Teledyne Vacuum Gauge 2002 User's Manual
Contents
1. 2 5 2 4 2 3 2 2 2 2 4 5 i 2 0 4 0 2 3 4 5 6 7 8 9 10 X 10 Torr 0 5 VDC Linear D ecade 3 5 3 0 2 5 a gt 20 1 5 1 0 0 5 0 0 1 0 5 1 0 4 1 0E 3 1 0E 2 1 0 1 1 0E 0 1 0E 1 1 0E 2 1 0E 3 Pressure Torr M ODEL 2002 Analog Output Figure 4 1 VDC volts vs Pressure Torr 4 3 TTL Outputs TTL outputs are provided for process control High and L ow set points are entered on the front panel see Section 3 4 and T T L signals are generated on the I O cable in the following manner 1 When the pressure as indicated by the M 2002 is above the H igh set point the High signal line 3 will beset to aT T L high level 5V When the indicated pressure is below the H igh set point the High signal line pin 3 will be set to aT T L low level 0V D 2 When the pressure as indicated by the M odel 2002 is below the L ow set point the L ow signal line pin 4 will be set to aT T L high level 5V DC When the indicated pressure is above the L ow set point the L ow signal line pin 4 will be to aT T L low level 0VDC T heseT T L signals are used for a variety of applications W ith these signals the user has the capability to turn off on various equipment such as valves flow controllers pumps heaters and safety equipment Model 2002 19 4 4 Power Entry Module T heAC power for the odel 2002 enters the instrument through a power en2. eene October 2005 Visit www teledyne hi com for WEEE disposal guidance N CAUTION Refer to accompanying documents N CAUTION If equipment is not used in the manner specified by this manual protection provided by the equipment may be impaired Hastings Instruments reserves the right to change or modify the design of its equipment without any obligation to provide notification of change or intent to change M odel 2002 Table of Contents 1 0 GENERAL INFORMATION u 5 1 1 uu aR hua re 5 1 2 Model 2002 SON SONS citri e cach E EAR REDE E ER 5 1 3 M del 2002 Control Unit eterno et ert ria e A 6 1 4 SPECI CAL ONS sn ee uama eI EVE te ade ee 6 2 0 INSTALLATION ee 7 2 1 ases 7 2 2 QUICK Stats reihen 7 2 3 Transducer Installation 8 2 4 Control anne en 8 2 5 O uu 8 3 0 FRONT PANEL OPERATION use 9 3 1 Overall Functional D scriptlon asni EEE Ka A 9 3 2 RUN ceno en fra ou E ERR E 10 3 3 Eland LOW Set PolntM Od6s rossi ee ae can 11 3 4 CAL Mode a D ER eh rr dot orsi cons Bae Dn ree ari ummm ER EA 11 3 5 G AS OB RE E 14 3 6 Ode 5 u 15 4 0 REAR PANEL DESCRIPTION I 17 4 1 Remote Zero
3. 17 4 2 Analog OULD UL uuu as 17 4 3 TTE OUMU EE 19 4 4 Power Enty Modules een a ruta UR e 20 5 0 THEORY OF OPERATION sine 21 5 1 PiezoresistiVe Sensor 22 5 2 Pirani Sensor 24 5 3 D val Sensor Operation ar c a EC ta neo atin ion 26 6 0 COMMUNICATIONS OPTION BOARD 29 6 1 R S 232 E Interface Specifications aana enne nnne nenas 29 6 2 RS 232 Interface Connector Pin Assignments sss eee eee 29 6 2 1 RS 485 Interface C onnector Pin Assignments ssssssse e 30 6 3 Operation of the Serial 1 nennen ene nennen nenas 30 M odel 2002 odel 2002 7 0 RELAY INTERFACE OPTION 4 4 35 7 1 Relay Board Specifications sse 35 7 2 Relay Connector Pin 510 35 7 3 OP CHALOM sis sua EE 36 8 0 4 20mA INTERFACE OPTION BOARD 37 8 1 4 20 mA Interface Connector Pin Assignments sss 37 8 2 Operation ucc one ose dede e a ne e P d d e d c n 38 9 0 0 10 Volt INT naeh nhu 39 9 1 0 10 Volt Interface C onnector Pin ssignment
4. Corrosion resistant 1 2 Model 2002 Sensors The Model 2002 transducer is comprised of an ion implanted piezoresistive direct force sensor and thin film Pirani type sensor T he Pirani sensing element is a Pt thin film serpentine element see Figure 5 3a deposited on a 1 micron thick Si N membrane T he membrane is peripherally supported by a Si box shaped die and is covered by a thick Si lid parallel to the membrane and open on two ends see Figure 5 3b T he piezoresistive unit is an ion implanted W heatstone bridge in a 50 micron thick Si membrane peripherally supported by a Si box shaped die which has been anodically bonded to a substrate T he dual sensor assembly is encased in a corrosion resistant 316 stainless steel tube shell T he durable tube design withstands high pressure 150 psig 10 2 bar and high pressure surges Since the Pirani sensor is miniaturized and employs a Pt thin film on a Si N membrane instead of a conventional long fragile wire the transducer can withstand high levels of mechanical shock T he M odel 2002 is designed for fast response T he micromachined sensing elements have a very small mass and operate in a constant temperature Pirani and a constant current piezo feed back mode T his makes response time very fast as compared to other commercially available sensors which have to change the temperature of a significant mass to reflect pressure changes and have a large internal volume wh
5. If a reference high pressure gauge is not available the ambient barometric pressure acquired from the weather channel or other weather service can be used to adjust the proper reading To adjust the atmosphere coefficient use the following procedure 1 Press the M ODE switch a sufficient number of times to enter the CAL mode 2 Simultaneously press both the UP and DOWN switches to bypass the interlock T he CAL light will start to flash signaling that the calibration can now be conducted 3 Press hold and release either of the UP and DOWN switches as necessary to adjust the display to match the pressure indicated by the reference N ote It may be neces sary to hold the desired switch down for a few seconds before any movement is seen 4 Pressand release the M ODE switch as necessary to return the M odel 2002 to the RUN mode and store the coefficients to permanent memory 3 5 GAS Mode page 14 M odel 2002 T he M odel 2002 can provide true pressure measurements in many gas environments At pressure levels above 32Torr where the direct force piezoresistive sensor is operative the instrument is gas composition insensitive and measures the true pressure regardless of gas composition T he Pirani is gas composition sensitive so below 32 Torr the actual composition must be known and the Pirani calibrated in that gas W hen the vacuum system s gas composition is dominated by a single gas species for example during system venting wit
6. TELEDYNE HASTINGS INSTRUMENTS MODEL 2002 VACUUM GAUGE 50 9001 10192 01 4 3 TELEDYNE INSTRUMENTS AN Acc redited by the Dutch H a stin g 5 I nstruments for Accreditation A Teledyne Technologies Company on Board AB 20 Manud Print History T he print history shown below lists the printing dates of all revisions and addenda created for this manual T he revision level letter increases alphabetically as the manual undergoes subse quent updates A ddenda which are released between revisions contain important change information that the user should incorporate immediately into the manual Addenda are num bered sequentially W hen a new revision is created all addenda associated with the previous revision of the manual are incorporated into the new revision of the manual Each new revision includes a revised copy of this print history page Revision A Document N umber 149 0798 sseemHe eee September 1998 Revision B Document N Umber 149 032000 M arch 2000 Revision Document N umber 149 052002 M ay 2002 Revision D Document N umber 149 102002 _ October 2002 Revision E Document N umber 149 062004 2 2 004000 40000 June 2004 Revision F Document N umber 149 082005 mme A ugust 2005 Revision F Document N umber 149 102005
7. EEPROM Calibration Restoration T hereare interlocks built into the CAL modeto minimize the chance of accidental alteration of the calibration coefficients but if calibration alteration does occur the EEPROM calibration data can be restored in the RUN mode by pressing the U P and DOWN switches simultaneously RUN light will flash then press the ZERO switch UP and DOWN switches all three simultaneously T his will not correct the calibration if the tube has become contaminated or damaged T his reset will not affect the gas selection units or setpoints Also see units mode for default calibration restoration 3 3 HIGH and LOW Set Point Modes T he 2002 providesT T L outputs for process control T he 1 0 cable is attached via 9 pin sub D connector to the rear panel of the control unit T he pinout is shown in Figure 4 2 To view the high set point place the M odel 2002 in theHIGH mode by pressing the M ODE switch to illuminate the HIGH light and no other mode light T he display will show the set point selected D uring normal operation the alarm light will illuminate and theT T L output pin 3 will go high 45V if the pressure exceeds the set point Similarly to view the low set point access LOW mode by pressing the mode switch until the LOW light is lit and no other mode light is illuminated D uring normal operation the LOW light will illuminate and the L OW alarm T T L output pin 4 will go high 5 V if the
8. T herelay contacts are rated for a maximum switching current of 250VA resistive load Connec tion to the relay contacts is made via connector mounted through the rear panel of the M odel 2002 Screw terminals on the mating connector are designed for wire from 28 AWG through 14 AWG 7 1 Relay Board Specifications Each relay board consists of 2 Form C SPDT relays with the contacts wired in parallel M ax switching power 120W 250VA 2A 125VAC 1A 250VAC ax switching voltage 220VDC 250VAC ax switching current 4A DC AC carrying 6A DC AC UL CSA rating 1 2 125 1 2 110VDC 4 0 30VD C Connector for Digital Analog option or dummy connector if no option HIGH SETPOINT is installed RELAY CONNECTOR COMMON NC NO LOW SETPOINT RELAY CONNECTOR COMMON NO Figure 7 1 M odel 2002 35 7 2 Connector Pin Assignment 7 3 Operation page 36 2002 SECTION 8 4 20 mA Interface ption Board T he Relay option board in the M odel 2002 operates off of the setpoints defined by the us
9. pressure is displayed in scientific notation T he analog to digital converter speed can be adjusted and the factory calibration can also be restored in this mode See Section 3 2 for further information HIGH High set point is displayed in scientific notation above this pressure the HIGH TTL output will be 5 LOW L ow set point is displayed in scientific notation below this pressuretheLOW TTL output will be 5V CAL Pressure is displayed and can be adjusted GAS G as number is displayed and selection may be changed UNITS Units used to display pressure are selected In theRUN HIGH and LOW modes it is possible to see the display indicate that the data is out of range verrange is indicated by 3 33x10 Underrange is indicated by 0 0 x10 mea sured pressure below 1x10 Torr is indicated by 0 0 x10 In the case of an unconnected or faulty sensor s itis possible to see LI LI LI See trouble shooting section section 8 for more detail HASTINGS INSTRUMENTS DUAL SENSOR VACUUM GAUGE MODEL 2002 Model 2002 Control Unit Front Panel UP SWITCH UNITS RUN HIGH GAS CAL LOW MODE ZERO DOWN SWITCH MODE SWITCH ZERO SWITCH Figure 3 1 odel 2002 page9 All six modes of the odel 2002 have features which can accessed and modified after bypassing the front panel interlock T he interlock is in place to prevent the accidental corruption of the instrument s confi
10. A common application of the RS232 version of the HPM 2002 is to connect the pressure gauge directly to the serial port of a PC T his is done by first wiring a communication cable in the 2 E Z s Carrier Detect O 6 V 26 Received Data O 1 Transmitted Data S Clear to O Send Data Terminal Ready 2 a Signal Ground 2 E Figure 6 1 9 Pin Female D Connector 9 Pin Female D Connector Connect to PC Laptop Connects to 2002 RS232 Option Board manner shown below Transmit D ata Transmits data within RS 232 E voltage levels Receive D ata Accepts data within RS 232 E voltage levels Signal Ground Establishes the common ground reference potential for all interchange circuits communicating via RS Clear to send H ost computer ready to accept data Reserved for future use not implemented by present software Ready Ready to receive data always high not Model 2002 page 29 6 2 1 Interface Connector Pin Assignments for RS 485 full duplex 4 wire jumper position 2 3 E MNEMONIC SIGNAL DESCRIPTION Transmit ifferential data nal levels to Transmit he 5 485 bus Receive ifferential data penal levels from the RS 85 bus 6 2 2 For RS 485 Half Duplex 2 wire jumper position 1 2 SIGNAL DESCRIPTION 2 Transmit Receive ifferential data nal levels to and fro
11. SMT C36 18 01 424 RES 200 1 8W 5 1206 17 01 066 INDUCT 100uH 80mA 5 1210 16 51 004 10 X 2 SHROUDED CONN MALE TERM STRIP 025 SQ 36 PINS 16 05 045 CONN 9 PIN FEMALE 16 05 044 CONN 9 MALE 13 01 110 DIODE 1N914 11 08 128 CAP 0 1 uF SMT 1206 C1 C3 C6 C12 C14 C17 C18 C21 C24 C35 C38 C39 11 03 111A 35V TANTALUM C23 11 03 176 CAP 25V TANTALUM SMT 1206 11 03 144A 22uF 25V TANTALUM REF DWG NO PARTS LIST IND ND IND Gal Gul Got Os CN N Ci In KO jO IN O1 O d 1 mo SIN 88 4 zo oo 9 o M odel 2002 51 12V C4 gt lt 25 I O Cable 12 100 C27 C33 O luF AUX BOARD INTERCONNECT page52 M odel 2002 Sensor Tube Cable 100 12V TP1 C22 220pF C13 1uF C14 0 1 TP2 M odel 2002 53 2 1UF 35V 5 d PII lel t 010 1 54 M odel 2002 M 3009 SZ 100 pf C15 5 lt SM ki n 9 h cem ACL
12. coefficient in the CAL mode T hereare three calibration coefficients T hese are the zero coefficient the midrange coefficient and the atmosphere coefficient O nce a tube has been fully calibrated the midrange coefficient should never need further adjustment but it may be helpful to adjust the zero coefficient or the atmosphere coefficient under certain situations Even though the operator inputs may be identical for adjustment of all three coefficients microprocessor will detect odel 2002 page 11 the power level of tube and adjust the proper coefficient for pressure level of the adjustment TheCAL MODE presupposes that the operator is applying a known pressure of the correct gas composition seeGAS M ODE T hefactory calibration points are 800 Torr 7 Torr and 1e 6 Torr T heusers calibration points are not required to be exactly those values but should be somewhat close and must be within the ranges shown in the following figure T he H PM 2002 detects the voltage signal within the sensor tube which is converted and displayed as a pressure reading T he resulting pressure reading determines which of the three coefficients will be ad justed DISPLAYED PRESSURE ADJUSTMENT VALUE FUNCTION 1024 Torr UP DOWN 512 Torr PIEZO ADJUSTMENTS SENSITIVITY ADJUSTMENT 256 Torr DO NOT ADJUST WITHIN THIS RANGE 8 Torr UP DOWN 1 Torr PIRANI ADJUSTMENTS SENSITIVITY ADJUST
13. fuse holder insert the spare fuse into the fuse clamp d Reassemble the power inlet assembly by reversing the above directions e Check the power supply for proper operation 4 Check the AC PC B connection a Removethe front panel by removing the bezel and four phillips head Disconnect AC power prior to removal of the front panel b Slide the display board and the main out of the case C Verify that the white AC connector is firmly seated over all five pins of P 4 5 Check the display board connection a Verify that the 13 pin SIP connector is firmly seated over all 13 pins of P3 and that the red strip is towards the rear of the case b Verify that the 5 pin ribbon connector is firmly seated over all 5 pins of P2 and that the silver side is toward the case 6 Consult the factory Rapidly running random digits on display 1 Consultthe factory Display shows decimal point and minus sign only 1 Check microprocessor a Removethe front panel b Verify that the microprocessor is properly seated in the chip carrier 2 Consult the factory M odel 2002 page41 page 42 2002 SECTION 11 W arranty and Repair 1L1Werranty Repair Policy Hastings Instruments warrants this product for a period of one year from the date of shipment to be free from defects in material and workmanship T his warranty does not apply to defects or failures resulting from unauthorized modification misuse or mishandling of
14. is no change in sensor output with pressure since all of the losses are constants with pressure In the molecular flow regime where gt 1 the thermal conductivity of the gas becomes directly proportional to the gas pressure as shown below We can expect then that E will be constant at high pressures and directly proportional to the pressure at low pressures T he energy loss changes between these two controlling equations as the system passes through the transition region 0 01 Kn 1 aL 273 T T T A P Where a accomodation coefficient L free molecule thermal conductivity T temperature of heated membrane T ambienttemperature P pressure A surface area of the heated portion of the membrane For nitrogen at a pressure of 760 Torr and a temperature of 20 C the mean free path A is less than 1 x 10 7 meters and is inversely proportional to pressure Since the thermal transfer distance Ax is a few micrometers this sensor will remain in the molecular flow regime at a much higher pressure 10 Torr than is typical for a thermal vacuum gauge T his extends the linear response part of the output curve up into the 1 Torr range T he nonlinear transition region will extend up to 1000 Torr 5 3 Dual Sensor Operation page 26 2002 T he microprocessor in the control unit continuously monitors the outputs of both the piezoresistive sensor and the Pirani sensor Figure 5 4 shows representations of
15. mTorr mTorr Conversions 1 mTorr 1 00 x 10 Torr 10 mTorr 1 00 x 102Torr 100 mTorr 1 00 x 10 Torr Table 2 gives conversion factors for the most often used pressure units TABLE 2 Torr atm mbar Pa psi Torr mm Hg 1 1 32x103 1 3332 133 32 1 934x102 mT orr micron H g 103 1 32 10 0 00133 13332 1 934x10 5 atm athmosphere 760 1 1013 23 1 013x10 14 7 mbar millibar 0 75 9 869 10 4 1 100 1 45x10 Pa 7 5 10 3 9 869 10 6 0 01 1 1 45x10 psi Ib in 51 72 6 805x10 68 953 6895 3 1 D efault Calibration Restoration TheUNIT S mode is also used to load default calibration data in rare cases where the transducer EEPROM has become corrupted T he default calibration data should be considered an approxi mate calibration because the values entered in the controller s software are based on averaged data collected over a large number of transducers W hile this type of calibration download is not a true calibration it does allow the user to return the unit to a reasonable status from which a full calibration can be easily performed M odel 2002 15 This was intentionally left blank page16 Model 2002 SECTION 4 Rear Panel D escription schematic of the rear panel of the M odel 2002 control unit is shown in Figure 4 2 Rear Panel Figure T hetransducer is connected to the control unit via an female 9 pin connector on the rear panel
16. output currents for a given pressure 16mA I Channel 1 4 mA P Torr ils 16mA I Channel 2 4 mA P mTorr 192222 Note that for both channels the output is always between 4mA and 20mA Specifically when the pressure is below 1 Torr channel 1 current will be approaching 4mA Also when the pressure is above 1 channel 2 current will be saturated at 20mA Internal loop power out 1 9 Loop in mE 3 lt lt Internal loop power out 8 e 9 Loop in m c 7 lt 19 Figure 8 2 SECTION 9 0 10V Interface ption Board T he 0 10V interface board is available as an option for the M odel 2002 T his board provides dual voltage channels linearly proportional to the H PM 2002 s pressure reading Please note that use of the M odel 2002 with this option requires a CPU with firmware version 1 6 or later for proper operation LOW SETPOINT OPTION BOARD HIGH SETPOINT RELAY CONNECTOR MALE RELAY TRANSDUCER CONN STANDARD FEMALE IO CONNECTOR Figure 9 1 9 1 0 10 Interface Connector Pin Assignmets Pin Connection Channel 1 Output 4 Channel 1 Shield A nalog C ommon Channel 1 Output Channel 2 Output Channel 2 Output W N Channel 2 Shield A nalog C ommon Both output channels are true differential and are short circuit protected with 100 Q output impedence W hile this allows either side of the output channel to
17. take affect the data to settle 5 Theunitis now fully zeroed Place the M odel 2002 back in the RUN mode to store the zero in permanent memory M idrange Coefficient Adjustment T he midrange coefficient corrects for errors in the slope of the power curve of thethin film Pirani Typically this is due to the geometry of a particular sensor and will only need to be performed once in the lifetime of the sensor T his adjustment might be needed if a full calibration is being performed in a gas other than nitrogen T he zero adjustment will need to be performed before making this adjustment To adjust the midrange coefficient use the following procedure 1 Evacuate the vacuum chamber and refill with the desired gas to a pressure of 7 Torr as indicated by a reference vacuum gauge 2 Pressthe M ODE switch repeatedly until the CAL mode is illuminated 3 Simultaneously press both the UP and DOWN switches T he CAL light will start to flash signalling that the calibration can now be conducted 4 hold and release the UP DOWN switches as necessary to adjust the display to match the pressure indicated by the reference ote It may be necessary to hold the desired switch down for afew seconds before any movement is seen M 2002 page 13 5 release the ODE switch as necessary to return the 2002 to the RUN mode and storethe coefficients to permanent memory Atmosphere Coefficient Adjustment
18. the sensors output over the pressure range from 10 Torr to 10 Torr T he microprocessor uses the output of the piezoresistive sensor at high pressures gt 32 Torr and usesthe output of the Pirani sensor at low pressures 8 Torr In the crossover region a software averaging algorithm ensures a smooth transition between the two sensors Zeroed Sensor Output Arbitrary Units Model 2002 Dual Sensor Vacuum Gauge 1 0E 03 1 0E 02 1 0E 01 1 0E 00 1 0E 01 1 0E 02 1 0E 03 1 0E 04 1 0E 05 1 0E 05 1 0E 04 1 0E 03 1 0E 02 1 0E 01 1 0E 00 1 0E 01 1 0E 02 1 0E 03 Pressure Torr Figure 5 4 Model 2002 page 27 This was intentionally left blank page28 Model 2002 SECTION 6 Communications ption Board Both RS 232 and 5 485 communication interface boards are available as an option for the odel 2002 T he communication option boards allow data to be output to a host computer with the appropiate interface Connection to the RS 232 or RS 485 communication interface boards are via a 9 pin D subminiature female connector 61 RS 232 E Interface Specifications Formal iste ads EIA standard S 232 E full duplex no handshaking asynchronous Data Rate EET 9600 baud Character Length amittit ennt Eight data bits nones o teret Cn T Oe e rr co parity DIES iet e dta es ers One stop bit
19. unit 250V 1 4 A Transducer MOUNTING uu Any position without recalibration Transducer internal volume asse inue Verc rc an coe dn rr na a s 1 5cc Wetted matetlal zuerst tree Ted Chr tette Au Si N Si Pt Pyrex ovar and 316 stainless steel Stability with voltage nenne na Variation in reading undetectable as power fluctuates within power specification Weight display cable and sensor oo eee 2 Net 2 5 Ibs Shipping 3 4 Ibs Transducer response time T ypically less than 150 msec for a step change from 10 Torr to 10 Torr Positive PRESSURE 150 psig Recalibration may be required if unit is exposed to pressures greatly exceeding measuring range page6 odel 2002 SECTION 2 nstallation T his section is designed to assist in getting a new pressure gauge into operation as quickly and easily as possible Please read the following instructions thoroughly before installing the instru ment 2 1 Receiving Inspection Carefully unpack astings M 2002 Instrument part 2002 transducer part H PM 20025 and cable part CB 2002 Inspect all items for any obvious signs of damage due to shipment Immediately advise the carrier who delivered the shipment if any damage is suspected Compare each component shipped against the packing list Ensure that all pa
20. 1 0 VDC EXP 6 MANT 1 2 t mg T he analog output voltage is given by the following equation W here EXP is equal to the exponent of the displayed pressure EXP 2 2 MANT 1 53 y E245 153 1 2 t g 2 0 0294 2 0294VDC example p 1 53 x 10 EXP 2 9 87 0240 08 mts Ue T a 4 0 4928 4 4928VDC 2002 page 17 If the analog output voltage is being used data aquisition system the following formulas can be used to calculate pressure EXP INT 2 V 6 MANT 1 18 V 9 EXP 9 Pressure T orr M ant x 10 T herefore N ote that the IN T function simply returns to the first digit in a number examples INT 2 56 22 INT 9 87 2 9 Voltage to pressure conversion example Given V 2 35 Volt First calculate the exponent EXP INT 2 2 35 6 INT 47 6 NT 4 6 2 N ext calculate the mantissa MANT 1 18 V 9 EXP 6 1 18 2 35 9 246 1 42 3 36 7 3 Finally the pressure is given Pressure torr MANT x 10 7 3 10 2 Torr 18 Model 2002
21. A D speed will respond to sudden pressure changes faster While in the RUN mode the user can adjust the A D speed of operation At start up the instrument will be operating with an A D frequency of about 60 H z T he speed can be adjusted one step faster or slower Each step will increase or decrease the A D frequency by a factor of two To adjust theA D speed press the M ODE switch until theRUN light is illuminated T hen simulta neously press the U P and DOWN switches T heRUN light will now flash indicating that the interlock has been bypassed and the A D speed can be adjusted Push the U P switch to speed up the A D converter one step and decrease the response time T his will result in a faster triggering of alarms or relays if a sudden catastrophic failure occurs Pressing the switch after the limit is reached has no effect Pushing the down switch will slow down the A D converter and increase its accuracy T his will improve the ability to resolvelow pressure readings If a certain speed is desired press the UP or DOWN switch three times and then press the other switch to select the other speed On older units T here will be no indication of the operating speed other than the least significant digits of the display will tend to run at higher speeds On units with software version 1 60 and page 10 M odel 2002 above press the ZERO switch to display the decimation ratio filtering T he larger the ratio the longer the response time
22. A number before returning any product repair TELEDYNE HASTINGS INSTRUMENTS 804 NEWCOMBE AVENUE HAMPTON VIRGINIA 23669 U S A ATTENTION REPAIR DEPARTMENT TELEPHONE 757 723 6531 1 800 950 2468 FAX 757 723 3925 E MAIL hastings instruments teledyne com INTERNET ADDRESS http www hastings inst com Repair Forms may be obtained from the Information R equest section of the H astings Instruments web site M odel 2002 43 This was intentionally left blank page44 Model 2002 SECTION 11 D iagrams and D rawings M odel 2002 45 2 35 59 7mm m T 1 20 30 5mm 11 E 1 20 diameter dimension of tube shell is typical on all H PM 2002 series tubes M ini Conflat HPM 2002 03 x 2 30 58 4mm u KF 16 HPM 2002 05 x 2 30 58 4mm KF 25 HPM 2002 06 Tube Outline D rawings all dimensions shown are approximate page46 M odel 2002 dr 1 8 NPT HPM 2002 01 cu 1 2 O D Smooth Tube 2002 07 1 4 VCR HPM 2002 02 2 57 65 3mm gt pos 2 3 4 Conflat H PM 2002 04 Tube Outline D rawings all dimensions shown are approximate M odel 2002 page 47 3 54 nn 90mm gt 5 6 75 171 X V 2 2002 line D 3 62 92mm 3 62 92mm Panel Cut Out D ime
23. An I O cable can be connected via a male 9 pin D connector on the rear panel T hel O cable provides an analog output signal a remote zero input capability high and low alarm T T L outputs and a 5bVDC Power Supply Output T he I O cable also provides an analog ground and a digital common 4 1 Remote Zero Input T he M 2002 can be zeroed remotely via the 1 0 cable using the remote zero input line Upon setting thislinetoT T L low level the instrument will set its current pressure reading to zero A common applica tion of this feature is to utilize a process control output from a high vacuum gauge for example an ion gauge controller to automatically zero the M odel 2002 whenever the pressure is below thelow 10 Torr range A D igital Common is provided on pin 5 which can be used with relay contacts or switch contacts to remotely zero the instrument 4 2 AnalogOutput T he M odel 2002 provides an analog voltage output signal 0 5 VD C linear per decade for process control and for pressure monitoring A plot of the analog output signal as a function of pressure is shown in Figure 4 1 N ote that the output voltage is directly proportional to the pressure over each complete decade see detailed region in Figure 4 1 and that each decade has a different linear slope A bove an indicated pressure of 10 Torr the analog output signal will be 5 VD C Below the minimal displayable pressure of 1 x 10 4 Torr the analog output will be
24. MENT 0 5 Torr DO NOT ADJUST WITHIN THIS RANGE 0 125 orr ADJUSTMENTS 0 0625 Torr PIRANI ZERO ADJUSTMENT UP DOWN 0 0 Torr To adjust a calibration coefficient press the M O D E switch until the CAL light is illuminated T hen simultaneously press the UP and DOWN switch T he CAL light will now flash indicating that the interlock has been bypassed and the calibration can be adjusted Press and hold the U P switch to increase the displayed value or the DOWN switch to decrease the displayed value If the switch is held down for an extended period of time the adjustment rate will start to increase Release the switch and then press and hold again to regain finer control of the displayed number An important point to be noted is the fact that after the adjustment the new calibration coeffi cient is only in temporary memory If the instrument were unplugged at this point it would revert page 12 Model 2002 back to the original displayed value upon restarting Place the 2002 back the RUN mode to store all of the current calibration coefficients in permanent memory To perform a full calibration on the M odel 2002 system first use the Zero Coefficient A djust ment Procedure Followed by the M idrange Coefficient Adjustment Procedure and finally perform the Atmosphere C oefficient Adjustment Procedure Zero Coefficient Adjustment T hezero coefficient corrects for the constant power level which is p
25. Present Pressure As Instrument ZERO if Piezo lt 32Torr amp Pirani lt 50 mTorr Force Zero lt CR gt Override L imit ChecksAnd Store Present PressureAs Instrument ZERO odel 2002 page 33 Device Status page34 Model 2002 When requested to transmit its status the M odel 2002 responds with a five digit number which is explained in the following digit 1 2 3 4 5 Serial R eceiver O verflow 4 Main Board EEPROM Error 2 ProbeEEPROM any Error 1 Probe EEPROM Not Responding 8 Probe EEPROM Read Error 1 Probe EEPROM Checksum Error 4 Probe EEPROM Verification Error 2 ProbeEEPROM Identification Error 1 Communications Syntax Error 4 Piezo Sensor Bad voltage out of range 2 Pirani Sensor Bad voltage out of range 1 High Setpoint Alarm pressure exceeds setpoint 4 Low Setpoint Alarm pressure less than setpoint 2 5 C hanged not the same as when unit last calibrated 1 SECTION 7 Relay Interface ption Board T he relay interface board is available as an option for the odel 2002 Additionally relays may be added to either the D igital option Board RS 232 or RS 485 or to theAnalog option Board 0 10 Volts or 4 20mA In either case the relays operate independently of the other options T he relay board allows theT T L logic setpoints High L ow to directly control two SPD T relays W henever the setpoint indicator light in the front panel is lit the corresponding relay is energized
26. T dd lt CR gt OTo 255 D ecimal N otes T he setpoints may also be entered as a decimal number e g H 2760 99 CR gt will be same as entering H 27 6099E 2 lt CR gt When inputting setpoint data it should be entered in the same Units of Pressure as the presently selected U nits of M easurement i e Torr mbar or Pascal T he data is only checked to be a valid number with a one digit exponent before being accepted T here are no limit checks on the data the user is free to choose any value appropriate to his use of the instrument T heT urnaround Delay and R S 485 address are unique to multipoint communications In order to prevent inadvertent modifications of these parameters the multipoint attention character and the M odel 2002 s present address aa UST be used and are checked for validity before the command is executed If the RS 485 address is unknown the UNIVERSAL ADDRESS 00 may be used to set the address to a known value e g 00 235 CR gt will change the R S 485 address to 35 Caution Since all units will respond to the UNIVERSAL ADDRESS make surethat only the unit to be modified is connected to the R S 485 Bus If more than one unit is connected this will result in all of the units being set to the same address T he value entered for the Turnaround D elay is used to modify an internal timer which normally runs at 8 millisecond e g aa T 10 lt CR gt will set the delay to 80 millisec
27. be grounded best results will be obtained by using a differential input measurement system T he output can be modified for single ended use if necessary contact the factory for details M odel 2002 page 39 40 2002 T he 0 10V output option board provides voltage outputs proportional to the H PM 2002 pressure reading T he first channel corresponds to the higher pressure range 0 1024 Torr T he second channel corrresponds to the lower pressure range 0 1000mTorr T he equation below gives the output voltage for a given pressure V channel 1 V channa 2 PmTorn Where V channel 1 is the voltgage between pins 1 and 3 V channel 2 is the voltgage between pins 8 and 7 P isthe indicated pressure Troubleshooting Guide Symptom Action ment the remove body and screws Symptom Action Symptom Action SECTION 10 Power on display activity 1 Check for proper AC voltage at the outlet 2 Ensure that the power cord connectors are firmly seated in their sockets at the outlet and at the instrument 3 Check the fuse Removethe power cord from the IE C 320 socket on the back of the instru b Pry the fuse holder out of the socket assembly by using a screwdriver in small slot inside the IE C 320 socket c Check the fuse that is in the fuse clamp If it is found to be defective it from the clamp Press the spare fuse case out of the
28. cts errors introduced by resistance changes since the sensor resistance is no longer part of the power equation A signal proportional to the power is obtained by multiplying the voltage across the heated sensor and the voltage impressed by the direct current across a constant series resistance T he power supplied to the sensor resistor must equal the heat dissipated T he three main heat loss routes from the heated sensor are thermal conduction through the silicon nitride membrane to the silicon substrate E radiation losses and thermal conduction through the gas to the silicon substrate E thus as shown in Figure 5 3c E E E E T he first term E is dependent on the thermal conductivity of the silicon nitride the tem perature difference AT between the heater and silicon substrate and geometric factors amp L E is given by AT A L 15 the membrane cross sectional area through which the heat transfer occurs T his is approxi mately the outer circumference of the membrane multiplied the membrane thickness L isthe distance from the edge of Rs the heated sensor resistor to the silicon substrate For any particular sensor all of the factors except AT are constants dependent on its construc tion T heAT is held constant by the control circuit T he thermal loss through the silicon nitride will be a constant value independent of the thermal conductivity and pressure of the ga
29. d down arrows simultaneously C A L light is now flashing 12 Pressthe ZERO switch once and return to the RUN mode using the mode switch T he gauge is now ready for normal operation and the display is a true indication of the system pressure lt 8Torr is N equivalent odel 2002 page 7 2 3 Transducer Installation T hetransducer may be installed in any orientation Although the transducer is rugged and will perform well in many harsh environments the tube should be installed in a clean and careful manner T he tube is configured with the vacuum fitting requested If your vacuum environment is highly contaminated or has unique fitting requirements a H astings filter or special adapter may be needed Please contact the H astings Instruments Sales D epartment for assistance in your system configuration 2 4 Control Unit Installation Environment e Indoor use e Altitude up to 2000 meters e Operating temperature range from 5 to 40 C e Maximum relative humidity 80 for temperatures up to 31 C decreasing linearly to 50 relative humidity at 40 C e Installation category II Panel M ount Instructions T he control unit can be panel mounted See detail on page 43 T he hole dimensions on the panel are 3 62 x 3 62 92 8mm x 92 8 mm Slide the neoprene gasket that was shipped with the control unit onto the case from the back Slide the controller through the panel cutout H old the hardware against the si
30. de and tighten the two screws Transducer Cable Attachment T he threaded connector attaches to the transducer A finger tight connection is adequate for proper operation T he 9 pin male D connector attaches to the back panel See Figure 4 2 T hetransducer cable connects to the left hand connector when looking at the back 1 0 Cable Attachment T he mating male plug to the 1 0 connector is supplied with the unit An 1 0 cable can be wired with the 9 pin female D connector to usethe analog output digital alarms or the remote zero functions T he connector will accept 20 gauge or smaller wire T he pinout is shown in Figure 4 2 back panel figure A detailed description of these pins is given in Section 4 2 5 Initial Operation page8 M odel 2002 U pon applying power to the control unit a pressure measurement will be given in Torr for nitrogen H owever it is recommended that the user follow the instructions for zeroing and adjusting the output at atmospheric pressure in Section 3 4 C al M ode 3 Front Panel Operation 3 1 Overall Functional Description T he front panel of the control unit is shown in Figure 3 1 T hefour circular blue buttons are used for the selection of display readout and the input of data T he green data field displays the data as determined by mode selection T he M OD E switch toggles the control unit in a clockwise fashion among the six modes of operation RUN Normal operation
31. er and programed into the M odel 2002 microprocessor For more information about configuring these setpoints refer to Section 3 of this manual T he 4 20 mA interface board is available as an option for the M odel 2002 T his board provides dual current channels linearly proportional to the H PM 2002 s pressure reading Please note that use of the M odel 2002 with this option requires a CPU with firmware for version 1 6 or later LOW SETPOINT OPTION BOARD HIGH SETPOINT Model 2002 RELAY CONNECTOR MALE RELAY Rear Panel Detail BOO also ES 5 1 1 5 Ambo er 9 6 e 9 TRANSDUCER CONN STANDARD FEMALE CONNECTOR Figure 8 1 81 4 20 Interference Connector Pin Assignmets Pin Connection 1 Internal loop power out channel 1 3 Loop in channel 1 8 Internal loop power out channel 2 7 Loop in channel 2 T he 4 20 mA board can only be operated with internal loop power A schematic Figure 8 2 is attached to show the proper method to wire into a loop Symptom Fixed display regardless of pressure Action 1 Check sensor for contamination Model 2002 page 37 82 Operation 38 2002 T he 4 20 mA output option board provides dual channel current output linearly proportional to the HPM 2002 s pressure reading T he first channel corresponds to the higher pressure range 0 1024 Torr T he second channel corresponds to the lower pressure range 0 1000mTorr T he equations below give the
32. guration and calibration T he interlock is bypassed using the following steps 1 Placethe instrument in one of the six modes 2 Simultaneously press the up and down switches T he mode light will now flash indicating that the interlock has been bypassed Scientific N otation T he M odel 2002 measures pressure that spans more than seven decades In order to easily display these readings H astings Instruments has employed scientific notation In scientific notation the mantissa the fixed point part is multiplied by some power of 10 given by the exponent Powers of 10 103 1000 10 1 0 1 10 100 10 0 01 10 2 10 103 0 001 10921 10 0 0001 example 7 60 x 10 Torr o mantissa exponent 7 60 multiplied by 100 2 760 Torr which is one atmosphere of pressure 3 2 RUN Mode Normal Operation T he 2002 will automatically enter RUN mode upon start up T his is the mode for normal operation and the mode in which the instrument will typically spend most of its time In the run mode the M odel 2002 unit will continuously monitor the pressure and update the alarm conditions at the speed of the A D converter and will update the display about four times per second A D Speed Adjust T he M odel 2002 utilizes a 24 bit sigma delta analog to digital converter T his type of converter averages the input over time to reject interference L onger averaging times result in more accurate readings Increasing the
33. h an inert gas the user can enter a gas selection into the M odel 2002 To view the gas selection place the instrument in the GAS mode TABLE 1 G as M ode Displayed umber 0 0 aa nitrogen Olsen argon 0 2 helium water vapor custom and reference T able 1 T he M 2002 is factory set to display N pressure readings To select different gas refer to T able 1 to find the number code of the gas to be entered Press the and DOWN switches simultaneously the G A S light will now flash U sethe UP and DOWN switches to individually select the desired code Return the odel 2002 to the RUN mode Note Factory calibration is performed using nitrogen only Displayed pressure surements using other gases are based on established gas thermal conductivity data 3 6 UNITS Mode T he M odel 2002 can display the measured pressure in different pressure units Torr mbar or Pascal To switch between these units press the M ODE switch until the UNIT S field is lit Press the UP and DOWN switches simultaneously T he UNIT S light will now flash U se the UP and DOWN switches individually to select the desired unit he units mode is also used to display the S 485 address see section 6 3 A commonly used unit is mTorr which is also known as the micron short for micron of Hg OneTorr is equal to 1000 mTorr T hetable below illustrates how to interpret the display in
34. he control unit s display T he M odel 2002 comes calibrated for nitrogen C onversion factors for other gases are selectable by the user see section 3 5 T his direct readout display allows for flexibility in user system configurations which operate with various gases An optional serial interface board can be installed to provide RS232 or RS485 support T he M odel 2002 control unit fits a standard DIN 43700 insert 1 4 DIN and mounts into a 3 62 in 92 mm square hole T he case is constructed of NORY L rated UL 94 V1 self extinguishing plastic and is equipped with mounting brackets that are adjustable up to 3 16 4 8mm L4 Specifications Measann Fages sco orien tent Coa tta nd Hee p b 1x10 to 10 Torr 1 3 10 to 1 3x10 3 mbar Accuracy N T 5230C M 15 of reading 5x10 to 3x10 Torr 1 596 of reading 3x10 to 1x10 Torr Ambient temperature operating sss 0 to 50 Bakeout temperature with transducer electronics 01 250 C Anal g output nennen 1 0 4 5 Volts 0 5VDC linear per decade Piroc amp ss CODO i een 2TTL outputs 1T T L auto zero input Four green L ED resolution is three digit plus exponent Equipment operating range 120 240V 0 25A 50 60 Hz A 6 ft 3 wire power cord is provided with each
35. ich must equalize in pressure with the system before the sensor can reach its final value he transducer s small internal volume 1 5cc permits rapid pneumatic response to system pressure changes Further the small geometry of the transducer prevents thermal convection currents which allows the sensor to be mounted in any orientation without calibration shifts M odel 2002 page 5 1 3 Model 2002 Control Unit The M odel 2002 control unit consists of the power supply Pirani resistance bridge control signal processing and display circuitry T he user interface consists of a flat panel display with smooth operat ing tactile switches and large green LED digits 0 56 14 2mm T he pressure is displayed in scientific format using a 3 digit mantissa and a 1 digit plus the sign exponent T he pressure can be displayed in Torr mbar or Pascal T he instrument comes standard with 2 alarm setpoints that have T T L level digital outputs An optional dual relay board can be internally mounted to trip on the alarm setpoints to turn on off various equipment such as pumps valves heaters bakeout ovens and safety equipment An optional 4 20 mA or 0 10V analog output board is also available T he M odel 2002 instrument accepts an external T T L level Remote Zero to zero the instrument when another instrument e g an ion gauge indicates that the pressure is less than 1x10 Torr T he standard analog output is linear per decade directly corresponding to t
36. ich provides pressure indication from 1000 Torr down to less than 1Torr T hethin film Pirani device is a thermal conductivity sensor that provides pressure indication from 100 Torr down to less than 1x10 Torr T he two decade overlap in measurement range is convenient for smooth transition either descending or ascending in pressure Both sensors are small micromachined die that are bonded to a Au coated AI O preform stress isolation which in turn is bonded to aT O 8 header T he header is resistance welded into a 316 stainless steel envelope as shown in Figure 5 1 5 1 Piezoresistive Sensor Cable connector T op cap TO 8 HEADER Electronics board contains EEPROM Piezoresistive sensor Pirani sensor T ube shell Dual Sensor E mbodiment Figure 5 1 M 2002 page 21 page22 Model 2002 Figure 5 2 shows atypical schematic of a B implanted W heatstone bridge network in a Si dia phragm inverted box type geometry T he inside of the box is evacuated during anodic bonding to a Pyrex substrate T he membrane has maximum deflection at atmosphere or higher pressure and the membrane resistances change value as the differential pressure is decreased during pumpdown T heresulting differential output is V SPV 4V where S is the sensitivity P isthe pressure V isthe applied bridge voltage is the no load output voltage Sincethe sensitivity changes so dramatically with temperature some correction is requi
37. m 8 TX RX Transmit R eceive RS 485 bus 6 2 Interface Connector Pin Assignments for RS 232 N ote an alternate method of connecting to a 2 wire bus is to leave the interface configured for full duplex and externally connect pins 2 and 3 to the bus and pins 4 and 8 to the bus 6 3 Operation of the Serial Interface Communication with the serial interface of the M 2002 is via an ASCII data string In the RS 232 mode the command message consist only of a command string and the terminator T he attention character and address string are not required but if they are used they M UST be valid If all compo nents of the ASCII data string are valid the command will be accepted and executed T he RS 232 mode is sometimes referred to as point to point mode since only one device may be connected to the controller at any given time A message to the 2002 in the R S 485 mode consist of an attention character followed by the address string the command string and the terminator If all components of the ASCII data string are valid the command will be accepted and executed T he RS 485 mode is also referred to as multipoint mode since up to 31 devices may be connected to the same controller in a network scheme T he RS 485 address may be display on the model 2002 front panel with software verson 1 60 or higher Press the M ODE switch until the units field is lit press both the UP nad DOWN switches simultaneously T he uni
38. nsions 2002 Outline D rawings all dimensions shown are approximate page48 Model 2002 GASKET optional Panel M ounting D eep M ounting L ocation Shallow M ounting L ocation M ounting Clip Attachment M odel 2002 page 49 50 2002 gt i 5V 5 Rt JUMPER SETTINGS JUMPERS 1 amp 3 ARE TO BE SET OPEN JUMPERS 2 4 amp 6 ARE TO BE SET CLOSED ow el R25 CONNECTS 2 VIAS AS SHOWN 220 8 01 469 RES 6 04 6 02 114 IC PISA392A FET SWITCH 6 01 171 IC PIC17c756 CPU 16 53 002 5 68 PIN PLCC 56 02 115 ADS1211U A D CONVERTER NOT USED 56 03 0156 56 02 113 ADR291GR VOLT REF 1 27 01 159 CRYSTAL 32 000 25C080 SPI SERIAL EEPROM CAP 100 pF 5 1206 16 20 056 CONN 5 PIN MOLEX BREAK AWAY HDR 28 10 106 TEST POINTS 26 04 851B 851 BARE ETCHED PC BOARD 56 02 105 AD706JR LOW PWR OP AMP NOT USED 56 01 162 IC AD7233AN 12 BIT SERIAL D A 51 06 006 TRANSISTOR 2N3904 MOT FREQ 18 01 432 RES 10 KOHM 1 8W 5 1206 18 36 007 RES 7 X 47K COM SIP NETWORK 18 02 485 RES CARB 20 MOHM 1 4W 5 18 01 451 18 01 429 ER 4 53 KOHM 1 8W SMT 1206 R24 11 08 134 1000 pF 1206
39. onds If the command syntax is not met or if the number is out or range the H PM 2002 will respond with the ASCII codes for bell C gt and the command will be ignored Calibration Adjustment Commands Command Description Format Valid Range Set Full Scale C alibration CF m d E e lt CR gt 5 12e 2 to 1 023e 3 Torr 6 83e 2 to 1 365e 3 mbar 6 83e 4 to 1 365e 5 Pascal Set M idpoint Calibration CM m d E e CR 4 00e 0 to 7 999e 0 Torr 5 34e 0 to 1 066e 1 mbar 5 34e 2 to 1 066e 3 Pascal Set Lowpoint C alibration CL m d E fe CR 0 to 1 249e 1 Torr 0 to 1 666e 1 mbar 0 to 1 666e 1 Pascal N otes T he calibration adjustment data may also be entered as a decimal number e g CF 2760 99 CR gt will be same as entering CF 27 6099E 2 lt C R gt When inputting calibration adjustment data it must be within the valid range of the presently selected U nit of M easurement i e Torr mbar or Pascal T he data is checked to be valid before being accepted If the command syntax is not met or if the number is out or range the H PM 2002 will respond with the ASCII codes for bell2 C gt and the command will be ignored Reset Restore Commands Command D escription Format Notes Escape Esc Reset Command Buffer ignore prior Input Software R eset IR lt CR gt R einitialize Software Restore Factory D efaults lt CR gt Restore alibration egister D efault Values Set Zero 0 CR Store
40. pressure becomes less than the set point T healarm lights cannot indicate an alarm condition while in the set point modes T herefore it is advisable not to leave the instrument in these modes for extended periods To adjust a set point press the mode switch until the set point is viewed T hen simultaneously press the UP and DOWN switches T heactive mode light will now flash indicating that the interlock has been bypassed and the set point can be adjusted T he display shows the present set point Enter the new set point by using the UP and DOWN switches Press and hold the U P switch to increase the set point and the DOWN switch to decrease the setpoint Allow a few seconds for the circuitry to respond If the button is held down for and extended period of time the adjustment rate will start to increase Release the button and press again to get finer control of the exact trigger point Atthis point the new set point is in temporary memory If the instrument were unplugged now the M 2002 would revert back to the original set point upon restarting Return the 2002 to the RUN mode to store the set point in permanent memory Once the interlock has been bypassed in the HIGH mode it will stay active until the CAL mode is entered T his will allow the user to set both setpoints without repeating the interlock bypass 3 4 CAL Mode O ptimal performance of the M odel 2002 is achieved by performing in situ adjustments to the calibration
41. red for compensation T he change in output voltage To insure temperature invariance dVo _ SdV us dr dT dT dVo _ 1 dV 1 05 dr 0 therefore dr at which requires for any change in sensitivity to be countered equal but opposite change in applied voltage T he temperature compensation is a network of temperature dependent resistive components and fixed temperature compensation current source compensation T CR 5 Sensitivity of the sensor is proportional to the sensor factor the strain gauge positioning of the diaphragm and the diaphragm geometry 0 thus S lt K 0 Once the defining geometry of the resistive film and piezo membrane have been established the sensor factor is dependent on the crystal orientation of the membrane material the doping level and diffusion parameters and the strain gauge geometry T he sensor factor is essentially the change in resistance for a change in strain or Boron ion implanted doped Si matrix resistance elements are employed as shown in Figure 5 2 T he dieis electrostatically bonded to substrate in a good vacuum so that the die cavity is evacuated this provides maximum deflection at atmospheric pressure W hen the sensor is exposed to vacuum the deflection becomes less and less as the die cavity pressure and the vacuum system pressure equalizes Eventually the strain in the membrane due to AP becomes zero and only the residual s
42. resent over the entire pressure range T ypically this adjustment corrects for low pressure errors T heinstrument will need to be re zeroed often if measurements are being made the 10 Torr range especially if the ambient temperature changes he transducer may have a temperature coefficient of up to 2 10 T he instrument remote zero input will allow an external gauge such as an ion gauge to automati cally re zero the M odel 2002 whenever the pressure drops below the desired pressure level if it hasaT TL output NOTE Do not attempt to zero the Model 2002 in pressures above 10 Torr the micro processor will not accept a zero above this pressure To manually adjust the zero use the following procedure 1 If possible evacuate the vacuum system into the low 10 Torr 1 33x10 mbar range or as low as possible below 10 Torr 2 Allow the sensor to operate in this condition for a minimum of 15 minutes 3 Placethe instrument in the CAL mode then simultaneously press the UP and DOWN switches to bypass the interlock T he CAL light will start to flash indicating that the calibration mode has been activated 4 Press the ZERO switch once if below 6x10 Torr otherwise use the UP and DOWN switch to adjust the display of the M odel 2002 to match the pressure indicated by the reference If using the UP and DOWN switch to adjust the display wait 20 seconds between presses at very low pressure to allow the adjustment to
43. rts are present i e transducer power supply cables etc In addition to the components listed on the packing list the shipment includes AC power cord panel mounting hardware 9 pin female D connector O ptional equipment or accessories will be listed separately on the packing list 2 2 Quick Start Follow this procedure to get your new M odel 2000 vacuum gauge up and running 1 Remove sensor from protective packaging 2 Transducer tube may be installed in any orientation H owever if condensation is likely to occur then the port should be orientated downward 3 When installing 1 8 style transducer tube use the 7 16 wrench flats on the tube stem 4 Connect transducer cable orange to controller 5 Connect other end of transducer cable to transducer A finger tight connection is adequate for proper operation 6 If you have computer interface or process control options these cables can now be attached 7 110 port diagram is given in the manual 8 Connect theAC power cord T he M 2002 automatically adjusts for 120 240 VAC 50 60 Hz 9 Turn on power switch Gauge is now reading pressure in units of Torr default 10 For best accuracy the gauge should now be zeroed Pump the vacuum system down to low 10 if possible Ideally the gauge should be operated in this condi tion for one hour 11 Place the M 2002 in the CAL mode by using the mode switch Press the up an
44. s nn 39 10 0 TROUBLESHOOTING GUIDE nennen 41 11 0 WARRANTY AND REPAIR Ka a9 E ax PA nennen 43 11 1 Warranty Repair enne ns 43 11 2 Non Warranty Repair Policy nsn 43 12 0 DIAGRAMS AND DRAWINGS anna anna 45 SECTION 1 General Information T he M odel 2002 is a wide range vacuum measuring instrument consisting of a digital microproces sor based display unit a miniature rugged thin film based sensing element that measures from below 1x10 up to 100 Torr a piezoresistive sensor that measures from 1 to 1000 Torr EEPROM Electrically Erasable P rogrammable Read Only M emory and an interconnecting cable Together these components provide accurate vacuum measurement over 7 decades of vacuum from 1x10 to 1000 Torr T his instrument is a new design approach based on over 50 years of experience by H astings Instruments with well known and widely used thermal conduc tion vacuum measurement techniques T he M odel 2002 is designed for quick easy installation and will provide the user with long lasting trouble free accurate vacuum measurement L1 Features Wide dynamic range 1x10 to 1000 Torr Compact rugged design Attitude insensitive Fast dynamic response Withstands 150 psig positive pressure Linear per decade Bakeable to 250 C TTL output process control Interchangeable transducer
45. s Radiation is another source of thermal losses It can be determined from oe T T HA where o Stefan Boltzmann radiation constant thermal emissivity of the silicon nitride membrane A surfacearea of the heated portion of the membrane T temperature of T ambienttemperature 555 Figure 5 35 Figure 5 3 M odel 2002 page 25 T his radiation loss is also independent of the thermal conductivity of the gas It is somewhat dependent upon the absolute temperature of and the ambient temperature but since AT is kept to less than 20 C this loss is only approximately 10 of E If ambient changes are small compared to the absolute values of the temperature this loss can approximated as a constant with temperature Sincethe first two losses are essentially constant at high vacuum for a given sensor we can measure these losses and subtract them from the input power which leaves only the rate of heat transmission through the gas E In the viscous flow regime the E loss is directly dependent on the thermal conductivity of the gas the surface area of the membrane the differential temperature and is inversely proportional to distance between the membrane and the lid It can be written as E K AT AJ Ax T he thermal conductivity of the gas is essentially constant when in viscous flow where the K nudsen number K n isless than 0 01 In the viscous flow regime there
46. s Command Description Format Sample R esponse Transmit Averaged Pressure P lt CR gt 1 23456e 0 Torr lt CR gt Transmit Pirani Pressure R lt CR gt 1 98765 3 lt gt T ransmit Piezo Pressure Z lt CR gt Pz 7 65432 2 lt R gt T ransmit R S 485 A ddress A lt CR gt M ultidrop Address 01 lt C R gt T ransmit D ecimation R atio D lt CR gt D ecimation Ratio 255 lt gt T ransmit Selected G as G lt CR gt 5 0 lt CR gt T ransmit H igh Setpoint H lt CR gt Hi 1 00000 1 lt R gt T ransmit L ow Setpoint L lt CR gt Lo 1 00000e 2Torr lt C R gt T ransmit D evice Status S lt CR gt 00044 lt CR gt T ransmit T urnaround D elay T CR Comm Delay 6 lt gt M odel 2002 page 31 page 32 Model 2002 Transmit Selected Units U lt CR gt Torr lt CR gt Transmit SoftwareVersion V lt CR gt H astings Instruments 2002 Version 1 60 07 02 2002 CR Parameter M odification Commands Command D escription Format Valid Range M odify H igh Setpoint H m dd E e lt CR gt 1 00000e 9 to 9 99999e 9 M odify Low Setpoint L m dd E e lt CR gt 1 00000 9 to 9 99999e 9 M odify Selected G as G d lt CR gt 0To4 Decimal M odify Selected U nits U u lt CR gt T or M or P if Available M odify D ecimation R atio D dddd lt CR gt 63 7936 D ecimal M odify RS 485 Address aa lt C R gt 1ToFF H exadecimal M odify T urnaround D elay aa
47. the product T his warranty does not apply to batteries or other expendable parts nor to damage caused by leaking batteries or any similar occurrence T his warranty does not apply to any instrument which has had a tamper seal removed or broken T his warranty is in lieu of all other warranties expressed or implied including any implied warranty as to fitness for a particular use H astings Instruments shall not be liable for any indirect or consequential damages astings Instruments will at its option repair replace or refund the selling price of the product if H astings Instruments determines in good faith that it is defective in materials or workmanship during the warranty period D efective instruments should be returned to H astings Instruments shipment prepaid together with a written statement of the problem and a Return M aterial Authorization RM A number Please consult the factory for your RM A number before returning any product for repair Collect freight will not be accepted 1L2 Non Warranty Repair Policy Any product returned for a non warranty repair must be accompanied by a purchase order RM A form and a written description of the problem with the instrument If the repair cost is higher you will be contacted for authorization before we proceed with any repairs If you then choose not to have the product repaired a minimum will be charged to cover the processing and inspection Please consult the factory for your RM
48. train in the lattice remains T he bridge resistive elements are oriented to give maximum change in bridge resistance which in turn gives maximum voltage out for a given strain Pressure D iffused bridge resistors Vs Diaphragm Backing surface or restrainer ViewA A Diffused bridge resistors Ground Figure 5 2 Model 2002 page 23 5 2 Pirani Sensor page24 2002 Figure 5 3a shows a thin film Pt resistive element on a one micron thick Si N continuous mem brane surrounded by a thin film Pt reference resistor on a Si substrate T he membrane is heated to a constant 8 C above ambient temperature that is monitored by the substrate resistor T he membrane resistor is approximately 60 and a constant substrate to membrane resistance ratio is maintained at 3 86 Figure 5 36 shows the Pirani die in cross section A parallel Si lid is eutectically bonded to the Au pads and sits 5 microns above the membrane As shown this dimension gives a K nudsen number of greater than 0 01 up to atmospheric pressure which insures a molecular flow component At 10 Torr the region above the membrane is totally in the molecular flow regime and thus provides a relatively linear output verses pressure overlapping the linear output versus pressure of the piezo T he measurement technique is to produce an output signal that is proportional to the power supplied to the heated resistor by using the product of the current and voltage T his reje
49. try module that contains a fuse on off switch and an IEC 320 power inlet T he fuse is rated for 250 V 1 4 A It can be accessed by unplugging the AC cord and prying the fuse compartment open with the tab and slot in the power inlet chamber T here is a spare fuse in the compartment within the fuse holder LOW SETPOINT OPTION BOARD HIGH SETPOINT RELAY CONNECTOR MALE RELAY ER opono Model 2002 Rear Panel Detail Figure 4 2 TRANSDUCER CONN STANDARD FEM ALE CONNECTOR Analog 0 10V OPTION SENSOR CONNECTOR BOARD CONNECTOR Pin Connection Pin Connection 1 Sensor 1 Analog Out 1 1024 Torr High 2 Bridge sense 2 Analog Out 1 1024 Torr Shield 3 Bridge Power 3 Analog Out 1 1024 Torr Low 4 Reference 4 5 Common 5 6 Common sense 6 7 N C 7 Analog 2 1000 mTorr Low 8 8 Analog 2 1000 mTorr High 9 Analog Out 2 1000 mTorr Shield I O CONNECTOR 4 20mA OPTION Pinf Connection BOARD CONNECTOR 1 Analog Output Pinf Connection 2 Analog Common 1 I Loop Out 1024 Torr 3 High Setpoint 3 LLoopIn 1024 Torr 4 Low Setpoint 5 Digital Common 8 I Loop Out 1000 mTorr 6 Remote Zero 7 I Loop In 1000 mTorr 7 5V 20 2002 SECTION 5 Theory of Operation T he odel 2002 transducer is comprised of two very different sensors which provide a span of measurement extending from 1000 Torr down to less than 1x10 Torr T he piezoresistive device is a direct force sensor wh
50. ts light will now flash Press the ZERO switch to display the page 30 M odel 2002 5 485 address the address is displayed in it s decimal form U se the UP or DOWN switch to modify the address U se the M ODE switch to exit this function and save the new address into EEPROM memory COMMAND SYNTAX In thefollowing examples of syntax codes the special characters are explained T he characters in square brackets represents a command string either upper or lower case command characters accepted All characters must follow each other in the string with no spaces or other charac ters T he characters within wavy brackets contain choices for the appropriate command T he characters within the symbols arethe common abbreviations for the one digit ASCII control codes which they represent e g lt C R gt represents carriage return When entering more than one command in the same data string they must be separated by a comma All command strings must be followed by the terminator character carriage return CR gt also known as ENT ER When a lower case character is present in an example it represents an option Character Description Valid Inputs a RS 485 Address hexadecimal 0 9 A F 01 FF m M ost Significant D igit Of M antissa 1 9 d D ecimal D igit 0 9 e Exponent 0 5 u Unit Of Pressure T M orP Command Separator comma N A lt CR gt Command Terminator carriage return N A Interrogation Command
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