq 4 The coefficients a b and c with units of cc mol cc mol and K are found in columns 23 25 of the Gas Table Several sources where used for these parameters including Fitting the above equation to values for the 2 virial computed over the operating temperature range from REFPROP or by using coefficients directly from Zuckerwar or from Kaye amp Laby or lastly fitting the above equation to values for the 2 virial computed from the Tsonopoulos correlation The 2 virial and its first and second temperature derivatives alter the speed of sound in a manner which increases linearly with gas density For many gases the virial correction for the speed of sound will be a small correction For example in methane at 1 6 atm and 300K virial effects reduce the speed of sound by only 0 12 However even this small factor may be important in determining relative concentrations of species which are close in molecular weight Third virial coefficient parameters Column 26 30 The 3 virial as a function of temperature is represented Eq 5 See Zuckerwar s Eq 4 35 de C T a exp 2 exp gy T Casymptote Eq 5 JSRS Stanford
16. 1984 1988 following PG amp L Eq 10 3 14 Heat capacity relaxation parameters Columns 37 40 There are a few gases for which vibrational energy levels which contribute to the heat Capacity do not have time to equilibrate with the translational energy during the period of an acoustic cycle The relaxation correction may be thought of as a correction to the heat capacity of the gas If the relaxation time T4 is longer than the acoustic cycle then vibrational degrees of freedom are partially frozen out the heat capacity is lower and so y and the speed of sound will be higher Without a correction for this effect the computed speeds of sound as is reported by NIST s REFPROP program for example which computes the speed of sound at zero frequency are lower than the actual speed of sound We follow Zuckerwar s approach for the relaxation correction to the square of the speed of sound W as shown in Eq 8 E WTq w wZ 1 _ a 1 eE 1 w7 Eq 8 Here W is the speed of sound squared corrected for the static heat capacity and virial effects but not relaxation effects e is the relaxation strength Tg is the relaxation time and w 27 f19 The vibrational temperature in K in column 37 allows the firmware to compute e and the coefficients in columns 38 40 allow the computation of Tz Computationally we cast Zuckerwar s correction as a frequency dependence of the heat capacity Vapor pressure Columns 41 43
17. 6 Temperature temperature Limit Enable Set query the enable state of the selected limit type to k Parameter i is the Measurement ID Parameter j 1 2 for Upper Lower limits Parameter k 0 for disabled k 1 for enabled Example LIME 1 2 1 Enable the Binary Gas Analyzer lower limit LIME 4 1 Query the enable mode for the Pressure Meter 1 upper limit Limit Hysteresis Set query the hysteresis value of the selected limit type to d Parameter i is the Measurement ID Parameter d is a floating point value in units of the associated measurement If omitted units default to the Measurement global units Example LIMH 1 3 Set the Binary Gas Analyzer hysteresis to 3 LIMH 6 5 Set the Temperature hysteresis to 5 using the global temp units LIMH 4 Pa Query the Pressure Meter 1 hysteresis value in Pascal JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Remote Programming 146 LIMS 1 Meter Scale Set query the meter scale value of the selected measurement to d Parameter i is the Measurement ID Parameter j 1 2 for Upper Lower scale Parameter d is a floating point value in units of the associated measurement If omitted units default to the Measurement global units The LIMM command is not valid for the Physical Measurement Mode An Error 11 Illegal Mode will be generated for i 3 Example LIMM 2 1 5 Set the Gas Purity Analyzer meter scale upper value to 5 LIMM 4 2 25 Set the Press M
18. 8 32 64 bit Windows Vista XP 32 64 bit Windows XP Embedded Windows CE 4 2 5 0 amp 6 0 Mac OS X Linux 2 6 amp greater Android 4 wire point to point non multidrop no parity 8 bits 1 stop bit no flow control 2400 115 2k gt 1000 meters for lower baud rates BGA244 Binary Gas Analyzer Specifications xiii Power USB Connector USB Type B Voltage 5 Voc 0 25 V Current 0 35 A with display 0 25 A w o display The USB voltage must be gt 4 75V at the BGA244 Be sure to use a device that can supply enough current and a large enough wire gauge cable that can support this voltage See Power in the Installation Guide for details Note that the USB current goes to O mA when 24V is connected 24 V opt 1 Connector 3 1 mm barrel jack 2 wire terminal strip Voltage 24 Voc 1 V Ripple lt 240 mV p p Current No Analog lO Heater 0 2A Max 2 7 A Environment Cavity Proof Pressure 2500 psi 17 MPa Operating Temperature 20 C to 70 C Storage Temperature 80 C max Humidity lt 90 relative humidity non condensing Altitude lt 2000 m for applications above this altitude contact SRS Pollution Degree Category 2 EN61010 1 only non conductive pollution Inbound Helium Leak Rate 1x10 sccs JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Specifications XiV Physical Display Version Color TFT LCD w touchscreen Power Communication and Error LED Indicators Display
19. All other enable registers are cleared at power on JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Remote Programming 164 Serial Poll Status Byte UU it a ul e 7 MSS EVNB Meaning An unmasked bit in the BGAO status register BGOR has been set An unmasked bit in the BGA1 status register BG1R has been set An unmasked bit in the FAULT status register FALR has been set An unmasked bit in the ANALOG status register ANAR has been set The interface output buffer is non empty An unmasked bit in the standard event status register ESR has been set Master summary bit Indicates that the instrument is requesting service because an unmasked bit in this register has been set An unmasked bit in the EVENT status register EVNR has been set The serial poll status byte may be queried with the STB command Standard Event Status Register Bit BR WN PR O oo UW 7 Name OPC Reserved QYE DDE EXE CME Reserved PON Meaning Operation complete All previous commands have completed See command OPC Query error occurred Unused Execution error A command failed to execute correctly because a parameter was invalid Command error The parser detected a syntax error Power on The unit has been power cycled The standard event status register may be queried with the ESR command The standard event status enable register ESE may be used to control the setting of
20. Formula Weight cas Naphthalene O A a EE o zotan O co eaa 106683 p octanone O co ea aaa 7 anal co ea pano Nonae amame O ezo eass amena 2 2 3 4 Tetrametiyipentane ezo iess 186534 2 3 3 4 Tetrametiyipentane fomo messi a6 787 28 Methyloctane fisnore O cazo rasa 322112 octanos os iaeoe Dibutylether S co oas iaoa fthyhexylether o co 10228 756434 1 2 3 4 i C10H12 132 202 119 64 2 Tetrahydronaphthalene AS 132202 119 602 Heptyl mercaptan PCTS 132 267 1639 09 4 1 1 2 Trichloroethane po C2H3CI3B 133 404 79 00 5 o esereane R 245ca C3H3F5 134 0479 679 86 7 Se ease R 245fa pestis 134 0479 460 73 1 Butylbenzene n Butylbenzene Butyl benzene C10H14 134 218 104 51 8 1 4 Diethylbenzene para Diethylbenzene p Diethylbenzene C10H14 134 221 105 05 5 To Durene C10H14 134 221 95 93 2 Tetramethylbenzene Methyl benzoate J ooo o caoz O16148 93 58 3 Benzyl ethyl ether J 9120 pages 539300 1 1 1 2 tetrafluoro 2 chloroethane e AOT a dl R 124 C2HCIF4 136 475 2837 89 0 tetrafluoroethane saints sa R 124a sae C2HCIF4 136 476 354 25 6 tetrafluoroethane Tetrafluorochloroethane Trichloro fluoro methane Trichlorofluoromethane CCI3F 137 368 75 69 4 Hexafluoroethane R 116 Perfluoroethane C2F6 138 0118 76 16 4 1 Decyne cto 138 25 764 93 2 4as 8as Decal 10H1 138 2 493 01 cis Decahydronaphthalene Decahyuronaphihal ne cis Decalin C10H18 38 253 93 01 6 trans 4ar 8ar 10H1 138 2 493 02 7 Decahydron
21. Gas Analyzer Operations Guide 76 If the cell temperature comes out of regulation try the following Ifthe cell temperature is above the set temperature increase the set temperature If the maximum set temperature is exceeded 70 C it may be necessary to either allow the BGA244 to operate without temperature regulation or to reduce the temperature of the gas or the environment Remember to not exceed the maximum operating temperature 70 C f the cell temperature goes below the set temperature increase the maximum heater current If the maximum allowable heater current cannot raise the temperature to the required temperature the operating environment temperature needs to be increased A simple way to do this is to add insulation around the BGA244 Degas Heater The Degas Heater can only be used during system bake out It is normally used in conjunction with the Block Heater to bake out the BGA244 cell for use high purity systems The Degas heaters operate by heating the speaker and microphone Kapton membranes directly They draw about 70 mA and provide about 0 25 W of heat The BGA244 cannot make gas measurements while the Degas Heater is active This is indicated on the Home Page by the DEGAS ON screen message Press Degas ON OFF to toggle the Degas Heater on and off Computer lO Computer 0 The BGA244 has three separate computer interfaces that can control and monitor all functions Details on contro
22. Help Screens 35 Map of Interface Functions 36 Power On 37 Appearance 38 Binary Gas Analyzer 40 Details 42 Gas Purity Analyzer 43 Details 45 Physical Measurements 46 Details 48 Screen Messages 49 Analysis Messages 49 Other Messages 50 LED Blink Codes 51 Controls 52 Limits 52 Scale Binary amp Gas Purity 53 Pressure Physical Measurements 53 Help 53 Event Relay 1 amp 2 53 Setup 55 Setup 56 Run Stop 56 Instrument Mode 56 Selecting Gases 57 REL 59 Pressure 61 Temperature 64 Store Recall 64 Default Setup 66 Control Panel 70 Display 70 Units 71 JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Table of Contents lil Measurement 72 Status 74 Heater 75 Computer lO 76 Analog IO 78 Faults 82 Alerts 84 Message Log 86 Self Test 86 About the BGA244 38 Password 88 Hardware Reset 89 User Gases 89 Updating Firmware 89 Chapter 4 Application Guide 91 Gases 91 Gas Requirements 91 Unusual Gas Properties 92 Condensation 93 Water Vapor in Air 94 Pressure 96 Pressure Effects in Gases 96 Minimum Operating Pressures 97 Ambient Pressure Variation 98 Operating Conditions 99 Interference 101 Measurements 102 Temperature Variations 102 Evacuating Cell 102 Using Averaging 103 REL to a Reference Gas 104 Converting Molar Fraction vs Mass Fraction 106 Accuracy amp Stability 107 Binary Gas Measurement Accuracy 107 Gas Purity Measurement Accuracy 109 Long Term Stability 109 High Purity Use 110 Fittings and tub
23. J to open the Instrument Mode list Press the desired mode to select it The currently selected mode is highlighted in yellow JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Operations Guide 40 Binary Gas Analyzer The Binary Gas Analyzer reports the fraction of one gas in a two gas mixture Both gases must be known The Binary Gas Ratio is reported as the ratio of gas 1 in the mixture Results are reported in percent parts per million ppm or fraction 0 1 0 Go to Setup Control Panel Units to change the units See the Units page 71 for details on selecting units Principle of Operation The speed of sound in an ideal gas can be approximated by Where W is the speed of sound y is the ratio of specific heat capacities y Cp Cy M the molar mass T the absolute temperature and R the ideal gas constant For a gas mixture y and M are determined by the properties of each gas and their ratio within the mixture By measuring the speed of sound and temperature of the gas mixture and knowing the properties of each gas the mole fraction of each gas can be precisely determined The speed of sound in real gases is somewhat more complicated There are a number of gas specific effects that complicate the ideal case These include thermo viscous frequency shifts temperature dependencies of heat capacity dispersive effects and intermolecular virial effects that depend on both pressure and temperature The BGA244
24. N Ep l Example STB TRG Meaning BGOB BGOR summary bit BG1B BG1R summary bit FALB FALR summary bit ANAB ANAR summary bit MAV message available ESB ESR summary bit MSS master summary bit EVNB Event summary bit A return of 113 would indicate that BGOB MAV ESB and MSS are set BGOB indicates that an enabled bit in BGOR is set MAV indicates that a message is available in the output queue ESB indicates that an enabled bit in ESR is set MSS reflects the fact that at least one of the summary enable bits is set and the instrument is requesting service Trigger This command currently does nothing TST Self Test Runs the instrument self test and returns O if successful Otherwise it returns the encoded errors per the following table Refer to Self Test page 86 for more details WAI The instrument will not process further commands until all prior commands Power Supply Display CODEC Bit o 4 Thermistors S 2 3 Reserved S Reserved Wait for Command Execution including this one have completed Example WAI SRS Stanford Research Systems Wait for all prior commands to execute before continuing BGA244 Binary Gas Analyzer Remote Programming 133 Instrument Status Commands Instrument Status Registers ALRD Disable All Alerts Disable all Alerts on the GUI This command disables all Alerts from appearing on the GUI It has no effect on any o
25. O CellUnderTemperature fault Page83 4 HeaterFautt O Page83 6 1 4 V Over Voltage Fault Page83 8 3 3 V Over Voltage Fault Page83 9 5V Under Voltage Fault Page83 Analog Status Register Bit Meaning EC O Measure Out Current Alert Page79 4 Output 2 Current Alert Page 79 6 Input 1 Over Current Alert Page78 8 Input 1 Over Voltage Page78 9 Input 1 Under Voltage Page78 Page 78 Loop Power Alert Page 78 JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Remote Programming 167 Event Status Register The Event Registers operate independently from the Event Relay configuration in the unit A single register group latched enable and immediate contains all of the event condition These registers have no effect on the Event Relay configuration User code should be used to determine the appropriate actions based on the event conditions Use the EVNC command to set the Event Relay Configuration Refer to Events page 53 for details on the specific conditions for items in the Event register Use the RLYF command to force the relays on or off Event Status Register Bit Meaning E O System Fault Page 4 Pressure 1 Limit Exceeded Page54 6 Pressure 2 Limit Exceeded Page54 8 Temperature Limit Exceeded Page54 9 Temperature Limit Exceeded Page54 10 15 reserved o d O JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Remote Programming 16
26. ON to toggle relaxation correction on and off Amplitude The amplitude of the speaker signal is optimized for the best signal to noise ratio of measurements within the acoustic cell In rare cases this amplitude may cause the acoustic signal to over or under load the preamplifier The BGA244 detects this and adjusts the amplitude accordingly When this occurs there is a brief period when measurements are invalid until the acoustic signal settles to the new value reported by an Invalid screen message Ordinarily the amplitude should be left in the default auto amplitude setting If there are numerous Invalid messages due to amplitude changes it may be helpful to set the amplitude to a lower fixed value View the message log to see if an Invalid message is due to an amplitude change Press lt Amplitude gt to open the selection list The allowed selections are auto Y and full scale The currently selected method will be highlighted in yellow Press the desired value to select it JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Operations Guide 74 Binary Gas Concentration Binary gas measurements can be reported in one of two formats mole fraction and mass fraction See Converting Mole Fraction page 106 for a detailed description of the relationship between them Binary Gas Measurement MASS FRACTION Press lt Binary Gas Measurement gt to open the selection list The currently selected method will be
27. Parity None RS 232 Baud Rate of Bits 8 Stop Bits 1 Flow Control CTS RTS The following RS 232 communication problems are reported in the Message Log page 86 Parity Error Break Frame Error RS 422 The RS 422 Interface page is similar to the RS 232 page ENABLE DISABLE lt Baud Rate gt and BUFFER all operate in the same manner There is no Flow Control for the RS 422 Note that the Industrial Control Option Option 1 must be installed and 24V must be present for the RS 422 interface to be operational EA The following RS 422 communication problems are reported in the Message Log page 86 Parity Error Break Frame Error J SRS Stanford Research Systems BGA244 Binary Gas Analyzer Operations Guide 78 Analog lO The BGA244 has two analog inputs and three analog outputs ae is that can be used to interface to external devices sensors or meters Refer to Analog I O page 26 for details on connecting the analog inputs and outputs to external circuits See the Specifications for details on the analog inputs and outputs performance The Analog Inputs and Outputs are only available if Industrial Control Interface Option 1 is installed and will only operate if an external 24V power supply is connected Analog Inputs The two Analog Inputs INPUT 1 and INPUT 2 can r each be set to measure either voltage current or CONFIG current with a loop power vo
28. a substance from those predicted by two parameter corresponding states principles CSP As CSP applies strictly only to spherical molecules the acentric factor is considered to be a measure of the acentricity of the molecule The acentric factor is dimensionless and is determined from the departure of vapor pressures from those predicted for spherical molecules such as noble gases Dipole moment Column 19 The electric dipole moment of the substance in the gas phase is given in Column 19 in units of D debye Debye are not SI units but provide a dipole value which is on order 1 for molecules 1 D 3 33564 x 1073 C m 0 208194 e A JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Gas Table 193 Chemical Family Column 19 The Tsonopoulos correlation uses different correlation terms depending on the nature of the species which are categorized into one of six chemical families as shown below Simple Normal gases Keytones Aldehydes Alkyl Nitriles Ethers Carboxylic Acid Esters 1 Alkanols except methanol Methanol Tsonopoulos a b parameters Column 20 21 These parameters which are detailed in Table 4 5 on page 4 15 in PG amp L are used in the Tsonopoulos correlation to compute the 2 virial coefficients and 2 cross virial coefficients via a CSP method Note there is an error in the table in PG amp L for the exponent for the a parameter for Alkyl Halides Mercaptans Sulfides and Disulfides 2
29. acoustic transducers Contact SRS if you have questions about compatibility of a particular gas or mixture with the BGA244 Unusual Gas Properties Certain gases have properties that may affect the accuracy of their measurements Relaxation Effect Relaxation or dispersion is a non linear molecular effect that is modeled as a frequency dependence of the heat capacity of a gas Most gases fully equilibrate or relax in less than one cycle of their resonant mode within the acoustic cavity The few that don t exhibit a pressure dependent error in the speed of sound in the gas In most cases this error is only a few 100 ppm Ordinarily this effect is only observed in nearly pure gases Adding a small amount of a second gas will cause the mixture to equilibrate more rapidly reducing the relaxation to less than one cycle of their resonant mode The amount of the second gas required to achieve this is quite small lt 1 A list of gases that exhibits relaxation is shown in Table 18 Carbon dioxide CO is unique in that it has a large relaxation effect at its resonant modes for medium to low gas pressures This distorts the acoustic signal leading to large errors or unrecoverable signals To avoid this effect the recommended operating pressure for CO is around 18 psia 124 kPa although the detection threshold is at 13 psia 90 kPa Again even a small amount of a second gas will allow the mixture to equilibrate much faster eliminating t
30. adapters to avoid damaging the port threads The fitting adapters are installed using Loctite 565 thread sealant This helps to seal leaks and prevent galling seizing of the threads Allow Loctite 565 at least 24 hours to cure before applying pressure or vacuum to the system JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Installation Guide 17 Options A and B are replaceable VCR fittings similar to option H Follow the Swagelok VCR Fitting Installation Instructions when connecting to the BGA244 Remember to install a new VCR gasket between male and female fittings Use 2 wrenches to tighten the fittings so as to not damage the unit Swagelok recommends tightening VCR fittings Y turn past finger tight for stainless steel or nickel gaskets Option C is a VCO fitting Follow the Swagelok VCO Fitting Installation Instructions when connecting to the BGA244 Use 2 wrenches to tighten the fittings so as to not damage the unit Swagelok recommends tightening VCO fittings turn past finger tight Option D is an adapter for a tube fitting Follow the Swagelok Gaugeable Tube Fittings and Adapter Fittings Installation Instructions when connecting to the BGA244 Use 2 wrenches to tighten the fittings so as to not damage the unit Do not over tighten these fittings Options E and F are female NPT adapters for and pipes Follow the Swagelok Pipe Fitting Installation Instructions when connecting to the BGA244 Swagelok rec
31. and isn t commonly done Press T to increase the back light intensity Press to decrease the back light intensity JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Operations Guide 71 Units Key Click The key click can be turned on and off They should normally be left on to provide feedback that a key was pressed but can be turned off if necessary Press Key Click ON OFF to toggle the Key Click sound on and off When turning the key click off you will hear the final click as the button is pressed When turning it on there is a longer beep Screen Calibration The resistive touch screen used in the BGA244 can drift over time This can cause the active location of buttons and controls to not align correctly with the graphics This drift is normally quite slow but large temperature changes can accelerate it If the key push location isn t aligned well with the screen graphics use the following procedure to calibrate the screen Press CAL SCREEN to begin the screen calibration process Touch the center of each crosshair as prompted When the calibration is complete the BGA244 will return to the Home page You can also enter the screen calibration routine by pressing a finger to the screen when power is applied Hold your finger down until the message Release Screen to start Screen Calibration appears then follow the instructions to complete the routine Units The BGA244 displays severa
32. as functions of temperature the translational vibrational relaxation of the heat capacity and the saturation vapor pressure In addition the Gas Table provides information on the critical parameters P V Te Ze the Pitzer acentric factor the electric dipole moment and chemical family allowing the computation of cross virial coefficients by the BGA244 firmware Finally to allow for gas specific corrections caused by uncertainties in all the other parameters there are three offset parameters to repair a fixed offset or offsets which change linearly with pressure or temperature As shown in Table 25 there are 46 data fields columns associated with each gas The table shows the column number names units value for nitrogen and a brief description for each of the column entries A more complete description of each column follows JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Gas Table 189 TABLE 24 LIST OF 46 GAS TABLE PROPERTIES PROVIDED FOR EACH GAS VALUES FOR NITROGEN ARE SHOWN IN TABLE eatin wae Units ra vaa fosron OO anrame phenome Aternate name or ASKRAE designation Example 434A tameme Abpha numere Aterate name or non H formula Example Sr rather tantes omus rito a ELTON 28 01348 Molecular weight in grams per mole a0 Cp 3 4379 Scaled coefficient of polynomial for isobaric heat capacity in units of R 1 a2 Cp x1E 05 1 a3 Cp x1e 08 0 6090 Scaled coefficient of polynomial for iso
33. be scaled to match a specific range using global units For example Measure Out can be scaled so a O to 1 gas concentration corresponds to a O to 10 V output to interface to an external device Use the Scale Min and Scale Max values to scale the analog output relative to the linked parameter Scale Min is the value for the minimum analog output 0 V or 4 mA Scale Max is the value for the maximum analog output 5 V 10 V or 20 mA Scale Min and Max are always set in the selected Global Unit for that parameter Example In Binary Gas Analyzer mode the Measurement Output is always linked to the Gas Concentration ratio ppm or fraction So Scale Min and Scale Max are entered as ratios Example Analog Output 1 can be linked to the gas temperature C K or F In this case Scale Min and Scale Max are entered as temperatures If the values of the linked parameters exceed the Scale Min or Scale Max values the Analog Outputs will pin to their respective minimum or maximum values If the full scale ranges of the external device and the analog output don t match you can still calculate what the measured output would be for the minimum and maximum analog output values JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Operations Guide 80 Example You need a 1 to 8 V output for a Gas Concentration of 10 to 20 Use the 0 10 V setting for the Measure Output 7V corresponds to 10 so 1V 1 43 Scale Min OV
34. be around 5x10 sccs after a few minutes and then decrease exponentially over time Run degas until the rate has dropped to around 1x10 sccs or whatever level is acceptable if the outgas rate is being monitored Otherwise run for at least 2 hours JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Application Guide 112 When complete turn off Degas and set the Block Heater to its operating value Remember that the BGA244 cannot make gas measurements under vacuum Fill the cell with a dry gas and cap it off if not in use While Flowing Gas This procedure can also be performed while flowing a dry gas through the BGA244 It may take longer to reach the same outgas rate since the Kapton transducers are cooled by the flowing gas Ideally the dry gas should be one of the gases being used in operation so a different gas species isn t absorbed into the membrane Set the block heaters to 70 C and turn on Degas Flow at least 10sccm of the dry gas through the BGA244 Run Degas for at least 2 hours This should reduce the outgas rate to lt 1x10 sccs When Degassing is completed turn off Degas and set the Block Heater to its operating value Remember that the BGA244 cannot make gas measurements when Degas is on Fill the cell with a dry gas and cap it off if not in use JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Application Guide 113 User Gases The BGA244 Factory Gas Table contains nearly 500 differe
35. by measuring the speed of sound of the gas in the cell and its temperature The amount of each gas is calculated based on these measurements and their physical properties As described in Chapter 8 Theory of Operation the speed of sound for an ideal gas is yRT M So at a given temperature T the speed of sound is proportional to Y RS Since y the ratio of specific heats only varies between 1 and 1 67 changes in the speed of sound are largely due to the change of mass which can vary from 2 to around 200 Because of this the BGA244 has the best resolution and accuracy when the difference in molar mass of the two gases is largest After the molar mass the next most influential parameter is y gamma After these there are several non ideal gas properties that cause additional shifts The BGA244 accounts for all of these factors The best measurement sensitivity occurs when measuring a small amount of a heavy gas in a lighter gas Absolute accuracies at the 10 ppm level are possible for a small amount of an extremely heavy gas with a carrier of Helium or Hydrogen Example Measuring the ratio of 1 SF mass 146 in Helium mass 4 gives an estimated accuracy of 0 0015 15 ppm Using the REL mode cancels out the uncertainties in temperature and pressure With this relative accuracies at the ppm level are achievable Poor Sensitivity The measurement sensitivity suffers for mixtures where both gases have similar speeds of sound
36. errors that occur while the BGA244 is operating These faults indicate a problem with the internal circuitry or a serious temperature problem The following faults are displayed on the Faults page and are indicated by the ERROR LED staying on continuously TABLE 13 SYSTEM FAULTS Fault Name Meaning Self Test Fault The BGA244 runs a series of Self Tests at power on or when requested from the Self Test page or the TST command over the computer interfaces A Self Test fault is generated if any of the Self Tests fail See Self Test page 86 for more details Faults Page The Faults page provides a list of all currently active Faults Use PAGE 7S and PAGE J to navigate the list of Faults If the faulting condition goes away the Fault will self clear and be removed from the list To view transient events go to the Message Log System Faults JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Operations Guide 84 Alerts Alerts are warnings of non critical conditions These may be problems with the BGA244 or with external devices or wiring If an alert occurs the yellow Alert button appears on the Home page and the Home button turns yellow on all pages Pressing Alert takes you to the Alerts page Each Alert can be cleared or disabled using its Alert Action Window Most Alerts will self clear if the problem causing them goes away Transient events can be viewed on the Message Log Th
37. heater on otherwise O JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Remote Programming 150 HETM d Block Heater Temperature Set query the Block Heater Temperature to d in C Example HETM 50 Set the Block Heater Temperature to 50 C JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Remote Programming 151 Pressure Commands There are two different methods used to enter pressure information the value can be directly entered or a pressure transducer can be interfaced using one of the Analog Inputs Direct entry can always be used regardless of options or external power supplies The analog inputs can be used to interface to a pressure transducer if the Industrial Control Option Option 1 is installed These commands will generate an Error 16 No Option 1 if Option 1 is not installed Note that even if the 24V power supply is not present all Pressure Meter parameters can be set even though they will not operate Use the EXPA command to confirm that the 24 V power supply is present If you attempt to query the pressure PRRD or PRES when the 24V supply is not available an Error 18 No 24V Available will be generated If an analog over or under range occurs during a pressure query PRRD or PRES an overload value 9 9E37 will be returned to inform the user that there was something wrong with the measurement The controlling program should identify this and check the BGAO and Analog status
38. highlighted in yellow Press the desired value to select it Status This page lists the present value of most of the parameters measured by the BGA244 If a parameter isn t currently configured in the BGA244 or is for an uninstalled option it will be dashed out Use PAGE 7S and PAGE J to navigate the list of measured parameters List of Monitored Parameters Speed of Sound Measured Speed of Sound NTP Gas Temperature Analysis Pressure Block Temperature PCB Temperature Heater Power USB Voltage External Voltage Analog In 1 Value Analog In 2 Value Measure Out Value Analog Out 1 Value Analog Out 2 Value SRS Stanford Research Systems Status Page 2 BGA244 Binary Gas Analyzer Operations Guide 75 Heater The BGA244 heaters serve several purposes They are used to stabilize the measured gas temperature to prevent condensation and to help with high purity bake out There are two separate heaters the Block Heater and the Degas Heater Information on settling time and specific uses of the heaters is available in the Chapter 4 Applications Guide Note The Gas temperature will usually not match the block temperature due to heat flow in the gas and acoustic cell In addition the Block and Set temperatures may differ by a few degrees This is normal for the BGA244 The Heaters can only be used if Option 1 Industrial Control Option is installed and an external 24 VDC power supply is connected
39. in the error buffer The error buffer may be queried with the LERR command Descriptions of all error codes can be found in the Error Codes section of this chapter starting on page 168 Parameter Conventions The command descriptions use parameters such as i d and v These parameters represent integers or floating point values expected by the command The parameters follow the conventions summarized in Table 24 JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Remote Programmin 125 TABLE 23 COMMAND PARAMETER CONVENTIONS An integer value An ASCII string An identifier of units Allowed units depend on the type as identified below psi atm bar Pa mmHg or torr Numeric Conventions Floating point values may be decimal 123 45 or scientific 1 2345e2 Integer values may be decimal 12345 or hexadecimal 0x3039 Measurement Errors If an error in a measurement command occurs the unit will return an overload value 9 9E37 to inform the user that there was something wrong with the measurement The controlling program should test for this value and check the appropriate Status bytes to determine what the problem is Missing Options or Power Supplies Commands that require an installed option or power supply that is not present will generate an execution error See the Chapter 3 Operations Guide for details on which functions require instal
40. is a mixture of several gases specify the dominant gas species for best results JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Operations Guide 49 Screen Messages There are a variety of operating conditions that can be reported by the BGA244 display versions only There are several groups of messages including Analysis Entry Fault and Alert messages There are two types of screen messages Normal messages appear as yellow or red text on the screen overwriting part of the Home page These are notifications only and are referred to as Messages Other messages are dual purpose being both a notification as well as a navigation button Pressing them will take you to the relevant page where more details are available These are referred to as Message Buttons Analysis Messages Home Binary Gas Anal Messages appear in the measurement section to indicate something is affecting analysis within the BGA244 These items include user settings that may halt analysis loss of signal and other analysis errors All of these messages appear as text in the numeric display portion of the display Degas On This indicated that the Degas heaters are on and measurements can t be made To return to the normal operating state turn off the Degas heaters See Heater page 75 for more details gt 102 lt 2 gt 102 or lt 2 or their equivalent in ppm or fraction indicate that the binary gas measuremen
41. less Version Power Communication and Error LED Indicators Dimensions 5 5 x 4 5 x 3 25 WHL Weight 7 lbs 3 2 kg Swept Volume 130 cc Acoustic Chamber Volume Gas Fittings Available Welded Y male VCR Non welded Y male VCR female VCR 4 male VCO compression fitting 27 female NPT 18 female NPT hose barb Wetted Materials Electro polished 304 stainless steel gold flashed OFHC copper gaskets nickel plated immersion gold copper traces on 0 001 Kapton film nickel plated NdFeB magnets glass constantan Cu55 Ni45 wire and vented 316 stainless steel screws nickel plated Dumet wire Environmental Enclosure When properly installed the BGA244E with Environmental Enclosure will meet the following NEMA UL 50 standards See Appendix x Environmental Enclosure for installation instructions Rating NEMA 6 with catch latched NEMA 6L with screws installed IP66 UL Type 4X UL 50 Gas Fittings 27 female NPT Electrical Y Flexible Non Metallic Conduit FNMC Pressure Transducer opt T A Pressure Transducer can be ordered with the BGA244E It must be ordered with the Industrial Control Option Option 1 Option BGA T Specifications O 150 psi absolute Signal Output 4 20 mA 9 30 VDC 0 20 Temp Coef 72 ppm C JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Manual Conventions and Organization XV Manual Convention The BGA244 is ope
42. measurement ID types and their associated units ID Measurement UnitFamily Speed of Sound Normalized Speed of Sound 4 PressureMetert p pressure 6 UserSetting none Analog Out Enable Set query the Measure Out enable mode Parameter i 1 2 for Analog Out 1 2 Parameter j is O for disabled i is 1 for enabled Example AOEN 1 1 Enable Analog Out 1 Analog Out Scale Min Set query Analog Out i Measurement j Scale Min to d Parameter i 1 2 for Analog Out 1 2 Parameter j is the Measurement ID shown at the beginning of this section Analog Out Scale Max Set query Analog Out i Measurement j Scale Max to d Parameter i 1 2 for Analog Out 1 2 Parameter j is the Measurement ID shown at the beginning of this section Example AOMX 1 4 10Pa Set Analog Out 1 Pressure Meter 1 Scale Max to O Pascal AOMX2 10C Set Analog Out 1 Cell Temperature Scale Max to 10 C AOMX 2 Query the Measure Out Scale Max of Physical Measurements in global units JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Remote Programming 157 AOSE i AOTY if j AOUS i d AOVA i Analog Out Measure Setting Set query the Analog Out i type to j Parameter i 1 2 for Analog Out 1 2 Parameter j is the Measurement ID shown at the beginning of this section Example AOSE 1 3 Set Analog Out 1 to Cell Temperature Analog Out Type Set query the Analog Out i type to j Parameter i
43. of sound as a function of pressure See Chapter 8 Theory of Operation for more information The graph below shows the shift in the speed of sound for pure SF6 a gas with a fairly large frequency shift vs pressure Speed of Sound in SF6 vs Pressure BGA244 measurement blue and NIST REFPROP orange 136 134 132 130 128 Speed of Sound m s 126 124 122 0 10 20 30 40 50 60 FO 80 90 100 110 120 Pressure psia _ meas W_NIST FIGURE 18 SPEED OF SOUND IN SF6 VS PRESSURE SRS Stanford Research Systems BGA244 Binary Gas Analyzer Application Guide 97 These frequency shifts directly affect the Gas Purity and Physical Measurements modes Their effect on the binary gas ratio is more complicated since this also depends on the relative molecular weights of the two gases The graph below shows two traces for a mixture with xx SF in N2 One trace shows the change in the reported concentration assuming a fixed pressure of 14 7 psi 101 kPa The second shows the change in reported concentration using the actual measured pressure Is Pressure Information Necessary There are cases where the BGA244 can make satisfactory measurements without precise pressure information Best accuracy is not required Some gases have small variations due to pressure The REL function can be used to improve accuracy at a fixed pressure Unless one or more of these is true it s necessary to know the gas pressure The BG
44. rate will usually help JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Installation Guide 26 Analog I O Connections The Industrial Control Interface Option 1 includes three analog outputs and two analog inputs These features can only be used if an external 24 Vpc power supply is connected to the BGA244 The analog I O signals are located on C6 and C7 There are a number of different parameters that can be set for the analog inputs and outputs Pin Signal ANALOG I O PINOUT Analog Output There are three separate Analog Outputs Measure Out Output 1 and Output 2 These can be independently set as voltage or current outputs Measure Out is always linked to the Instrument Mode measured value Outputs 1 and 2 can be linked to one of several different measured parameters or set explicitly by the user The output full scale ranges can be scaled to match external devices See Analog I O page 78 for information on configuring the outputs Voltage Outputs The voltage outputs are unipolar and are ground referenced at the BGA244 The minus outputs are connected to the BGA244s chassis ground Avoid connecting the minus outputs to ground at the destination to avoid ground loops The voltage outputs have a maximum drive current of 20 mA and can drive capacitive loads of up to 1uF without oscillation The output voltage may be reduced by resistive losses for long cable lengths and high currents Make sure that the wir
45. return of 7727 37 9 indicates that gas 2 is set to nitrogen JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Remote Programming 148 GASH s Set Physical Measurements Gas Set query the Gas for Physical Measurements to s s is a String that identifies the gas This can be the CASH the User gas number or NONE for GAS NONE Example GASH USER 1 Set the Physical Measurements gas to User gas 1 GASP 7 s Set Purity Analyzer Gas Set query the Gas for the Purity Analyzer to s s is a String that identifies the gas This can be the CASH the User gas number or NONE for GAS NONE Example GASP 7727 37 9 Set Gas Purity gas to 7727 37 9 nitrogen PURS v u Purity Mode User Speed of Sound Set query the Gas Purity User Speed of Sound when GAS NONE to v If omitted units default to the global speed units Example PURS 320 Set the Reference Speed of Sound to 320 in global speed units PURS mph Query the Reference Speed of Sound in miles per hour SWAP Swap Binary Gases Swap Gas 1 and Gas 2 No return This command only operates on the Binary Gas Analyzer An Error 26 Invalid Gas will be generated in either Gas 1 or Gas 2 is not specified JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Remote Programming 149 BLTM u HEDG i HEEN i HEIL d HEPW HEST Heater Commands The Heaters only operate if the Industrial Control Option Opt
46. select it GAS TEMPERATURE Press lt Linked toy gt to open the selection list The currently PRESSURE 1 selected type will be highlighted in yellow Press the desired value to select it PRESSURE 2 If User Value is selected a User Setting entry box will appear below Linked to Enter a value within the full scale range for that output type Otherwise enter the Scale 0 10V Min and Scale Max values for the linked parameter USERVALUE 10 0000 V The present Output Value voltage or current is displayed just below Scale Max or User Setting JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Operations Guide 82 Faults The BGA244 monitors several critical parameters An Instrument Fault is generated if any of these goes out of range These faults indicate that something serious is wrong with either the BGA244 or the power supplies connected to it These faults are listed on the Faults page and can be read over the computer interface see Remote Programming page 136 See Troubleshooting page 173 for further details Faults will self clear if the problem causing them goes away To view transient events go to the Message Log There are three main types of faults External Power Supply Faults General Faults and Self Test Faults If any fault occurs the red System Fault button appears on the Home page and the Home button turns red on all pages Pressing System Fault takes you to the Faults page
47. specific fitting guidelines for more details TABLE 2 GAS FITTING DIMENSIONS B FemaleVCR_ SS 4 WVCR 1 2 5 320 D____ Compression Fitting SS 400 1 2 4 715 Y 18 Female NPT SS 4 RA 2 4 680 Y Hose Barb ID hose SS 4 HC 1 2 5 100 H 4 Welded Male VCR SS 4 VCR3 4MTW 4 770 SS 4 VCR 4 VCR Gasket SS 4 VCR 2 0 028 Welded Fittings Option H uses welded non replaceable Male VCR fittings intended for high purity systems These fittings are assembled without any pipe thread sealant or tape If these fittings are damaged the unit needs to be returned to SRS for repair Follow the Swagelok VCR Fitting Installation Instructions when connecting to the BGA244 Remember to install a new VCR gasket between male and female fittings Use 2 wrenches to tighten the fittings so as to not damage the unit Swagelok recommends tightening VCR fittings turn past finger tight for stainless steel or nickel gaskets Non welded Fittings The remaining fitting options are non welded These can be replaced in the field if damaged The body of the BGA244 is machined with two gas ports each with 27 FNPT threads The fitting adapters are fastened to these ports If damaged the adapters can be replaced by the customer See the Chapter 7 Service for details on the proper procedure to replace the gas fittings It is not recommended that NPT pipes are directly connected to the BGA244 Instead use NPT thread
48. temperature or pressure may affect the settling time as described in Transients page 100 TABLE 20 RESPONSE TIME 100 200 500 1000 2000 5000 High Flow Rate The BGA244 is specified for flow rates up to 5000 sccm 5 liters min Customers have successfully operated at rates of up to 20 000 sccm 20 liters min At very high flow rates there may be some noise in the readings that averaging may help stabilize See Using Averaging page 103 for details Variations in flow rate can cause transients in the measurement results as described in Transients page 100 JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Application Guide 100 Transients Changes in flow pressure or gas temperature may cause small transients in the measured readings even if the gas does not change This is caused by a disruption in the thermal profile in the BGA244 cell The transient settles as the new thermal profile is established The magnitude of the transient is a function of the measurement being made the gases and the magnitude of change The change in the speed of sound is typically less than 0 1 The change for ratio measurements is typically less than the accuracy estimation For the best accuracy allow the readings to settle after large changes in flow pressure or gas temperature A cell in equilibrium has a temperature profile that is a function of the gas mixture flow rate pressure temperature of the gas and the tempera
49. the ESB summary bit in the serial poll status byte Instrument Status Register Model The BGA244 has five groups of Instrument Status Registers INSRs Each group contains three separate 16 bit registers The first register contains a latched copy of each bit The second register is an enable register for the first register and is used as a mask for the summary bits in the Status Byte register The third register contains the unlatched version of each bit The unlatched or immediate register shows the value of the bits at the instant it was read Each Status Register is described below together with the page in the Operations Guide that refers to specific meaning of each bit JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Remote Programming 165 BGA Status Register 0 Bit Meaning See Oo Dual Concentration BGA Mode only Page 42 Degas Heater on Page 6 Measurement is stopped Page 56 Measurement is below allowable range Page 49 Cell Temperature lt 0 C 8 CellTemperature gt 70 C Page 84 9 BadAnalysis Pressure Reading Page 63 141 14 reserved S G O BGA Status Register 1 Bit Meanings See CSI G 4 Pressure Meter 2 Limits exceeded Page 63 6 USB Voltage is over range _ Page85 8 24Visoverrange Page 5 9 freserved o G 11 reserved o G 14 15 reserved o d O JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Remote Programming 166 Fault Status Register Bit Meaning See
50. the ESR register Standard Event Status Register Query the Standard Event Status Register Upon executing a ESR query the returned bits of the ESR register are cleared The bits in the ESR register have the following meaning Bit Meaning OPC operation complete Reserved QYE query error DDE device dependent error EXE execution error CME command error Reserved PON power on NOU BWN FP OO Example ESR A return of 176 would indicate that PON CME and EXE are set Identification String Query the instrument identification string Example IDN Returns a string similar to Stanford Research Systems BGA244 s n004025 ver1 00 0B Operation Complete The set form sets the OPC flag in the ESR register when all prior commands have completed The query form returns 1 when all prior commands have completed but does not affect the ESR register JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Remote Programming 131 PSC i RCL i RST SAV i SRE i STB Power on Status Clear Set query the Power on Status Clear flag to i The Power on Status Clear flag is stored in nonvolatile memory in the unit and thus maintains its value through power cycle events If the value of the flag is O then the Service Request Enable and Standard Event Status Enable Registers SRE ESE are stored in non volatile memory and retain their values through power cycle e
51. the following output types Output Type 1 0 5V 2 0 10V 3 4 20mA Example MOTY 2 Set Measure Out to O 10V Measure Out Value Query the present Measure Out value The return value is in volts or amps determined by the Measure Output Type An Error 18 No 24V Available will be generated if the 24V power supply is not available An Error 24 Output Error will be generated if the output is disabled If an over temperature or current alert is active the command will return an overload value 9 9E37 The controlling program should identify this and check the Analog status register if it occurs Refer to Instrument Status Registers page 164 for more information JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Remote Programming 156 Analog Output Commands AOEN i j AOMN i j d u AOMX i j d u The Analog Outputs can be linked to user values or one of several different measurements See Analog Outputs page 79 for more details Note that although the Analog Out is only linked to the selected measurement any of the Analog Out parameters can be set at any time A parameter ID is used to specify the Measurement for some commands Each measurement has its own unit family associated with it If units are omitted the selected global unit is used If units are included with the command they must be in the correct unit family or an Error 127 Illegal Units will be generated The table below lists the
52. the gas is measured using a cylindrical resonator using acoustic transducers The gas temperature is measured using thermistors inside the resonant cavity The Normalized Speed of Sound and Gas Concentration is calculated based on the cylindrical resonator characteristics and the thermodynamic properties of the gases 4 4 Hz None or 2 to 100 samples averaged Accuracy 0 1 C Resolution 0 001 C Accuracy 0 02 Resolution 10 ppm Stability 10 ppm Accuracy typically 0 1 Resolution 1 ppm Stability 10 ppm BGA244 Binary Gas Analyzer Specifications Xi t All concentration specifications depend on the gas species being measured See Accuracy in the Application Guide for more information Heater opt 1 Set Temperature Current Limit Settling Time to final temperature Protection Analog I O opt 1 Outputs Function Measure Out Output 1 2 Range Voltage Current Resolution Voltage 5V range Voltage 10V range Current Accuracy Voltage Current 0 C to 70 C 0 05 to 2 5 A 16 minutes for 25 C to 50 C temperature step with 2 A max current Over temperature and Over Current Protected Gas Ratio Gas Purity or Normalized Speed of Sound Speed of Sound Normalized Speed of Sound Temperature Pressure or User Value Oto 5V O0to 10V 4 to 20 mA 0 2 mV 0 1 mV 0 5 WA 0 025 1 mV 0 1 10 uA Output accuracy specifications are for User values For Measure Out or Linked output valu
53. to the BGA244 The maximum Block Heater current drawn from the external supply can be set between 50 mA and 2 2 A The current draw of the Degas Heater is fixed at about 140 mA The Block Heater can be used during either analysis or bake out The Degas Heater cannot be used during analysis If the Degas Heater is active a DEGAS ON message is displayed on the Home page See Screen Messages page 49 for more information Block Heater The Block Heater can apply over 50W of power to heat the cell temperature to as high as 70 C The Block Heater is over temperature and over current protected Heater The Block Heater uses a temperature servo to maintain the temperature of the cell to the set point It will hold the temperature stable assuming the following conditions are true The Block Heater temperature set point is at least 3 degrees above the highest ambient temperature The Maximum Heater Current is large enough so the heater can raise the cell temperature up to the Block Heater set temperature for the lowest ambient temperature Press Heater ON OFF to toggle the Block Heater on and off Enter the Heater Temperature between 0 and 70 C Enter the Maximum Current between 0 05 and 2 2A The endplate temperature and power being applied to the BGA244 is reported The Regulating Indicator shows when the temperature servo is actively regulating the temperature J SRS Stanford Research Systems BGA244 Binary
54. units are psi atm bar Pa mm Hg and torr Press lt Pressure gt to open the selection list The currently selected unit will be highlighted in yellow Press the desired value to select it Note that for pressure setting and entry the pressure units are defined as either absolute units relative to vacuum or gauge units relative to atmospheric pressure This selection is made on the Configure Pressure Gauge or Configure User Pressure pages See the Pressure section earlier in the chapter for more information Measurement The default configuration for the BGA244 is optimized fora wide range of gases pressures temperatures flow rates and ON other environmental conditions However there are CET ee circumstances when measurement and analysis can be tuned for better performance Refer to Chapter 4 Application Guide for conditions when optimizing these parameters may be useful Averaging Averaging successive measurements can improve accuracy and repeatability of the measurements by reducing interfering signals and noise See Using Averaging page 103 for more information The BGA244 takes a measurement every 228 ms This is quite a bit faster than most processes change so a moderate number of averages doesn t create a noticeable delay JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Operations Guide 73 The averaged output is continuously calculated producing a new averaged measurement for e
55. 0 or 1000000 ppm or 1 0 fraction The value required to force the displayed value to 100 is displayed in the Rel Value REL TO 0 button in global ratio units 15 000 Press REL TO 0 to set the measured value to 0 or O ppm or 0 0 fraction The value required to force the displayed value to 0 is displayed in the Rel Value button in global ratio units You can also directly enter the Rel Value between 110 and 210 or their equivalent in ppm or fraction This value will be subtracted from the measured value to produce the displayed value J SRS Stanford Research Systems BGA244 Binary Gas Analyzer Operations Guide 60 Gas Purity Press Use REL or No REL to select or deselect the REL function Measurement Rel Press REL TO 0 to set the measured value to 0 or O ppm or 0 0 fraction The value required to force the displayed value to 0 is displayed in the Rel Value button in global ratio units You can also directly enter the Rel Value between 110 and 210 or their equivalent in ppm or fraction This value will be subtracted from the measured value to produce the displayed value JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Operations Guide 61 Pressure The speed of sound in an ideal gas is independent of pressure The speed of sound in real gases does depend on pressure For many gas es satisfactory measurements can be made without knowing the exact pressure Ho
56. 00 202 565 59 3 methane 2 2 Dimethyipentane O ra aooaa 590 35 2 2Methyihexane iomeptane O jes aooo S27 sempena O jes oaa ora Oooo i emn o ear 1 1 2 2 Tetrafluoroethane R 134 oo C2H2F4 102 032 359 35 3 Dihydroperfluoroethane 1 1 1 2 Tetrafluoroethane R 134a Tetrafluoroethane C2H2F4 102 032 811 97 2 1 2 Dichloroethane 1 2 DCE 1 2 Ethylene dichloride C2H4Cl2 98 959 107 06 2 Acetic anhydride id CAH6O3 102 089 108 247 Ethyl propionate J id oo 102132 105 37 3 Pentanoic acid o doo 02132 109524 2 Methylbutanoic acid CY coo 102132 116 53 0 Methyl butyrate Pd ooa 102132 623 427 Di isopropyl ether J ooo o demo 102175 108 20 3 AAA Dichlorofluoromethane CHCI2F 102 92 75 43 4 Pp GHIA 102 175 628 808 Dichloro fluoro methane Dichlorofluoromethane IS Malo acid eos ooe rareza icon tetrafluoide O A Js ro ora rear D ooo oa os resso cris oa oos S ANNIE Y TA Styrene 1 2 Dimethoxypropane Pentyl mercaptan C5H12S 104 214 110 66 7 C5H12S 104 214 2084 19 7 JSRS Stanford Research Systems BGA244 Binary Gas Analyzer 2 Pentyl mercaptan Gas Table 183 Preferred Name Alternate Name Alternate Name2 Formula Weight cass Mechyibuty slide feas oana oss Diethanolamine PO ooa osae anaa E amp ybezee A O TT oers faoa 2a Dimethyipyidine 2a utidine O Somon nas faosara 2 6 Dimethylpyridine _ 2 6 tidne foon faoss roses 3 4 Dimethylpyridine _ 3 4 Lutidne O jean faoss S SB 3 S Dimethy
57. 4 6 Vpc a Fault is generated and the unit will not operate Refer to Faults page 82 for more details Most USB chargers desktop and laptop computers can supply the proper voltage and current A dedicated USB charging port or charging downstream port is specified to supply enough current to operate the BGA244 A plain downstream port can probably supply enough current JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Installation Guide 22 The USB voltage will droop below the acceptable range if a device cannot supply enough current Add a powered hub to increase the voltage and current Make sure that the powered hub is capable of providing around 0 5 amps to a single port USB Power Cables All USB cables are not created equal Some USB cables have power wires as thin as 24 AWG These produce large voltage drops that cause the BGA244 voltage to drop below its operating range Thin USB cables typically have small gauge power wires Use USB cables that have 20 AWG power wires The power wire gauge is frequently printed on the cable or packaging SRS recommends Belkin Gold Series Hi Speed USB 2 0 cables These are available from Amazon CDW and other distributors Belkin p n 6 1 8M F3U133 06 GLD 10 3 0M F3U133 10 GLD BGA 5 USB Power Supply Accessory BGA 5 is a 5V 1A USB power supply suitable to power the BGA244 24V Power If the Industrial Control Interface Option 1 is installed the BGA244 can be p
58. 4 uses the absolute pressure of the gas as part of its calculations However pressure can be input in either absolute pressure units or in gauge pressure units combined with the ambient pressure This is true for both direct entry of User pressure or when integrating a pressure transducer Absolute pressure is relative to vacuum while gauge pressure is relative to the ambient pressure outside the gauge The correct pressure units gauge or absolute must be selected in the BGA244 to avoid errors If gauge pressure units are selected the ambient pressure must also be entered Refer to Pressure page 96 for details Hint If a pressure gauge or transducer can report negative pressures it is reporting the gauge pressure If it reports only positive pressures it can be either absolute or gauge This should be listed on the pressure gauge specifications J SRS Stanford Research Systems BGA244 Binary Gas Analyzer Operations Guide 62 Pressure Gauge Setu Press PRESSURE to access the pressure gauge setup menu Here you can view the current pressure or select the pressure entry method for analysis and configure the external pressure gauge if needed Pressure units are set on the Units page Setup Control Panel Units section Allowable units include psi atm bar Pa mmHg and torr CONFIGURE INPUT 2 JAMETER ENTER USER PRESSURE Selecting Analysis Pressure Press lt Use for Analysis gt to select the pressure entry method T
59. 40 for more information Measured Speed of Sound Query the Measured Speed of Sound for the current Measurement Mode If omitted units default to the global speed units Example SSOS m s Query the Speed of Sound in m s Cell Temperature Query the Cell Temperature If omitted units default to the global temperature units lf an error in a temperature measurement occurs during a query the unit will return an overload value 9 9E37 to inform the user that there was something wrong with the measurement The controlling program should identify this and check bits 6 7 amp 8 of the BGAO status register if it occurs Example TCEL C Query the Cell Temperature in C JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Remote Programming 143 AVGE i AVGN i BCTP i MSMD i RELH RELM Related Commands These commands configure measurements and set the screen appearance of the BGA244 Certain commands require that the BGA244 is in the proper Instrument Mode If not an execution error will be generated Error 11 Illegal Mode Enable Averaging Set query Average Enable to i i O for disabled i 1 for enabled Example AVGE1 Enable Averaging Number of Averages Set query the number of spectrums to be averaged to i i 2 1000 Example AVGN20 Set the number of averages to 20 Binary Concentration Type Set query the Binary Concentration Type to i i 1 for mole fracti
60. 44 5 Ethylisopropyl ether C5H120 88 148 625 54 7 C a IEEE EAN Methylbutylether OOO feo ess sasa Ethylpropylether LO o ees e283 Tetrahydrothiophene ess en pooo Onlicacid ON 3 Butenediol fi Dimethonyethane f 2 Butanediol iY T OOO i earn oos aer Oooo ao onn 207 88 0 ooo o on ease ooo o on aos ooo aos 90 187 209 795 ooo aos oar 2551 219 Methylpropyisulfide o feas oor asrasa Methylbenzene Toen O jara jazz rose Butyl mercaptan 2 Methylpyridine _ 2Picoline O fonn jasa 109068 Dime said LO casa oao feao Bromomethane O ear paso a aso Fuorobenzene LO cese oeoa faeo mepe O era ar enr cyclohexanone O coo sas oeoa Methyleyclohexane PO era nc oeer JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Gas Table 182 Preferred Name Alternate Name 1 Alternate Name 2 Formula Weight CASH Ethylcyclopentane O O E 98 186 1640 89 7 Heptylene C7H14 98 186 592 76 7 oo aS M C7H14 98 188 1759 58 6 Dimethylcyclopentane Dimethylcyclopentane Dimethylcyclopentane lid aes C7H14 98 188 2532 58 3 Dimethylcyclopentane Dimethylcyclopentane 1 Dichoroethane arnes cama peso saaa Methyl methacryate O esoz oone foes Methylsobutylketone O co 1059 108 404 Ethylsopropylketone O cmo 1059 seseo 3 Hexanone meramaone O c mo 10059 se9388 Beana O A TR EAS 2 4 Dimethyipentane Disopropyimettane feme 100 202 108087 Hepta fwen O e ooo fasas 2 3 Dimethylpentane Puy opp mer C7H16 1
61. 44 Binary Gas Analyzer Operations Guide 36 Map of Interface Functions Display Pressure Gauge Units Start Stop Limits Measurement Instrument Mode Scale Status Gases O AE Events Heater Rel Setup Computer IO Control Panel Analog lO Store Recall Faults Temperature Alerts Help Pressure Message Log Self Test Password About FIGURE 13 MAP OF USER INTERFACE FUNCTIONS SRS Stanford Research Systems BGA244 Binary Gas Analyzer Operations Guide 37 Power On When power is first applied a power on splash screen About will appear i Serial Number 1 After a few seconds the About information page samara alld alee which displays the unit serial number firmware Scie IO Hardware Rev A 0 version installed options calibration date and hardware version After about 15 seconds the currently selected Home page will appear The three LEDs also indicate power on behavior This is especially useful for units without displays Options 2 When power is first applied the Power LED will light for 1 second followed by all 3 LEDs lighting for 5 seconds At this time the Power LED should blinks once indicating the code is loading properly You can enter the screen calibration routine by pressing a finger to the screen when power is applied Hold your finger down until the message Release Screen to start Screen Calibration appears then follow the instructions to complete the routine See Di
62. 8 Error Codes The instrument contains an error buffer that may store up to 20 error codes associated with errors encountered during power on self tests command parsing or command execution The ERR LED will flash when a remote command fails for any reason The errors in the buffer may be read one by one by executing successive LERR commands The meaning of each of the error codes is described below Execution Errors 0 10 11 12 13 14 15 16 17 18 19 No Error No more errors left in the queue Illegal Value A parameter was out of range Illegal Mode The action is illegal in the current mode This would happen if the user tries to RELZ when the Instrument Mode is set to Physical Measurements Flash Read Error There was an error when attempting to read flash memory Recall Failed The recall of instrument settings from nonvolatile storage failed because its instrument settings were invalid Flash Write Error There was an error when attempting to write flash memory Flash Erase Error There was an error when attempting to erase flash memory No Option 1 The requested action failed because the Industrial Control option Option 1 is not installed No Option 2 The requested action failed because the No Display option Option 2 is not installed No 24V Available The requested action failed because 24V power supply was not available Cal Error The requested action failed because of an e
63. 94089 Phone 408 744 9040 Fax 408 744 9049 www thinksrs com Printed in the USA JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Table of Contents Contents Contents Safety Procedures and Precautions Symbols You May Find on SRS Products Specifications Manual Convention Unit Conventions and Abbreviations How this Manual is Organized Chapter 1 Getting Started Binary Gas Analyzers What is a Binary Gas Analyzer Uses for Binary Gas Analyzers Features and Accessories Gas Fittings Electrical Connections Industrial Control Option Option 1 Standard and No Display Option Option 2 Accessories BGA244E Pressure Transducer Option T Unpacking Quick Start Quick Test Installation and Configuration Chapter 2 Installation Guide Operating Environment Access Installation Gas Fittings Electrical Connections Electrical Noise Precautions Grounding Electrical Connectors Connector Pinouts Terminal Strip Connectors Power Computer Interfaces SRS Stanford Research Systems XV xvii xviii ha Oo O 01 UN kh HP gt 0 UY NFP UR Ha O ha W Rh e a a nu ba WwW NNNPRP RP RP PB Pe Wr e WO WO 00 00 009 BGA244 Binary Gas Analyzer Table of Contents li Analog I O Connections 26 Event Relays 30 Pressure Transducers 31 Mounting Location 31 Types of Pressure Transducers 31 Chapter 3 Operation Guide 35 BGA244 User Interface 35 Display and Display less Version 35 Navigation 35
64. AMon software can indicate measurement sensitivity to pressure variations To meet the specified accuracy for all gases the pressure must be known to within 1 psi 6 9 kPa This information can be directly entered into the BGA244 or measured by a pressure transducer interfaced to one of the analog I O ports as described in the Pressure Transducers page 31 Estimating pressure Tip If your system vents to the atmosphere the operating pressure is probably around 1 atm 14 7 psia or 101 kPa Compensating using REL The REL function can be used to compensate for a lack of pressure information in some cases This technique works best when deviations from a reference gas or mixture are more important than the absolute accuracy It is most accurate for small deviations from the reference point larger deviations are less well compensated This REL will only be valid for the gas or mixture it was performed on A new REL should be performed whenever anything that can affect the gas pressure is changed This may include different flow rates new gas cylinders regulators or MFC s Minimum Operating Pressures The minimum operating pressure that the BGA244 can make reliable measurements depends on the mass of the gas mixture Below this minimum the BGA244 cannot reliably recover the acoustic signal A No Signal message will be displayed in place of the measurement if this occurs See Screen Messages page 49 for details The following t
65. BGA244 Binary Gas Analyzer User Manual Certification Stanford Research Systems certifies that this product met its published specification at the time of shipment Warranty This Stanford Research Systems product is warranted against defects in materials and workmanship for a period of one 1 year from the date of shipment Service For warranty service or repair this product must be returned to a Stanford Research Systems authorized service facility Contact Stanford Research Systems or an authorized representative for a RMA Return Material Authorization Number before returning this product for repair These are available at www thinksrs com under Support Repair Calibration All users returning a BGA244 back to the factory for repair and or service must submit a correctly completed Declaration of Contamination of Equipment form available as part of the RMA process The SRS personnel carrying out repair and service of the BGA244 must be informed of the condition of the components prior to any work being performed Warning All returns to SRS must be free of harmful corrosive radioactive or A toxic materials Dedication In memory of Jim Williams 1948 2011 Legendary Analog Design Guru and Author Information in this document is subject to change without notice Copyright Stanford Research Systems Inc 2015 All rights reserved Stanford Research Systems Inc 1290 C Reamwood Avenue Sunnyvale California
66. F16 388 052 335 579 Octadecafluorooctane ___ Perfluorooctane C8F18 438 059 307 346 Docosafluorodecane ___ Perfluorodecane __________ ferorzz 538 075 307 45 9 JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Gas Table 188 Gas Table Properties The BGA244 binary gas analyzer determines gas purity and mixture compositions by measuring the temperature and the speed of sound in the gas The speed of sound in an ideal gas is given by the follow equation RT M Where W is the speed of sound in the ideal gas low pressure limit Y the ratio of heat capacities M the molar mass T the absolute temperature and R the ideal gas constant For argon Y Cp Cy Cp Cp R 5 3 and M 0 039948 kg mol and so the ideal speed of sound at 20 C 293 15 K is about 318 89 m s For the BGA244 to determine the purity of an ideal gas it needs to know the isobaric heat capacity C and M The measurement of real gases will be improved if the other thermodynamic and transport properties and the gas pressure are also known The Gas Table contains information on about 500 gases listed by common names formulas and registration numbers In addition to the molar mass the Gas Table provides parameters to estimate each of the following all of which can modify the speed of sound in the gas The temperature dependence of the heat capacity the second and third virial coefficients the viscosity and thermal conductivity
67. Factory Gas table contains data for these effects for nearly 500 different gases For a detailed description on the science behind the BGA244s operation see Chapter 8 Theory of Operation JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Operations Guide 41 Page Identification Binary Gas Analyzer Home Page Units REL Accuracy Upper Limit Upper Scale FIGURE 15 BINARY GAS ANALYZER HOME PAGE Page Identification Binary Gas Analyzer Selected Gases Gas 1 in Gas 2 Refer to Selecting Gases page 57 for details Measured Value Concentration of Gas 1 in the mixture Units ppm or fraction and Mole Mass fraction See Setup Control Panel Units for units and Setup Control Panel Measurement for Mole Mass fraction REL Visible when the REL function is active Pressure Measured or entered pressure used for analysis See the Pressure page 61 for more information Temperature Measured gas temperature Accuracy Estimated accuracy Upper amp Lower Limits Set by LIMIT in the Control section See Limits page 52 for more information Upper and Lower Scale Set by METER SCALE in the Control section See Scale page 53 for more information Meter Graphical display of the Measured Value on a graph scaled by the upper and lower scale values The red areas are set by the upper and lower limit values SRS Stanford Research Systems BGA244 Binary Gas Analyzer Opera
68. Flexible Non metallic Conduit type B Use the following procedures to install or remove the conduit To install simply push the liquid tight conduit over the ferrule end of the fitting While pushing the connector turn the conduit slightly clockwise to seat it To remove unscrew the nut and disassemble the connector Re assemble the connector for re use Electrical Make sure that the BGA244 is properly grounded Depending on the installation the power supply wiring and gas tubing may not be properly connected to earth ground If necessary connect the BGA244 chassis ground lug C1 to a suitable earth ground Be sure that your installation confirms to all safety and electrical code requirements For CE compliance it is recommended that all power and I O cables are shielded and grounded The BGA244 has no line voltages connections Applying line voltage to any pin of any connector on the BGA244 will cause severe damage to the instrument and is a fire and smoke hazard The BGA244E has the same electrical connections that are in the standard BGA244 See the Electrical Connections page 18 for more details on the electrical connections Pay special attention to the following sections that may be more critical for BGA244E installations JSRS Stanford Research Systems BGA244 Binary Gas Analyzer BGA244E 204 Electrical Noise Precautions Installations may require long cable runs Pay special attention to the grouping o
69. Gas Selection Commands GASB i s Page 147 Set Binary Analyzer Gas GASH s Page 148 Set Physical Measurement Gas GASP s Page 148 Set Purity Analyzer Gas PURS v u Page 148 Purity Mode User Speed of Sound SWAP Page 148 Swap Binary Gases JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Remote Programming 128 Heater Commands HEPW Page 149 HEST Page 149 Heater Power Status HETM d Page 150 Block Heater Temperature Pressure Commands Measure Analog Output Commands Analog Output Commands Analog Input Commands AILP i d Page 158 Analog Loop Power Voltage AINE i j Page 158 Analog Input Enable AIRE i Page 158 Read Analog Input AITY i j Page 159 Analog Input Type JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Remote Programming 129 Miscellaneous Commands Page 161 JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Remote Programming 130 Detailed Command List Common IEEE 488 2 Commands CAL CLS ESE i ESR IDN OPC Auto calibration This command currently does nothing and returns O Clear Status Clear Status immediately clears the ESR BGOR BG1R FALR ANAR and EVNR registers as well as the LERR error buffer Standard Event Status Enable Set query the Standard Event Status Enable register to i Bits set in this register cause ESB in STB to be set when the corresponding bit is set in
70. However if the measurement mode is changed to Gas Purity the new selection will be used for those measurements Commands that require an installed option that is not present will generate an execution Error 16 No Option 1 Installed Gas Selection Commands Gases from either the Factory Gas table or User Gas table can be set over the remote interface Gases from the Factory Gas Table are selected by their CAS numbers only CAS The CAS is a string and must include the dashes The CAS of a gas can be found online using Google Wikipedia or in Appendix A which lists all supported gases and their CAS s The preferred gas name will be displayed on the Home page when the gas is set over the remote interface If an invalid CAS is set an Error 26 Invalid Gas will be generated Gases from the User Gas table are selected by the string USER i where i is the User Gas table index number of the gas 1 99 See User Gases page 113 for details on entering User gases The gas name will be displayed on the Home page as User name where name is the User table gas name If an invalid User Gas value is set an Error 26 Invalid Gas will be generated Set Binary Analyzer Gas Set query Gas i for the Binary Gas Analyzer to s Parameter i is 1 for Gas 1 and 2 for Gas 2 s is a String that identifies the gas This can be the CAS or the User gas number Example GASB 1 7440 37 1 Set Gas 1 to 7440 37 1 argon GASB 2 A
71. Input 1 is not available as a general purpose input Analog Input 1 is configured as follows See Pressure page 62 for additional details Analog Input 1 Loop Power Voltage Min 4 ma Max 20 mA 150 psi Use as pressure gauge Enabled Analysis Pressure Analog Input 1 BGA244 Binary Gas Analyzer SRS Stanford Research Systems
72. Measurements Each Instrument Mode has its own unique gas selection So if you enter a gas for the Binary Gas Analyzer mode it won t appear for either the Gas Purity Analyzer or Physical Measurements The BGA244 Factory Gas Table contains nearly 500 different gases Each entry includes the formula common name CAS and up to two alternate names All of these are scanned when selecting a gas Besides naming information an array of physical properties is stored with each gas for calculating gas ratios and speeds of sound Appendix A contains a list of Factory Gas Table gases and a description of all of the gas properties Additional gases can be added into the User Gas Table These can include mixtures or blended gases made up of 2 or more single species gases See User Gases page 113 for information about adding new gases to the User Gas Table To view the currently selected gas or gases go to Setup Select Gases This page displays the information about the currently selected gas es or Reference Gas None if no gas is selected The following information is displayed for each gas selected Gas number for Binary Gas Analyzer mode only Chemical formula The simple non structural formula of the gas Common Name of the gas CAS The CAS Number is a unique identifier for every chemical substance described in open scientific literature MW Molecular Weight of the gas molecule in AMUs for Binary Gas Analyzer mode
73. Organization xviii How this Manual is Organized This manual provides instructions on how to install and operate a BGA244 Binary Gas Analyzer Before installing your BGA244 in a system and or operating it carefully read and familiarize yourself with all precautionary notes in the Safety and Installation sections at the beginning of this manual In addition observe and obey all WARNING and CAUTION notes provided throughout the manual Chapter 1 Getting Started Describes the BGA244 including measurements and applications and a quick start guide Chapter 2 Installation Guide Explains the environmental requirements and describes how to install the BGA244 in your system Chapter 3 Operation Guide Describes how to configure and operate the instrument and explains all of its functionality in detail Chapter 4 Applications Guide Describes how to optimize the BGA244 for the best performance in your application Chapter 5 BGAMon Describes how to configure and control the BGA244 using the BGAMon Windows software Chapter 6 Remote Programming Describes how to control the BGA244 using the computer interfaces Chapter 7 Service Troubleshooting Maintenance and Calibration of the BGA244 Chapter 8 Theory of Operation Theory of operation of the BGA244 Chapter 9 Circuit Description Description of the BGA244s electronic circuitry JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Manual Conventions and Organization Xix A
74. Other Messages Two Sol Two Sol Two Solutions indicates there are two valid molar ratios for a given speed of sound This can only occur for binary gas measurements Concentration 1 is the smaller value and is displayed on top Concentration 2 is the larger value and is displayed on the bottom This only occurs for a few gas pairs with similar masses but different y s Refer to Gases page 91 for more information Home Binary Gas Analyzer System Fault This Message Button indicated that a serious problem has occurred with the BGA244 Pressing SYSTEM FAULT takes you to the Fault page See Faults page 82 for more details Alert This Message Button indicates that non critical problem has occurred Pressing ALERT takes you to the Alert page See Alerts page 84 for more details Stopped This indicated that the BGA244 has been placed in the STOP mode and no measurements are being made Pressing the STOP key will take you to the Setup page where the Run mode can be selected Refer to RUN STOP page 56 for more details Invalid Entry This message appears if an entered number is outside the allowable range The minimum or maximum value for that entry is displayed ura JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Operations Guide 51 LED Blink Codes The Power and Error status LEDs are used to indicate the operating state of the BGA244 They can indicate power faults system faults analysi
75. Purity Analyze Measured Value Accuracy Pressure Lower Limit Lower Scale Page Identification Gas Purity Analyzer Selected Gas Gas name or reference speed of sound See the Selecting Gases page 57 for details Measured Value AW W Units ppm or fraction See Setup Control Panel Units for unit selection REL Visible when the REL function is active Pressure Measured or entered pressure used for analysis See the Pressure section later in this chapter for more information Temperature Measured gas temperature Accuracy Estimated accuracy Upper amp Lower Limits Set by LIMIT in the Control section See the Limits section later in this chapter for more information Upper and Lower Scale Set by METER SCALE in the Control section See the Scale section later in this chapter for more information Meter Graphical display of the Measured Value on a graph scaled by the upper and lower scale values The red areas are set by the upper and lower limit values SRS Stanford Research Systems BGA244 Binary Gas Analyzer Operations Guide 45 Details sep pa193 95 This is a description of some of the items specific to the Gas Purity Analyzer Instrument Mode Select gas Measurements can be made from a reference value but whenever possible the gas species should be selected to improve the measurement accuracy There are nearly 500 different gases contained in the BGA244 Factory Gas Table G
76. RE 17 PHYSICAL MEASUREMENTS HOME PAGE Page Identification Page Identification Physical Measurements Analyzer Speed of Sound Normalized to NTP 20 C 1 atm Measured Speed of Sound Temperature Measured gas temperature Pressure Measured or entered pressure used for analysis See the Pressure section later in this chapter for more information Units See Setup Control Panel Units The Upper and Lower Limits are not displayed in Measurement section since there is no graph but they are active See Limits page 52 for more information JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Operations Guide 48 Details This is a description of some of the items specific to the Physical Measurements Instrument Mode Select gas Measurements can be made from a reference value but whenever possible the gas species should be selected to improve the measurement accuracy There are nearly 500 different gases contained in the BGA244 Factory Gas Table Go to Setup Select Gas to view the Gas Selection page where you can select the Gas by name chemical formula or CASH See Selecting Gases page 57 for information on selecting gases Gases not entered into the Gas Table can be measured Press GAS NONE to enter an unknown gas Setting GAS NONE removes any gas specific corrections and only corrects using the ideal gas law Avoid using this if gas data is available for the best accuracy If the gas
77. Research Systems BGA244 Binary Gas Analyzer Gas Table 194 The parameters of this equation dy ey fy Jy and Casymptote are given in columns 26 30 of the Gas Table The units for these parameters are cc mol cc mol K K and cc mol Coefficients for the 3 virial were sourced from Zuckerwar computed from a CSP method by Orbey or extracted from NIST s REFPROP program All three methods provided reasonable agreement for common gases but very disparate results for less common gases There is a scarcity of reliable experimental results for the 3 virial and the method of Orbey does not address polar compounds hence coefficients for the 3 viral are missing for many substances The 3 virial and its first and second temperature derivatives alter the speed of sound in a manner which increases quadratically with gas density The impact is vanishingly small below a few atmospheres for most gases but impacts the speed of sound by about 0 3 in SF at ten atmospheres at 25C Finally we suspect that literature reports of 2 virial measurements have often conjoined 3 virial effects into their fits We have seen cases where explicitly adding in the 3 virial overcorrects Viscosity Columns 31 33 The viscous boundary layer typically a few 0 001 impacts the cavity resonance frequency by a fraction of a percent The effect can be compensated for if we know the gas viscosity The viscosity of a gas is approximated by the polynomia
78. Setup See Event Relays Page 30 for details on wiring the relays to outside circuits See the Specifications section for details on relay ratings and life time Using Event Relays Event Relays are normally used to signal an out of range or error condition They could be connected to a bell or horn to notify an operator of an out of range condition or connected to a valve to increase the flow of a gas A common set up for Event 1 and Event 2 would be as follows Event 1 Above Upper Limit Below Lower Limit Event 2 System Fault No Signal The Event 1 Relay indicates if the measured value was above or below the set limits and Event Relay 2 would indicate that there was a problem with the measurement SETUP takes you to the Instrument Setup page which is described in the following section From here you can access the remaining controls and settings of the BGA244 JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Operations Guide 56 Setup The Setup menu accesses all the BGA244 controls instrument Setu i i STOP that aren t directly available on the Home page Press IA SETUP on the Home page to reach the Instrument BINARY GAS ANALYZER 4 Setup page SELECT GASES The most important functions in the BGA244 can be R directly accessed from the Setup page Less commonly used functions are reached via the Control Panel See the Map of Interface Functions page 36 for the locations of different
79. The enable registers control the reporting of events in the serial poll status byte STB If a bit in the event status register is set and its corresponding bit in the enable register is set then the summary bit in the serial poll status byte STB will be set The enable registers are readable and writable Reading the enable registers or clearing the status registers does not clear the enable registers Bits in the enable registers must be set or cleared explicitly To set bits in the enable registers write an integer value equal to the binary weighted sum of the bits you wish to set The serial poll status byte STB also has an associated enable register called the service request enable register SRE This register functions in a similar manner to the other enable registers except that it controls the setting of the master summary bit bit 6 of the serial poll status byte Besides the latched INSRs there are unlatched or immediate copies of some of the status registers that reflect the value of the bits the instant the register was read Having both the latched and unlatched copies of the registers can make it easier to determine the state of the BGA244 Power On Behavior of Status Registers The PSC flag determines the behavior of the SRE and ESE mask registers upon power on If the value of the flag is O their values are loaded from non volatile memory If the value of the flag is 1 both registers are cleared upon power on
80. This leads to somewhat poorer estimated accuracy Example Nitrogen mass 28 and oxygen mass 32 have similar speeds of sound around 349 and 326 m s At an 80 20 ratio the estimated accuracy is 0 24 J SRS Stanford Research Systems BGA244 Binary Gas Analyzer Application Guide 108 Problem Mixtures Other gas mixtures can be even more problematic In some gas combinations over a portion of their range there can be two different gas ratios which have the same speed of sound In these cases the speed of sound is not a monotonic function of composition Argon oxygen is a notorious example Both of these ratios are equally valid as far as the BGA244 can determine The BGA244 detects if this occurs and reports both solutions Two Solutions as described in Screen Messages page 50 These mixtures can be measured in some circumstances For a portion of their range there is only the single molar ratio value Or if the approximate ratio is known the larger or smaller solution can be selected These mixtures normally are for gases with slightly different molar masses and different molecular types monatomic diatomic or polyatomic The effect can be modulated by temperature and pressure You can determine if this problem exists for your gas combination pressure and temperature using BGAMon In some cases this effect can be minimized by operating at a different pressure or temperature This problem exists for any binary gas analyzer
81. able lists typical minimum pressures for pure gases All values are listed in absolute pressure units relative to vacuum Use Averaging at low pressures to improve the detection limit and stability of measurements The default value of 10 JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Application Guide 98 averages is a good place to start but values of 20 or more may be necessary for extremely low pressures TABLE 18 MINIMUM DETECTION PRESSURES FOR PURE GASES Gas Minimum Pressure Pure CO2 carbon dioxide has an especially high minimum detection pressure due to relaxation effects Adding even a small amount of a second gas reduces the detection pressure dramatically Refer to Relaxation Effects page 92 for more details Since the average mass of the gas is what sets the minimum detection pressure mixtures of He or H and any other gas will be able to be measured at lower pressures than pure Helium or Hydrogen Ambient Pressure Variation Ambient pressure varies only slightly due to weather The default ambient pressure is 14 7 psia 101 kPa which corresponds to the average atmospheric pressure at sea level A typical low ambient pressure at sea level is about 14 5 psia 100 kPa a typical high pressure is about 14 9 psia 103 kPa Elevation has a much larger effect on ambient pressure The typical atmospheric pressure in Denver Colorado at 5280 1610 m is 12 2 psia 84 kPa Setting the ambient press
82. adienyl Cp2Mg C10H10Me 154 491 1284 72 6 magnesium magnesium IO aooo 156 265 112 312 ETE O E cama PESE 1120 214 Triethylgallium teca CCH ASGa_ 156 906 1115 997 Bromobenzene CSB 157 008 108 86 1 Nonanoicacid t802 158238 112 05 0 2 Methyloctanoicacid CHARO 158 238 3004 93 1 Bromine rd 159 808 7726 95 6 Trimethylindium TM _ Ye 159 922 3385 78 22 Nonylmercaptan CCHS 032 1455 21 6 Vinyl trichlorosilane CB CIBSI_ 6149 75 94 5 1 3 5 Triethylbenzene ag Ethyltrichlorosilane sasi 163 506 115 21 9 Bromo chloro difluoro R 12B1 Erro RI uote CBrCIF2 165 365 353 59 3 methane methane Terephthalic acid C8H604 166 131 100 21 0 WPIA Pentafluorobenzene C6HF5 168 066 363 72 4 Pentafluorobenzene Tetrachlorosilane Silicon tetrachloride SiCl4 Cl4Si 169 896 10026 04 7 1 1 1 2 3 3 3 R 227ea C3HF7 170 0289 431 89 0 heptafluoropropane Diphenyl ether oo et2H100 170 207 101 84 8 Dodecane i nDodecane CAG 170 3348 112 403 ee R 114a Dichlorotetrafluroethane C2CI2F4 170 921 374 07 2 tetrafluoroethane Bee ON ee R 114 Cryofluorane C2CI2F4 170 921 76 14 2 tetrafluoroethane JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Gas Table 187 Preferred Name Alternate Named Alternate Name2 Formula Weight cass Decano add esoao0z 72 265 330485 f undecanol Leo ara 08 fw Dibromomethane PO era aras rasa Decyl mercaptan LO comas aa aoa Phenanthrene O eso es jasa Anthracene LO co ar
83. amethylethane cama fina 229 594821 semeen O ca razo foose Methyldichlorosilane Butyl acetate CC CHO 116 158 123 86 Ethyl butyrate C6H1202 116 158 142 62 1 2 Ethyl butanoic acid C6H1202 116 158 88 09 5 BHeptanol O ero ros 5 03 09 7 Cyclohenyl mereaptan O ceras feza 1569693 lA Ethyl lactate C5H1003 118 133 687 47 8 hydroxypropanoate falpha Methyl styrene Hexylmercaptan J ots feaa 111319 Phenyl isocyanate J HSNO 449 121 103 71 9 Propylbenzene n Propyibenzene comi 120192 103 65 1 1 2 3 Trimethylbenzene _ Trimethylbenzene CSHA2 120 192 526 738 Benzamide HNO 121 137_ 55 21 0 Benzoicacid Yer 122121 65 85 0 2 4 Dimethyiphenol AXylenol C8H100 122 167 105 679 1 H 2 3 2 3 Dimethylphenol CORY ar Xylenol C8H100 122 167 526 75 0 dimethylbenzene 2 6 Dimethylphenol dad 2 6 Xylenol C8H100 122 167 576 26 1 dimethylbenzene 3 Ethylphenol 3 Ethylbenzolol 1 Hydroxy 3 ethylbenzene C8H100 122 167 620 17 7 2 Ethylphenol 2 Ethylphenyl alcohol 1 Hydroxy 2 ethylbenzene C8H100 122 167 90 00 6 1 2 Dimethyl 4 3 4 Dimethylphenol na 3 4 Xylenol C8H100 122 167 95 65 8 hydroxybenzene Propenyicycloherene O oa or sa Benzylmercaptan O oes aos 100538 aNonyne O ers aaas 3052 00 38 nones menea ess ians JSRS Stanford Research Systems BGA244 Binary Gas Analyzer 1 Heptanol 1 Hydroxyheptane Heptan 1 ol C7H160 116 201 111 70 6 Gas Table 185 Preferred Name Alternate Name i Alternate Name2
84. ange of 4 20 mA Currents can be either positive or negative The output can be scaled for absolute pressure or gauge pressure The BGA244 can provide a loop power voltage source 6 19 V if the transducer can accept a ground referenced voltage See the pressure transducers manufacturers information for specific details Refer to Analog Input page 27 for details on devices that are loop power compatible with the BGA244 Hint If either the or signal lines are connected to the pressure transducers body or drain wire it probably won t work with the BGA244 loop power voltage source JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Installation Guide 33 Transducers with External Power Supplies Connect the appropriate power supply as described by the pressure transducer manufacturer If needed the Drain wire can be connected to ground at the BGA244 ground lug C1 Connect the Signal and Signal Return or Signal to In 1 or In 2 on C7 on the BGA244 Refer to Analog Input page 27 for details on connecting the transducer to the BGA244 Configure the BGA244 as follows Set the analog input to Enabled Current Select Absolute or Gauge units depending on the transducers specifications If Gauge units are selected make sure to enter the ambient pressure Set the Min and Max to the transducers minimum and maximum values Check Use as Pressure Gauge Set the Analysis Pressure to the appropriat
85. ange of either of the inputs is 0 1 to 20 V relative to ground The differential voltage range from to is 2 to 10 2 V This allows measurement of signals that are biased above ground V Source FIGURE 8 VOLTAGE INPUT JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Installation Guide 28 Current Input The current input measures the absolute value of the current from the plus input to the minus input The signal can be either polarity with a maximum of 24 mA The voltage range at each input must be between 0 5 and 20 V the burden voltage is 5 5 V for 20 mA The wide voltage range and low burden voltage allows for multiple sense resistors or an external power supply in series with the current loop FIGURE 9 CURRENT INPUT Current with Loop Power Voltage Source Current Input with Loop Power is a special configuration of the current input mode that allow both signal and power to be transmitted over a pair of wires The Loop Power voltage source is ground referenced at the BGA244 and requires that the measured current returns to the minus input Devices that ground either current loop lead or require a floating loop power supply must use an external supply Hint In general devices using this feature should float with respect to the BGA244 s ground This feature may not operate properly if either current loop lead is connected to ground The maximum current amplitude is 24 mA The Loo
86. aphthalene Decahydronaphthalene TAERE ada 2 2 5 Trimethylheptane oa faa 20291 95 6 1 Methylnaphthalene Methyl t naphthalene Cmm 1422 90 12 0 Nonanal o cst mag 124196 2 2 3 3 Tetramethylhexane HOH 142 2817 13475 815 3 3 5 Trimethylheptane dco 122817 7154 805 decane mdecane ooo Caoa 1422817 124 185 SiF6 Dihydrogen l Hexafluorosilicic acid H2F6Si 144 09 16961 83 4 hexafluorosilicate Octanoic acid GOR 144 211 124 07 2 SRS Stanford Research Systems BGA244 Binary Gas Analyzer Gas Table 186 Preferred Name JAlemateNamel Alternate Name2 Formula weight cass Ex hexano OOOO coa aan 149575 AS AN O A aaas aso loctylmercaptan O RWS 204 imag p Dichlorobenzene LO caca aaroo 206 8657 imDichlorobenzene PO caca aroo ST o Dichlorabenzene LO caca aaroo ossoa es Jess fas fs Phthalic anhydride LO feos pee Jess Ethylbenzoate O eo aos paso 1 1 1 2 3 3 R 236ea C3H2F6 152 0384 431 63 0 hexafluoropropane 1 1 1 3 3 3 R 236fa C3H2F6 152 0384 690 39 1 hexafluoropropane 2 2 Dichloro 1 1 1 R 123 Dichlorotrifluoromethy C2HCI2F3 152 931 306 83 2 trifluoroethane methane Phosphoric trichloride Phosphoryl chloride Phosphorus oxychloride CI3OP 153 332 10025 87 3 Tetrachloromethane Carbon tetrachloride CCl4 153 823 56 23 5 Biphenyl 1 1 Biphenyl Phenylbenzene C12H10 154 208 92 52 4 dala eal R 115 1 Chloropentafluoroethane C2CIF5 154 4664 76 15 3 pentafluoroethane Di 1 3 cyclopentadien 1 yl Bis cyclopent
87. as Analyzer Getting Started 9 Quick Start This guide is intended to help users get started making measurements with the BGA244 These instructions are designed for units with displays non Option 2 For units without displays Option 2 it is recommended to use the BGAMon software to configure the unit and monitor the results Refer to Chapter 5 BGAMon for details Quick Test Connect power using either USB power or 24V Option 1 required If using USB power make certain that the USB device and cable are sufficient to power the device See Power page 21 for more information When power is first applied a power on splash screen will appear After a few seconds the About information page which displays the unit serial number Serial Number 1 firmware version installed options Firmware Build 3008 calibration date and hardware version Control Option INSTALLED Cal Date Thu Jan 1 00 00 00 1970 Hardware Rev A 0 After about 15 seconds the Gas Purity Home Gas Purity Analyzer iia Analyzer Home page will appear Assuming the unit has come from the factory and the METER dust caps haven t been removed it should display close to 0 deviation from Argon HELP EVENT RELAY 1 EVENT RELAY 2 SETUP Disconnect power before continuing with the following steps JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Getting Started 10 Installation and Configuration Plan your installation including mo
88. baric heat capacity in units of R 1 i N K 2 a4 Cp x1e 11 aK o 0 2508 Scaled coefficient of polynomial for isobaric heat capacity in units of R Cp Tnorm R 3 5026997 Isobaric heat capacity in units of R calculated from polynomial at T T norm 2 irst a1 Cp x1E 03 ak 0 7884 Scaled coefficient of polynomial for isobaric heat capacity in units of R Wo Tnorm P 0 348 963 Ideal gas speed of sound at T_norm Wo sqrt yRT M 33 958 Critical pressure bar m K Chemical formula carbon s first hydrogen s next alpha thereafter 0 3505 Scaled coefficient of polynomial for isobaric heat capacity in units of R Pitzer acentric factor Dipole moment D debye Electric dipole moment oo 000 Integer 1 6 to describe chemical family per table below For CSP methods atsono dimensionless 0 00 Tsonopouloscorrelationa parameter for 2nd virial see PG amp L Pg 4 15 btsono dimensionless _ 0 00 Tsonopoulos correlation b parameter for 2nd virial see PG amp L Pg 4 15 Ko 126 192 Critical temperature K 0 289387 Critical compressibility E 115 778 Zuckerwar parameter for exponential form of 2nd virial See Eq 4 30 pg 94 18 Acentric factor dimensionless K K A C K Geeta 1 cc mol 42 1188 1 Zuckerwar parameter for exponential form of 3rd virial See Eq 4 35 pg 98 a0 n 1 66702397 Polynomial coefficient for viscosity n T a1 n x100 uPa s K 6 22979799 Polyno
89. by the computer interface TST command cae ct CODEC PASS To begin Self Test press START SELF TEST The tests ae HOME and their results will be written to the screen Upon completion the BGA244 will display SELF TEST PASS or SELF TEST FAIL Use PAGE and PAGE to navigate the list of tests If Self Test fails it will be listed on the Faults page In a properly operating unit Self Tests should pass every time See Troubleshooting page 173 for information about Self Test failures JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Operations Guide 87 TABLE 17 SELF TESTS 3 3 V Supply Internal 3 3 V Power Supply is within range 1 4 V Supply Internal 1 4 V Power Supply is within range 4 5 V Supply Internal 4 5 V Power Supply is within range USB Supply External USB Power Supply is within range 24 V Supply External 24 V Power Supply is within range 5 V Industrial Internal 5 V Power Supply is within range Display Display is detected CODEC ADC 0 ADC 1 Thermistor 1 Thermistor 2 Membrane 1 Membrane 1 resistance is within range Membrane 2 Membrane 2 resistance is within range Not performed on Rev C hardware Not performed on Rev C hardware Performed only if USB power or host is connected Performed if Option 1 is installed and 24V is present Performed if Option 1 is installed and 24V is present DAC x Measure Out DAC is detected O performan i Option 1s sealed and 20Vis p
90. ccuracy and repeatability of the measurements by reducing interfering signals and noise However this occurs at the expense of having a slightly slower response to changes in the measurement The BGA244 takes a measurement every 228 ms which is quite a bit faster than most processes change A moderate number of averages doesn t affect the response time and can minimize variations in a measurement The averaging method used in the BGA244 cancels out any signals that are not synchronous to its measurement signal This suppresses interfering signals and noise as a function of the number of averages Averaging can dramatically reduce the noise on a signal The graph shown is for Argon in Air Because the speeds of sound of the two gases are similar the signal is fairly noisy Using 10 averages decreases the peak variation by about 4 times Argon in Air No Averaging wall tt N 50 60 Time sec FIGURE 19 GAS CONCENTRATION WITH AND WITHOUT AVERAGING FOR ARGON AND AIR Larger numbers of averages may be required to suppress interfering signals or recover low pressure signals in the presents of a lot of noise This will slow the response time You may need to experiment to find the best balance between stable answers and response time See Averaging page 72 for details SRS Stanford Research Systems BGA244 Binary Gas Analyzer Application Guide 104 REL to a Reference Gas Using REL to a reference gas can help improve
91. ce down on a flat soft surface to avoid marring the cover Place the mounting flanges over the square bosses along the top and bottom edges Fasten the two flanges using the 20 flat head Philips head screws Tighten the screws to 20 in lbs 2 26 N m Mount the BGA244E from either the front or rear using four screws or bolts per the mechanical drawing Appendix C Figure C 3 Mount to the long slots only the longer slots are not reinforced to support the weight of the BGA244E JSRS Stanford Research Systems BGA244 Binary Gas Analyzer BGA244E 203 It may be necessary to remove the left side conduit nut to access screws in the lower flange Alternatively bolts can be used to fasten the flanges Do not over tighten screws or bolts to the flanges so as to not damage them Gas Fittings The gas fittings are Swage 1 8 27 NTP female female couplings SS 2 HGC Follow the Swagelok Pipe Fitting Installation Instructions when connecting to the BGA244E Swagelok recommends using a pipe thread sealant when assembling tapered threads Use Loctite 565 thread sealant or equivalent Avoid getting thread sealant on the enclosure as it may react with polycarbonate Be sure to clean out gas lines prior to connecting them to the BGA244E to avoid contamination Conduit The conduit connectors on the BGA244E are Arlington Snap IT Non metallic Push On Connectors NMLT7 They are designed to connect to LFNC B conduit Liquid tight
92. ce has its own set of transmit and receive buffers that show the most recent commands and responses over that interface These can be helpful for remote interface debugging The buffers are located on the specific computer I O pages Home Setup Control Panel Computer IO See Computer I O page 76 for details JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Remote Programming 122 Break Signal The RS 232 and RS 422 interface supports a break condition This is a non command based low level abort signal used to reset the interface if communications are locked When a break is received the input and output queues and buffers are all flushed Any currently in process set commands are completed but no responses are returned Status bits are not modified when a break occurs The break signal is a framing error of all zeros USB A USB Type B communication port is included on the front panel of the instrument The BGA244 complies with the High Speed USB 2 0 standard Refer to Computer Interfaces page 23 for details on cabling requirements when connecting the BGA244 to a host computer The appropriate software driver must be installed on the host computer to properly communicate with BGA244 over the USB interface There are two separate drivers available for the BGA244 a Virtual Com Port VCP and a Direct Driver USB driver DLL The VCP allows communication in the same fashion as any other COM port The Dire
93. cessory BGA 24 is a 100 240 Vac input 24V 2 5 A output power supply suitable to power the BGA244 with Option1 It connects to the BGA244 using the 3 1 mm barrel jack C5 Computer Interfaces The BGA244 can be remotely operated over the USB interface the RS 232 serial interface or the optional RS 422 serial interface Any host computer interfaced to the instrument can control and monitor all of its functions For details on configuring and monitoring the interfaces see Computer I O page 76 All interfaces communicate with the BGA244 using the commands listed in Chapter 6 Remote Programming USB The USB type B connector C2 is located on the front of the BGA244 The interface is USB 2 0 Full Soeed compatible USB 2 0 is specified for a maximum cable length of 5 meters If powering the BGA244 over USB be sure cable is able to support the operating current See USB Power Cables in the previous section for details Before a computer can control the BGA244 over USB it needs to have the appropriate USB driver installed Refer to Using the USB Drivers page 172 for details on installing and using the USB drivers If you connect the BGA244 using a computer running Microsoft Windows it may detect the USB Interface Chip and offer to install two drivers for the device VCP and D2XX drivers Depending on the version and configuration Windows may either automatically install the drivers or prompt you to search for them If you need to sea
94. ch Systems BGA244 Binary Gas Analyzer Remote Programming 139 Example EVNR A return of 4 indicates that the signal exceeded the Measurement Limit since the last read or cleared RLYF i j Relay Force Set query the Event Relay i Force value to j i 1 for Event Relay 1 and 2 for Event Relay 2 j can be one of the values in the table This command is the same as the Event Relay Force functions described in Events page 53 This command will generate Error 16 No Option 1 if Option 1 is not installed If 24 V is not present you can set the relay position but the relay is inoperable until 24V is applied Use the EXPA command to check the 24V power supply meanin No Force Force Off Force ON NF OFF Example RLYF 1 1 Force Event Relay 1 ON RLYU i Relay Position Query the position of Event Relay i i 1 for Event Relay 1 and 2 for Event Relay 2 The return value is O for OFF and 1 for ON This command will generate an Error 16 No Option 1 if Option 1 is not installed It will generate an Error 18 No 24 V Available if 24 V is not present Example RLYU 2 A return value of 1 indicates that Event Relay 2 is in the ON position JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Remote Programming 140 Interface Commands Set Baud Rate BAUD i j LERR Set query the Baud Rate of interface i to j Parameter i O for RS 232 i 1 for RS 422 Parameter j baud rate is set pe
95. ch between the temperature sensors and that the temperature has exceeded lt 0 C since last read or cleared BG1E i BGA Status Enable Register 1 Set query the BGA1 status enable register to i Bits set in this register cause BG1B in STB to be set when the corresponding bit is set in the BG1R register JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Remote Programming 136 BG11 BGA Status Register 1 Immediate Query the BGA1 status register This register is not latched and reflects the value of the register the instant it was read Refer to the Instrument Status Register Model page 164 for a description of the different conditions reported The bits in the BG1I register have the following meaning Bit Meaning S o reseved S 4 Pressure Meter 2 Limits exceeded__ 6 USBVoltageisoverrange 8 24Visoverrange 9 reserved S Example BG1I A return of 1026 would indicate that REL mode was active and the Heaters were not regulating BG1R BGA Status Register 1 Latched Query the BGA1 status register This register is a latched version of the BG1I register Upon executing a BG1R query the register is cleared The meaning of the bits in the BG1R register is the same as the BG1I register Example BG1R A return of 4 would indicate the measurement limit has been exceeded since last read or cleared FALE i Fault Enable Register Set query the FALE enable register to i Bits se
96. configurations that are query only These indicate that the current input is in its overload protection state See Analog Inputs page 78 for details Input Configuration Voltage Current Current w Bias Current overload protection Current w Bias overload protection E Mm BR WN RF E Query only values Example AITY 1 1 Set Analog Input 1 to Current AITY 2 A return of 4 would indicate that Analog Input 2 was set to current and in the overload protection state JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Remote Programming 160 Miscellaneous Commands BAKL i BLTM u DSPO i ERAS i EXPA MUTE i These commands control functions that aren t described elsewhere Backlight Set query the Display Backlight Intensity to i Parameter i is varies from 1 10 where 1 is the dimmest and 10 the brightest Example BAKL 5 Set the Backlight Intensity to 50 Endplate Temperature Query the End Plate Temperature If omitted units default to the global temperature units Example BLTM C Returns the temperature of the End Plates in C Display Orientation Set query the Display Orientation to i Parameter i is defined per the following table The orientation is viewed relative to the front panel name and logo Display Orientation O 90 1 0 2 90 3 180 Example DSPO 1 Rotate the Display to 0 Erase Stored Setting Erase instrument sett
97. cord the amount of water vapor in the wet air to compare with future measurements A new REL should be performed whenever the amount of water vapor changes It may be helpful to track the atmospheric temperature and relative humidity JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Application Guide 95 Next select dry air and the second gas to be measured in the gas selection menu Be sure that wet air is still flowing through the cell Go to the REL menu select Use REL and press either REL to 0 or REL to 100 depending on your measurement Remember that the BGA244 graph reports the fraction of gas 1 in the mixture Return to the Home page The reading should be very nearly the exact value selected on the REL page either 0 or 100 Water Vapor in Other Gases This technique is generally applicable to any gas that contains water vapor JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Application Guide 96 Pressure Pressure Effects in Gases Several thermodynamic properties of gases have pressure dependent terms that cause their behavior to diverge from the ideal gas law These effects are significant for some gases Sudden changes in pressure may also cause transients in the measured readings See Transients page 100 in this chapter for more details The largest departure from the ideal gas law is caused by intermolecular effects effects between gas molecules This causes a change in the speed
98. creases over time For a 10 sccm flow this corresponds to a contamination of a few ppm The outgassing rate can be decrease to about 5x10 sccm by using the following Degas procedure This corresponds to a contamination of 0 05 ppm for the same 10 sccm flow Minimize exposure to the atmosphere or other contaminants to reduce the amount absorbed Fill the cell with a dry gas and cap it off if not in use Follow the Degas procedure if exposure has occurred or different gasses are being used The Degas and Block Heaters can be used to dramatically reduce the outgassing rate of the Kapton transducers This procedure is optimally done under vacuum where the outgas rate can be monitored If necessary it can also be done while flowing a dry gas through the cell for an extended period of time Degas requires Option 1 and an external 24 V power supply rated for at least 1A If degas is being done under vacuum a residual gas analyzer ion gauge or other suitable vacuum gauge can be used to track the outgassing rate until it reaches an acceptable level The SRS RGA100 200 300 and IGC100 are well suited for this Refer to Heaters page 75 for details on operating the heaters Under Vacuum Set the block heaters to 70 C and turn on Degas The initial outgassing rate of the Kapton transducers will be around 1x10 sccs for water vapor Argon or Nitrogen After the heaters are first turned on the rate will initially increase Typically the rate should
99. ct Driver allows function calls to be embedded directly into a controlling program Refer to Using the USB Drivers page 172 for more information USB Configuration There is no status information is available for the USB interface The transmit receive buffers can be viewed at Home Setup Control Panel Computer IO USB Buffer RS 232 An RS 232 communication port is included on the front panel of the instrument This is a standard 9 pin DB female connector configured as a DCE transmit on pin 2 receive on pin 3 See Computer Interfaces page 23 details on cabling requirements when connecting the BGA244 to a host computer RS 232 Configuration The RS 232 interface can be enabled or disabled Status information and the transmit receive buffers can be viewed at Home Setup Control Panel Computer IO RS 232 In order to communicate properly over RS 232 both the BGA244 and the host computer must be set to the same configuration The following baud rates are supported 2400 4800 9600 default 19 2k 38 4k 57 6k and 115 2k The remaining communication parameters are set as follows no parity 8 data bits 1 stop bit and CTS RTS hardware flow control JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Remote Programming 123 RS 422 ASRS Stanfo An RS 422 communication port is included on the front panel of the instrument as part of the Industrial Control Option Option 1 It is configured as a 4 wire point to point
100. ct p n Digikey p n C4 C6 5 pin 1803604 277 1164 ND C7 8 pin 1803633 277 1167 ND C8 6 pin 1803617 277 1165 ND JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Service 176 JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Gas Table 177 Appendix A Gas Table Factory Gas Table The Factory Gas Table contains data for about 500 different gases that are supported by the BGA244 Each entry includes the formula common name CAS number up to two alternate names and physical data about the gas The gas es to be analyzed are chosen on the Setup page page 57 The individual gas can be selected using any of the names the chemical formula or the CAS number Data on additional gases can be added to the BGA244 using the User Gas Table See Entering the User Gas Table page 119 for the procedure on adding new gases to the User Gas Table The table below lists all of the gases in the Factory Gas Table sorted by molecular weight Each entry contains the preferred name up to two alternate names the formula in Hill notation the molecular weight and the CAS number FACTORY GAS TABLE A1 Preferred Name Alternate Name Alternate Name2 Formula Weight casa Hydrogen normal Normalhydrogen e 201588 isa 7400 Hydrogen ortho Orto hydrogen 2 201588 13327400 Hydrogen para Parahydragen 2 zoss f1332740p C O zos E 9 70 0 Beima ha oo es eos fressa Deuteriumhydride O o po eos a CTE O ON bewei O S
101. d is received when unit is in the Binary Gas or Physical Measurements mode an Error 11 Illegal Mode will be generated Binary Gas Ratio Measurement Query the Binary Gas Ratio of Gas i i 1 for Gas 1 i 2 for Gas 2 If omitted units default to the global ratio units The answer is returned in either mole or mass fraction depending on the concentration type BCTP JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Remote Programming 142 RAT2 i u SSOS u TCEL u This command is valid for Binary Gas Analyzer Mode If the command is received when unit is in the Gas Purity or Physical Measurements mode an Error 11 Illegal Mode will be generated Example RATO Query the Gas Ratio in RATO Query the Gas Ratio in the global ratio units Binary Gas Ratio 2 Measurement Query the 2 result of the Binary Gas Ratio of Gas i i 1 for Gas 1 i 2 for Gas 2 If omitted units default to the global ratio units The answer is returned in either mole or mass fraction depending on the concentration type BCTP This command is valid for Binary Gas Analyzer Mode If the command is received when unit is in the Gas Purity or Physical Measurements mode an Error 11 Illegal Mode will be generated t This is the second concentration larger value of a dual concentration measurement If there isn t a dual concentration it will return the same value as the RATO command Refer to Binary Gas Analyzer page
102. dition in the Event list is displayed in red whether it is enabled or not JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Operations Guide 54 Above Limit Activates if the measured value is above the process upper limit Setting the upper limit is described in Limits page 52 Below Limit Activates if the measured value is below the process lower limit Setting the lower limit is described in Limits page 52 Pressure Meter 1 Above Limit Activates if Pressure Gauge 1 is above the upper pressure limit This selection is only available if Pressure Gauge 1 has been configured Configuring the pressure gauge and limits is described in Pressure page 61 Pressure Meter 1 Below Limit Activates if Pressure Gauge 1 is below the lower pressure limit This selection is only available if Pressure Gauge 1 has been configured Configuring the pressure gauge and limits is described in Pressure page 61 Pressure Meter 2 Above Limit Activates if Pressure Gauge 2 is above the upper pressure limit This selection is only available if Pressure Gauge 2 has been configured Configuring the pressure gauge and limits is described in Pressure page 61 Pressure Meter 2 Below Limit Activates if Pressure Gauge 2 is below the lower pressure limit This selection is only available if Pressure Gauge 1 has been configured Configuring the pressure gauge and limits is described in Pressure page 61 Temperature Above L
103. e Upper Limit must be greater than the Lower Limit and within the operating range of the measured parameter If not an Invalid Entry message will appear with guidelines for a legal value If the Upper Limit has been exceeded the measurement must drop below Upper Limit Hysteresis to deactivate the Upper Limit Similarly if the Lower Limit has been exceeded it must rise above Lower Limit Hysteresis to deactivate the Lower Limit Example For an upper limit set at 90 and the hysteresis set at 5 If the measurement increased above 90 the Upper Limit would be active When deceasing the Upper Limit wouldn t deactivate until the measurement dropped below 85 JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Operations Guide 53 Scale Binary amp Gas Purity Meter Scale The SCALE button on the Home page opens the Meter Scale page The Upper and Lower scale values are set in units of the measured value for the Binary Gas Analysis and Gas Purity modes This control doesn t appear for the Physical Measurements mode The Upper Scale value must be greater than the Lower Scale value and within the operating range of the measured parameter If not an nvalid Entry message will appear with guidelines for a legal value Pressure Physical Measurements The PRESSURE METER button on the Home page opens the Analysis Pressure Meter page See Pressure later in this chapter for more details Help
104. e frequency and a cavity factor which has been corrected for perturbations and transducer resonances Uncertainties in all of these corrections can lead to discrepancies between the measured and the computed speed of sound on order of 100 ppm An empirical speed of sound offset Wof fset ppm pressure correction Wp_siope ppm psi and temperature correction Wr_sione ppm K for each gas are used to repair these discrepancies Values for those corrections are given in columns 44 46 of the Gas Table and are initially set to zero JSRS Stanford Research Systems BGA244 Binary Gas Analyzer 8 o Gas Table 197 References REFPROP Reference Fluid Thermodynamic and Transport Properties NIST Standard Reference Database 23 Version 9 1 E W Lemmon M L Huber and M O McLinden U S Dept of Commerce 2013 Second virial coefficients of normal alkanes linear 1 alkanols and their binaries C Tsonopoulos J H Dymond and A M Szafranski Pure and Appl Chem Vol 61 No 8 pp 1387 1394 1989 Handbook of the Speed of Sound in Real Gases Allan J Zuckerwar Acedemic Press 2002 Tables of Physical and Chemical Constants Section 3 5 Kaye amp Laby Critical constants and second virial coefficients http www kayelaby npl co uk chemistry 3 5 3 5 html Correlation for the third virial coefficient using Tc Pc and w as parameters H Orbey and J H Vera AIChE J 29 107 1983 Perry s Chemical Engineers Handbook 8 Ed B E Polin
105. e input Analog Input 1 or 2 Transducers with Loop Power Connect the transducer Signal or wire to In 1 or 2 on the BGA244 Connect the Return or wire to In 1 or 2 on the BGA244 If needed the Drain wire can be connected to ground at the BGA244 ground lug C1 Refer to Analog Input page 27 for details on connecting the transducer to the BGA244 Configure the BGA244 as follows Set the analog input to Enabled Current w Loop Power Set the Loop Power Voltage to the voltage specified by the pressure transducer manufacturer typically 12 15 V Select Absolute or Gauge units depending on the transducers specifications If Gauge units are selected make sure to enter the ambient pressure Set the Min and Max to the transducers minimum and maximum values Check Use as Pressure Gauge Set the Analysis Pressure to the appropriate input Analog Input 1 or 2 JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Operations Guide 35 Chapter 3 Operation Guide BGA244 User Interface Display and Display less Version The BGA244 comes either with a display Normal or without a display Option 2 Both versions have the same capabilities and specifications Each can be fully configured and monitored over a computer interface The display version has a touch screen display that allows the user to set and display all settings and measurements The description of the BGA244 features in this chapter is direc
106. e present REL value in global ratio units REL to Zero Set the REL value to so the measured value reads 0 or Oppm O fraction This command is valid for Binary Gas and Gas Purity Modes If the command is received when unit is in the Physical Measurements mode an Error 11 Illegal Mode will be generated Example RELZ REL the present measurement to 0 or Oppm O fraction RUNM i SETT Run Mode Set query the Run Mode to i i O for STOP i 1 for RUN Example RUNMO Set the BGA244 to STOP Averaged Measurement Settled Query the Measurement Settled status Returns O for no averaging or average not settled Returns 1 for average settled JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Remote Programming 145 Limits LIME i j k LIMH i d u Limit commands configure the upper and lower limits for the six measurements that can have limits See the Limits section for each measurement in the Chapter 3 Operations Guide for more details on their specific Limits Each measurement has its own unit family associated with it If units are omitted the selected global unit is used If units are included with the command they must be in the correct unit family or an Error 127 Illegal Units will be generated The table below lists the measurement ID types and their associated units ID Measurement UnitFamily 4 Pressure Meter 1 p pressure Pressure Meter 2 p pressure
107. e size length and load current do not create excessive errors FIGURE 6 VOLTAGE OUTPUT JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Installation Guide 27 Current Outputs The current outputs are unipolar and return to the BGA244s ground The minus outputs are connected to the BGA244s chassis ground Avoid connecting the minus outputs to ground at the destination to avoid ground loops The current outputs have a compliance voltage of 16 5 V and can drive inductive loads up to 50 mH without oscillation The maximum load resistance including cable resistance is 825 Q Cable resistance can be large depending on the length and wire size Make sure that the cable resistance plus the load resistor is less than 825 Q Sense Resistor FIGURE 7 CURRENT OUTPUT Analog Input There are two separate Analog Inputs Input 1 and Input 2 These can be independently set to measure voltage or current inputs An internal loop power voltage source can be enabled for current input Inputs 1 and 2 can be read on the front panel or over the computer interfaces They can also be linked to a pressure transducer to monitor gas pressure See Analog I O page 78 for details on configuring the inputs See Pressure Transducers page 31 for details on connecting pressure transducers to the analog inputs Voltage Input The voltage input measures the differential voltage between the plus and minus lines The input voltage r
108. e speed of sound Such a sort provides prospective on the ability of the BGA244 to measure the composition of a gas mixture It is difficult to measure the composition of a mixture of two gases which have nearly the same speed of sound Tsonopoulos correlation The Tsonopoulos correlation is a CSP method which is used to estimate the 2 virial Absent experimental measurements this method was used to estimate the 2 and 3 virial coefficients of pure gases in the Gas Table The method is also used by the BGA244 firmware to estimate the 2 cross virials of a gas mixture This computation is done in firmware instead of listed in the Gas Table due to the large number 125 000 possible mixtures for 500 different gases To compute the 2 cross virial via the Tsonopoulos correlation the firmware will require the critical constants P V Te and Z acentric factor dipole moment and categorization into one of six chemical families The details for those values are detailed below Critical constants Columns 13 17 The critical constants for each substance P V Te and Z are listed in Columns 13 17 The critical pressure is in units of bar 1 bar 100 000 Pa The critical volume is in units of cc mole The critical temperature is in units of kelvin and the critical compressibility is dimensionless Acentric Factor Column 18 The Pitzer acentric factor is used to characterize the departure of thermodynamic properties of
109. each Instrument Mode Screen messages can appear in the Measurement section These indicate operating states errors or problems with the measurements See Screen Messages page 49 for details on these functions JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Operations Guide 39 Control Section The Control Section is common to all Home pages The Control buttons LIMITS are used to set parameters and access menus within the user interface Press the appropriate button to access that control See Controls later in METER this chapter for details on setting each control HELP Note The touch screen on the BGA244 must be actually be EVENT pressed to activate functions This is normally indicated by a key BETAAM click or beep Hovering over the button like you would on a cell Ae phone or tablet won t activate the control SETUP Instrument Modes The BGA244 can operate in one of three Instrument Modes Binary Gas Analyzer Mode Gas Purity Analyzer Mode and Physical Measurement Mode The Instrument Mode determines the measurements made by the BGA244 Each Instrument Mode has a unique home page and measurement specific parameters like gas selection limits and meter scale See Instrument Mode page 56 for more information Select Instrument Mode Press SETUP to access the Setup page This page has controls to configure the all of the instrument function besides those in the Control section Press Instrument Mode
110. eas 120127 Benzophenone PO aoo ias Goera maecenas asasen e29505 Hexafluorobenzene _ Perfluorabenzene osre J186 0s6 392563 1 2 Dibromoethane Ethylene dibromide C2H4Br2 187 861 106 93 4 1 1 Dibromoethane o o ChaB 187 861 557 915 Dihydroperfluoropropane Dimethyl terephthalate COHN 194 184 120 616 Dimethyl phthalate COHN 194 184 131 113 trifluoroiodomethane trifluoroiodomethane CRB 195 9104 2314 97 8 Tetradecane nTetradecane f ci m3o 18388 629 59 4 Octafluorocyclobutane B 200 04 115 25 3 A G Perfluorochlorobenzene Chloropentafluorobenzene C6CIF5 202 511 344 07 0 pentafluorobenzene Tetraethyl orthosilicate TEOS Dibromo difluoro methane R 12B2 Dibromodifluoromethane Pentadecane mPentadecane CASHB2 212415 62962 9 1 3 5 Trinitrobenzene CHO 213 105 99 35 4 Radon TDMAT Tetrakis dimethylamido CH3 2N 4Ti C8H24N4Ti 224 17 3275 24 9 titanium IV za6 Trintrotoene O esos oaas eor eeen A AO an ECETIA CET perftuorobutane decafiuorobutane feo 23803 355259 Hepa O S ae oas Gerr Octadecane rocan LO cae faseasa so3a53 Noasca o S aoo hesa 29925 Eose O ea easa ass Tetrabromomethane Carbon etrabromide m s1627 sse134 Tetrakis diethvlami CI annes TDEAT C2H5 2N 4T1 C16H40N4Ti 336 383 4419 47 0 titanium IV Tetrabromosilane Silicontetrabromide_ Brasi 347702 7789 6564 Hexadecafluoroheptane _ Perfluoroheptane C7
111. ed to enable a choice Unlike Radio Buttons you can select any or all of check boxes as needed E JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Manual Conventions and Organization Xvi Home Here Over_There This denotes a location in the user interface hierarchy To reach Home Here Over_There from the Home Page you would press Here followed by Over_There Home This returns you to the BGA244 Home Page Note that the Home display has different appearances depending on the Analyzer Mode selected lt or Back This returns up one level from the display you are currently on Help This takes you to the Help screen for that page This page will have information about the settings and displayed parameters Page T and Page 4 are active if the Help screen is more than one page long Note The touch screen on the BGA244 must be actually be pressed to activate functions This is normally indicated by a key click or beep Hovering over the button like you do on a cell phone or tablet won t activate the control Throughout the manual text in talics refers to another section of the manual JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Manual Conventions and Organization xvii Unit Conventions and Abbreviations Normal Temperature and Pressure NTP Several different conventions are used to normalize measurements to a fixed temperature and pressure The BGA244 uses Normal Tempera
112. elected Event 2 Configuration Nothing Selected Event 1 Force No Force No Force 5 1 c o o i N ol Slololo 5 Active Active 1 C d O 10 Units Settings i Dispersion Compensation O egrees m C ps 10 s i n JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Operations Guide 67 Heater Settings o Computer I O Settings ooo Analog Inputs Settings Jo o oo E E Analog Output 1 Settings J o o Analog Output 2 Settings J o o Measure Output Settings J o o Misc Settings o 0000 Analog Input 2 Type Settings marked with are only operational with the Industrial Control Option Option 1 and 24V connected to the unit They can be configured if Option 1 is installed even if 24V is not present JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Operations Guide 68 TABLE 11 INACTIVE PARAMETERS Value Argon Air 105 95 102 98 Active Active 1 No REL 0 Physical Measurement Settings Physical Gas Argon Physical Upper Limit 1000 m s Physical Lower Limit O m s Purity Upper Limit Active Inactive Purity Lower Limit Active Inactive Purity Hysteresis 1 m s Pressure Meter 1 Settings Use Analog In 1 as Pressure Gauge 1 Inactive Gauge 1 Units Gauge Gauge 1 Min O psi Gauge 1 Max 150 psi Gauge 1 Upper Scale 150 psi Gauge 1 Lower Scale O psi Gauge 1 Upper Limit 100 psi Gauge 1 Lower Limit 10 psi Gauge 1 Upper Limit Active Inactive Ga
113. en a cell has been exposed to moist air solvents or if the gas species in the cell have changed Normally it can only be detectable at very low flow rates and will diminish over time To accelerate outgassing follow the Degas procedure later in this section JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Application Guide 111 Degas The primary source of outgassing in the BGA244 is the Kapton acoustic transducers While Kapton has excellent resistance to nearly all chemicals it is hydrophilic and porous to some gases Substances that are readily absorbed by Kapton include water alcohols and many solvents generally polar molecules There is about 2 9 in 18 5 cm of 1 mil 0 025 mm thick Kapton in the two acoustic transducers If fully saturated they can absorb around 2 7 g of water At NTP this becomes about 3 3 cc of water vapor Similar amounts of other polar molecules will also be absorbed Kapton is also somewhat porous to many gases Gases present in the cell will diffuse into the transducers If the gas is changed or the cell is put under a vacuum this gas will gradually diffuse out This will have no effect if the gas species hasn t changed but it can be detected if the cell is filled with a different gas or under vacuum Does outgassing matter In most cases it will be completely undetectable At room temperature the outgassing rate of Argon Nitrogen or water vapor starts at about 5x10 sccm and de
114. ents The Physical Measurements Analyzer reports the physical measurements of a gas made by the BGA244 These include the Measured Speed of Sound Speed of Sound normalized to NTP 20 C 1 atm Temperature Pressure The speeds of sound are reported in m s kph or mph The temperature is reported in C K or F The pressure is reported in psi atm bar Pa mmHg or torr Go to Setup Control Panel Units to change units See Units page 71 for more details Principle of Operation The measured speed of sound temperature and pressure are the raw values used by the BGA244 to calculate gas mixtures and gas purity The normalized speed of sound is computed from these measurements and data on the selected gas to compensate for temperature and pressure variations The normalized speed of sound is typically the most useful measurement since it can be compared to data taken at other temperatures and pressures It is computed for NTP 20 C 1 atm Since temperature and pressure affect each gas differently it s important to specify the gas being measured for best accuracy For a detailed description on the science behind the BGA244s operation see the Chapter 8 Theory of Operation JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Operations Guide 47 Physical Measurements Analyzer Home Page ye Td Horacuremente Speed of Sound Home Physical Measurements NPT Speed of Sound Measured a AN i FIGU
115. er is the same as the ANAI register Example ANAI A return of 1 would indicate that Measure Out had a current fault since the last time this register has been read or cleared BGOE 7 i BGA Enable Status Register 0 Set query the BGAO status enable register to i Bits set in this register cause BGOB in STB to be set when the corresponding bit is set in the BGOR register JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Remote Programming 135 BGOI BGA Status Register 0 Immediate Query the BGAO status register This register is not latched and reflects the value of the register the instant it was read Refer to the Instrument Status Register Model page 164 for a description of the different conditions reported The bits in the BGOI register have the following meaning Bit Meaning o O 2 Concentration Values BGA Mode only 4 Measurement is above allowable range 6 gt 5 C mismatch on temperature measurements 8 CellTemperature gt 70 C 9 Bad Analysis Pressure Reading Example BGOI A return of 2 would indicate that the Membrane Heater is on BGOR BGA Status Register 0 Latched Query the BGAO status register This register is a latched version of the BGOI register Upon executing a BGOR query the register is cleared The meaning of the bits in the BGOR register is the same as the BGOI register Example BGOR A return of 192 would indicate that there had been a mismat
116. ere are three main types of alerts Analog I O Alerts Temperature Alerts and General Alerts Analog I O Alerts There are a number of alerts that can occur for the Analog Inputs and Outputs These normally indicate a problem with whatever is connected to the Analog Input or Output and not a problem with the BGA244 All Alerts except the Input 1 2 Loop Overcurrent will self clear when the condition causing them is eliminated See Analog I O page 78 for details on the specific alerts TABLE 14 ANALOG I O ALERTS Temperature Alerts There are several alerts that indicate that the cell temperature is out of range or there are discrepancies between the two temperature sensors JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Operations Guide 85 TABLE 15 TEMPERATURE ALERTS Alert Name Under Temperature Cell Temperature lt 0 C Over Temperature Cell Temperature gt 70 C Temperature Mismatch Mismatch between temperature sensors gt 5 C General Alerts These are alerts that indicate non optimal power supply levels or that the heater isn t regulating properly The 5V USB power supply is monitored only when the unit is powered over USB no 24V Otherwise the External 24V power supply is monitored TABLE 16 GENERAL ALERTS The Under and Over Voltage Alerts indicate that the power supply input voltages are marginal This may indicate a problem with the power supply or cabling See Power page 21 for deta
117. es the accuracy is determined by the measured parameter being output Voltage accuracy specifications apply for V gt 0 4 of the Range Max Output Current Voltage Out Max Load Resistor Current Out Inputs Function Input 1 2 Range Voltage Current Loop Power Voltage Range Resolution Accuracy Voltage Current Input Impedance Voltage Current SRS Stanford Research Systems 20 mA 840 Q Pressure Sensor or User Value Oto 10 V 4 to 20 mA 4 to 20 mA with Loop Power 6to19V 0 1 V 0 025 1 mV 0 1 10 uA 10 MQ 20109 BGA244 Binary Gas Analyzer Specifications xii Event Relay opt 1 Function Events Relay Contact Rating Max Switching Power Max Switching Voltage Max Switching Current Max Carrying Current Computer IO RS 232 Format Baud Rate Max Cable Length USB Connector Format Drivers available OS Support Microsoft Other RS 422 opt 1 Format Baud Rate Max Cable Length SRS Stanford Research Systems 2 independently configurable DPDT relays that can be set to toggle on a combination of events Measurement limits pressure limits temperature limits No Signal and System Fault 30 W 62 5 VA 220 Voc 250 Vac 1A 2A No parity 8 bits 1 stop bit CTS RTS flow control 2400 115 2k gt 100 meters for lower baud rates USB Type B WHQL high speed USB2 0 Virtual COM Port VCP and Direct Drivers USB drivers DLL Windows7
118. eter 1 lower scale to 25 global pressure units LIMM 1 2ppm Query the Binary Gas Analyzer lower scale value in ppm Limit State LIMT i j d u Query the state of the selected limit type Parameter i is the Measurement ID Returns the following 0 within limits 1 below limit 2 above limit Example LIMS 1 Query the limit state for the Binary Gas Analyzer mode Limit Trip Value Set query the limit trip value of the selected measurement to d Parameter i is the Measurement ID Parameter j 1 2 for Upper Lower limits Parameter d is a floating point value in units of the associated measurement If omitted units default to the Measurement global units Example LIMT 1 1 60 Set the Binary Gas Analyzer upper limit value to 60 LIMT 6 2 10C Set the Temperature lower limit upper value to 10 C LIMT 4 2 Query Pressure Meter 1 lower limit value in global units JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Remote Programming 147 Configuration Commands GASB i s Configuration commands set the BGA244 to make measurements Some commands may set parameters that are not currently relevant depending on the unit s operating configuration If so the newly set parameters will be applied when the configuration is changed to make them relevant Example The instrument is in Binary Gas mode and the gas selection is changed for Gas Purity The gas selection for the Gas Purity has no effect on Binary Gas measurements
119. etup Press STORE RECALL to access the Store m Recall menu A If a setup is over written or erased it cannot be retrieved There are two setups that cannot be changed or deleted The Default Setup configures the BGA244 as described in the Default Setup Table page 66 The Factory Setup places the BGA244 into the same configuration as when it left the factory See Factory Setup page 69 for details Note Setups are stored into Flash memory with a life time of about 100 000 erase cycles Don t continuously store settings especially over the computer interfaces to avoid wearing out the memory If storing recalling or erasing a setup fails once try a second time If it fails repeatedly try a different location This failure indicates a problem with the storage memory See Troubleshooting page 173 for more information Setup List z Pag Pressing STORE RECALL or ERASE will open the 2 empry Stored Setup list This list contains the Default Setup 3 empry and 20 available setup locations and their names Use al empry Page T and Page to navigate the entire list s EMPTY Filled setup locations are named if no alpha numeric s EMpTY name was entered the name Setup x is used x is 7 EMPTY the setup location Empty setups are denoted by Empty JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Operations Guide 65 Store Press STORE to open the Setup list Pre
120. f the gas is fairly simple For a single species gas it s just the molecular weight in AMUs atomic mass units To find the molecular weight of a blended gas take the molecular mole fraction of each gas times its weight MF1 and MF2 are the mole fractions of each gas mass mass1 x MF1 mass2 x MF2 Cp The minimum thermodynamic property required for a gas is Cp the specific heat at constant pressure Cp is related to the heat capacity ratio y gamma of the gas by the following equation Both y gamma and Cp values for many gases can be found in literature or on line A simplified value for Cp can be entered into the User Gas Table by variable a where ao Cp R y y 1 Both Cp and R can be expressed in different units Make sure that you use the same units for both Cp and R when calculating ao The following rules are generally true for single species gases at room temperature and near atmospheric pressure JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Application Guide 115 Monoatomic gases do 2 5 Diatomic gases do 3 5 4 Polyatomic gases do 3 5 50 Try to obtain values for y or Cp at or near the temperature and pressure the BGA244 will be operating for best accuracy In contrast to the mass finding a or y or Cp for single species gases can be more difficult than that of a blended gas Since the factory gas table already contains most of the monoatomic and diatomic gases ne
121. f the status registers or the actual Alert conditions Example ALRD This would stop any Alert messages from appearing on the BGA244 display ALRE Enable All Alerts Enable all Alerts on the GUI This command disables all Alerts from appearing on the GUI It has no effect on any of the status registers It is the equivalent to the ENABLE ALL ALERTS key on the Alerts page ANAE i Analog Enable Register Set query the ANAR enable register to i Bits set in this register cause ANA in STB to be set when the corresponding bit is set in the ANAR register JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Remote Programming 134 ANAI Analog Status Register Immediate Query the ANAI register This register is not latched and reflects the value of the register the instant it was read Refer to the Instrument Status Register Model page 164 for a description of the different conditions reported The bits in the ANAI register have the following meaning Bit Meaning o o O Measure Out Current Alert 7 10 11 12 13 14 preserved S reserved C 6 7 B3 9 Input 1 Under Voltage 10 u n2 B 14 Example ALAI A return of 2048 indicates that Input 2 was under current ANAR Analog Status Register Latched Query the ANAR status register This register is a latched version of the ANAI register Upon executing an ANAR query the register is cleared The meaning of the bits in the ANAR regist
122. f wires in the conduits Separate the power and computer interface wires from the analog lO wires if possible Electrical Connections It may be more difficult to identify wires that have been pulled through conduits Be sure to properly identify each wire before connecting it to the terminal strips Be especially careful to properly identify the 24V wire since connecting it to an incorrect pin can damage the unit Be sure to use the correct pinout for each connector Failure to do so can result in damage to the BGA244 Pay special attention to C4 and C6 as they are adjacent and have the same number of pins Tip It s usually easier to remove the terminal strip from the BGA244 before connecting wires Unplug the terminal strip by pulling straight back from the unit Loosen the screws before inserting the wires Make sure to observe the correct pinouts USB The USB interface is not particularly well suited to power and control the BGA244E although it can work in some circumstances This would typically involve a USB adapter located near the BGA244E A USB type B connector will fit through the conduit It is more common to power the BGA244E over 24 V using the Industrial Control Interface Option 1 and control it using either RS 232 or RS 422 The maximum cable length for USB is about 5m 16 4 A 5m cable should perform adequately for data communications but powering the BGA244E over long cables is challenging Voltage dr
123. function controls CONTROL PANEL Run Stop It s occasionally necessary to stop analysis and output updates For example you may not want alarm relays to activate or analog outputs to pin while changing gas cylinders or performing other system maintenance Pressing RUN STOP toggles between the run and stop states When the BGA244 is stopped a STOPPED message button will appear on the Home Page Pressing this button takes you to the Setup Page where the RUN STOP control is located When the BGA244 is stopped the following functions do not update Gas Ratio Gas Purity Speeds of Sound Event Relays Analog Outputs Temperature Readings Instrument Mode The BGA244 can operate in one of three Instrument Modes Binary Gas Analyzer Gas Purity Analyzer and Physical Measurement Each Instrument Mode has a unique Home page and measurement specific parameters gas selection limits and meter scale Se ect n st r u m e nt M od e Instrument Mode Press INSTRUMENT MODE J to open the Instrument Mode list Press the desired mode to select it The currently selected mode is highlighted in yellow JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Operations Guide 57 Selecting Gases Measurements made with the BGA244 ordinarily require selecting the gases to be measured Two gases must be selected for the Binary Gas Analyzer a single gas is normally selected for the Gas Purity Analyzer and Physical
124. g et al Section 8 McGraw Hill 2008 The Properties of Gases and Liquids 5 Ed B E Poling J M Prausnitz J P O Connell McGraw Hill 2001 Chung T H M Ajlan L L Lee and K E Starling Ind Eng Chem Res 27 671 1988 Chung T H L L Lee and K E Starling Ind Eng Chem Fundam 23 8 1984 10 Physical Properties of Liquids and Gases Appendix C http booksite elsevier com 9780750683661 Appendix_C pdf JSRS Stanford Research Systems BGA244 Binary Gas Analyzer BGA244E 199 Appendix B BGA244E The BGA244E Enclosure Option allows the BGA244 to be mounted in exposed locations When properly installed it should meet the following NEMA Type specifications Type 6 with cover latched This is intended for indoor or outdoor use primarily to provide a degree of protection against solid foreign objects falling dirt hose directed water the entry of water during occasional temporary submersion at a limited depth and damage from external ice formation Type 6P with cover screws installed This is intended for indoor or outdoor use primarily to provide a degree of protection against solid foreign objects falling dirt hose directed water the entry of water during prolonged submersion at a limited depth and damage from external ice formation Operation The BGA244E operates the same manner as the regular BGA244 Configuration and control can be performed over either the front panel or one of the com
125. gas lines prior to connecting them to the BGA244E to avoid contamination Mounting Whenever possible mount the BGA244E in a location that is free of large vibrations or impacts If there are strong mechanical vibrations it may be necessary to mount the BGA244E in a different location Never rely on the inlet and outlet tubing or the conduit to support the weight of the BGA244E as it weighs about 9 Ibs 4 kg and is likely to damage either the tubing or itself Plan the location of the BGA244E gas pipes and electrical conduit prior to mounting the unit See the mechanical drawings Appendix C Figure C 2 and C 3 for the location of the gas fittings electrical connectors and mounting points There is no preferred gas flow direction either gas port can be input or output The enclosure is a modified Integra Enclosure H8084HCF 6P It includes hardware to mount it to a fixed location The BGA244E can be installed in two different ways The enclosure can be directly fastened to a mounting plate if the back of the mounting plate is accessible Or mounting flanges can be installed on the BGA244E if the back of the mounting plate is not accessible Direct Mount Mount the BGA244E from the rear of the mounting plate using four 4 20 UNC B2 screws per the mechanical drawing Appendix C Figure C 2 The maximum penetration depth of the screws is 0 25 6 35mm Tighten the screws to 20 in lbs 2 26 N m Flange Mounting Place the BGA244E fa
126. ght out of the box without any adjustments or fine tuning However certain measurements may benefit from the following techniques Temperature Variations The BGA244 measures the gas temperature as part of its measurements However large ambient temperature changes or extremely precise measurements may benefit from operating the Block Heater to stabilize the cell temperature The Block Heater is typically operated at least 3 5 C above the highest expected ambient temperature The Maximum Heater Current should be large enough to raise the cell temperature at least 5 10 C above the set temperature This is normally between 0 5 and 2 A Evacuating Cell At very low flow rates it can take a long time for changes in gas concentrations to completely settle to their final value see Response Time page 99 Rather than wait until the total volume of the cell turns over several times it may be much faster to first evacuate the cell and then refill it This speed is at the expense of additional complexity in the gas manifold A vacuum pump and inlet and outlet valves are required But in some cases most of this may already be part of the system For extremely precise measurements it may be necessary to allow the cell to reach thermal equilibrium prior to getting completely settled measurements JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Application Guide 103 Using Averaging Averaging successive measurements can improve a
127. give a purity measurement of 1 of SF a heavier gas in N gives a purity measurement of 1 of O similar mass in N gives a purity measurement of This problem becomes more difficult when dealing with multiple contaminating gases If the reading is positive the combined contaminants are lighter gases If negative the contaminants are usually heavier However it is possible for the contaminant to be a mixture of both heavier and lighter gases In this case measurements can be unpredictable Long Term Stability Measurements made by the BGA244 are extremely stable assuming no dramatic changes in the operating conditions Long term aging effects are in the ppm level Changes in ambient temperature of a few degrees will produce ppm level changes in the speed of sound This corresponds to the same relative change in Gas Purity measurements The change for binary gas measurements is more complicated and depends largely on the gas species The graph below shows drift in the speed of sound and gas concentration measurements versus time for mixture x JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Application Guide 110 High Purity Use Certain applications are extremely sensitive to any contamination These may involve low flow rates sensitivity to contamination operating below atmospheric pressure or a combination of these The following section provides some guidelines to help minimize contamination in sens
128. he correct pinouts The terminal blocks can accept wire sizes from 16 28 AWG 1 29 0 32 mm dia Wires are secured by screw connection Wires may be attached to the terminal block when it is disconnected from the base strip to simplify assembly Make sure the wire installation is stripped back far enough to ensure good electrical contact A Be sure to use the correct pinout for each connector Failure to do so can result in damage to the BGA244 Pay special attention to C4 and C6 as they are adjacent and have the same number of pins Replacement terminal blocks are available from Digikey or other distributors Phoenix Contact p n Digikey p n C4 C6 5 pin 1803604 277 1164 ND C7 8 pin 1803633 277 1167 ND C8 6 pin 1803617 277 1165 ND Power USB Power A BGA244 without Option 1 must be powered through its USB Type B connector C2 If Option 1 is installed the unit can operate over either 24V or USB power Remember that most of the Option 1 features require 24V to operate It s frequently convenient to configure units at a desktop computer using USB power even units with Option 1 All parameters can be configured under USB power but features that depend on 24V won t operate until 24V is supplied When running the BGA244 draws about 0 35 amps from the USB interface It requires the USB voltage to be within 4 75 to 5 25 Voc If the voltage is outside this range an Alert is displayed If the voltage drops below
129. he effect and allowing the mixture to be measured at lower pressures The BGA244 includes data to correct relaxation effects for ratio and purity measurements This correction can be turned on or off Relaxation Correction page 73 The correction should be turned on when measuring relatively pure gases and otherwise turned off for mixtures Note Using the relaxation correction will not lower the recommended operating pressure for CO But it will maintain the measurement accuracy for pressures down to 18 psia 124 kPa JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Application Guide 93 Dimerization A dimer is a molecule made up of two identical simpler molecules The analysis techniques used in the BGA244 assumes that the molecules are non reactive and non dimerizing Condensation The BGA244 cannot measure gases that are at or near their condensation point There are two main reasons for this Actual condensation will interfere with the acoustic cavity making it difficult or impossible to accurately determine the speed of sound Plus the thermodynamic properties of a gas change radically as it transitions from its gaseous to liquid state This change makes it impossible to calculate the gas composition and normalized speed of sound In extreme cases condensation can actually fill the cell with liquid Before actual condensation occurs pre condensation can interfere with measurements During each cycle of the acoust
130. he molecular weight is slightly different than the value from the Factory Gas Table This is because Air in the Factory Gas Table is atmospheric air 78 09 N2 20 95 02 0 93 Ar The extra mass of Argon 39 95 increases the mass slightly However since it is such a small fraction of the total it has no real effect on the thermodynamic data Name Air Molecular Weight 28 86 q 3 5 both gases are diatomic Example Adding a Blended Gas Heliox Another common blended gas is Heliox 80 20 He 0 The calculations are a little more complicated than air since Helium is monatomic and Oxygen is diatomic To find the molecular weight of the gas take the mole fraction of each gas times its weight Gas Mol Fraction Mol Weight Fraction Weight Ay mixes as the mole fraction of the two gases To find a for the gas take the mole fraction of each gas times its value for ao Gas Mol Fraction Cr Name Heliox 80 20 Molecular Weight 9 62 q 2 7 calculated above Operating with User Gases Typically there will be larger pressure and temperature dependent errors associated with User entered gases since they are not specified as thoroughly as factory gases Try to operate at a fairly constant temperature and pressure to avoid these errors Changes in gas parameters with temperature and pressure may create significant errors in some cases But there are plenty of situations where they will have an i
131. here are 3 choices User Entered Analog Input 1 and Analog Input 2 The currently select method is highlighted in yellow The ANALOG INPUT 1 Analog Inputs will be grayed out unless they have previously been configured as pressure gauges Analysis Pressure Gauge User Pressure r Configure User Pressure Press ENTER USER PRESSURE to manually enter the Pressure Pressure can be entered in absolute pressure units relative to vacuum or in gauge pressure units relative to INS GAUGE ambient pressure If you select gauge pressure units you must enter the ambient pressure Example The display to the right shows a gauge pressure of O atm with an ambient pressure of 1 atm 14 7 psi Configure Pressure Gauge Press CONFIGURE INPUT 1 2 to open one of the a E Configure Pressure Gauge pages Typically only one of Y the two inputs is configured as a pressure gauge but Lid both selected can be if desired Check the Use as Pressure Gauge box and select absolute or gauge pressure units Be sure to enter the ambient pressure if using Gauge Pressure Verify that the analog input is enabled and check that the Min and Max input format matches your transducer V vs mA If not configure the input as described below Assuming the formats match enter the pressure values for the minimum and maximum analog input values If the analog output of your pressure gauge doesn t match the span of the analog input calculate
132. hout Displays Option 2 The simplest way to verify the operation of a BGA244 without a display Option 2 is using the BGAMon software This software runs on a Windows compatible computer and communicates with the BGA244 over USB See Chapter 5 BGAMon for details JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Installation Guide 13 Chapter 2 Installation Guide The BGA244 can be installed in a variety of ways to interface with gas systems For bench top experiments it can operate freestanding on its non slip feet For more robust installations it can be bolted to a mechanical plate in any orientation There is no preferred direction of gas flow The LCD display can be rotated to any orientation for convenient viewing There is a wide range of different gas fittings available to easily connect to different systems Units can be power over the USB interface or by 24 Vpc The BGA244 can be easily connected to an automated system over any of its three computer interfaces In addition there are configurable event relays and connections for analog input and output signals The standard BGA244 is designed to be operated in a clean and dry environment The BGA244E is recommended for locations that may be exposed to wet or dirty conditions The BGA244E packages the standard BGA244 in a NEMA Type 6 6P enclosure for use in exposed locations See Appendix B for information on the BGA244E Operating Environment Temperature The o
133. ic signal the pressure within the acoustic chamber increases and decreases slightly For a gas near condensation this pressure increase can take the gas into the non linear region causing large measurement inaccuracies Condensation is a function of a particular gas species its current vapor pressure and temperature The relative concentration of the gas in a mixture has no effect Condensation will occur if the temperature is low enough that the vapor pressure of the gas exceeds its saturation value Ordinarily gases flowing through the BGA244 aren t near their condensation point But there are several things that could cause them to condense A reaction may occur at elevated temperatures relative to the BGA244 Condensation may occur when the gas passes into the cooler BGA244 The BGA244 can be used to monitor and control the output of a bubbler in a dilution flow The temperature of the gas bath is adjusted to control the gas concentration If the BGA244 is operated at a lower temperature than the bath condensation can occur The BGA244 may be operated at an ambient temperature that is below that of the gas leading to condensation Condensation Warning The BGA244 contains condensation data on the gases in the Factory Gas Table By knowing the gas species concentration temperature and pressure the BGA244 can detect if the gas is near its condensation point and display a Condensation Warning screen message The BGAMon sof
134. ils on power supplies and cabling Heater Not Regulating indicates that the heater servo is set to its minimum or maximum values and is not correctly regulating the cell temperature It is only active when the heaters are on See Heater page 75 for more details Alerts page Each Alert appears as a separate multipurpose button on the Alerts page Use PAGE T and PAGE J to navigate the list of Alerts System Alerts PAGE PAGE Most Alerts self clear and vanish when the problem ALLALERTS causing them goes away Pressing a particular ALERT button will take you to its Alert Action Window that allows you to control the appearance and behavior of the alerts Note that all alert actions are lost if the power is cycled Analn 1 Undercurrent Alert Actions E CLEAR ALERT Press CLEAR ALERT to clear a currently active alert This is only useful for alerts that are not self clearing Other Alerts will DISABLE ONCE immediately re assert themselves after being cleared since they DISABLE ALWAYS are still active JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Operations Guide 86 Press DISABLE ONCE to ignore a currently active alert This will cause the alert to be ignored and clear the alert indicators assuming this is the only active alert The Alert button will turn lite grey to indicate its disabled once state If this alert is cleared and later re asserted it will revert to the n
135. imit Activates if the Temperature Gauge is above the upper temperature limit Configuring the Temperature gauge and limits is described in Temperature page 64 Temperature Below Limit Activates if the Temperature Gauge is below the lower temperature limit Configuring the Temperature gauge and limits is described in Temperature page 64 System Fault Activates if there is a serious fault with the BGA244 See Faults page 82 for a list of possible System Faults No Signal Activates if the BGA244 cannot determine the speed of sound in the gas This can occur if the gas pressure in the BGA244 is too low See Troubleshooting page 173 for possible causes Force On Force Off Buttons There are two additional buttons that manually control the Event Relays regardless of any event conditions FORCE ON sets the relay to the ON state FORCE OFF sets the relay to the OFF state The selected Force button will turn yellow as will the Event button on the Home page to indicate the force condition Press the button a second time to release the force condition Event Relay Connections Each Event Relay has three pins normally open NO normally closed NC and common COM In the OFF state NC is connected to COM and NO is open In the ON state NO is connected to COM and NC is open The relays are in the OFF state when the BGA244 is powered off JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Operations Guide 55
136. inary Gas Analyzer Remote Programming 170 114 115 116 117 118 120 121 122 126 127 128 Null Parameter The parser detected an empty parameter Extra Parameters The parser detected more parameters than allowed by the command Missing Parameters The parser detected missing parameters required by the command Parameter Overflow The buffer for storing parameter values overflowed This probably indicates a syntax error Invalid Floating Point Number The parser expected a floating point number but was unable to parse it Invalid Integer The parser expected an integer but was unable to parse it Integer Overflow A parsed integer was too large to store correctly Invalid Hexadecimal The parser expected hexadecimal characters but was unable to parse them Syntax Error The parser detected a syntax error in the command Illegal Units The units supplied with the command are not allowed Missing Units The units required to execute the command were missing Communication Errors 170 171 Communication Error A communication error was detected This is reported if the hardware detects a framing or parity error in the data stream Over run The input buffer of the remote interface overflowed All data in both the input and output buffers will be flushed JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Remote Programming 171 Other Errors 254 Too Many Errors The erro
137. ing 110 Leak Testing 110 Dead Volumes 110 Outgassing 110 J SRS Stanford Research Systems BGA244 Binary Gas Analyzer Table of Contents Iv Degas 111 User Gases 113 Adding a User Gas with BGAMon 113 Determining Gas Coefficients 114 Adding Gases 115 Chapter 5 BGAMon 118 BGAMon 118 Entering the User Gas Table 119 Updating Firmware 120 Chapter 6 Remote Programming 121 Introduction 121 Interface Configuration 121 Front Panel Indicators 121 Transmit and Receive Buffers 121 Break Signal 122 USB 122 RS 232 122 RS 422 123 Command Syntax 124 Parameter Conventions 124 Numeric Conventions 125 Measurement Errors 125 Missing Options or Power Supplies 125 Abridged Index of Commands 126 Detailed Command List 130 Common IEEE 488 2 Commands 130 Instrument Status Commands 133 Interface Commands 140 Measurement and Related Commands 141 Configuration Commands 147 Analog I O Commands 154 Miscellaneous Commands 160 Status Byte Definitions 163 Serial Poll Status Byte 164 Standard Event Status Register 164 Instrument Status Register Model 164 Event Status Register 167 Error Codes 168 Execution Errors 168 Query Errors 169 Parsing or Command Errors 169 JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Table of Contents Communication Errors Other Errors Using the USB Drivers Chapter 7 Service Troubleshooting Calibration Calibration Maintenance Appendix A Gas Table Factory Gas Table Gas Table Properties
138. ing at location i The parameter i may range from 1 to 20 Example ERAS 3 Erase the setting at location 3 External Power Available Query if External 24 V power is available Returns 1 if available otherwise O Example EXPA A Return of 1 indicates 24V is present Keyclick Mute Set query the Key Click Mute to i Parameter i O for Mute off and 1 for Mute on no sound JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Remote Programming 161 Example MUTE O Turn the Key Click off OPTN i Installed Options Query whether Option i is installed Returns 1 if the option is installed otherwise O The parameter i identifies the option i Option 1 Industrial Control Interface 2 No Display PASE i Password Enable Set query the Password Lock mode to i Parameter i 1 for enabled i 0 for disabled Example PASE 1 Set Password lock PASL Password Locked Status Query the Password Locked status Returns O for unlocked 1 for locked PASS i Set Password Set the Password to i Parameter i must be between 0 and 9999 Example PASS 1234 Set Password to 1234 PCTM u PCB Temperature Query the PCB Temperature If omitted units default to the global temperature units Example PCTM Returns the temperature of the PCB in global temperature units UNFA i s Global Units Set query Global Unit i to s Parameter i and the allowable strings for s are listed below io unit type all
139. ings there are no user serviceable parts in the BGA244 Chapter 7 Service for details on servicing the unit JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Installation Guide 15 Installation Plan the location of the BGA244 gas pipes fittings and electrical connectors prior to mounting the unit and forming tubing Take into account cable routing to minimize electrical interference Refer to Electrical Connections page 18 for more details The BGA244 can be mounted in any orientation There is no preferred gas flow direction either gas port can be input or output See Figure C 1 in Appendix C for the location of the gas ports electrical connectors and mounting points Clean out the gas lines before connecting the BGA244 to remove any particulates or oils These can contaminate or damage the acoustic cell Strong mechanical vibrations may interfere with obtaining accurate measurements Whenever possible mount the BGA244 in a location that is free of large vibrations or impacts Do not rely on the inlet and outlet tubing to support the weight of the BGA244 to avoid damaging either the tubing or the unit Either mount the BGA244 to a rigid plate or rest it on its non stick feet The distance between the two gas fittings depends on selected gas fitting options The spacing between outside of each fitting is given by dimension X in the Gas Fitting Table Remember to take into account any gaskets VCR or VCO ferrules o
140. ion JSRS Stanford Research Systems BGA244 Binary Gas Analyzer BGA244E 201 Unpacking Before You Open the Box Do not remove the gas port dust caps until just prior to connecting the unit to your gas manifold to reduce the chance of contamination of the cell Read the nstallation section on the following page prior to installing the BGA244E into your system Read the Chapter 3 Operations Guide and Chapter 4 Applications Guide in the main manual prior to operating the BGA244E Inspect all components of the SRS BGA244E upon unpacking Report any damage to Stanford Research Systems immediately Compare the contents of the shipping container to the list below and report any discrepancies What is included Standard BGA244E 1 One BGA244E 2 One 6 1 8 m USB cable 3 One Operation and Service Manual Options 1 Option 1 Industrial Control Option installed at Factory 2 Option 2 No Display Option installed at Factory 3 Option T Pressure Transducer installed at Factory Accessories 1 BGA 5 USB Power Supply 2 BGA 24 24V Power Supply JSRS Stanford Research Systems BGA244 Binary Gas Analyzer BGA244E 202 Installation Installation of mounting the BGA244E consists of the following steps First mount the units in its operating location Next connect the gas lines conduit and cables Plan the mounting of the BGA244E gas pipes and electrical conduit prior to beginning installation Be sure to clean out
141. ion 1 is installed These commands will generate an Error 16 No Option 1 if Option 1 is not installed Note that even if the 24V power supply is not present all Heater parameters can be set even though the heaters will not operate Use the HEST command to see if the heater is operational or the EXPA command to confirm that the 24 V power supply is present Bit 1 of the BGA1 status register will report if the Block Heater is actively regulating the temperature Endplate Temperature Query the End Plate Temperature Returns the endplate temperature If omitted units default to the global temperature units Degas Heater Enable Set query the Degas Heater Enable Mode to i i O for disabled i 1 for enabled Example HEDG 1 Enable the Degas Heater Block Heater Enable Set query the Block Heater Enable Mode to i i O for disabled i 1 for enabled Note that enabling the Block Heater will turn the heater only if 24 V is present Use the HEST command to confirm that the heater is actually on Example HEEN 1 Enable the Block Heater Maximum Heater Current Set query the Maximum Heater Current to d in amps Example HEIL Query the maximum heater current in amps Heater Power Query the Block Heater Power Return value is in watts float Example HEPW A return value of 10 indicates the heater is delivering 10 watts of power to the BGA244 block Block Heater Status Query the Block Heater Status Returns 1 for
142. itive systems Fittings and tubing Metal tubing and all metal seals should be used Avoid elastomeric seals as they are porous and prone to outgassing VCR fittings options A B amp H are recommended for applications operating below atmospheric pressure Use welded VCR fittings option H for the most stringent contamination requirements Leak Testing All BGA244s are leak tested at the factory Leak tests are commonly performed on systems after any significant changes are made to the gas manifold or fittings Depending on the application either outbound or inbound leak testing may be appropriate Dead Volumes There are several small volumes in the BGA244 that are poorly vented to the cell These total about 1 cc and vent to the cell by diffusion through fairly low conductance paths For normal operation these volumes contain the same gas as the rest of the cell and have no effect on measurements However if the gas species has changed significantly the gas in these volumes will gradually diffuse into the cell over a few minutes The diffusion occurs faster for lighter gases than for heavy gases For low flow rates this may introduce a small error for the first few minutes after the gas species has changed If this presents a problem the cell can be briefly evacuated under vacuum to vent these volumes Otherwise flow gas for a few minutes to allow these volumes to diffuse into the cell Outgassing Outgassing is only a concern wh
143. itted units default to the global pressure unit Example PRAM 14 7 psi Set the Atmospheric Pressure to 14 7 psi PRAM torr Query the Atmospheric Pressure in torr Pressure Gauge Enable Set query the Pressure Gauge enable mode i 1 2 for Pressure Gauge 1 2 Parameter j 0 for disabled j 1 for enabled Example PREN 1 1 Enable Pressure Gauge 1 PREN 2 Query if Pressure Gauge 2 is enabled Analysis Pressure Query the Cell Analysis Pressure If omitted units default to the global pressure units Example PRES Query the Analysis Pressure in global pressure units Pressure Gauge Reading Query the pressure of analog pressure gauge i i is 1 2 for Pressure Gauge 1 2 If omitted units default to the global pressure units If the selected source is not configured as a pressure gauge an Error 23 Illegal Gauge will be generated Example PRRD 1 psi Query the value of Pressure Gauge 1 in psi Pressure Measurement Scale Units Set query pressure measurement I scale units to j Parameter j O for absolute units j 1 for gauge units Parameter i is set per the following table Pressure Measurement O User Entered 1 Analog Input 1 2 Analog Input 2 Example PRSU 1 0 Set the Pressure Gauge 1 to absolute pressure PRSU O Query User Pressure scale units JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Remote Programming 153 PUSR p u User Cell Pressure Set query the User Pressure If omitted u
144. ix Symbols You May Find on SRS Products Symbol Description Alternating Current al Caution risk of electrical shock Frame or Chassis terminal Caution refer to accompanying document Earth ground terminal o MN MS A rm ES o me mm rom Eo Battery ps Power On Power Off Power Standby pp JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Specifications Operational Measurement Modes Operating Pressure Operating Temperature Flow Rate Gas Species Response Time for a step change 2000 sccm flow rate Minimum Detection Pressure Measurement Measurement Technique Reading Rate Averaging Temperature Measurement Speed of Sound Measurement Concentration SRS Stanford Research Systems Binary Gas Analyzer Concentration in mole or mass fraction Gas Purity Analyzer Deviation in speed of sound from ideal speed of sound ideal speed of sound AW W Physical Measurements Measured Speed of Sound Normalized Speed of Sound temperature and pressure O to 150 psia 1000 kPa 20 C to 70 C O to 5000 sccm 500 gases supported in Factory Gas Table Users can add gases to the User Gas Table 9 seconds to 90 18 seconds to 99 27 seconds to 99 9 Gas Species Dependent examples of pure gases H 10 psia 69 kPa He 10 psia 69 kPa CH 4 psia 27 kPa N 1 psia 7 kPa Ar 1 psia 7 kPa SFe 1 psia 7 kPa The Speed of Sound of
145. kg mole An accurate molar mass is critically important as a 200 ppm error in the molar mass results in a 100 ppm error in the speed of sound The molar mass is often rounded to two or three digits in published tables which is insufficient for the lighter gases Isobaric heat capacity C R Columns 7 12 The isobaric heat capacity in the ideal gas limit in units of the ideal gas constant is computed from the scaled coefficients to the 4 order polynomial given in Columns 7 11 The coefficients are scaled to keep their magnitude on order 1 Cp R is computed from Eq 2 where T is the temperature in K Es al T a2 T a3 T a4 T a ae a ee a Eq 2 R a 1000 E 100 000 100 000 000 t 100 000 000 000 And the ratio of heat capacities yy is computed from Eq 3 o G Cp R FF F Eq 3 AR Re i Column 12 of the Gas Table holds the value of Cp Tnorm R where Thorm 293 15 K This value serves as a computational check point allowing the BGA244 firmware to validate the table contents and its method for computing heat capacity J SRS Stanford Research Systems BGA244 Binary Gas Analyzer Gas Table 192 Speed of sound at normal temperature Column 13 The speed of sound at normal temperature 293 15 K and in the zero pressure limit is given in Column 13 in units of meters second This value can serve as a computational check of other table values and firmware algorithms and is useful for sorting the Gas Table by th
146. l as shown in Eq 6 n An t Bp T C T Eq 6 Here T is the absolute temperature in K Coefficients for the polynomial Ay By and C are tabulated for each gas and scaled so that the result has units of Pa S Polynomial coefficients were determined by least squares fitting to viscosity data points over the operating temperature range Data points were extracted from NIST s REFPROP computed from correlation functions provided by Perry or PG amp L or computed from the CSP method of Lucas see PG amp L 9 9 Thermal conductivity Columns 34 36 The thermal boundary layer typically a few 0 001 impacts the cavity resonance frequency by a fraction of a percent The effect can be compensated for if we know the thermal conductivity of the gas The thermal conductivity of a gas is approximated by the polynomial in Eq 7 n Ap Be T CT Eq 7 Here T is the absolute temperature in K Coefficients for the polynomial Ax B and Cx are tabulated for each gas and scaled so that the result has units of mW m K 1000x larger than SI value with units of W m K JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Gas Table 195 Polynomial coefficients were determined by least squares fitting to thermal conductivity data points over the operating temperature range Data points were extracted from NIST s REFPROP computed from correlation functions provided by Perry or PPL amp G or computed from the CSP method of Chung
147. l different types of measurements including ratios speeds of sound temperatures and pressures Each measurement can have one of several different units Ratio Ratio units are used in measurements that are ratios of one quantity to another They are used for gas concentration Binary Gas Analyzer and ratio of speeds of sound Gas Purity Analyzer Gas Ratio Units Allowable units are fraction 0 to 1 0 percent and ppm part per million Press lt Ratio gt to open the selection list The currently selected unit will be highlighted in yellow Press the desired value to select it fraction JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Operations Guide 72 Speed Speed units are used for speeds of sound measurements They are primarily used on the Physical Measurements page Speed Units Allowable units are m s kph kilometers hour and mph miles hour kph Press lt Speed gt to open the selection list The currently selected unit mph will be highlighted in yellow Press the desired value to select it Temperature Temperature units are used for gas temperature readings and heater settings Temperature Units Allowable units are C K and F Press lt Temperature gt to open the selection list The currently selected unit will be highlighted in yellow Press the desired value to select it Pressure Pressure units are used for gas pressure readings Pressure Units Allowable
148. led options and the 24V power supply If a command cannot be successfully executed because of a missing Option 1 an Error 16 No Option 1 is generated Similarly if a command cannot be successfully executed because of a missing 24V power Supply an Error 17 No 24V Available will be generated If a command requires 24V power supply it is usually a good practice to query if the 24V is available using the EXPA command prior to sending the command Similarly you can use the OPTN command to confirm an option is present before attempting to configure it These can be done at the beginning of the controlling program during initialization J SRS Stanford Research Systems BGA244 Binary Gas Analyzer Remote Programming 126 Abridged Index of Commands Common IEEE 488 2 Commands TRG Instrument Status Commands Event Register Commands EVNC i j Page 138 Event Configuration Register EVNE i Page 138 Event Enable Register EVNI Page 138 Event Status Register Immediate EVNR Page 138 Event Status Register Latched RLYF i j Page 139 Relay Force RLYU i Page 139 Relay Position JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Remote Programming 127 Interface Commands BAUD i j Page 140 Set Baud Rate LERR Page 140 Inspect Error Buffer UARE i j Page 140 Enable Computer Interface XTRM if j k Page 140 Measurement Commands Measurement Related Commands Limit Commands
149. lling the BGA244 over the computer interfaces are described in Chapter 6 Remote Programming The USB and RS 232 interfaces are installed on all BGA244s The RS422 is only available if the Industrial Control Interface Option 1 is installed and requires that an external 24V power supply is connected to operate The RS 232 and RS 422 interfaces can be enabled and disabled and have settable baud rates from 2400 to 115 2k baud The USB has no enable or configuration functions Press USB RS 232 or RS 422 to access that interfaces page r USB Buffer Receive and Transmit Buffers Each interface has its own set of receive and transmit buffers that show the most recent commands and responses over that interface They can be helpful when debugging communication problems Press the BUFFER key on the interface page of interest to view JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Operations Guide 77 USB Nothing can be set for the USB interface The only control on the USB page is the BUFFER key Press it to view the transmit and receive buffers RS 232 Press DISABLE ENABLE to enable or disable the RS 232 interface Press BUFFER to view the transmit and receive buffers Press lt Baud Rate gt to open the selection list The currently selected rate will be highlighted in yellow Press the desired value to select it Most of the remaining parameters are read only
150. losion should the system pressure rise Refer to the product specifications for the cavity proof pressure KEEP THE UNIT FREE OF CONTAMINATION Do not allow contaminants to enter the unit before or during use Contamination such as dust dirt lint glass chips and metal chips may permanently damage the unit or contaminate the process ALLOW PROPER WARM UP TIME The unit may not meet all specifications unless sufficient time is allowed for the unit to stabilize at the designed operating temperature Do not REL or calibrate the unit until the warmup is complete GROUNDING Proper operation of this instrument requires that it be connected to earth ground If the power source does not provide the required grounding you should add a protective ground to the device COVERS Do not operate the unit with the instrument covers removed RETURNS All returns to SRS must be free of harmful corrosive radioactive or toxic materials Users returning a BGA244 back to the factory for repair and or service must submit a correctly completed Declaration of Contamination of Equipment form available as part of the RMA process The SRS personnel carrying out repair and service of the BGA244 must be informed of the condition of the components prior to any work being performed See Appendix H for information required on the Declaration of Contamination of Equipment form JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Table of Contents
151. lpyridine _ 3 S utidne aan Jamas fsor220 Anisole C7H80 108 138 100 66 3 Sulfur tetrafluoride Tetrafluoro A4 sulfane SF4 108 06 7783 60 0 4 Methylphenol 4 Hydroxytoluene C7H80 108 138 106 44 5 1 H 3 m Cresol 3 Methylphenol li C7H80 108 138 108 39 4 methylbenzene Bromoethane Sr 108 965 74 96 4 Benzenethiol CHGS 077 108 98 5 Sea C8H16 112 213 2207 01 4 Dimethylcyclohexane C8H16 112213 111 660 Ethylcyclohexane HA par 1678917 1 1 Dimethylcyclohexane C8H16 112 213 590 66 9 lid C8H16 112 213 6876 23 9 Dimethylcyclohexane 2 Dichloropropane Propylene dichloride feneo2 112986 78875 1 1 Dichoropropane O eee razas B 98 _ B Heptanone O eo as oso Heptamal O eo es arar Diisopropylketone LO ero ass ses800 1 Methyieyeloneramol O ero fass 500 67 0 transz Methyicycohean O Jero ia 8s fraas Lis 2Methyleyclohexanol ero ass ras oa octane oane oo ca razo eso 2 2 4 Trimethylpentane S0octane C8H18 114 229 540 84 1 trimethylpentane 3 3 Dimethyherane O ca iaa sa 2 23 Trimetiyipentane O ca razo seors 3 4 Dimettyinerane O ca razo seee 2 3 Dimettyinerane O ca aa sega z a Dimethyherane Y ca ra 229 seas JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Gas Table 184 Preferred Name Alternate Name i Alternate Name2 Formula weight cas faMethyheptne LO cesa aao sosar 2 2 Dimetyinerane O ca iaa 590 73 2 5 Dimettyihexane isobutane O fome ina 229 soan 2 233 Tetrametiyibutane Hex
152. lt Setup Erase Stored Settings 1 20 Delete the User Gas Table Press FACTORY to load the factory setup A confirmation prompt will appear if the factory setup was recalled successfully JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Operations Guide 70 Control Panel The remainder of the controls and measurements in the BGA244 are accessed through the Control Panel Press CONTROL PANEL to access this menu Use PAGE 7 or PAGE J to navigate the different functions Press the Function name to enter that page The Control Panel menu includes Display Since the BGA244 can be mounted in any orientation the display needs to be rotated for proper viewing The back light intensity and key clicks can be set In addition the screen coordinates can be calibrated Press DISPLAY to access the Display controls Display Orientation The display can be viewed from 4 different orientations indicated by the four arrow buttons Press whichever arrow points up to rotate the display where that direction is up Backlight Intensity The display backlight intensity can be varied from full on 10 to nearly off 1 In high brightness conditions the backlight should always be set to full intensity Reducing the backlight intensity minimize the power supply current Setting it to the minimum reduces the current by nearly 100 mA This is really only useful when operating the BGA244 off of poor quality USB power
153. ltage source The diaa ENABLED measured voltage or current can be viewed on the BGA244 or read over one of the computer interfaces Press INPUT 1 or INPUT 2 to go to their configuration page Analog inputs can be used as either general purpose inputs or together with a transducer as a pressure meter If an analog input is configured as a pressure meter it may not be used for general purpose measurements In either case the input must be configured properly for the desired measurement The Input reading displayed on this page is in V or mA regardless if the analog input is used as a pressure meter CONFIG PRESSURE takes you to the Configure Pressure Gauge page as described in Pressure page 61 earlier in this chapter To set an input to general purpose uncheck Use as Pressure Gauge on the Configure Pressure Gauge page Press ENABLE DISABLE to enable or disable the analog input Press lt Type gt to open the selection list The currently selected type will be highlighted in yellow Press the desired value to select it Current The Loop Power Voltage can be entered if Current w Loop Power Current w Lp Pwr is selected This can vary from 6 and 19 V See Analog Input page 27 for details on devices that can use loop power There are several alerts that can occur for the Analog Inputs They appear as red text at the bottom of the Analog Input page as well as on the Alert page These normally indicate a pr
154. measurements by removing uncertainties in the temperature pressure and other parameters The procedure involves flowing a reference gas through the cell and then nulling the measured value to the expected value This technique works well near the conditions at which it was performed Errors increase as the operating conditions move the further away from the REL conditions The BGA244 is relatively insensitive to variations in temperature pressure or flow However large changes in the operating conditions will produce measurable changes in the measurements The REL should be repeated whenever a significant change in the operating conditions occurs This would include changes in temperature pressure and flow or changing the gas used as the reference new gas bottle A Reference Gas is usually One of the two gases in a binary mixture An extremely well measured blend of the gases The pure Gas for the Gas Purity Mode The usual magnitude of the correction in a REL for a Reference Gas is a few percent or less A larger than expected REL value may indicate that the gas you are using fora reference isn t as pure as expected It is best to perform a REL as close to the operating condition as possible This means operating at the same pressure flow rate and temperature Note that the REL function refers to the value of Gas 1 in the Binary Gas Analyzer Mode There are two techniques to purge the acoustic cell of all residual non Reference gas
155. mial coefficient for viscosity n T a2 n x10 000 uPa s K 2 0 28410365 Polynomial coefficient for viscosity n T 1 904 Polynomial coefficient for thermal conductivity k T a1 k x100 mW m K22 8 706 Polynomial coefficient for thermal conductivity k T 36 a2 k x10 000 mW m K13 0 267 Polynomial coefficient for thermal conductivity k T a K c a far mens 265 coeficient tor relaxations x pressure product usatm 9 fr es res coeficient tor reiaton time xpresure product usatm o far Je 000 cooficient or relaatonstime pressure product usatm a faw runpa 0 00 Coeficient for the Antoine Equation for vapor pressure PSBL E4 731 p74 a2 faw Resutinpa 0 00000 coeficient for the Antoine Equation for vapor pressure PSBL EQ 73 1 74 42 ew reut pa 0 00000 Coeficient for the Antoine Equation for vapor pressure PEBL EQ 7 31 74 aa woofer opm 000 empirical offset forthe computed speed ofsound as worse ppm 0 00 Empria pressure slope for the computed speed ofsound ooo em SRS Stanford Research Systems BGA244 Binary Gas Analyzer A S mol 2 49 618 Zuckerwar parameter for exponential form of 3rd virial See Eq 4 35 pg 98 552 72650 Zuckerwar parameter for exponential form of 3rd virial See Eq 4 35 pg 98 1 2 3 4 5 7 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 38 39 40 41 42 43 4 Gas Table 190 CAS Registry number
156. n screws in opposite corners to 10 inch lbs 1 13 N m to seal the box JSRS Stanford Research Systems BGA244 Binary Gas Analyzer BGA244E 200 Do not use PVC cement to connect fittings to the enclosure Keep solvents that may react with polycarbonate away from the enclosure This includes the following acetone ammonium hydroxide ammonium nitrate phenol carbon tetrachloride hydraulic brake fluid lacquer thinner Loctite methylene chloride perchlorethylene potassium hydroxide sodium hydroxide toluene and xylene Use light soapy water to clean the enclosure if necessary Access Leave adequate clearance around the door if you will need to access the unit after installation See the mechanical drawings Appendix C Figure C 2 and C 3 for dimensions The door requires a minimum of 1 625 41mm clearance past the side of the box to fully open to 90 Be sure to leave adequate clearance to release the cover latch The gas fittings require a wrench to tighten or loosen Be sure there is sufficient clearance both in length and rotation See the Installation section below for details The conduit fittings are tightened or loosened by hand Be sure there is sufficient clearance both in length and rotation See the following nstallation section for details Leave adequate clearance for the mounting flanges if used If the flanges are to be fastened with bolts be sure to have sufficient wrench clearance both in length and rotat
157. ndled together without adverse effects Try to avoid combining wires from different groups especially for long cable runs Group 1 Power ground computer interfaces and relay signals Group 2 Analog Inputs Analog Outputs Avoid passing current through the BGA244 and its gas tubing This can be accomplished by providing a current return path for high current wiring and making sure that all metal surfaces are properly grounded Grounding Make sure that the BGA244 is properly grounded Depending on the installation power supply wiring and gas tubing may not be properly connected to earth ground If necessary connect the BGA244 chassis ground lug C1 to a suitable earth ground JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Installation Guide 19 Electrical Connectors Basic BGA244 A BGA244 without Option 1 is powered over the USB connector This can be connected to a computer a powered USB hub or a USB charger In addition a RS 232 DCE port is provided as well as a ground lug See Figure 1 for the connector locations page 6 Ground Lug C1 USB for Power and Computer Control C2 RS 232 Interface for Computer Control C3 Option 1 Industrial Control Interface Option 1 adds the following power supply and electrical I O features to the basic BGA244 It also adds internal heaters used to bake out the unit and stabilize the internal temperature See Figures 1 and 2 for the connector locations page 6
158. nector This can be connected to a computer a powered USB hub or a USB charger Instrument functions can be controlled over either the USB or RS 232 computer interfaces See Figures 1 amp 2 page 6 for the connector locations There are three LEDs that indicate the status of the BGA244 Power green Shows that power is applied Flashes for power fault codes commit Communication Error red Flashes for communication error Repetitive blink for various no signal errors Constant on for System Fault JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Getting Started 4 Industrial Control Option Option 1 The Industrial Control Option Option 1 adds the following features to the basic BGA244 See Figure 2 page 6 24V power input RS 422 computer interface Analog I O 3 outputs amp 2 inputs 2 configurable Event relays Standard and No Display Option Option 2 The standard BGA244 includes a color TFT LCD w touchscreen This can be used to configure the unit and display results The unit can also be configured using the computer interfaces See Figure 3 page 7 The No Display Option Option 2 replaces the display with a rugged solid cover Units with Option 2 can only be configured over the computer interfaces using the BGAMon program or user written code See Figure 4 page 7 Accessories There are several different accessories available for the BGA244 USB Power Supply BGA 5
159. nfiguring the Analog Inputs Mounting Location Locate the pressure transducer on the BGA244 side of any restriction to minimize offsets in the measured pressure Make sure to account for any drop in pressure between the measured or regulated pressure and the BGA244 for large flow rates Follow the proper installation procedure when connecting the transducer to the gas system as described in Gas Fittings page 16 Install the pressure transducers following their manufacturer s instructions Types of Pressure Transducers The choice of which pressure transducer to use largely depends on the application it will be used in Transducers come in many different ranges fittings and accuracies Choose a transducer with good sensitivity and accuracy and that matches the operating pressure of your system If possible use a transducer that reads in absolute pressure to eliminate ambient pressure variation The BGA244 can interface to most pressure transducers that output a voltage or current within the nominal analog input range The BGA244 includes a selectable loop power voltage source that can be used to power many current output transducers Transducers of this type are the simplest to integrate with the BGA244 Input Minimum Maximum J SRS Stanford Research Systems BGA244 Binary Gas Analyzer Installation Guide 32 Voltage Output Transducers Voltage output pressure transducers have separate signal and power connections In addi
160. nits default to the global pressure units Example PUSR 20psi Set the User Pressure to 20 psi JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Remote Programming 154 Analog I O Commands MOCN i MOEN i The Analog Inputs and Outputs are part of the Industrial Control Option Option 1 These commands will generate an Error 16 No Option 1 if Option 1 is not installed Some Analog I O commands may set parameters that are not currently relevant depending on the unit s configuration The newly set parameters will be applied when the configuration is changed to make them relevant Even if the 24V power supply is not present all Analog I O parameters can be set although they will not operate Use the EXPA command to confirm that the 24 V power supply is present The following command will generate an Error 18 No 24V Available if the 24V power supply is not present AIRE MOMA and AOMA Measure Analog Output Commands The Measure Output is linked to the active Measurement Mode See Measure Output page 80 for more details Note that although the Measure Out is linked to the current Measurement Mode any of the Measure Out parameters can be set at any time A parameter ID is used to specify the Measurement Mode for some commands Each measurement has its own unit family associated with it If units are omitted the current global unit is used If units are included with the command they must be in the correc
161. non multidrop that is connected via a terminal strip It supports single transmitter and receiver pair only not multi drop See Computer Interfaces page 23 details on cabling requirements when connecting the BGA244 to a host computer Note that the RS 422 interface requires that a 24V power supply is connected to the BGA244 RS 422 Configuration The RS 422 interface can be enabled disabled Status information and the transmit receive buffers can be viewed at Home Setup Control Panel Computer IO RS 422 In order to communicate properly over RS 422 both the BGA244 and the host computer must be set to the same configuration The following baud rates are supported 2400 4800 9600 default 19 2k 38 4k 57 6k and 115 2k The remaining communication parameters are set as follows no parity 8 data bits 1 stop bit and no hardware flow control rd Research Systems BGA244 Binary Gas Analyzer Remote Programming 124 Command Syntax Although the BGA244 doesn t communicate over GPIB its commands follow IEEE 488 2 Standard All commands use ASCII characters are 4 characters long and are case insensitive Standard IEEE 488 2 defined commands begin with the character followed by 3 letters Instrument specific commands are composed of 4 letters The four letter mnemonic shown in capital letters in each command sequence specifies the command The rest of the sequence consists of parameters Commands may take either set or q
162. nsignificant effect JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Application Guide 117 f the User gas is used as a dopant to a much lighter factory gas the differences in mass may overwhelm any small errors in the gas model The thermodynamic properties of the user gas may not vary much over the operating pressure and temperature range Many processes depend more on changes in values rather than the actual value REL can be used to establish a baseline and track variations from that value If possible find values for a y or Cp at or near the operating temperature and pressure for best accuracy Operate at a stable temperature The block heater is an easy way to achieve this Using REL with User Gases In some cases the BGA244 will operate at high concentrations of the User gas In this case you can REL to the User gas as a Reference Follow the procedure REL to a Reference Gas described earlier in this chapter JSRS Stanford Research Systems BGA244 Binary Gas Analyzer BGAMon 118 Chapter 5 BGAMon BGAMon JSRS Stanford Research Systems BGA244 Binary Gas Analyzer BGAMon 119 Entering the User Gas Table JSRS Stanford Research Systems BGA244 Binary Gas Analyzer BGAMon 120 Updating Firmware JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Remote Programming 121 Chapter 6 Remote Programming Introduction The BGA244 can be remotely programmed over the USB inte
163. nt gases However there are many more gases that can be measured including mixtures or blended gases Blended gases are made up of two or more single species gases The BGA244 supports a User Gas Table that allows a nearly unlimited number of new gases to be added by the end user Gases in the BGA244s Factory Gas Table have detailed information about how a gas behaves over a wide temperature and pressure range as well as how it interacts with any other gas However gases don t need to be specified this completely to be able to make accurate measurements especially at fairly constant temperatures and pressures Factory Gas Table The Factory Gas Table contains a comprehensive list of data for each gas including names formula molecular weight and various thermodynamic properties This information allows accurate measurements to be made on a wide variety of gases over the entire operating range of the BGA244 See Appendix A Gas Table and Chapter 8 Theory of Operation for a detailed explanation of all of the terms contained in the Factory Gas Table and their effects on measurements User Gas Table The User Gas Table is used to store data on gases that aren t available in the Factory Gas Table This information is stored using the BGAMon Software Typically only a subset of the physical properties contained in the Factory Gas Table are entered for new gases in the User Gas Table The following parameters can be entered for User gases
164. ntains no carbons everything is listed in alphabetical order of the element symbols including hydrogen This system yields sensible results in most cases for example methane is CH4 There are a few exceptions however SF6 is written F6S in Hill notation In such cases the formula SF6 is included as one of the alternate names so that a user looking for SF6 will indeed find sulfur hexafluoride Source of data Many references listed at the end of this section were used to compile or calculate the data used in the Gas Table Data from those references was critically evaluated primarily by comparison between the various references but also taking into consideration the sources used by those references Not all references had all of the data required for the Gas Table Different references also used different correlation functions and applied those functions to different temperature ranges As an example consider the parameterization of the isobaric heat capacity vs temperature The BGA244 uses a 4 order polynomial for this task This polynomial is well behaved and offers more than enough flexibility to accurately follow the heat capacity over the BGA244 s operating temperature range This is the same polynomial as used in one of the references however the accuracy of the coefficients presented in that reference where found to be less accurate than could be found by fitting a polynomial over the operating temperature range to data extracted f
165. o make The best solution is to make sure that the BGA244 is mounted in a vibration and impact free location Follow the mounting guidelines in Chapter 2 Installation Guide Averaging may help stabilize the readings It may require a large number of averages to suppress a large interfering signal You may need to experiment to find the proper balance between stable answers and response time See Using Averaging page 103 for more details Electrical and Magnetic Interference Even though the BGA244 is shielded for EMI motors or transformers can generate large enough fields to overwhelm the acoustic transducer signals It may be necessary to add shielding if the BGA244 and the interfering source cannot be separated far enough apart For low frequencies lt 1 kHz use cold rolled steel At higher frequencies gt 1 kHz conductive materials copper or aluminum can be used Avoid passing currents through the BGA244 from the gas lines This can generate interfering signals Make sure that all pipes are properly grounded Averaging may help stabilize the readings It may require a large number of averages to suppress a large interfering signal You may need to experiment to find the proper balance between stable answers and response time See Using Averaging page 103 for more details JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Application Guide 102 Measurements In most cases the BGA244 can make accurate measurements ri
166. o oras Propionaldenyde O eso feo isase Butane atan oo fe 106978 JSRS Stanford Research Systems BGA244 Binary Gas Analyzer 1 2 Butadiene es Gas Table 179 Preferred Name Alternate Name i Alternate Name2 Formula Weight cas cetamide O oo oo eos Trimethylamine OOo Methyl formate ___ Methylmethanoate omoz Jeoosz f1or313 weca A O oo a carbonyl sulfide carbon oxide suide feos feoors1 Jassse1 Ethylenediamine i C2H8Si 60 17 1111 74 6 IS EEE Dimethyisine O INitromethane miras fonoz feroa DS Ethyienegyeo OO eso aos oraa Mininor LO oa oas poa sulfurdioxde ooo o os faoss freos 2Difuoroethane OO S o eo oane 1H Pyrrole Azole C4H40 68 074 110 00 9 3 Methyl 1 butyne rT C5H8 68 117 598 23 2 3 Methyl 1 2 butadiene C5H8 68 117 598 25 4 renye O es er oraa Buyon A O oos oono N yclopentane Pentamethyiene fomo fois 287923 Methyl eso os 569 46 2 CS AO A AA T 7 EN Nitrogen tifoidea reses aic O S eos os ooa Butyraldenyde O o e s Isopentane methyi butane O foma ranere ramsa INNN Dimethyl formamide O eno eoa Gen JSRS Stanford Research Systems BGA244 Binary Gas Analyzer 2 Methyl 1 butene be ee eee Gas Table 180 Preferred Name Alternate Name Alternate Name2 Formula Weight cass aButanamine en rss orne Propionic Sd ida ao rasa Methylacetate Methylethanoate O fcmeo2 raora 79209 Methylpropylether A O A FT STAI Merhyisopropy eterno aa osse 1 2 Propylene gal esos e
167. o to Setup Select Gas to view the Gas Selection page where you can select the Gas by name chemical formula or CASH See Selecting Gases page 57 for information on selecting gases Gases not entered into the Gas Table can be measured by entering a reference speed of sound for the gas Press GAS NONE then either directly enter the speed of sound using the keypad or press REL ZERO to use the current speed of sound as a reference Setting GAS NONE eliminates any gas specific temperature and pressure corrections Avoid using this if gas data is available for the best accuracy If you want to zero the measurement from a reference value use REL as described below rather than GAS NONE Table of sensitivities This table shows AW W gas purity for some common gases with a 1 contaminant TABLE 9 GAS PURITY ANALYZER SENSITIVITY Ar CO2 CF4 SF6 0 00 0 00 0 00 0 06 Accuracy Estimator The BGA244 calculates a real time accuracy estimation of the gas purity measurement The accuracy estimation is based on temperature uncertainty of 0 1 C and a pressure uncertainty of 1 psi REL The REL relative function can be used to zero the measurement to a pure reference gas See the REL section later in this chapter for more information on using this feature The REL indicator only appears when the REL function is active JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Operations Guide 46 Physical Measurem
168. oa erse Carbon disalfide LO rea rss Prop mercaptan LO ess ea ors Methyiethyisuia LO ess eaa eases its rete 75332 set rez rara las s aa 2 Propyl mercaptan Germane S2 Dimethyl sulfoxide CHGS 78133 67 68 5 1 Chloropropane Propyichloride CHC 78541 540 545 2 chloropropane C7854 75 29 6 Pyridine Azabenzene gt osn 79101 10 861 Sulfur trioxide d os 0063 7446 119 Methylchlorosilane HSCS 80 589 993 000 cyclohexene CHA 82 144 110838 3 Methyleyclopentene CHO 82 144 1120 623 Herne cot azam 693 02 7 1 Methylcyclopentene CHA 82 144 693 89 0 aHeryne O cet 82 144 764352 Herne Cet 82 144 928 494 Krypton kr 88 798 7439 90 9 1 1 2 Trifluoroethane R143 CAH 84 041 430 66 0 cyclopentanone SHB 84 118 120923 Thiophene Thiofuran CaS aaa 4t0 02 1 cyclohexane Methylcyclopentane CHA 84 159 96377 4 Methyl I pentene 4 Methylpent ene_ CGHI2 8415948 691 372 Vinyl acetate CAOS 089 108 05 4 Methacrylicacid dH 089 79 41 4 Methyl acrylate G02 86 089 96 33 38 2 Pentanone JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Gas Table 181 Preferred Name Alternate Name Alternate Name2 Formula Weight cass Peman O eo a oe 2 2 Dimethylbutane Neohexane foma fes17536 75832 BMethylpentane O cea e oo Methylpropionate O ooa feos ssaa azDiwne esos esoe 505 226 memke PO feo e ass T 2 Pentanol 2 Pentanol O C5H120 88 148 6032 29 7 Methylisobutyl ether C5H120 88 148 625
169. oblem with the device connected to the Analog Input or wiring rather than the input itself JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Operations Guide 79 Name Validfor Indicates O O OOOO o Undervoltage Voltage Input lt 0 V Overvoltage Voltage Input gt 10 2 V Input lt 4 mA Input gt 20 mA Current w Loop Power Loop Power current is gt xx mA Note that the Loop Power Alert is shared between Input 1 amp 2 All other alerts are separate for Input 1 amp Input 2 This alert does not self clear and must be cleared manually The Input 1 2 Overcurrent condition switches out the current sense resistor when the input current exceeds 26 mA It will automatically switch the current sense resistor back in when the input voltage drops below 5 8 V In some cases it may be necessary to manually reset an overcurrent fault due to the behavior of the external circuitry All of these Alerts except Loop Power self clear if the condition that caused them goes away See the Message Log for a history of transient events See Alert page 84 for details on alert behavior Analog Outputs There are three separate Analog Outputs that can be configured as 0 5 V 0 10Vor 4 20 mA outputs Measure Out is always linked to the measured value of the selected instrument mode Outputs 1 and 2 can be linked to one of several different measured quantities or set explicitly by the user Outputs linked to a measured quantity can
170. observe proper safety precautions completely purge the instrument when necessary and ensure the material used is compatible with materials in this product including any sealing materials PURGE THE INSTRUMENT After installing the unit or before removing it from a system purge the unit completely with a clean dry gas to eliminate all traces of the previously used flow material USE PROPER PROCEDURES WHEN PURGING Purge the instrument under a ventilation hood Wear gloves for protection during this procedure DO NOT OPERATE IN AN EXPLOSIVE ENVIRONMENT To avoid explosion do not operate this product in an explosive environment unless it has been especially certified for such operation USE PROPER FITTINGS AND TIGHTENING PROCEDURES All instrument fittings must be consistent with instrument specifications and compatible with the intended use of the instrument Assemble and tighten fittings according to manufacturer s directions CHECK FOR LEAK TIGHT FITTINGS Carefully check all connections to ensure leak tight installation OPERATE AT SAFE INLET PRESSURES Never operate at pressures higher than the maximum operating pressure refer to the product specifications for the maximum pressure JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Table of Contents viii INSTALL A SUITABLE BURST DISK When operating from a pressurized gas source that may exceed the cavity proof pressure install a suitable burst disk to prevent system exp
171. om an entered value may be useful This can be used to track deviations from a reference gas or improve the measurement accuracy at a particular operating point Typical uses for the REL function include Setting a carrier gas to O or 100 when working with small concentrations of a dopant gas Zeroing readings to a reference mixture and measuring the deviation from that value Using a REL value to compensate for an unknown pressure Using REL to measure deviations from a reference point when complete thermodynamic data isn t available for a User gas The REL function is available for the Binary Gas Analyzer and the Gas Purity Analyzer Instrument Modes When active the REL indicator is displayed below the measurement units as shown on the Home pages The REL function performs the following operation displayed value measured value Rel Value A REL is typically performed using a reference gas either a pure gas or a well known mixture In general REL works best when operating near the conditions that the REL was performed at Large deviations in temperature pressure or concentration may make the technique less effective Situations and techniques where the REL function can improve measurement accuracy are described in the Chapter 4 Application Guide Binary Gas Analyzer Press Use REL or ONo REL to select or deselect the REL f it function O O Press REL TO 100 to set the measured value to 10
172. ommends using a pipe thread sealant when assembling tapered threads Options G is a ID hose end connections for soft tubing and hose Follow the Swagelok Hose and Flexible Installation Instructions when connecting to the BGA244 JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Installation Guide 18 Electrical Connections A A A Be sure that your installation confirms to all safety and electrical code requirements For CE compliance it is recommended that all power and I O cables are shielded and grounded The BGA244 has no line voltages connections Applying line voltage to any pin of any connector on the BGA244 will cause severe damage to the instrument and is a fire and smoke hazard The BGA244 supports a wide variety of electrical connections for power control and monitoring Power is provided over USB 5Vpc or a separate 24 Vo power supply Computer interfaces include USB RS 232 and RS 422 There are multiple user configurable analog inputs analog outputs and two configurable event relays Electrical Noise Precautions Electrical Noise can cause interference between different devices AC line wiring motors pumps relays and their control wiring are common noise sources Wherever possible route the BGA244 wiring separate from noise sources This is a particular concern for the Analog I O signals There are two main groups of connections used by the BGA244 Wires within each group can normally be bu
173. on i 2 for mass fraction Instrument Mode Set query the Instrument Mode to i The value of i is determined from the following table Note that some measurements depend on the Instrument Mode and are only valid for that particular mode meaning Binary Gas Analyzer Gas Purity Analyzer Physical Measurements WN RI Example MSMD3 Set the Instrument Mode to Physical Measurements MSMD A return value of 1 indicated the BGA244 is in the Binary Gas mode REL to 100 Set the REL value to so the measurement reads 100 or 1 000 000 ppm or 1 0 fraction This command is valid for Binary Gas Mode If the command is received when unit is in the Gas Purity or Physical Measurements mode an Error 11 Illegal Mode will be generated REL Mode Set query the REL Mode to i i O for no REL i 1 for REL JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Remote Programmin 144 This command is valid for Binary Gas and Gas Purity Modes If the command is received when unit is in the Physical Measurements mode an Error 11 Illegal Mode will be generated Example RELM1 Set REL Mode RELV r u RELZ REL Value Set query the REL value to r If omitted units default to the global ratio units This command is valid for Binary Gas and Gas Purity Modes If the command is received when unit is in the Physical Measurements mode an Error 11 Illegal Mode will be generated Example RELV Query th
174. only y gamma The ratio of specific heat capacities for Binary Gas Analyzer mode only Speed of Sound at NTP for Gas Purity Analyzer and Physical Measurements modes only Select the Gases ata How to select gases Gases are selected at Setup Select Gas es Press SELECT GAS 1 SELECT GAS 2 or SELECT GAS to open the alpha numeric keypad J SRS Stanford Research Systems BGA244 Binary Gas Analyzer Begin typing the name formula or CAS of the desired gas As you enter characters the BGA scans the entire gas Table for matches to the entered text and displays that number in the Matches field If no gases match the entered text it displays Matches 0 If you press an incorrect key press to erase the last character or CLR to erase all characters When the number of matches is down to a manageable number lt 20 or so press ENT or ENTER This will open up a list of all of the matches from the gas table Note that matches can occur at any position in the gas name formula or CAS If there are more than 7 matches use Page T and Page 4 to view the entire list If you don t see the expected gas press to return to the alpha numeric entry window Operations Guide 58 Gas List Pag Argon Arsine PAGE 4ar 8ar Decahydronaphthalene CANCEL carbinol Carbon dioxide Carbon dioxide Select the desired gas by pressing its entry This will ente
175. ops in the power wires may cause the voltage to drop below the minimum required voltage 4 75 V Always use USB cables with 20 AWG power wires to minimize voltage drops The BGA244 has been verified to operate with 3m USB cables with the appropriate power wires RS 232 Since a standard 9 pin RS 232 connector will not fit through the conduit a DB9 to terminal strip adapter is provided with the BGA244E Its pinout is listed below The minimum RS 232 implementation is 3 wires Rx Tx and Ground The CTS and RTS wires can be added to provide handshaking The CD and DSR wires are pulled high to the asserted state and can be connected if required As with the other connections it is usually easier to detach the adapter from the BGA244 prior to connecting the wires Reattach it to the BGA244 RS 232 port using the thumb screws after the wires are connected JSRS Stanford Research Systems BGA244 Binary Gas Analyzer BGA244E TABLE 25 C9 RS 232 TERMINAL STRIP FOR BGA244E Pin Signal Pin Signal i 1 Signal Ground 2 R 0 0902 Ri n Bm LTR nc 4 jor ATS 5 eb E E 6 DR 6 RTS 7 Rs RR a3 os SR 3 CN O E o O Chassis Ground Pressure Gauge 205 Option T Pressure Transducer comes pre installed from the factory if ordered This includes wiring and configuration The Industrial Control Option Option 1 must be installed to use Option T The transducer is wired to Analog Input 1 This means Analog
176. ormal un ignored state with the alert indicators active Press DISABLE ALWAYS to permanently ignore an active alert This will cause the alert to be ignored and clear the alert indicators assuming this is the only active alert The Alert button will turn dark grey to indicate its disabled always state If this alert is cleared and later re asserted it will remain inactive with the Alert added to the list in dark grey until power is cycled Press ENABLE ALL ALERTS to return all alerts to the active state This will clear any Disable Once or Disable Always behavior Note that power cycling the BGA244 will always enable all alerts Message Log The Message Log is a list of the most recent events that occur osave to slo 37 8 Autos ave complete to slot 1 in the BGA244 This includes stored and recalled settings 56 4 ALERT 24V Supply Overvoltage 31 0 Auti ed alerts faults and other messages The Message Log can be J de ides particularly useful in diagnosing transient events that may ee disappear before they can be properly diagnosed Self Test The Self Test page provides access to the Self Test functions and their results Running Self Test r safest Running Self Test will stop all measurements and can memm temporarily modify inputs outputs and relay settings he ee as for several seconds Self Test is the same procedure sl detecte Checking USB Supply that is run upon power on or
177. out 500 different gases allow the BGA244 to make ratio measurements with a typical accuracy of better than 0 1 This technique isn t just reserved for gases of a single species Blended gases can also be measured as long as physical data is available for each gas blend The best known blended gas is air made up of nitrogen oxygen argon and carbon dioxide There are many other blended gases that can be used in the BGA244 Most binary gas analyzers are factory configured to support a handful of gases or only a single mixture and limited range In contrast the BGA244 comes configured with data on nearly 500 gases with a wide range of concentrations This gas information is easily selected from the front panel or can be configured remotely allowing over 50 000 mixtures to be measured In addition to binary gas ratio measurements the BGA244 can report purity of a gas expressed as the ratio of the measured speed of sound to the expected speed of sound To support other research goals measurements of the speed of sound temperature and pressure can be reported directly JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Getting Started 2 Uses for Binary Gas Analyzers Binary gas analyzers are used in a wide range of applications They are often used in applications where no dedicated sensors exist for a gas or for indirectly controlled mixtures in a process A few typical applications are Leak Detection Semiconducto
178. owed unit strings ppm frac HE m s kph mph 3 Temperature C K F pressure psi atm bar Pa mmHg torr Example UNFA 1 Set the Global Ratio Units to UNFA 4 A return of Pa indicates the Global Pressure units are Pascal JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Remote Programming 162 VOLT i External Power Voltage Query Power Supply Voltage i Returns voltage in volts float Parameter i 1 for USB supply i 2 for 24 V Supply JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Remote Programming 163 Status Byte Definitions The BGA244 reports on its status by means of several status registers These include the serial poll status byte the standard event status register ESR and several additional instrument status registers INSRs These read only registers record the occurrence of defined events inside the unit If the event occurs the corresponding bit is set to one Bits in the status registers are latched Once an event bit is set subsequent state changes do not clear the bit All bits are cleared when the registers are queried with a ESR for example The bits are also cleared with the clear status command CLS The bits are not cleared however with an instrument reset RST or a device clear break signal Each of the unit s event status registers has an associated enable register
179. owered by 24 Voc If the USB port is connected to an external device its current goes to 0 A when the BGA244 is powered by 24 V The acceptable voltage range is 24 1 Voc The maximum ripple voltage is lt 240 mVpp The maximum 24 V power supply current is 2 7 A However the BGA244 can be operated at much lower currents With the heaters turned off the 24 current draw is between 0 2 0 35 A depending on the analog I O configuration The maximum heater current can be set to anywhere from 0 01 to 2 2 A No Heaters No Analog IO Using Analog lO Add 0 15 A Using Heaters Add Max Heater Current setting 0 01 2 2 A Make sure that the wire gauge used to connect the 24 V power supply can support the maximum current required without excessive voltage drops If operating at the maximum heater current 100 feet 30 meters of 18 AWG wire will have a voltage drop of 3 5 Voc Lower currents and shorter wires will minimize this drop JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Installation Guide 23 There are two different connectors that can be used to provide 24 V power Power can be provided using connector C5 a 3 1 mm barrel jack see figure or on pins 4 and 5 of terminal strip C6 Make sure to connect the 24 V power supply with the correct polarity to the correct pins Failure to do so may cause serious damage to the BGA244 CS C6 C6 pin 5 Return O 24 Voc BGA 24 USB Power Supply Ac
180. p Power supply can be set between 6 and 19 V with a maximum output current of 50 mA Suitable Device Loop Power Supply Sensor Source FIGURE 10 CURRENT INPUT W LOOP POWER SUITABLE DEVICE JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Installation Guide 29 Unsuitable Device Sensor Source FIGURE 11 CURRENT INPUT W LOOP POWER UNSUITABLE DEVICE JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Installation Guide 30 Event Relays There are two separate SPDT relays that are linked to the BGA244 s Event 1 and Event 2 conditions Events can be configured to switch for things like exceeded limits loss of the measurement signal and system faults They can also be directly set and cleared on the front panel or over the computer interfaces See Events page 53 for detail on configuring and controlling the Event Relays Relay 1 Normally Open Relay 1 Common EVENT RELAY PINOUT The relays are floating with respect to each other and chassis ground Each relay consists of acommon a normally open and a normally closed connection Normally open and normally closed refer to the relay in the de energized state O NO ee NO Comm Comm mi NE o NC Inactive off Active on FIGURE 12 EVENT RELAY CONTACTS The Event relay contacts are rated for the following conditions Max Switching Power 30 W 62 5 VA Max Switching Voltage 60 Voc 42 4 Vox 30 Vac Maximum Car
181. pen the gas selection window Type the first few characters of its name formula or CAS number then press ENTER to open a list of gases that match that string Select the desired gas from that list Configure the Pressure HOME SETUP PRESSURE Press ENTER USER PRESSURE to open the User pressure window This is simplest way to enter the pressure Set the Meter Scale and Limits HOME METER SCALE and HOME LIMITS appropriately Binary Gas and Gas Purity Analyzers only Flow gas through the system The BGA244 should display the selected gases and concentration purity or physical measurements of the gas JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Getting Started 11 Windows Drivers for the BGA244 If the BGA244 is connected to the USB port of a computer running Microsoft Windows you may be prompted with a New Hardware Found message and an invitation to search for the USB Driver There are two USB drivers for the device VCP and D2XX drivers Depending on the version and configuration Windows may either automatically install the drivers or prompt you to search for them Allow it to install the drivers if you plan to configure or control the BGA244 using this computer If there are difficulties installing the driver see Appendix E for details on manually installing the drivers If you have no plans of using this computer to configure or control the BGA244 cancel the driver installation Units wit
182. perating temperature range of the BGA244 is from 20 to 70 C Do not expose the BGA244 to bake out temperatures above 80 C If the BGA244 is being operated at an ambient temperature below 20 C use the heaters to raise the operating temperature It may be necessary to insulate the unit to bring the temperature within the operating range Pressure The BGA244 can make reliable measurements with pressures ranging from around 5 psia 34 kPa to as high as 150 psi 1000 kPa depending on the gas species The design proof pressure is 2500 psi 17 2 MPa making secondary containment chambers unnecessary The nominal operating pressure is 10 psig 69 kPag Flow The BGA244 is specified for flow rates from O to 5000 sccm Customers have successfully operated at flow rates as high as 20 000 sccm Gas Gases must be clean and dry free of any solid or liquid particulates In addition they must be non condensing at the operating temperature and pressure See Gases page 91 for more details J SRS Stanford Research Systems BGA244 Binary Gas Analyzer Installation Guide 14 Electrical and Magnetic Fields Strong electrical or magnetic fields can interfere with the BGA244 These can make measurements noisy or even impossible to make The best solution is to make sure that the BGA244 is separated from interfering sources If this isn t possible see Interference page 101 for suggestions on shielding techniques Avoid passing current
183. ppendix A Gas Table A list of all supported gases in the Factory Gas Table plus a description of the data contained in the Gas Table Appendix B BGA244E Description of the BGA244E a NEMA enclosed version of the BGA244 Appendix C Mechanical Drawings Mechanical drawings and mounting locations for the BGA244 and its derivatives Appendix D Declaration of Contamination Sample of the Declaration of Contamination form Appendix E Instruction on manually installing the USB Drivers Appendix F Parts List Parts list of the BGA244 and derivatives Appendix G Schematics Electrical Schematics for the BGA244 Appendix H Revisions List of manual revisions JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Manual Conventions and Organization XX Trademarks The trademarks of the products mentioned in this manual are held by the companies or organizations that produce them CAS Registry Number is a Registered Trademark of the American Chemical Society VRC VCO and Swagelok are Registered Trademarks of Swagelok Company Windows Windows XP Windows 7 Windows 8 and Windows 10 are Registered Trademarks of Microsoft Corporation Combicon and Phoenix Contact are trademarks of Phoenix Contact FTDI is a Trademark of Future Technology Devices International Ltd All other brand and product names are trademarks or registered trademarks of their respective companies JSRS Stanford Research Systems BGA244 Binary Gas Analyze
184. pplied when the configuration is changed to make them relevant AILP i d Analog Loop Power Voltage Set query the Analog Input i Loop Power Voltage to d in volts i 1 2 for Analog Input 1 2 Example AILP 1 9 0 Set the Loop Power Voltage of Analog Input 1 to 9 0 V AILP 2 Query the Loop Power Voltage of Analog Input 2 AINE i j Analog Input Enable Set query the Analog Input i Enable Mode to j Parameter i 1 2 for Analog Input 1 2 Parameter j O for disabled j 1 for enabled Example AINE 1 1 Enable Analog Input 1 AIRE Read Analog Input Query Analog Input i The returned value is in volts or amps determined by the Analog In Type i 1 2 for Analog Input 1 2 An Error 18 No 24V Available will be generated if the 24V power supply is not available An Error 25 Input Error will be generated if the input is disabled The controlling program should check the Analog status register to ensure that no voltage or current alerts are active when reading the Analog Input to determine that the reading is valid See Instrument Status Registers page 164 for more information Example AIRE 2 Query Analog Input 2 JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Remote Programming 159 AITY if j Analog Input Type Set query the Analog Input I type to j Parameter i 1 2 for Analog Input 1 2 Parameter j selects one of the following input configurations Note that there are two input
185. puter interfaces Results are reported over the front panel the computer interfaces or the analog outputs Because the BGA244E is inside of an enclosure it is less convenient to access the front panel This is especially true if the enclosure is configured to Type 6P with the cover screws installed If regular access to the front panel is necessary be sure to allow adequate clearance to open the cover Often measurements are monitored remotely over one of the computer interfaces or analog outputs after the unit is configured Environment The enclosure permits a harsher ambient environment protecting the unit from dirt water and ice The same temperature pressure flow and gas requirements apply for the BGA244E as for the standard BGA244 No extra ventilation is required Refer to Operating Environment page 13 for details If the unit will not be exposed to prolonged submersion insert the plugs into the cover screw holes to keep debris out In this case the latch alone can adequately seal the cover to the box Be sure to align the gasket in the cover with the sealing bead of the box when closing the cover Fasten the latch to seal the box However if the unit will be exposed to prolonged submersion you must install the four 10 32 x 0 75 cover screws to prevent leakage Be sure to align the gasket in the cover with the sealing bead of the box when closing and fastening the cover latch Insert and loosely tighten the four screws Tighte
186. r Getting Started 1 Chapter 1 Getting Started Binary Gas Analyzers What is a Binary Gas Analyzer A Binary Gas Analyzer or BGA measures the ratio of two gases based on physical properties of the gases Other instruments do this by measuring the thermal conductivity of the gas mixture or by measuring the speed of sound in the gas using a time of flight technique Both the thermal conductivity and speed of sound of a gas vary inversely with their molecular weight along with several other gas properties So the ratio of two gases can be calculated if you know the properties of the two gases and the thermal conductivity or speed of sound in the mixture A different method of measuring the speed of sound uses a resonant acoustic cell Measuring the resonant frequencies and knowledge of the cell s geometry allows the speed of sound to be accurately calculated This information combined with knowledge of the physical properties of the gases allows you to accurately determine the ratio of the two gases The BGA244 works by injecting a wideband acoustic signal into a gas cell using a speaker The resonant modes of the cell are excited producing large amplitudes at the resonant frequencies This signal is measured using a sensitive wideband microphone Advanced signal processing extracts the frequencies of the resonant peaks and from them the speed of sound Combining the speed of sound temperature and pressure with a detailed list of ab
187. r Processing Food Processing Quality Control Environmental Monitoring Purge Gas Analysis Shielding or Blanketing Gas Monitoring Generator Cooling Gas Monitoring Heat Treating Gas Monitoring Gas purity monitoring Measuring Helium Deuterium ratio Measuring He 3 He 4 ratio BGA244 Binary Gas Analyzer SRS Stanford Research Systems Getting Started 3 Features and Accessories The BGA244 consists of a compact package which includes the resonant cell acoustic transducers sensitive electronics and advanced signal processing It can be powered over USB or 24 V and can interface to external devices by computer interface or analog signals and features a touch screen LCD to configure and monitor measurements There are two models in the BGA244 series the standard BGA244 and the BGA244E enclosure Both models share the same acoustic resonant cell transducers signal processing and basic computer interfaces The standard BGA244 is available with several options See Appendix B for information about the BGA244E Gas Fittings The BGA244 is ordered with one of the following gas fittings TABLE 1 GAS FITTING OPTIONS Option BGA244 Gas Fitting Y Male VCR B Female VCR Y Male VCO Body D Compression Fitting Ye 27 Female NTP Y 18 Female NTP Hose Barb ID hose Welded Male VCR Electrical Connections All versions of the BGA244 can be powered via their USB con
188. r buffer is full Subsequent errors have been dropped JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Remote Programming 172 Using the USB Drivers The BGA244 uses an FTDI FT220X USB interface chip FTDI provides two different types of software drivers to communicate with the interface chip VCP a Virtual COM Port and D2XX a dynamic linked library DLL Drivers are available for various versions of Microsoft Windows Mac OS X Linux 2 6 amp greater and Android Some operating systems may not have both drivers available Detailed information of the drivers and their installation is provided on the FTDI web site www ftdichip com Drivers VCP or Virtual COM Port makes the BGA244 look like an additional COM port available to the computer Application software can access the BGA244 in the same way as it accesses any standard COM port This is usually the simplest way to control the BGA244 using the USB port The D2XX driver gives access the BGA244 through a DLL Application software can access the BGA244 through a series of DLL function calls See the D2XX Programmer s Guide on the FTDI web site for a list of available functions The D2XX driver is a bit more complicated to use but is faster than the VCP Both methods use the remote commands previously described in this chapter to communicate with the BGA244 Be sure that the appropriate driver is installed on any computer that communicates with the BGA244 over USB Window
189. r the following table Baud Rate 2400 4800 9600 19200 38400 57600 6 115200 Example BAUD 0 3 Set RS 232 baud rate to 19200 mB WNP OF LERR InspectError Butter Query the last error in the error buffer Upon executing a LERR the returned error is removed from the error buffer See Error Codes on Page 168 fora description The Error Buffer can store up to 20 errors If more than 19 errors occur without being queried the 20 error will be 254 too many errors indicating that errors may have been dropped Enable Computer Interface UARE i j Set query computer interface i enable mode to j Parameter i O for RS 232 i 1 for RS 422 Parameter j 1 for enabled otherwise 0 The RS 422 interface requires Option 1 Enabling the RS 422 interface without Option 1 installed will generate an Error 16 No Option 1 Example UARE 0 0 Disable RS 232 Interface Terminator XTRM if j k Set the interface terminator that is appended to each response to i j k The default terminator is 13 10 which is a carriage return followed by a line feed JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Remote Programming 141 Measurement and Related Commands NSOS u PRES u PUDL u RATO i u Measurement commands report results from the BGA244 Certain commands require that the BGA244 is in the proper Instrument Mode If not an Error 11 Illegal Mode will be generated Measurements If an e
190. r the selected gas and return to the Select Gases page If you wish to change the gas press the desired gas selection key and re enter the gas When selecting gases User Gas Table gases will appear as User gas_ name to differentiate from a gas in the Factory Gas Table Swap Gases Binary Gas Analyzer For the Binary Gas Analyzer Mode results are displayed for the concentration of Gas 1 relative to the total mixture If you want to view the concentration of Gas 2 press SWAP GASES which will exchange the Gas 1 and Gas 2 entries This key only appears for the Binary Gas Analyzer Gas None Gas Purity Analyzer For the Gas Purity Analyzer gases without physical data can be measured by entering a Reference speed of sound at NTP Press GAS NONE then either directly enter the speed of sound using the keypad or press REL ZERO to use the current speed of sound as a reference Gas None Physical Measurements For Physical Measurements gases without physical data can be measured by pressing GAS NONE SRS Stanford Research Systems Gas for Pressure Corrections SELECT GAS GAS NONE REL ZERO 320 000 m s Gas for Pressure Corrections SELECT GAS GAS NONE BGA244 Binary Gas Analyzer Operations Guide 59 REL The BGA244 provides excellent accuracy using its internal calibration and its stored thermodynamic data But there are circumstances where displaying deviations fr
191. r thread insertion when determining pipe length Refer to Gas Fittings page 16 for more details The BGA244 is mounted using four 10 32 screws The maximum penetration depth of the screws is 0 38 9 6 mm Either remove the rubber feet or relieve the area beneath them for hard mounting to a rigid plate This helps to avoid vibration problems The use of stainless steel mounting screws is not recommended However if it is required use lubricant to prevent galling Procedure Fasten the BGA244 to the mounting surface as described in the previous section If rigid preformed tubing is used it may be necessary to remove the caps from the gas fittings before mounting Connect the gas lines as described in Gas Fittings page 16 following the Swagelok Installation guidelines See the Swagelok Installation guidelines for any washers or O rings that may be required Connect the electrical cabling for power analog and computer I O as described in Electrical Connections page 18 J SRS Stanford Research Systems BGA244 Binary Gas Analyzer Installation Guide 16 Gas Fittings The BGA244 is available with a number of different gas fitting options that are listed in the following table Each BGA244 has two identical gas fittings All of the fittings are Swagelok products whose part numbers are included for reference Dimension X refers to the outside dimension of the gas fittings as shown on Figure C 1 in Appendix C Refer to the
192. rated thru a multilevel graphical user interface The following conventions are used in the manual to describe different functions of the interface Key This key is either a navigation key that will take you to a different display or LIMITS a direct action key that will perform the action listed on the key On Off This is an on off or enable disable key Pressing the key toggles the setting from one state to the other This indicates On or Enabled J ON This indicates Off or Disabled OFF lt Entry gt This indicates that a value needs to be entered where Entry is the 35C name of the parameter Pressing the key will open up the alpha numeric keypad for data entry If the entered value is out of range it will be ignored and an Invalid Entry prompt will appear indicating the maximum allowable value ESC This key on the alpha numeric keypad allows you to exit without entering a new value lt Entry J gt This indicates that a value needs to be selected from a list where Entry Y is the name of the list Pressing the key will open a drop list of possible selections Press the desired selections to choose it The current selection is normally highlighted in yellow C Choice This indicates a radio button that is used to select one of a number of possible choices Press the circle to select that choice and de select all other choices C Choice This indicates a check box that is us
193. ration page as described in Events page 53 Bits set in this register do not affect behavior of the Event Status registers This command will generate an Error 16 No Option 1 if Option 1 is not installed Example EVNC1 3 This would configure Event Relay 1 to switch to the ON position for either System Fault or No Signal EVNE i EventEnable Register EVNI Set query the EVNE enable register to i Bits set in this register cause EVENT in STB to be set when the corresponding bit is set in the EVNR register The meaning of the bits in the EVNE register is the same as the EVNI register Event Status Register Immediate EVNR Query the EVNI register This register is not latched and reflects the value of the register the instant it was read See Events in the Operations Guide for details on the Event registers The bits in the EVNI register have the following meaning Bit Meaning oo O System faut o 4 Pressure1LimitExceeded 6 Pressure 2LimitExceeded 8 Temperature Limit Exceeded __ 9 Temperature Limit Exceeded Example EVNI A return of 2 would indicate that the BGA244 cannot recover the acoustic signal Event Status Register Latched Query the EVNR status register This register is a latched version of the EVNI register Upon executing a EVNR query the register is cleared The meaning of the bits in the EVNR register is the same as the EVNI register JSRS Stanford Resear
194. rch for them the drivers are located at the FTDI web site www ftdichip com Drivers If there are difficulties installing the driver refer to Appendix E for details on manually installing the drivers JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Installation Guide 24 RS 232 RS 232 connector C3 is located on the front of the BGA244 The connector is a standard 9 pin type D female connector configured as a DCE transmit on pin 2 receive on pin 3 CTS and RTS are supported See figure for the connector pin numbering 54 321 987 6 RS 232 PINOUT In order to communicate properly over RS 232 both the BGA244 and the host computer must be set to the same configuration The RS 232 interface supports baud rates from 2400 to 115 2 k baud In general the highest baud rates will operate successfully for shorter cable lengths At lower baud rates cable lengths over 100m 300 ft should be possible Communication errors can be caused by excessive cable length overly high baud rates or electrical noise If errors occur operating at a lower baud rate will usually help RS 422 The RS 422 connector C4 is part of Option 1 Industrial Control Option and can only be used if an external 24 VDC power supply is connected to the BGA244 Connections to the RS 422 interface are made using terminal block C4 located on the front of the BGA244 The RS 422 interface is implemented as a 4 wire point to point non multidrop connection
195. rd locking and reset the password to the default value of 0000 JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Operations Guide 89 Hardware Reset The BGA244 has a hardware reset button that can be used if the BGA244 is frozen in an inoperable state There are two different types of resets with slightly different behaviors Use an unbent paper clip or a small screw driver to press the reset button Normal Reset Press the reset button once Releasing the button forces a Normal Reset This acts the same as power cycling the BGA244 This is ordinarily used if the BGA244 is in an unknown state and it is difficult to remove power to restart the unit Hard Reset Press the reset button once Release it then immediately press and hold the button down for at least 10 seconds to execute a Hard Reset This acts the same as power cycling the BGA244 and Recalling Setup O Default Setup This is ordinarily done if something has occurred to put the BGA244 in an inoperable state where loading the Default Setup is impossible or to reset a forgotten password Note that this will replace the current settings of all parameters with the Default Settings See Default Setup page 66 for details User Gases Gases can be added to the User Gas Table using the BGAMon software See User Gases in Chapter 5 BGAMon for details on this procedure Updating Firmware The BGA244 Firmware can be updated by the user using the BGAMon soft
196. registers if it occurs See Instrument Status Registers page 164 for more information t if Analog In 1 or 2 are configured as pressure gauges PMAX i p u Pressure Gauge Scale Maximum Set query Pressure Gauge scale maximum to p Parameter i 1 2 for Pressure Gauge 1 2 If omitted units default to the global pressure unit Example PMAX 1 100psi Set the Scale Maximum for Pressure Gauge 1 to 100 psi PMIN i p u Pressure Gauge Scale Minimum PRAC i Set query Pressure Gauge scale minimum to p Parameter i 1 2 for Pressure Gauge 1 2 If omitted units default to the global pressure unit Example PMIN 1 0psi Set the Scale Minimum for Pressure Gauge 1 to O psi PMIN 2 Query the Scale Minimum for Pressure Gauge 2 in global units Select Analysis Pressure Source Set query the pressure analysis source to i iis set per the following table If the selected source is not configured as a pressure gauge an Error 23 Illegal Gauge will be generated Value Pressure Analysis Source 1 Analog Input 1 2 Analog Input 2 3 User Entered J SRS Stanford Research Systems BGA244 Binary Gas Analyzer Remote Programming 152 PRAM p u PREN i j PRES u PRRD i u PRSU i j Example PRAC 1 Set the Pressure Analysis Source to Analog Input 1 PRAC A return value of 3 indicates User Entered pressure is selected Set Atmospheric Pressure Set query the Ambient Atmospheric Pressure to p If om
197. resent Performed if Option 1 is installed and 24V is present JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Operations Guide 88 About the BGA244 The About the BGA244 page displays the following f ai information This is the same information that is displayed on the display during power on Serial Number 1 Firmware Build 3008 Control Option INSTALLED Serial Number Cal Date Thu Jan 1 00 00 00 1970 Hardware Rev A 0 Firmware Version Hardware Version Installed Options Calibration Date Password The BGA244 keypad can be locked out with a password enable to keep unauthorized personnel from changing settings on the BGA244 When locked out only the home page can be viewed If keypad is locked a message appears at the top left of the screen Any key press will open the numeric key pad to allow the user to enter the password An Invalid Password prompt will appear if an incorrect password is entered After the correct numeric password has been entered all functions can be accessed If locking is enabled the keypad will be re locked after 30 seconds of no keypad activity Press ON OFF to toggle locking on and off A new password r abi can be entered if locking is on Enter a 4 digit numeric value to change the password If you forget the password the unit can be reset using Hard Reset function described in the Hardware Reset section This will disable passwo
198. rface the RS 232 serial interface or the optional RS 422 interface Any host computer interfaced to the instrument can easily control and monitor its operation Note that the RS 422 interface is only available if the Industrial Control Option Option 1 is installed and a 24 V supply is connected to the BGA244 Interface Configuration The interface configuration parameters can be controlled from the Computer I O pages located at Home Setup Control Panel Computer 10 See Computer I O page 76 for details The only two configuration parameters are the baud rates for the RS 232 and RS 422 interfaces The default baud rate for both interfaces is 9600 baud All interfaces are enabled by default but the RS 232 and RS 422 interfaces may be disabled individually if desired Any modification made to an interface takes effect immediately Responses to commands are returned to the interface that sent the command For example if you query ESE over RS 232 the reply will only be sent back over the RS 232 interface Front Panel Indicators Two front panel LED indicators located to the right of the RS 232 connector help assist with programming COMM and ERR The COMM LED is an activity indicator that flashes every time a character is received or transmitted over one of the remote interfaces The ERR LED will flash when a remote command fails to execute due to illegal syntax or invalid parameters Transmit and Receive Buffers Each interfa
199. rom the correlation functions of other references or to data extracted from NIST s REFPROP JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Gas Table 191 The same methodology was applied to other gas parameters and parameters for correlation functions to estimate the second and third virial coefficients the viscosity and thermal conductivity as functions of temperature the translational vibrational relaxation of the heat capacity and the saturation vapor pressure The distillation of all of these estimates and the parameters for new correlation functions are presented in the Gas Table Corresponding States Principle CSP CSP methods allow the estimation of fluid properties which depend on intermolecular forces by correlation functions scaled with the critical constants of the fluid For example the departure from ideal gas compressibility can be described with a virial equation of state EOS The first two coefficients of that EOS called the 2 and 3 virial coefficients can be measured directly or estimated using CSP methods CSP methods were used to estimate the gases 2 and 3 virial coefficients thermal conductivity and viscosity These results would be used in the Gas Table if experimental results or correlation functions derived from those results were not available Molar mass Column 6 The molar mass is in units of grams per mole Note that these are not SI units for which the molar mass is in
200. rror in a measurement occurs during a query the unit will return an overload value 9 9E37 to inform the user that there was something wrong with the measurement The controlling program should identify this and check the BGAO status register if it occurs A return value of 0 in the BGAO status register confirms that a measurement is valid Any other value indicates there is some problem with the measurement See BGAO Status Register page 164 for more information Each measurement has its own unit family associated with it If units are omitted the selected global unit is used If units are included with the command they must be in the correct unit family or an Error 127 Illegal Units will be generated Normalized Speed of Sound Query the Normalized Speed of Sound for the current Measurement Mode If omitted units default to the global speed units Example NSOS kph Query the normalized speed of sound in kilometers per hour NSOS Query the normalized speed of sound in global units Analysis Pressure Query the Cell Analysis Pressure If omitted units default to the global temperature units See Pressure Commands page 151 for a list of possible errors that occur with the PRES command Example PRES Query the Analysis Pressure in global pressure units Purity Mode Measurement Query the Gas Purity Measurement If omitted units default to the global ratio units This command is valid for Gas Purity Mode If the comman
201. rror in the calibration data JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Remote Programming 169 20 21 22 23 24 25 26 27 Firmware Error The requested action failed because of an error in the Firmware Update Time Out Error The requested action failed because of a Time Out error Binary Stream Error The requested action failed because of an error in the binary stream Illegal Gauge The requested action failed because the Analog Input is not defined as a pressure gauge Output Error The requested action failed because the Analog Output is disabled Input Error The requested action failed because the Analog Input is disabled Invalid Gas The requested action failed because of an improperly specified gas Not allowed The requested action failed because another operation blocked it Query Errors 30 Lost Data Data in the output buffer was lost This occurs if the output buffer overflows or if a communications error occurs and data in output buffer is discarded Parsing or Command Errors 110 111 112 113 illegal Command The command syntax used was illegal A command is normally a sequence of four letters or a followed by three letters Undefined Command The specified command does not exist Illegal Query The specified command does not permit queries Illegal Set The specified command can only be queried JSRS Stanford Research Systems BGA244 B
202. rying Current Maximum Switching Current 1A Lifetime 42 Voc 0 1 A resistive load 10 operations Switching high power loads can dramatically reduce the relays lifetime If driving an inductive load make sure to use catch diode to minimize inductive fly back Common uses of the relays include Turning on an alarm when a limit is exceeded Opening a valve to control a process Computer control of devices JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Installation Guide 31 Pressure Transducers In some cases real time monitoring of the gas pressure can improve measurement accuracy The simplest way to do this is by connecting a pressure transducer to one of the BGA244 s analog inputs This feature is only available for units with Industrial Control Interface Option 1 installed and 24 V power Using the voltage or current analog inputs the BGA244 can interface with a variety of different transducers Scale factors for minimum and maximum pressures can be set in either absolute or gauge pressure There is a wide variety of pressure transducers that can interface with the BGA244 Differences among them include gas fittings pressure ranges and electrical connections When selecting a pressure transducer select one that matches the system operating pressure Transducers typically have the best linearity and accuracy when not operated at their extreme limits Refer to Analog Inputs page 78 for details on co
203. s Drivers for the BGA244 If you connect the BGA244 using a computer running Microsoft Windows it may detect the USB Interface Chip and offer to install two drivers for the device VCP and D2XX drivers Depending on the version and configuration Windows may either automatically install the drivers or prompt you to search for them If you need to search for them the drivers are located at the FTDI web site www ftdichip com Drivers If there are difficulties installing the driver see Appendix E for details on manually installing them JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Service 173 Chapter 7 Service Troubleshooting FaultName Meaning Action Required Magnet Fault The magnets used in the acoustic transducer is damaged SRS Over The temperature sensors are bile IOMA voltage voltage Internal supplies under voltage SPI ADCs or DACs not working CODEC values out of range If you are contacting SRS about a problem with your BGA244 please have the following information readily available The unit serial number The firmware version number A description of the problem Any error messages JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Service 174 Calibration Calibration JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Service 175 Maintenance Replacement terminal blocks are available from Digikey or other distributors Phoenix Conta
204. s condensation point the BGA244 will indicate a condensation warning message See Condensation page 93 for more information Gases that can be used The BGA244 Factory Gas Table contains nearly 500 different gases These include common industrial gases and a wide range of specialty gases See Appendix A Gas Table for a list of supported gases Gases not included in the Factory Gas Table can be added to the User Gas Table The minimum data required is the mass and y ratio of specific heats of a gas Other thermodynamic properties can also be added if available See User Gases page 113 for more details Gases aren t constrained to single species Gases mixtures or blended gases can also be used Atmospheric air N O Ar CO is included in the Factory Gas Table Other mixed gases can be added to the User gas table using the procedure described later in this chapter J SRS Stanford Research Systems BGA244 Binary Gas Analyzer Application Guide 92 Gases that can t be used SRS does not recommend using explosive corrosive flammable or reactive gas mixtures in the BGA244 Avoid gases that react with the wetted materials See Specifications for a list of wetted materials In particular avoid Gases that react strongly with copper may damage the acoustic membranes Strong bases NaOH KOH may react with Kapton acoustic transducers Gases that contain oils or waxes that can coat the inside of the acoustic cell or Kapton
205. s errors and communication errors using blink codes These features are active on all units and are especially useful for units without a display Option 2 See Figure 1 page 6 for the LED locations Normal Behavior When power is first applied the Power LED will light for 1 second followed by all 3 LEDs lighting for 5 seconds At this time the Power LED should blinks once indicating the code is loading properly then operational After this the Power LED remains on The Comm Communications LED will flash during communication over any of the computer interfaces The Error LED will remain off unless an error occurs ERROR LED Codes These codes use the red ERROR LED to indicate various errors System Fault The ERROR LED is continuously on as long as the condition persists Stopped Degas Invalid Bad Pressure Condensation or No Signal The ERROR LED flashes at about 4 Hz as long as the condition persists Communication Error ERROR LED flashes once for each error POWER LED Codes The BGA244 can indicate if the USB or 24 V power supplies are out of range using blink codes on the Power LED Refer to External Power Supply Faults page 82 for details Note that the BGA244 must have a minimum power supply voltage to generate the blink codes Active Power Supply Fault The POWER LED will flash at about 4 Hz Minimum Operational Voltage USB gt 3 5V 24 gt 18 V USB Fault Voltage lt 4 5V or gt 5 3V 24 V Faul
206. s through the BGA244 from the gas lines This can generate interfering signals Make sure that all pipes are properly grounded Access Front Panel As the BGA244 can be operated or viewed from the front panel it is necessary to have a clear view and easy access to the LCD and touch screen This is less important if operating over a computer interface although it is useful to have access to the front panel for debugging purposes Visibility of the status LEDs is helpful especially for units without displays Option 2 Wrench Clearance Most of the gas fittings that connect to the BGA244 require one or more wrenches to fully tighten Make sure there is sufficient clearance both in length and rotation See the Swagelok Installation guidelines for the different gas fittings for details Cable Clearance Typical USB and RS 232 and RS 244 cables require about 2 5 65 mm clearance from the BGA244 The 24 V barrel connector Option 1 with BGA 24 and terminal strips analog I O and relay connections need about 2 0 50 mm of clearance Ventilation Clearance When the heaters are not operating the BGA244 dissipates between 2 to 5 watts depending on the operating condition Therefore ventilation clearance isn t required When operating the heaters adjust their power to maintain a constant temperature This eliminates the need for any additional ventilation Service Access Besides the terminal block connectors and the gas fitt
207. sducer that can be ordered with the BGA244E It comes installed inside of the enclosure Note that this accessory is only available on units with the Industrial Control Option Option 1 JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Getting Started 6 Reset C3 RS 232 Button IN Max pressure 150 psig 1000 KPag Communications Interface Nom pressure 10 psig 69 kPag Max flow 5000 sccm USB 2 0 O Power Blinks im i Cell volume 130 cc O power fau omm O Error DCE 9600 N 8 1 i C1 500 mA max DEFAULT Indicator GND Lug LEDs FIGURE 1 BGA244 PLAIN NON OPTION 1 Max pressure 150 psig 1000kPag Communications Interface Nom pressure 10 psig 69 kPag Max flow 5000 sccm 2 0 RS 232 Power Blinks for Cell volume 130 cc O power fault ef Ce 85 Reset Error pae DCE 9600 N 8 1 O 500 mA max DEFAULT Industrial Interface Control Interface RS 422 7 Aux Ports sa IN1 WI C4 RS 422 o f oUt U al IN IN 2 V I f RxD OUT 1 V 1 3 t pi E Analog I O OUT 2 V 1 f C5 24V 5 di Event Relays 2 1 mm Event1 ps 24V 2 5A 24V enables analo output heater control MEASURE Aux Ports and Relays 5 C6 3 OUT V T Configure 1 0 for voltage Event 2 7 C8 Relays or current 4 to 20 mA Measure Out FIGURE 2 BGA244 OPTION 1 JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Getting Star
208. splay later in this chapter for more information JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Operations Guide 38 Appearance The BGA244 uses a touch screen display to configure measurements and display measurement results The Home page displays the primary measurements and has controls to navigate the instrument functions and secondary measurements You can always return to the Home page directly from any page by pressing Home Each Instrument Mode has a unique Home page Home pages consist of a Measurement Section that is specific to the Instrument Mode and a Control Section that is common to all Instrument Modes There are two possible appearances of the display depending on the orientation vertical with the control section below the measurement section and horizontal with the control section to the right of the display section Measurement Home Binary Gas Section METER Limits ff METER Y HeLp EVENT EVENT RELAY1 E SETUP E RELAY Control Section HOME PAGE VERTICAL VIEW HOME PAGE HORIZONTAL VIEW FIGURE 14 BGA244 HOME PAGE Measurement Section The Measurement Section displays the operating mode measurements and status information The meter scale limits and other functions are set using keys in the Control section See the sections on Binary Gas Analyzer page 40 Gas Purity Analyzer page 43 and Physical Measurements page 46 later in this chapter for details on
209. ss the desired setup If the selected location is currently filled a prompt will appear asking if you want to continue You cannot store a setup to Location O Default Setup Enter the setup name using the alpha numeric keypad If you selected a currently filled location a prompt will appear asking if you want to change the setup name A confirmation prompt will appear containing the setup name and if the setup was stored successfully When entering a name for a setup try to be descriptive For example ARGON IN OXYGEN 1 could indicate Gas 1 Argon Gas 2 Oxygen full scale output 1 This makes it easier to identify each setup Recall Press RECALL to open the Setup list Note that Setup O is the Default setup Press the desired setup A confirmation prompt will appear containing the setup name and if the setup was recalled successfully Erase Press ERASE to open the Setup list Press the desired setup A prompt will appear asking if you want to erase the selected setup A confirmation prompt will appear if the setup was successfully erased JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Operations Guide 66 Default Setup TABLE 10 ACTIVE PARAMETERS Value Gas Purity Analyzer Run Argon 318 956 m s Analysis Pressure User User Pressure User Pressure Units Gauge Ambient Pressure 14 7 psi Meter Settings 2 10 10 5 Active Active 1 No REL 0 Nothing S
210. t Voltage lt 20V or gt 26V JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Operations Guide 52 Controls Each Home page has the same Control section Control buttons are used to saa access menus within the user interface Several functions can be directly at accessed from the Home page while others are accessed through the Setup Menu sae EVENT Note that the Physical Measurements Home page omits the Meter Scale AA control button since there is no meter It replaces it with a Pressure Meter ae button SETUP Limits Process limits are used to indicate that the measurement is above or below a set value Limits serve two purposes in the BGA244 They are displayed on the meter to provide visual feedback Binary Gas and Purity Analyzers and are used in Events to control external devices The LIMITS button on the Home page is a dual purpose control At any time pressing LIMITS takes you to the Process Limits Page where the limit values can be entered Additionally the LIMIT button will turn red if either the Upper or Lower Limit is exceeded Process Limits Page The upper and lower limits are set in units of the measured value Each limit can be separately enabled The Hysteresis value provides a guard band around the limit thresholds to avoid oscillating between the limit amp non limit states This is particularly helpful when using the Event Relays to stop relay chatter Process Limits Th
211. t in this register cause FALT in STB to be set when the corresponding bit is set in the FALR register JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Remote Programming 137 FALI Fault Status Register Immediate Query the FALI register This register is not latched and reflects the value of the register the instant it was read Refer to the nstrument Status Register Model page 164 for a description of the different conditions reported The bits in the FALI register have the following meaning Bit Meaning O O o O Cell Under Temperature fault 10 11 12 13 14 Example FALI A return of 128 would indicate that the 3 3V power supply was under voltage FALR Fault Status Register Latched Query the FALR status register This register is a latched version of the FALI register Upon executing a FALR query the register is cleared The meaning of the bits in the FALR register is the same as the FALI register Example FALR A return of 32768 would indicate that Self Test Failed since last time this register has been read or cleared JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Remote Programming 138 EVNC i j Event Registers Event Configuration Register EVNE i Set query Event Relay Configuration Register i to j i 1 2 for Event Relay 1 2 The meaning of the bits in the EVNC registers is the same as the EVNI register This command sets the Event Relay Configu
212. t is out of range for the selected gas combination This can be caused by measurement inaccuracies especially in gases with similar speeds of sound or an additional contaminating gas es in the cell or if the wrong gas es have been selected No Signal This indicates that the BGA244 cannot recover the acoustic signal or identify a valid speed of sound for the gas This most often occurs if the gas pressure in the cell is too low See Troubleshooting page 173 if this message is displayed with adequate gas pressure Invalid This indicates that the BGA244 cannot calculate a valid solution for the gas concentration given the measured speed of sound Binary Gas Analyzer only Usually this only appears for a brief instant after a major disruption of the signal occurs See Troubleshooting page 173 if this message remains on for more than a few seconds JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Operations Guide 50 Bad Pressure This indicates that the measured pressure is invalid It s usually caused by a problem with a pressure transducer or wiring connected to an Analog Input See Pressure page 62 for more information Condensation This indicates that one or both of the gases is nearing its condensation point When condensation occurs the BGA244 cannot correctly calculate the gas concentration gas purity or normalized speed of sound Refer to Condensation page 93 for information on dealing with this problem
213. t unit family or an Error 127 Illegal Units will be generated The table below lists the measurement ID types and their associated units ID Measurement Unit Family Binary Measurement Gas Purity Measurement Physical Measurement v speed Measure Out Concentration Set query the Measure Out Binary Gas concentration type to i Parameter i 1 for 1 solution i 2 for 2 solution This command is only active for Binary Gas mode Refer to Details page 42 for more information description Measure Out Enable Set query the Measure Out enable mode Parameter i 0 for disabled i 1 for enabled Example MOEN 1 Enable Measure Out JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Remote Programming 155 MOMN i d u MOMX i d u MOTY i MOVA Measure Out Scale Min Set query the Measure Out Scale Min of Measurement Mode i to d Parameter i is the Measurement ID shown at the beginning of this section Measure Out Scale Max Set query the Measure Out Scale Max of Measurement Mode i to d Parameter i is the Measurement ID shown at the beginning of this section Example MOMX 1 0 Set the Measure Out Scale Max of the BGA to 0 MOMX 2 10 Set the Measure Out Scale Max of the Purity Analyzer to 10 MOMX 2 Query the Measure Out Scale Max of Physical Measurements in global units Measure Out Type Set query the Measure Out type to i Parameter i selects one of
214. ted 7 Model BGA244 Binary Gas Analyzer ASRS Stanford Research Systems Inc FIGURE 3 BGA244 WITH DISPLAY NON OPTION 2 Model BGA244 Binary Gas Analyzer Stanford Research Systems Inc FIGURE 4 BGA244 WITHOUT DISPLAY OPTION 2 JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Getting Started 8 Unpacking Before You Open the Box Do not remove the gas port dust caps until just prior to connecting the unit to your gas manifold to reduce the chance of contamination of the cell Read the Chapter 2 Installation Guide prior to installing the BGA244 into your system Read the Chapter 3 Operations Guide and Chapter 4 Applications Guide prior to operating the BGA244 Inspect all components of the SRS BGA244 upon unpacking Report any damage to Stanford Research Systems immediately Compare the contents of the shipping container to the list below and report any discrepancies See Appendix B for information specific to the BGA244E What is included Standard BGA244 1 One BGA244 w selected Gas Fittings Option A H 2 One 6 1 8 m USB cable 3 One Operation and Service Manual Options 1 Option 1 Industrial Control Option installed at Factory 2 Option 2 No Display Option installed at Factory Accessories 1 BGA 5 USB Power Supply 2 BGA 24 24V Power Supply 3 BGA S Acrylic shield for the LCD display JSRS Stanford Research Systems BGA244 Binary G
215. ted toward the display version Chapter 5 BGAMon contains information on configuring either version of the BGA244 using the BGAMon software Chapter 6 Remote Programming contains information on the remote commands that can also be used to configure either version Navigation There are several navigation keys that are present on many of the pages to make it easier to navigate the different instrument functions of the BGA244 See Manual Conventions page xv at the beginning of this manual for a list of conventions used to describe the different functions of the interface The following rules will help you navigate the menus HOME returns you to the Home Page SETUP take you to the configuration pages that aren t displayed on the Home page lt or back key returns up one level from the display you are currently on PAGE T and PAGE J are used to scroll through a page that can t all be displayed on the screen at the same time Different pages are referenced by their location in the interface hierarchy Home Setup Control Panel Units would be reached from the Home page by pressing Setup Control Panel Units Help Screens Most screens have a Help page associated with them accessed by a Help key This page will have information about the settings and displayed parameters on the screen The Page T and Page J are active if the Help screen is more than one page long JSRS Stanford Research Systems BGA2
216. ter the Scale Min and Scale Max values Select Gas Concentration 1 or 2 using lt Linked to 4 gt Normally these values are identical However there are rare cases where there are two possible solutions for a given speed of sound In this case Gas GAS CONC 1 Concentration 1 is always the lower concentration and Gas Concentration 2 the higher one Refer to Gases page 91 for details Concentration Value Enter Scale Min and Scale Max to scale the Measure Output relative to the value of the measured parameter They are in ratio units for the Binary Gas and Gas Purity or in speed units for Physical Measurements JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Operations Guide 81 Output 1 and Output 2 r Eia Analog Output 1 and 2 can be linked to several different parameters or be explicitly set from the GUI or computer interface as a User value Analog Output 1 and Output 2 scale in the same manner as the Measure Output if linked to a 0 000 C measured parameter Possible linked parameters include Measured Speed of Sound Normalized Speed of Sound Gas Temperature Pressure Meter 1 or 2 if configured User Set thru the GUI or over the computer interfaces Press ENABLE DISABLE to enable or disable the output Press Output Selection lt Typey gt to open the selection list The currently selected SPEED OF SOUND type will be highlighted in yellow Press the desired value to SPEED NTP
217. that relies on the thermodynamic properties of gases including those measuring time of flight or thermal conductivity It may be more visible on the BGA244 because it supports so many different gas pairs and concentrations This doesn t necessarily occur for the same gas pairs but does occur for some pairs for all techniques Most other analyzers support at most a hand full of gas combinations and will not support combinations or ranges where this can occur Example A common mixture that exhibits this behavior is Argon mass 36 y 1 67 in Oxygen mass 32 y 1 45 At NTP there is a single solution reported for O 43 5 but two solutions above that JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Application Guide 109 Gas Purity Measurement Accuracy In the Gas Purity Analysis mode the measured speed of sound of the gas in the cell is compared with expected speed of sound This measurement is sensitive to small amounts of a contaminating gas However the magnitude of the reported value depends on the species of the contaminating gas See Table 9 page 45 for an example of this Gas Purity measurements are most sensitive when the contaminating gas es have a much higher or lower speed of sound Gases with similar speeds of sound are problematic Higher speeds of sound are normally associated with lighter gases while slower speeds of sound are associated with heavier gases Example 1 of He a lighter gas in N
218. the amount of water vapor in the wet air must be fixed If it changes anew REL must be performed The amount of water vapor must also be low enough to avoid condensation Note that the condensation point of water or any liquid is independent of any other gas species But it does depend on both temperature and pressure BGAMon can be used to see the saturation point maximum amount of water vapor for your operating temperature and pressure It may be necessary to operate at an elevated temperature if the water vapor is approaching condensation As with any REL this technique works best near the conditions the REL was performed at This means operating at a similar temperature pressure and most importantly amount of water vapor in the wet air Errors will increase the as the operating conditions move further away from the REL conditions Refer to REL to a Reference Gas page 104 for more details about this procedure Procedure It is usually a good idea to know the approximate amount of water in the air before performing a REL This serves two purposes First it determines if the cell temperature should be increased using the heaters to avoid condensation Second it provides a check to see if the amount of water vapor has changed since the unit was last REL d Select dry air and water in the gas selection menu Flow 100 wet air through the cell If a condensation warning occurs increase the cell temperature using the block heaters Re
219. tio of the number of molecules of one gas relative to the total number of molecules in a volume Mass fraction is the ratio of the mass of one gas relative to the total mass of the gas in the volume Mole fraction is commonly used in gas blending while Mass fraction is used in monitoring combustion products The BGA244 supports both methods The formula for converting from mole fraction to mass fraction is x1 M1 a cel O Gl MD x2 M2 and for converting mass fraction to mole fraction o Owm MYu m2 where w1 mass fraction of gas 1 x1 mole fraction of gas 1 M1 mass of gas 1 and w2 mass fraction of gas 2 x2 mole fraction of gas 2 M2 mass of gas 2 x1 Example Determine the mass fraction of Nitrogen in air For the simple 2 gas case ignoring other gases air made up of 78 Nitrogen molecules N2 and 22 Oxygen molecules O2 In this case the mole fraction of Nitrogen in air is 78 or 0 78 ee 0 78 28 01348 _ 786 ISS ETOCS 0 78 28 01348 0 22 31 9988 Example Determine the mole fraction of Hydrogen H2 for a mixture of 1 kg Hydrogen and 100 kg Carbon Dioxide C02 707 201588 100 Mole fraction of H2 00 707 201588 377 44 0098 0 179 JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Application Guide 107 Accuracy amp Stability Binary Gas Measurement Accuracy In the Binary Gas Analysis mode the gas concentration is determined
220. tion they often have a drain wire that connects to the cable shield They require an external power supply The BGA244 supports transducers with a full scale output range that lies between 0 and 10 V Voltages must always be gt 0 V no bipolar outputs The output can be scaled to either absolute pressure or gauge pressure Connect an appropriate power supply per the manufacturer s instructions If needed the Drain wire can be connected to ground at the BGA244 ground lug C1 Connect the Signal and Signal Return or Signal to In 1 or In 2 on the BGA244 Refer to Analog Input page 27 for details on connecting the transducer to the BGA244 Configure the BGA244 as described below Set the analog input to Enabled Voltage Select Absolute or Gauge units depending on the transducers specifications If Gauge units are selected make sure to enter the ambient pressure Set the Min and Max to the transducers minimum and maximum pressure values Check Use as Pressure Gauge Set the Analysis Pressure to the appropriate input Analog Input 1 or 2 Current Output Transducers Current output pressure transducers come in several different configurations They can have separate power and signal lines or the power can be provided in series with the signal lines loop power In addition they may have a drain wire that connects to the cable shield The BGA244 supports current output transducers with a full scale r
221. tions Guide 42 Details This is a description of some of the items specific to the Binary Gas Analyzer Instrument Mode Range The maximum range for the Binary Gas Analyzer is 2 to 102 or its equivalent in fraction or ppm The 2 over range is to allow for measurement inaccuracies Outside of this range the display will limit at gt max or lt min to indicate out of range Selecting gases Both gases must be selected before measurements can be made There are nearly 500 different gases contained in the BGA244 Factory Gas Table Go to Setup Select Gas to view the Gas Selection page Here you can select Gas 1 and Gas 2 by name chemical formula or CASH See Selecting Gases page 57 for more information Note that the BGA244 reports the ratio of Gas 1 to the total mixture of Gas 1 and Gas 2 To report the concentration of Gas 2 press SWAP GASES on the Gas Selection page Molar Fraction vs Mass Fraction The BGA244 can report the gas ratio in either mole or mass fraction These differ by the atomic weights of the gases Certain applications commonly use one or the other Go to Setup Control Panel Measurement to change between mole and mass fractions See Binary Gas Concentration page 72 for more details Accuracy Estimator The BGA244 calculates a real time accuracy estimation of the gas ratio measurement The accuracy estimation is based on temperature uncertainty of 0 1 C and a pressure uncertainty of 1 psi REL
222. ture and Pressure NTP for all of its normalized readings This is defined as the following Temperature 20 00 C 293 15 K or 68 00 F Pressure absolute 1 atm 101 325 kPa or 14 696 psia Flow There are a few abbreviations used to describe flow rate SCCM standard cc ml per minute SCCS standard cc ml per second Speed of Sound The Speed of Sound is occasionally abbreviated as SOS in the manual Normalized Speed of Sound The speed of sound in a gas varies as a function of several environmental parameters The dominant effects are caused by pressure and temperature An additional effect is caused by the frequency at which the speed of sound is measured The frequency dependent effect is due to vibrational population relaxation effects in the gas molecules This effect is specific to the particular gas being measured The BGA244 normalizes the speed of sound to NTP at the measured frequency The Normalized Speed of Sound is occasionally abbreviated as NSOS in the manual Pressure Pressure can be referred to in either absolute or gauge pressure units Absolute pressure units are relative to vacuum while gauge pressure units are relative to the ambient pressure on the outside of the gauge When using gauge units it is important to enter the ambient pressure as the BGA244 uses absolute pressure in its calculations JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Manual Conventions and
223. ture of the BGA244 gas cell The thermistors measure the temperature at 2 specific points in that distribution If any of the conditions change a new temperature profile will gradually be established The thermistor temperature will lag the overall gas temperature until the new equilibrium is reached How long it takes to reach this new equilibrium is a function of the thermal conductivity and flow rate of the gas For low flow rates lt 100 sccm settling occurs primarily through the thermal conductivity of the gas in the cell This typically takes less than 60 seconds and depends heavily on the gas species The following table shows the transient settling time for a few different gases at zero flow TABLE 21 LOW FLOW TRANSIENT SETTLING TIME Gas Transient At higher flow rates gt 100 sccm settling becomes more of a property of the gas flow rate The gas at the thermistors is replaced by outside gas rather than relying on the thermal conductivity to reach equilibrium The following table shows the transient settling time for Nitrogen N2 at several flow rates TABLE 22 TRANSIENT SETTLING TIME FOR DIFFERENT FLOW RATES Flow sccm Transient Or em ing Time 100 200 500 JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Application Guide 101 Interference Vibration Mechanical vibrations can be picked up by the BGA244 This causes an interfering signal that can make measurements noisy or even impossible t
224. tware also provides information if the conditions and selected gas species are near condensation J SRS Stanford Research Systems BGA244 Binary Gas Analyzer Application Guide 94 Avoiding Condensation To avoid condensation ensure that the saturation point pressure at which condensation occurs of the gas species exceeds the partial pressure of the gas within the BGA244 The following techniques can be used to eliminate condensation The Block Heaters can be used to raise the cell temperature The temperature should be high enough so the saturation value of the gas exceeds the partial pressure of the gas If this temperature is unknown set the Block Heater to operate at least 3 5 C above the highest expected gas manifold temperature up to the maximum of 70 C Make sure the power supply and Maximum Heater Current are large enough to raise the cell temperature to the set point typically 0 5 to 2 amps Refer to Heater page 75 for information on setting the heater Water Vapor in Air Atmospheric air usually contains some water vapor in addition to the usual nitrogen oxygen argon and carbon dioxide This is referred to as humidity It will affect measurements since water vapor is an additional gas species Ordinarily mixtures containing water vapor as a third gas should be dried prior to measurement However in some cases drying can be avoided by using the REL function to compensate for the third gas For this technique to work
225. uery form depending on whether the character follows the mnemonic Set only commands are listed without the query only commands show the after the mnemonic and guery optional commands are marked with a Parameters shown in and are not always required Parameters in are required to set a value and are omitted for queries Parameters in are optional in both set and query commands Parameters listed without any surrounding characters are always required Do NOT send or or as part of the command The command buffer is limited to 64 kbytes with 25 byte buffers allocated to each of up to 3 parameters per command If the command buffer overflows both the input and output buffers will be flushed and reset If a parameter buffer overflows a command error will be generated and the offending command discarded Commands are terminated by a semicolon a lt CR gt ASCII 13 or a lt LF gt ASCII 10 Execution of the command does not begin until a command terminator is received Errors Aside from communication errors commands may fail due to either syntax or execution errors Syntax errors can be detected by looking at bit 5 CME of the event status register ESR Execution errors can be detected by looking at bit 4 EXE of the event status register In both cases when an error occurs the red ERROR LED will flash and an error code indicating the specific cause of the error is placed
226. uge 1 Lower Limit Active Inactive Gauge 1 Hysteresis 1 psi Pressure Meter 2 Settings Use Analog In 2 as Pressure Gauge 2 Inactive Gauge 2 Units Gauge Gauge 2 Min O psi Gauge 2 Max 150 psi Gauge 2 Upper Scale 150 psi Gauge 2 Lower Scale O psi Gauge 2 Upper Limit 100 psi Gauge 2 Lower Limit 10 psi Gauge 2 Upper Limit Active Inactive Gauge 2 Lower Limit Active Inactive Gauge 2 Hysteresis 1 psi Analog Output 1 Settings Analog Output 1 Speed Scale Min O m s Analog Output 1 Speed Scale Max 2000 m s Analog Output 1 Speed NTP Scale Min O m s Analog Output 1 Speed NTP Scale Max 2000 m s Analog Output 1 Temp Scale Min 0 C JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Operations Guide 69 Analog Output 1 Temp Scale Max Analog Output 1 Press 1 Scale Min Analog Output 2 Settings J o S Measure Out Settings Analog Output 2 Press 1 Scale Min Settings marked with are only operational with the Industrial Control Option Option 1 and 24V connected to the unit They can be configured if Option 1 is installed even if 24V is not present Factory Setup Caution Loading the Factory Settings will erase all stored setups as well as the User A Gas Table This procedure cannot be Un done so be certain that you want to do it before starting The Factory Setup is used to set the BGA244 to its initial condition with no user defined setups or User Gas Table It consists of the following steps Recall O Defau
227. unting and gas tubing connections Depending on your application this can be as simple as setting the BGA244 on a bench and connecting flexible tubing or may involve hard mounting the unit and forming metal tubing Be sure to clean out gas lines prior to connecting them to the BGA244 to avoid contamination Refer to Chapter 2 Installation Guide if you have any questions regarding these procedures as improper installation can damage the unit 1 5 Mount the BGA244 as appropriate to your application Connect the gas tubing to the gas ports following the appropriate procedure for the gas fittings Connect either USB power or 24V Option 1 required If using USB power be certain that the USB device and cable are sufficient to power the device Refer to Power page 21 for more information The splash screen and About page should appear as described in Quick Test Configure the BGA244 Note that it may be easier to configure the unit prior to installing it into your system especially if access is restricted See Chapter 3 Operation Guide for more information on each of the following steps a Set the Instrument Mode HOME SETUP INSTRUMENT MODE JJ There are 3 choices Binary Gas Analyzer Gas Purity Analyzer or Physical Measurements Select the Gas es HOME SETUP SELECT GAS Set Gas 1 and Gas 2 for Binary Gas Analyzer mode or set a single Gas for Gas Purity and Physical Measurements modes Press SELECT GAS to o
228. ure and pressure is well known Impurities will change this speed as a function of their mole fraction molar mass and y per the equation described in the Binary Gas Analyzer mode yRT W M The definition of the Gas Purity in the BGA244 is AW _ measured speed of sound expected speed of sound W expected speed of sound Both the expected speed of sound and the measured speed of sound are normalized to NTP 20 C 1 atm before calculating the ratio to eliminate temperature and pressure dependencies Since temperature and pressure affect each gas differently it s important to specify the gas being measured for best accuracy For a detailed description on the science behind the BGA244s operation see the Chapter 8 Theory of Operation The gas purity is most sensitive when contaminants significantly heavier or lighter than the selected gas If the purity measurement AW W is positive the contaminating gas is ordinarily lighter than the selected gas Similarly if AW W is negative the contaminating gas is ordinarily heavier than the selected gas Often a likely contaminating gas is known Air nitrogen CO or a previously purged gas may be an expected contaminate JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Operations Guide 44 Gas Purity Analyzer Home Page Selected Gas Page Identification a Upper Limit Upper Scale FIGURE 16 GAS PURITY ANALYZER HOME PAGE Home Gas
229. ure based on the elevation and ignoring any weather effects should only introduce a small error for devices using gauge pressure units However for best accuracy the ambient pressure should be measured and updated whenever it changes by more than 0 5 psi 3 4 kPa JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Application Guide 99 Operating Conditions Warm Up Time The BGA244 can make measurements immediately after power on The accuracy may improve slightly after warmup due to thermal gradients stabilizing Depending on the operating conditions this can take up to 5 minutes for the internal temperature to completely stabilize There may be a small change in reading during this time depending on the specific measurement The temperature settling when the heaters are on varies on a number of factors including the ambient and set temperatures the maximum heater current gas temperature and flow Examples for several different temperatures and heater current are listed below See Heater page 75 for information on setting the heaters TABLE 19 HEATER SETTLING TIME Initial Temp Final Temp Regulating Response Time The response time of the BGA244 is primarily a function of the gas flow rate required to turn over the volume of the acoustic cell 130 cc The following table shows the step response time for a 100 step in gas species assuming a constant temperature pressure and flow rate At low flow rates changes in
230. vents If the value of the flag is 1 then these two registers are cleared upon power cycle All other status registers are cleared at power on Example PSC 1 Set the Power on Status Clear to 1 PSC Returns the current value of Power on Status Clear Recall Instrument Settings Recall instrument settings from location i The parameter i may range from O to 20 Location O is reserved for the recall of factory default instrument settings Locations 1 to 20 are user configurable Example RCL 3 Recall instruments settings from location 3 Reset the Instrument Reset the instrument to default settings This is equivalent to RCL O It is also equivalent to recalling Setup O Default at Home Setup Store Recall Recall See Default Setup page 66 for a list of the Default settings Example RST Resets the instrument to default settings Save Instrument Settings Save instrument settings to location i The parameter i may range from 1 to 20 Example SAV 3 Save current settings to location 3 Service Request Enable Set query the Service Request Enable register to i Bits set in this register cause the BGA244 to generate a service request when the corresponding bit is set in the STB register Status Byte Query the standard IEEE 488 2 serial poll status byte The bits in the STB register have the following meaning J SRS Stanford Research Systems BGA244 Binary Gas Analyzer Remote Programming 132 Y NOM bh 0
231. very input measurement following the formula Averagen 1 N Measuren 1 1 N Average For signals without large transients the averaged value settles to within 1 of its final value in about 5 N measurements or N 1 14 seconds For the default value of 10 averages the averaged output settles in about 11 4 seconds Large transients may persist in averaged measurements for a long time They may take several times as long to decay as the settling time Similarly any changes in a measurement will only be visible if they last for a sufficient number of samples Press OFF ON to toggle averaging on and off Enter the number of averages between 2 and 100 Relaxation Correction Gases take different amount of times to reach thermodynamic equilibrium between their translational rotational and vibrational degrees of freedom If that amount of time is comparable with an acoustic cycle of the resonant mode a small correction factor is applied to the applied to the heat capacity used to compute the speed of sound This phenomena is most prevalent in pure gases with CO2 being the most egregious example However if even a small amount of a second gas is added the effect largely vanishes See Relaxation Effects page 92 for a list of gases that exhibit this Relaxation Correction should be used if you are measuring relatively pure gases that are highly dispersive It should be turned off if you are measuring mixtures Press OFF
232. w non blended gases being added are almost always polyatomic For most of these gases a0 varies from 3 5 11 Hint If you can t find a value for ay for the gas you are adding use a value from a similar gas Calculating a0 is relative simple for blended gases assuming a0 is available for each species of the blend ag mixes as the mole fraction of the two gases Note that y does not Take the mole fraction of each gas times its value for ag MF1 and MF2 are the mole fractions of each gas a0 blend a0gas1 x MF1 a0gas2 x MF2 Adding Gases Example Adding a Single Species Gas Argon To add a gas at a minimum you need the three previously mentioned items a name molecular weight and ao For this example we will add a simple model for Argon to the User Gas Table Name Argon Molecular Weight 39 95 q 2 5 Argon is monatomic Example Adding a Blended Gas Air Blended gases are made up from two or more single species gases The molecular weight and a must be calculated based on the ratio of the gases in the blend The most familiar blended gas is air As a commercial product air is usually considered to be 79 Nitrogen and 21 Oxygen To find the molecular weight of the gas take the mole fraction of each gas times its weight Gas Mol Fraction Mol Weight Fraction Weight 28 02 22 14 sum 8B JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Application Guide 116 Note that t
233. ware See Updating Firmware in Chapter 5 BGAMon for details on this procedure JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Operations Guide 90 JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Application Guide 91 Gases Chapter 4 Application Guide This section provides information on using the BGA244 It includes details on gases pressure operating conditions measurements high purity use and adding User gases The BGA244 determines the concentration and purity for a wide variety of gases It does this by measuring the speed of sound and temperature and then determines the mixture ratio or gas purity using the physical properties of the gases The fastest speed of sound that can be measured is 1400 m s the speed of sound for hydrogen 2 amu The slowest is less than 130 m s the speed of sound for SF 146 amu This range covers nearly all compounds that are gaseous within the operating temperature and pressure range of the BGA244 Gas Requirements Gases must be clean and dry This means they cannot contain any solid or liquid particulates Gases that contain solid particulates must be filtered before entering the BGA244 It may be necessary to operate the BGA244 at an elevated temperature to ensure there are no liquid particulates in the gas stream Gases must be non condensing and contain no liquid particulates at the temperature and pressure the BGA244 is operating If a gas is nearing it
234. wever to meet its specified accuracy for all gases the BGA244 must know the gas pressure to within 1 psi 6 9 kPa See the Applications Guide for information on the effects of pressure on measurement accuracy Pressure is the only external parameter that needs to be input to the BGA244 besides the gas species It can be directly entered using the keypad or computer interface Ora pressure transducer can be integrated with the BGA244 using one of the analog inputs units with Option 1 Direct entry of the pressure is well suited for processes that operate at a fairly constant known pressure Typically the pressure is known by the system design or by monitoring an external gauge This is the only method available for units that do not have Option 1 Other processes may experience pressure variations over time or operating conditions These applications will benefit from integrating a pressure transducer using one of the BGA244 s analog inputs This provides a simple integrated solution to provide the best accuracy across a range of operating conditions Using an external pressure transducer requires the Industrial Control Interface Option 1 and 24V SRS offers a pressure transducer that is suitable for many applications Accessory BGA T but there are many other transducers available Refer to Pressure Transducers page 31 for information on connecting a pressure transducer to the BGA244 Gauge Pressure vs Absolute Pressure The BGA24
235. what the pressure would be at those points Example Your pressure transducer outputs 0 5 Vp for O 50 psi Set the following Min OV Max 10V 0 00 psi 100 00 psi JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Operations Guide 63 r Input 1 Configure Input Enable the Analog Input Press CONFIG INPUT to open the ENABLED Configure Analog Input page Press lt Type J gt to select the appropriate input type Voltage Current and Current w Loop Power The currently select method is highlighted in 6 000 V yellow Certain pressure transducers can operate using loop power provided by the BGA244 This is the simplest type of transducer to integrate since it only requires 2 wires See Analog Inputs page 78 for details on different input types If Current with Loop Power is selected enter the appropriate loop power supply voltage Current w Lp Pwr An improperly configured analog input broken pressure transducer or wiring can lead to out of range pressure readings If this occurs a BAD PRESSURE screen message will appear in place of the measurement and no results will be reported There are also several alerts that can occur for the analog inputs These normally indicate a problem with the device connected to the Analog Input or wiring rather than the input itself See Analog Inputs page 78 for details Input Type Pressure Meter There are pressure meter pages associated
236. with each ASE analog input when it s configured as a pressure gauge Press METER on either the Pressure Gauge Setup or Configure Pressure Meter pages to view the pressure meter associated with that input If an analog Input IS not configured as a pressure gauge that selection will be grayed out PHONE The Pressure Gauges each have a meter scale and limits similar to the Home page displays Press METER SCALE to set the graph scale and LIMITS to set the Pressure Limit values These are the over and under pressure limit values used on the Event Relay page JSRS Stanford Research Systems BGA244 Binary Gas Analyzer Operations Guide 64 Temperature The cell temperature can also be displayed ona meter with limits and a scale Press TEMP from the a Setup page to view the temperature meter METER The Temperature Gauge has a meter scale and limits CALE similar to the Home page displays Press METER SCALE to set the gauge scale and LIMITS to set the Temperature Limit values These are the over and HOME under values limit used on the Event Relay page Store Recall r Store Recall The BGA244 can save and recall up to 20 different setups Each setup contains all parameters that can be set on the STORE BGA244 including the instrument mode gas selection display setup and I O parameters Stored setups can be given hecat an alpha numeric name making it easy to identify details ERASE about each s

User`s Manual - Stanford Research Systems

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