Instruction Manual - Delta Instrument LLC
Contents
1. 13 Battery Current Status Only use the Charger supplied with SADPmini The battery Icon in the bottom left hand corner of the display indicates the status of the battery The internal battery is a 3 6V 2 3Ah Lithium Ion rechargeable cell The Icon indicates the battery voltage as follows OFF Less than 3 3V de 3 3 to 3 38V de 3 38 to 3 46V dc 3 46 to 3 54V de 3 54 to 3 62V de Greater than 3 62V dc qn The Icon fills from the left when the external power supply is connected This indicates that the battery is receiving a charging current and should be fully charged within 6 hours Note It is recommended that the unit be charged overnight when first received to ensure the battery is fully charged Note The 4 20mA output should not be operated while the instrument is charging 14 Performing an AutoCal Before an AutoCal can be performed successfully the user must have a reference moisture reading This reading is entered into the SADPmini in the AutoCal process as the AutoCal value The AutoCal routine can be performed using a known reference gas or under ambient conditions Note The AutoCal process will automatically correct any SPCs see section 11 2 5 already in the SADPmini 14 1 Ambient conditions Pump the SADPmini head up and down a few times to ensure that the air surrounding the sensor in the SADPmini head is representative of the ambient moisture value Leave the head Page 22 of 33 out and allo2. The setup menu it activated by pressing the S O and 1 keys simultaneously From this menu the user has the choice of several options detailed below 11 1 1 Select Units Description This sub menu has eight options allowing the user to select any one of seven Moisture Engineering Units and to exit the menu Note 1 Once an engineering unit is selected the SADPmini will only display and accept inputs in that chosen unit This means that 4 20mA settings where fitted offsets and SPCs are all performed in the chosen units 2 The 4 20mA range settings are reset to full span whenever the moisture units are altered Operation In the Setup Menu move the cursor bar to highlight the Select Units option and press the key The Primary Units sub menu is displayed Run through the options until the required engineering unit is highlighted confirm the Page 10 of 33 11 1 2 selection by pressing the J key The SADPmini automatically reverts to the Exit option in the Setup Menu Note The PPB Moisture Engineering Units has an upper display limit of 10000 PPB Change units to PPM above this moisture level Pressure Cale Description This sub menu has five options allowing the user to select any one of four Pressure Engineering Units and to exit the menu This function then allows the SADPmini to display Dewpoint C and F at pressure When this function is selected the mai
3. Model SADPmini Instruction Manual Alpha Moisture Systems Alpha House 96 City Road Bradford BD8 8ES England Tel 44 1274 733100 Fax 44 1274 733200 Email mail amsytems co uk Web www amsystems co uk Page ii Instruction Manual For the SADPmini Automatic Dewpoint Hygrometer 1226 SADPmini User Manual doc Issue 13 1 12 03 14 Page 111 Table of Contents 1 GENERAL INEORMATION ut tad OE daa 1 D TREATURES ds is A e a feud etd DA O ide cerelhe cs eek 1 37 SAFETY INFORMATIONS dd ld datada 2 3 1 WARNING s a E A A A AA A av NRE ss 3 2 BATTERY 00 cccee0es 3 2 1 Lithium Ion 3 2 2 Initial Charging 4 INSTALLING THE AIR GAS SAMPLING SYSTEM cconconccccnnnnononnnonecnonnnnnnnnnnonenonnnnnanonononocronannnnanonenin ss 3 4 1 PIPINGINSTALTEATION SCHEMA TIC atte 4 4 2 PIPING SCHEMATIC COMPONENT INDEX lt cssescustecvasovecstucosnecuateveesceccedeccuessdeccveascavesnesnve dhiccelesustevtendsecseess 4 5 PURGING THE SAMPLE CONNECTION ccceccccccccessssscecccccesssssseecccccecsesssssescescecauaueescecseeauanaaeneecess 5 6 USING THE SADPMINI TO TAKE A MOISTURE READING cononononononononononononononononononononononononananonononons 5 6 1 TAKING A MEASUREMENT cccccssssssececececeessscaecececsesesscaeceeeceesessaaeceeececsesaaeceeecscsesaaeceecesesensaaeaeseeeens 6 7 SAMPLING INFORMATION ccccccccccccccssesseccccccccssssssesccccceusessse
4. 1 key to move to the block selection screen The selection screen shows the TAG reference block number plus the date amp time when data was stored The SADPmini by default displays the most current data block first and subsequently runs through the remaining blocks in chronological order Pressing the G key displays the next block of information Pressing the J key displays the select block and the associated data in graphical format Note EMPTY means the TAG reference has not been defined using Create TAG The graphical displayed shows the stored data vs number of readings TAG Reference y Block Number Default TAG 1 Cursor Moisture curve Moisture value cursor position Number of Data Points 0 35 7 20 Page 18 of 33 11 2 3 11 2 4 11 2 5 Pressing the A and V keys moves the cursor along the X axis of the graph The Moisture value printed in the middle of the X axis changes to indicate the value at the point where the cursor crosses the moisture curve Pressing the S O key changes the format of the displayed from tabular to graphical and visa versa The tabular display shows the TAG reference block number moisture units and 6 moisture readings The A and V keys allow the user to scroll in both directions through the stored data values Pressing the key from either display format returns the user to the Logging
5. Output 4 20mA loop powered Display Type Keyboard Type Sensor Operating Principle Temperature Operating Temperature Storage Temperature Serial Communications logging version 80 C DP to 20 C DP 80 C DP to 0 C DP 80 C DP to 20 C DP 110 C DP to 20 C DP 100 C DP to 0 C DP 2 C DP over full range 12 bits lt 0 25 full range error Blue 128 x 64 Dot LCD Graphics display with LED backlight 5 key metal dome tactile membrane keyboard Ultra High Capacitance ALO Sensor 10 C to 50 C 20 C to 60 C Type RS485 Data Format 1 Start bit 1 Stop bit No Parity and No hardware handshaking Baud Rate 9600 No of Addresses 32 Power Supply Supply Voltage 100 240VAC 50 60Hz 400mA Output 6VDC 15W Battery Cell 3 6V Li Ion 2 3Ah capacity Charging Full Charge in 6 hours Only use the Charger supplied with SADPmini Capacity Minimum of 250hrs on full charged battery Enviromental Approvals CE EMC Certified to BS EN 61000 2001 Physical Weight 1 1kg 2 4lbs Dimension W H D 97 x 112 x 202mm 3 82 x 4 41 x 7 95 SR Battery capacity is quoted at room temperature The battery capacity will degrade as the ambient working temperature falls Page 33 of 33
6. 20 INSTRUCTIONS FOR REPLACING DESICCANT IN THE SADPMINI ccccsssceceessececeesseeeeeesseeeenenes 29 21 APPENDIX A SADPMINI SETUP MENU MAP uu cccccccceesssceceessececeessececsessececeesseeeenesseeeenesaeeeeneaes 30 22 APPENDIX B SADPMINI LOGGING MENU MAP ccccssssccceessececeesececeessececsesseeeesesseeeenesaeeeenaes 31 23 APPENDIX C TROUBLE SHOOTING eo aoaaa E AE E E EEEE AA EEEE 32 24 APPENDIX D SADPMINI SPECIFICATION cccccccsssceceessececeessececessseeecsesseeecsesseeecsesseeeenesaeeeeneaas 33 Page v 1 General Information The SADPmini is a battery powered portable instrument It is a fully self contained unit incorporating the moisture sensor signal conditioning circuitry memory management graphics display membrane keyboard Real Time Clock onboard battery and charger circuit The SADPmini operation is controlled by a user friendly software interface incorporating multiple menus hot key combinations information displays and control functions 2 Features Basic SADPmini 128 x 64 dot backlight LCD graphical display Tactile membrane keypad coupled with an easy to operate user interface Operates from an internal rechargeable Lithium Ion battery Battery life in excess of 250 hours continuous use from fully charged Full charge time approximately 6 hours Only use the Charger supplied with SADPmini 7 selectable moisture units C F ppm V ppm W ppb g m3 and Ib MMSCP Pressur
7. Menu PC Comms Description This function is selected by the user to download store data or to Real time log data to a connected PC Operation In the Logging Menu select the PC COMMS option Ensure the SADPmini is connected to the PC using the cable supplied Start the PC software See SADPmini Logger software user guide and press the key twice Note Pressing the A key terminates communications with the PC and returns the display to the Logging Menu Delete Data Description This function allows the user to completely delete all data stored on the SADPmini Once deleted the data is not recoverable Operation In the Logging Menu select the Delete DATA option The unit displays a warning and allows the user to return to the Logging Menu without deleting the data by pressing the 1 key Pressing the G D key deletes all the data irretrievably Create TAG Description This function allows the user to define 19 bespoke references of up to 11 characters in length TAG1 is predefined and cannot be created Operation In the Logging Menu select the Create TAG option The Enter TAGS screen then allows the user to create a TAG reference by pressing the GD key or return to the Logging Menu by pressing the 2 key The Create TAG screen enables the user to produce an 11 character reference using an alphanumeric editor
8. The Information sub menu allows the user to run through the displayed data using the A and Y keys The menu can be exited by pressing the J key at any location or by scrolling to the Exit option Note There are no selectable operations from this menu it is purely for information purposes Displayed Information Description VerNo 5 11 Software Version Number Serial 500101 Unit Serial Number Read L 80 0 Lower Limit Read H 20 0 Higher Limit ACAL 10 0 AutoCal Value SPC Pt 20 0 Single Point Calibration Action Point SPC Va 20 0 Single Point Calibration Offset Value Units C Currently Set Engineering Units P Unit barg Currently Set Pressure Units Press 00 0 Currently Set Pressure Value in Current Units Sensor B Type of Sensor fitted to SADPmini 4mA 80 0 Low mA output in Currently Set Engineering Units 20mA 20 0 High mA output in Currently Set Engineering Units Epot 384 Position of the electronic AutoCal potentiometer Exit Exit option Page 16 of 33 11 1 10 Temperature Description This function allows the user to see the current temperature within the SADPmini head in both C and F Operation In the Setup Menu select the Temperature option 11 1 11Exit Description The Exit option allows the user to return to the normal display Operation In the Setup Menu select the Exit option 11 2 T
9. The current engineering units are clearly indicated on the display as well as any pressure compensation performed 10 SADPmini operating principles Two distinct and separate menus control the SADPmini Each of these menus is described in a separate section below 10 1 Navigating through Menus The SADPmini is predominantly menu driven To navigate around the menus use the A and V keys to move the cursor bar negative image through the options available within the menu and use the 1 key to select the option required The S 9 key has no function within menu screens 10 2 Entering Numerical Data The basic principle used to enter numerical values is described here The display will indicate a number in a format appropriate to the required input the first character of which will be displayed as a negative image to indicate it is active Use the A and Y keys to select the required number between 0 and 9 then press the GD key to select and proceed to the next character Continue this process until all characters are entered Pressing the key at any point enters the numerical value currently displayed Page 9 of 33 Notes e Where control values are entered such as 4 20mA the currently set value is displayed when first entering the screen This allows the user to simply press the key and leave the screen without altering any information Useful when entering a function by accident e
10. ce 17 11 2 THE LOGGING MENU a E AREEN AEA EA 17 Pdo Internal 072421 N A E EE EE E E E E E E E CT 17 11229 Review DAA SA EEA E EEE nb EEE EA EEA 18 11 2 3 PC Comms Ses 11 2 47 Delete Data ia ici 19 11 2 5 AN RO 19 11 2 6 Edit TAG a 137 O A ee BRAG Rs he Ae RA BERL Ee OS eee A Printer LOG sos soso A A NO 11 2 9 Unit Address 11 2 10 Free Space 11 2 11 O BEI AANE E TER EAE E O O 13 BATTERY CURRENT STATUS sce ta aio 22 14 PERFORMING AN AUTOGA cinta tantra ct tt tt dd lens at tdi 22 14 1 AMBIENT CONDITION Sii a ia aes 22 14 2 REFERENCE GAS oaee nait i a cd testi tido idas id Ai det 23 15 SADPMINI 4 20MA oococcconoconcnooonnncnnnnnnnonnnnnnonnnnnnonnnnnn nn nro nn rn non ARN rE A Aan 23 15 1 SADPMINT4 20MA CIRCUIT e scons chek tag cd sa sasec aur Bt Gesee het fas oA E E RR 23 15 2 CALCULATING MAXIMUM OUTPUT LOAD Ruy cessssssesseessessecseeeseeeseeseeeeeceseceseceseenaecaeeseceeeaeeeneeaes 24 16 RS485 COMMUNICATIONS 3 3084 52 d5e0s 00ds0ds aiii bedi Misstitlaa beds ii 24 17 SADPMINI LOGGING SOFTWARE CABLES AND INTERFACES ccesssceseessececeesseeecesaeceeesseeeenenes 25 17 1 RS232 TO RS485 CABLES amp INTERFACE cccssccescsessseceereeesseceeeecsaeceeneecsaeceeneecsaeceeeeeesaeceeneeeaeeenees 25 17 2 WSBiTO RS485 CABLES amp INTERFACE a 26 18 TECHNICAL DETAILS OF THE RS485 4 20MA CONNECTER CON066 ccscceeseeeeeseeeeseeeeeeenes 27 19 SADPMINI PROTOCOL cuts led hatte iid eke dais eee 28
11. the sensor Ammonia NH3 Ozone O3 and chlorine C1 must be avoided at all times even in small quantities Hydrogen chloride HCl also attacks the sensors very quickly Some less aggressive acidic gases such as sulphur dioxide SO2 can be monitored as long as the moisture content is low generally less than 100ppm v If in doubt please ask your supplier Sulphur hexaflouride SF6 has no effect on the sensor If the gas has been exposed to arcing however it is possible that various acidic species will have been formed that will corrode the sensor When testing SF6 that may have been arced therefore an acidity test should be carried out first if the gas proves to be acidic then the moisture test should not be carried out Sample conditioning The main principle when considering the presentation of the gas sample to a portable dewpoint meter is to keep the sample system as simple as possible and of minimum swept volume so that it has the least possible influence on the gas sample Pressure and flow control In most cases the gas to be sampled will be at a positive pressure which will need to be reduced to atmospheric pressure At low pressures up to around 10 barg this can be done by including a simple needle valve 5 to control the flow and thereby the pressure dropping across it Ideally this would be the isolation valve 1 on the sample Page 7 of 33 7 5 7 6 8 point thus keeping the number of joints and glan
12. DATA Warning Data for all TAG settings will Be Erased Erase dp Abort 4 Enter TAGS Create dp Quit e Delete TAG Delete Tag TAG 1 ozzy EMPTY EMPTY EMPTY EMPTY Interval Mins 0001 0 Space Free Space Free 16000 logs EXIT ie Logs Free 16000 Using Block 19 Tag ozzy 29 06 03 12 45 56 De Activated DATA DELETED Create Tag 2 Edit Tag 2 Interval Mins 0001 0 TAGL 117 C DATA PTS 32 LOGGING DATA LOGGING STOPPED LOGGING STOPPED These screens are not displayed until TAGS have been created Page 31 of 33 23 Appendix C Trouble Shooting Fault Explanation Required Action Notes Unit does not turn on Screen remains blank Back light off Battery low level Connect the battery charger unit for a minimum of 6 hours charging Connecting the external battery charger will not allow the unit to turn on as the charger unit is not a PSU and the battery level will need to rise before the unit will turn ON Battery dead Replace battery Order BAT005 from supplier Unit refuses to turn on Screen remains blank uProcessor locked up Press the reset switch under the port cover Situated It may be necessary to press the 1 O key whist pressing although the backlight behind the pinhole the reset switch may be on Logging Menu Does
13. DPmini Protocol Contact your supplier for the SADPmini Protocol Manual Page 28 of 33 20 Instructions for Replacing Desiccant in the SADPmini Ne 99 DESICCANT HEAD RETAINING COLLAR 2 DESICCANT CHAMBER a BASE ASSEMBLY 4 eL 3 DESICCANT CHAMBER 1 DESICCANT CHAMBER ae ld KS BASE O RING 3 DESICCANT FILL LEVEL 5 Fully extend the Desiccant head 1 of the SADPmini Unscrew the Retaining Collar 2 turning it counter clockwise anti clockwise which will unfasten the desiccant filled head from the main body of the SADPmini Gently pull out the Desiccant Head from the main body of SADPmini Remove the Desiccant Head Base O Ring 3 and keep in safe place Holding the Desiccant Head with the Desiccant Base Assembly 4 on top fully unscrew the Desiccant Head Base Assembly turning it counter clockwise anti clockwise The Desiccant Head base may require slight loosening by placing in a soft jaw vice before this step is carried out Do not fully unscrew with Head Base at the bottom as this will spill desiccant on floor ONLY USE SOFT JAWS DO NOT USE TOOLS OR VICE WITH HARD JAWS Dispose of used desiccant and re fill with new up to a level of 3mm 5 from the bottom of the screw thread Gently insert the Desiccant Head Base Assembly in the desiccant and tighten USE SOFT JAWS DO NOT USE TOOLS OR VICE WITH HARD JAWS Fit Desiccant
14. Delete TAG screen The bottom item on the menu is an EXIT function that returns the user to the Logging Menu The Delete TAG screen allows the user to delete the TAG reference by pressing the P key or return to the Logging Menu without deleting the TAG reference by pressing the G O key Note When a TAG reference is deleted all the associated data blocks are also lost When a TAG reference is deleted its slot is filled with the word EMPTY TAG1 cannot be removed when deleted it is renamed back to the predefined reference of Default TAG Printer LOG Description This function allows the user to real time log the moisture value seen by the SADPmini to any ASCII thermal printer via the RS485 D type connector Page 20 of 33 communications port The SADPmini outputs ASCII strings unsolicited without the need for handshaking at the interval selected Operation In the Logging Menu select the Printer LOG option The user is required to enter a value for the interval between readings in minutes The default setting is 0 1 minutes or 6 seconds Pressing the key starts the logging process and brings up the External LOG display screen which indicates the current moisture value Pressing the A key at any point will stop logging Note By default the SADPmini will output a moisture value in the current units every 6 seconds 11 2 9 Unit Address Descripti
15. Head Base O Ring 3 Insert Desiccant Head in the main SADPmini body and tightly screw in the Retaining Collar Page 29 of 33 21 Appendix A SADPmini Setup Menu Map SELECT UNITS PRESSURE CALC 4 20mA OUTPUT AUTO CAL SPC SECURITY A SET PRESSURE 000 0 barg 4 20mA OUTPUT Edit 20mA value 20 0 t Edit 4ma value 80 0 ES AUTO CAL Autocal value 10 0 ACAL CODE 1000 Extend Desiccant Head abort Please wait E SPC POINT SPC VALUE 020 0 0250 J de oc SPC SPC Feature Allows Single Pt calibration Against a Reference Gas SPC CODE 1000 ENTER NEW CODE 1000 ENTER OLD CODE SENSOR DATA EXIT TIME AND DATE 29 10 03 b 30 SET CLOCK SET CLOCK DATE SET CLOCK DATE 3058 2 00 A v eje sje Serial L Rng 80 0 H Rng 20 0 ACAL 0 00 e l 0 00 These screens can be disabled by setting the security codes to 0000 TEMPERATURE TEMPERATURE 27a 19C SO7AE EXIT Page 30 of 33 22 Appendix B SADPmini Logging Menu Map LOGGING MENU Internal LOG Review DATA Export DATA Delete DATA Create TAG Edit TAG Internal LOG se Log Tag TAG 1 ozzy EMPTY EMPTY lex ewery f Review DATA Review Tags TAG 1 ozzy EMPTY EMPTY EMPTY EMPTY PC COMMS Comms Mode Activated A To Exit Delete
16. The A and V keys allow the user to scroll through the Page 19 of 33 11 2 6 11 2 7 11 2 8 full alphanumeric character set in both directions The S O key moves on to the next character Note When the 11 character is highlighted the GD key moves the cursor to the 1 character Pressing the key saves the TAG reference and returns the user to the Enter TAGS screen so another TAG can be created Edit TAG Description This function allows the user to edit any of the 20 TAG references TAGI is predefined as Default TAG but can be edited Operation In the Logging Menu select the Edit TAG option The user is then presented with the Edit TAG menu showing all current TAG references Highlight the required TAG reference and press the 1 key to move to the Edit TAG screen The bottom item on the menu is an EXIT function that returns the user to the Logging Menu The Edit TAG screen operates in exactly the same way as the Create TAG screen See 11 2 5 Delete TAG Description This function allows the user to delete any of the 19 TAG references produced using the Create TAG function Operation In the Logging Menu select the Delete TAG option The user is then presented with the Delete TAG menu showing all current TAG references Highlight the required TAG reference and press the Wl key to move to the
17. The decimal point dp will always appear in the correct location e Onsome screens when using C or F the first digit is the negative sign selector This is either ON or OFF e Pressing the G key when the last character is active will make the first character active 10 3 Entering Alphanumerical Data Full Logging SADPmini only Some functions such as the Create TAG allow the user to enter a combination of letters and numbers The principle for entering data is the same as that for entering numerical data 10 2 above except that the A and Y keys scroll through the 26 letters of the alphabet as well as the 10 numerical characters Note There is a dual speed function when entering alphanumerical data When either the A or W key is pressed and held the speed of scroll will increase 10 4 Security Protection Screens Several of the SADPmini functions can be protected with security codes These are the main Setup Menu the AutoCal function and the SPC Single Point Calibration function Each of these functions can be protected with an independently activated user defined 4 digit security code Once activated a screen requesting the correct code will be displayed when the associated function is selected Failure to enter the correct code will prevent access to the function Default setting 1000 11 Operating the SADPmini 11 1 The Setup Menu See Appendix A SADPmini Setup Menu Map
18. andard reference For example the SADPmini reads 70 C dewpoint and the standard reference gas is certified by the gas supplier as being 69 C dewpoint The instrument can now be removed from the gas sample to conserve the reference gas Select SPC from the Set up Menu and Press the 2 key i ii iii iv v vi On the warning screen press the 1 key to continue pressing Scroll key will abort the procedure and go back to the Set up Menu Enter the password if required and press the key Highlight the ENTER NEW SPC option to add a SPC to the SADPmini and Press the key The display asks for the SPC POINT enter the value measured for the reference gas i e 70 C in the above example using the Scroll and A and Y keys and press the J key The display asks for the SPC VALUE enter the stated value for the reference gas i e the value that you want the SADPmini to read at this point 69 C in the above example using the Scroll and A and Y keys and press the 1 key The SADPmini will revert to the Set up Menu with EXIT highlighted pressing the J key will return the instrument to the operating mode and all readings taken will be modified in line with the offset introduced in the above procedure Note The integrity of the calibration will now be dependant on the integrity of the reference standard against which the adjustment has been made T
19. ds which are points of potential moisture ingress to a minimum At higher pressures it is advisable to reduce the pressure across a pressure regulator 4 Any regulator used should be stainless steel and of a low swept volume Typical laboratory or welding type regulators are not suitable because they have elastomeric diaphragms which are permeable to water vapour and the high swept volume will be slow to purge Particulate contamination If the sample gas is likely to contain particulate material this should be kept away from the sensor by including a small in line particle filter 3 in the sample system If the surface of the sensor becomes partly coated with particles it will not affect the calibration of the sensor but will restrict the movement of water molecules across the surface so increasing the time it takes for the sensor to come to equilibrium with the water vapour concentration around it If the solid material is hygroscopic such as desiccant dust whenever there is a change in the moisture concentration in the sample this material must come to equilibrium with the moisture content before the sensor can respond to the change which will cause delays in obtaining accurate results Liquid contamination If the sample gas may contain liquid contamination such as oil mist this should be kept away from the sensor by including a coalescing filter If the surface of the sensor becomes partly coated with liquid again it will no
20. e compensated moisture readings in 4 selectable units of pressure psig barg kg cm2g and Kpag Battery life Indicator Built in Automatic Calibration AutoCal Built in Single Point Calibration SPC On board Real Time Clock User settable security access Sample gas flow temperature indication 4 20mA Option all the Basic SADPmini features plus 4 20mA Loop Powered output Full Logging Option all the 4 20mA option features plus Stores up to 16000 data points 20 definable alphanumeric TAG references including 1 preset Up to 20 blocks of data stored under each TAG reference Review stored data in tabular and graphical form RS485 Serial Communication to dedicated PC software Download stored data in CSV format Real Time logging to connected PCs Thermal printer driver facility Page 1 of 33 3 Safety Information Read the safety information below before installation 3 1 Warning The SADPmini is not Intrinsically Safe Therefore 1t should not be used in hazardous areas The maximum pressure to which the telescopic measuring head is exposed must not be more than 0 3barg 4 35psig 30kpag or 0 3kg cm g Exposing the measuring head to higher pressures may damage the instrument and result in injury to the operator or other personnel in the area 3 2 Battery 3 2 1 Lithium Ion The SADPmini contains a Lithium Ion battery which to conform to current legislation should always be partially discharged b
21. e of a gas in contact with it It is important to ensure that the gas passing through the sensor head is the same as the gas being sampled Page 6 of 33 7 1 7 2 7 3 7 4 Sample Pipe The SADPmini is supplied with 2 connections a fir tree on one side and a Swagelok compression fitting for 4in s in or 6mm OD pipe as specified on your order on the other Either can be used as the inlet connection 6 PTFE and stainless steel are recommended materials for sample pipes Some specialist flexible tubing may be suitable as sample pipe but common flexible tubing such as pvc nylon polythene or rubber should not be used as they are permeable and water vapour from the atmosphere will diffuse through them into the sample gas A 2m PTFE sample pipe is supplied for use with the fir tree connection The first time this is used it is advisable to warm the end that will go over the fir tree for a few seconds with a heat source to soften it slightly which helps to get a gas tight seal Gasses to avoid The moisture sensors are suitable for many different industrial and research applications Most gases can be checked for their moisture content with no need for the calibration to be altered when changing between different gases as the sensor operates only with reference to the water vapour content There are however some gases that must be avoided as they are not compatible with the material of construction of
22. efore shipping 3 2 2 Initial Charging e It is recommended that the SADPmini be put on charge overnight when first received Only use the Charger supplied with SADPmini e To attain maximum battery life the SADPmini should always be re charged at room temperature e The battery life hours of use from a fully charged cell will reduce when used in cold conditions 250 hours is quoted as the expected battery life when used at room temperature Note The 4 20mA output should not be operated while the instrument is charging Page 2 of 33 4 Installing the Air Gas Sampling System The piping installation schematic diagram see section 4 1 shows all components which could be used in a dry gas measurement application although not all the items shown will be required for every installation Care should be taken to ensure that the sample presented to the SADPmini is not contaminated with any component that will damage contaminate or affect the SADPmini in a way that will impair the unit s accuracy It is strongly recommended that the sample should not contain particulate matter oil hydrocarbon or any other condensate Ifthese components contaminate the sample system and or the measuring sensor the SADPmini response time will be lengthened although the sensor calibration will not be effected The sample must not contain Ammonia Chlorine Ozone or any wet acid vapours or liquid as these will permanently damage the SADPmini sensor and
23. einserted The instrument is OUT OF CALIBRATED 2 If the Instrument fails to AutoCal excessive sensor degradation a message to this effect will be displayed on the LCD screen until acknowledged by the user 3 In both cases the instrument will be OUT OF CALIBRATION until a successful AutoCal is performed This will mean replacing the sensor in some cases 4 The entered AutoCal Value must not be pressure compensated see 11 1 2 11 1 5 SPC Single point Calibration Description The SPC facility allows users of the SADPmini to check the reading of the instrument against a standard reference gas or instrument such as a chilled mirror unit at a particular value that may be considered to be critical and make any adjustment necessary to give agreement with that standard reference Rather than making the adjustment to the SPC adjusts 1 point on the curve span of the instrument as with AutoCal leaving upper and lower limits as 3 set Note the Upper limit is the the SPC adj ustment is made by AutoCal Point introducing a two part straight line po response curve with a break point at the i i a 6 48 0 46 0 Tasi Reading set point or standard reference Page 13 of 33 SPC Procedure firmware 6 06 or later l An AutoCal must be carried out before performing an SPC 2 Measure the value of the reference gas with the SADPmini in the normal way and note the indicated value and the stated value of the st
24. ent temperature is below around 12 C Page 12 of 33 Operation of SADPmini units with full scale values of 20 C dewpoint i The ambient dewpoint should be determined using reference standard such as a chilled mirror hygrometer or a psychrometer unless the instrument is being checked against a known calibration standard from a moisture generator 11 Extend the desiccant head and press the key 111 The SADPmini will display a moving bar until it assesses that the sensor has stabilised Up to 10 mins vii The SADPmini will now display the full scale value 20 C dewpoint Whether the instrument is being checked against the measured ambient level or against a known calibration standard from a moisture generator for example the scroll and A and W keys are used to set the value accordingly If a different value has been entered in this way previously the SADPmini will display that value rather than 20 C dewpoint Press the 1 key when done iv The SADPmini will display a moving bar whilst the calibration data is modified Up to 5 mins viii Close the desiccant head when instructed to do so and press the Wl key ix The SADPmini will return to the Set up Menu with EXIT highlighted Pressing key again will return the instrument to operational mode Note 1 Pressing the scroll key during the AutoCal ABORTS the process The AutoCal value present at the start of the aborted AutoCal process is r
25. he Logging Menu See Appendix B SADPmini Logging Menu Map Full Logging SADPminis only The Logging menu it activated by pressing the A and W keys simultaneously From this menu the user has the choice of several options detailed below 11 2 1 Internal Logging Description This function allows the user to store data to the unit s internal memory from where it can be exported or reviewed There are 20 available TAG references each of which can store up to 20 data blocks a file where data points or measurements are stored This means that a maximum of 400 separate data blocks can be stored The SADPmini has a capacity of 16000 individual data points Note If the number of data points in a single block exceeds 12800 only the first 12800 will be downloaded from the SADPmini to a PC It is therefore recommended that a sample rate be chosen that over the logging period will result in less than 12800 readings being taken Operation In the Logging Menu select the Internal LOG option The user is then presented with the Select Log TAG menu showing available TAG references for data storage See Create Edit amp Delete TAG options for more information Highlight the required TAG reference and press the key to select Note TAGI is the default TAG reference and cannot be deleted If no other TAG references have been created the Select Log TAG menu does not appear and the unit will automatica
26. impair calibration accuracy The flow rate although not critical to the sensor measurement should be low enough to avoid abrasion to the sensor surface without being so low as to extend the SADPmini response time to an unacceptable level In general a flow rate of between 5 and 8 litres min at NTP will give the right balance The sensor used in the SADPmini is a variable capacitor which is directly affected by changes in partial pressure of water vapour and these changes that are proportional to the dew frost point temperature are displayed on the instrument indicator Page 3 of 33 4 1 Piping installation Schematic Main Process Line The sample point should be on the upper surface of the horizontal pipe or from a vertical section of pipe wherever possible The sample tube should run upwards from the sample point If this is not possible then an inspection port or drain tap should be installed at the lowest point in the sample system 4 2 Piping Schematic Component Index 1 De Sample Isolation Valve This is a recommended item as it allows access to the sample system without interrupting the main process line Sample Tube This should be stainless steel for dry air or gas applications but copper or carbon steel can be used where wetter gases are to be measured If any section of the sample tube must be flexible then PTFE should be used In most cases 3mm OD 1 8 is sufficient as it provides good system res
27. ini Head Raised Restrict the outlet of the SADPmini 7 by placing a finger over the sample exhaust 9 so that the pressure of the sample lifts the telescopic head As soon as the head is fully extended remove the finger to prevent pressure build up Pull gently on the head to make sure it is fully extended If there is not enough pressure to lift the head assembly assist it by pulling it up do this very slowly so that ambient air is not drawn in through the outlet It may help to turn the head to break the sticktion be sure to turn clockwise so as not to loosen the locking ring The sensor will respond to the moisture level present in the sampled gas The displayed moisture value will continue to change until the sensor reaches equilibrium at which point the displayed value is representative of the moisture level in the sampled gas When the test is finished push down the telescopic head fully and carefully turn off the sample flow and disconnect the sample pipe With the head in the down position the desiccant will dry the sensor ready for the next test NOTE It is important that the head assembly is either fully up or fully down to keep the desiccant isolated from ambient air so avoiding wetting it When the SADPmini is not in use it should be stored with the head in the down position 7 Sampling Information Refer to the sample system schematic in section 4 1 The SADPmini sensor will respond to the water vapour pressur
28. ll key will abort the procedure and go back to the Set up Menu 11 Enter the password if required and press the key 111 The display asks for the SPC POINT enter the value measured for the reference gas i e 70 C in the above example using the Scroll and A and V keys and press the J key 1v The display asks for the SPC VALUE enter the stated value for the reference gas 1 e the value that you want the SADPmini to read at this point 69 C in the above example using the Scroll and A and Y keys and press the 1 key v The SADPmini will revert to the Set up Menu with EXIT highlighted pressing the 1 key will return the instrument to the operating mode and all readings taken will be modified in line with the offset introduced in the above procedure Note The integrity of the calibration will now be dependant on the integrity of the reference standard against which the adjustment has been made To restore the factory calibration and thus the traceability stated in the Certificate of Calibration the SPC adjustment must be removed 5 To remove a SPC from the SADPmini select C dewpoint units and carry out the SPC procedure above and enter the SADPmini lower limit values for both the SPC Point and Value Security Description This sub menu allows the user to alter any of the three user defined 4 digit security codes see 8 4 above Operation In the Setup Menu select the Secu
29. lly select to log data to TAG1 Also EMPTY means the TAG reference has not been defined using Create TAG and as such is not useable Each TAG can store up to 20 separate data files called data blocks which can hold up to 12800 downloadable measurements Once the required TAG reference is selected the user is required to enter an interval between readings in minutes The default setting is 0 1 minutes or 6 seconds As the interval is changed the SADPmini displays the length of time that the unit could successfully log data for in terms of memory space Note this forecast is not an indication of battery life long tests should be performed on external power Page 17 of 33 11 2 2 Pressing the key starts the logging process and brings up the Internal LOG display screen which indicates the current moisture value the number of data points read and the TAG reference where the data is stored Pressing the A key at any point will stop logging Note A minimum of 4 stored data readings is required for the data to be reviewed by the SADPmini Review Data Description This function allows the user to review data stored in the unit s internal memory in both tabular and graphical format Operation In the Logging Menu select the Review DATA option The user is then presented with the Review TAGs menu showing all current TAG references Highlight the required TAG reference and press the
30. n 1 GND Connector Pin 8 Viewed from solder bucket side RS485 A RS485 B GND CON066 Page 24 of 33 17 SADPmini Logging Software Cables and Interfaces There are 2 types of interface that can be used with the SADPmini and SADPmini Logging software 17 1 RS232 to RS485 Cables amp Interface Recommended for Windows XP Vista and Windows 7 The Interface unit INT007 has two 9 way D type connectors The connector marked with a B connects to a PC or Laptop serial Port using a 2 0m serial cable Part No CABO029 The connector marked with a S connects to the SADPmini using a 1m special cable Part No CAB032 The INT007 has a facility to connect a 12v DC power supply 2 5mm plug with positive tip This supply is only required when the PC or Laptop connected to the SADPmini is not able to supply 100mA Generally PC s do not require this power supply Laptops may require the supply for distances above 15m RS232 side and 275m RS485 side B CAB029 m me a INT007 S PC Page 25 of 33 17 2 USB to RS485 Cables amp Interface Recommended for Windows XP Vista and Windows 7 The Interface unit INTOOS has a 9 way D type connector and a USB connector The USB connects to a PC or Laptop USB Port using a 1 8m USB cable Part No CABO031 The D type connects to the SADPmini using a 1m special cable Part No CAB033 Note The drivers for the USB Interface are supplied on the included CD Whe
31. n Windows asks for the drivers simply insert the CD and navigate to it USB Cable CABO31 me gt Page 26 of 33 18 Technical Details of the RS48514 20mA Connecter CON066 The CON066 connecter can be wired as a 4 20mA connector or as a dedicated RS485 connecter The CON066 is a kit of parts consisting of 2 half shells 1 2 locating screws 2 2 fixing screws 3 a D type connecter and 4 assorted size clamps 4 To assemble the CON066 follow the sequence below using the diagram for reference l Ze 3 4 Solder wires to the correct bucket pins of the D connecter see appropriate section for pinouts 16 1 for 4 20mA and 16 2 for RS485 Select the appropriate clamps 4 for the cable being used Insert 1 half of the clamp 4 in the bottom half shell 1 Place the D connecter in the bottom half shell 1 ensuring the bottom edge of the connecter is situated in the slot Pass the cable over the half clamp 4 Connect the top half of the clamp Insert the 2 locating screws 2 ensuring the screw threads protrude through the D connecter Offer up the top half shell Secure using the 2 fixing screws 3 Ho d Ce 47 3 38 3 La Note This connecter is not used in conjunction with the SADPmini logging software See section 17 0 for cables used with the SADPmini logging software Page 27 of 33 19 SA
32. n display screen will display the pressure at which the Dewpoint reading is calculated Operation In the Setup Menu select the Pressure Calc option In the Pressure Units sub menu run through the options until the required engineering unit is highlighted confirm the selection by pressing the lt key The SADPmini then requires that a numerical pressure value be entered in the selected units The display format relates to the pressure units chosen Once a pressure value is entered the SADPmini automatically reverts to the Exit option in the Setup Menu Note See SADPmini Specification for detailed information on Pressure Engineering Units Warning This function is purely an internal calculation and DOES NOT allow an elevated pressure to be applied to the measuring head 11 1 3 4 20mA Output 4 20mA and Full Logging SADPminis only Description The 4 20 option allows the user to set the range over which the 4 20mA output will span The default setting is for the output range to cover the full operating range of the sensor type fitted in the SADPmini e g for a B type sensor output 4mA equals 80 C and 20mA equals 20 C However it is possible to set a more focused range such as 4mA equals 60 C and 20mA equals 20 C Operation In the Setup Menu select the 4 20mA Output option The SADPmini requires that a value be entered for the 4mA lower limit The current val
33. not Not a Logging N A Upgrade unit to Logging Work version see Type version 1f required Contact Label Alpha No communication with PC See Logging Software trouble shooting section 4 20mA output does not work Not a 4 20mA version see Type Label N A Upgrade unit to 4 20mA version if required Contact Alpha Unit does not read the Unit needs AutoCal Perform AutoCal as per Upper Limit when head manual open AutoCal Failure Sensor sensitivity Repeat AutoCal If AutoCal Fails contact too low supplier to replace sensor Unit always reads Lower Sensor cable broken Repair Cable Limit Unit will not dry down to Sieve Wet Perform service on unit Service kit available from Lower Limit using Service Kit supplier O Ring Failure Perform service on unit Service kit available from using Service Kit supplier Battery has short life between charges Battery reaching end of life Replace battery Order BAT005 from supplier Unit does not respond to key presses uProcessor Locked Up Press the reset switch under the port cover Situated behind the pinhole Keypad damaged Check function of keypad electrically Contact Supplier If Required Action does not correct the fault then contact your supplier Page 32 of 33 24 Appendix D SADPmini Specification Unit Details Dewpoint Ranges Accuracy Resolution
34. o restore the factory calibration and thus the traceability stated in the Certificate of Calibration the SPC adjustment must be removed 4 To remove an SPC from the SADPmini follow the above procedure to step iii Then select the REMOVE SPC option and Press the J key The SADPmini will revert to the Set up Menu with the SPC removed SPC Procedure firmware 6 05 or earlier 1 Ze An AutoCal must be carried out before performing an SPC For SADPmini s with firmware versions 6 05 and earlier the SPC procedure can only be carried out with the instrument set to read in C dewpoint The firmware version can be read in the INFORMATION section of the Set Up Menu Page 14 of 33 11 1 6 3 Measure the value of the reference gas with the SADPmini in the normal way and note the indicated value and the stated value of the standard reference For example the SADPmini reads 70 C dewpoint and the standard reference gas is certified by the gas supplier as being 69 C dewpoint If the value for the standard reference gas is stated in other units such as ppm v it must be converted to C dewpoint a Moisture Calculator is available on www dew point com that can be used to do this The instrument can now be removed from the gas sample to conserve the reference gas 4 Select SPC from the Set up Menu and press the key i On the warning screen press the 1 key to continue pressing Scro
35. on It is possible to communicate with up to 32 SADPmini units via the RS485 However for this to operate correctly each unit must have a different address The default address setting for the SADPmini is 1 Operation In the Logging Menu select the Unit Address option The user is then required to enter the required address using the standard numerical editor format Pressing the key confirms the new address 11 2 10Free Space Description This routine allows the user to see how much space is available in the SADPmini memory in terms of logged readings Operation In the Logging Menu select the Space Free option The screen automatically reverts to the Logging Menu after 3 seconds 11 2 11Exit Description The Exit option allows the user to return to the normal display Operation In the Logging Menu select the Exit option 12 Pressure Correction When a line pressure is entered see 11 1 2 and C or F have been selected the displayed moisture value is pressure corrected The fact that pressure correction is active is indicated by the phrase 10 barg or some variation been displayed Pressure corrected values are also used in the External Log and Internal Log screens when C or F are the selected units Page 21 of 33 Warning This function is purely an internal calculation and DOES NOT allow an elevated pressure to be applied to the measuring head
36. ponse time with minimum flow 6mm OD 1 4 tube can be used where pressure drops across the 3mm tube are too high Filter Unit A filter unit is recommended when the samples are likely to contain particulate matter If the air gas sample contains heavy hydrocarbon condensate the Page 4 of 33 filter must be of the coalescing type with a drain The filter unit should be positioned as close to the sample point as practical 4 Pressure Reduction Valve or Pressure Regulator the sample is measured at atmospheric pressure requiring that valve 4 is fitted to the system 5 Flow Control Valve 6 Sample Connection 7 SADPmini 8 Flow Indicator The recommended sample flow is 5 to 20 L M 9 Sample Exhaust The exhaust is vented to atmosphere or returned to an atmospheric pressure line Purging the sample connection Refer to the sample system schematic in section 4 1 It is advisable to carry out an initial purge of the sample loop before connecting the SADPmini in order to avoid the possibility of sensor damage on start up Open the sample isolation valve 1 slowly until there is a small flow of air gas at atmospheric pressure from the pressure reduction valve 4 into SADPmini line Allow the air gas to exhaust through the sample connection 9 The SADPmini is not flow sensitive however the sample flow needs to be enough to purge the sensor head effectively so anything less than 1 litre min would mean that the in
37. rity option In the Select Code sub menu run through the options until the required code is highlighted confirm the selection by pressing the key The user is then requested to enter the current old security code If the correct code is entered the user is then requested to enter the new security code Failure to enter the correct code will drop the user back into the Setup Menu The default value for all security codes is 1000 Note 0000 is a special code that deactivates the security code for the selected functions Where 0000 is used the security code screen will be bypassed Page 15 of 33 11 1 7 11 1 8 11 1 9 Time and Date Description This function allows the user to view the set Time and Date without having to enter the Set Clock function see section 11 1 8 Operation In the Setup Menu select the Time and Date option Set Clock Description The Clock option allows the user to set the SADPmini internal Real Time Clock Operation In the Setup Menu select the Set Clock option The user is prompted to enter the Date in the DD MM YY format followed by the time in the HH MM SS in 24 hour format Note Although the seconds digits are displayed they are not selectable Information Description The Information menu displays all of the SADPmini current settings Operation In the Setup Menu select the Information option
38. scecsceseessacsesecceeeaueuessscecsesseuneasncesess 7 1 SAMPLE PIPE T2 GASSES TO AVOID 7 3 SAMPLE CONDITIONING 7 4 PRESSURE AND FLOW CONTROL 7 5 PARTICULATE CONTAMINATION 7 6 LAQUID CONTAMINATION EEEE EEN T S E TE E E E ET 8 SADPMINI INITIAL CONFIGURATION ccccecsccccccccsssssceccccccssesssssceccceccausaesesccesceaeeaeaseesceseeaeanenss 9 THE NORMAL DISPLAY SCREEN i0scs2 i3 720 28 ss svtnend iaa e 10 SADPMINI OPERATING PRINCIPLES ccccccccccccsssssceccccceucesssesccccceceusessseecccceeauausssececceeceuaaaeneesess 10 1 NAVIGATING THROUGH MENUS 10 2 ENTERING NUMERICAL DATA ccccocoocononnnonconononnnnononconononnananoncnoos 10 3 ENTERING ALPHANUMERICAL DATA 10 4 SECURITY PROTECTION SCREENS cccessessscecececeeseaececccecsensneceeececeeseaeseeececsenesaseseeseeesesssaeeeeeeeeeeneea 1 OPERATING THE SADPMINT ssdcccsvadscwes obs acevsvabanvesca E iaa ias 11 1 THE SETUBMEN Ut EEE A AO Nets intra 11 1 1 Select Units 11 1 2 Pressure Calc 11 1 3 4 20mA Output 4 20mA and Full Logging SADPminis only cee cceeeseseeeceseeeceeseeeeeseeeceeeeecneveesneaees 11 11 1 4 AutoCal ods 11 1 5 SPC Single point Calibration sy seid eee ead ae a A i 13 E A A A RAS RON 15 11 1 7 Time and Date 16 11 1 8 Set Clock 16 11 1 9 Information 16 11 1 10 Temperature 17 11 1 11 Elida soot ge SUG A Meh ariel inte RelA Gk Ane Gin ek
39. strument would take too long to settle to a stable reading The flow should also not be so high that the gas velocity could physically damage the sensor or cause backpressure in the sensor head so should not exceed about 20 litres min Allow this purge to continue for 2 minutes to remove any residual moisture from the sample pipe work and components Check that no liquid or particulate contamination which could damage the sensor is passing through the sample pipe Directing the sample onto a piece of white paper such as a filter paper will make it easier to see any dust or oil mist in the sample Using the SADPmini to take a Moisture Reading Refer to the sample system schematic in section 4 1 The first purpose of the SADPmini is to provide a rapid easy and reliable means of carrying out moisture content measurements of gases To ensure rapid response the sensor is kept dry by surrounding the sensor with desiccant in the head assembly when it is not in use The SADPmini can display moisture readings in any one of six Engineering Units and can also display pressure compensated readings The SADPmini should be setup as required See The Setup Menu section before progressing to take sample readings Page 5 of 33 6 1 Taking a Measurement After purging the system to be monitored fit the SADPmini sample pipe to the sample connection 6 Allow the gas to purge for a further 2 minutes with the head down SADPmini Head Lowered SADPm
40. t affect the calibration of the sensor It will restrict the movement of water molecules across the surface so increasing the time it takes for the sensor to come to equilibrium with the water vapour concentration around it If the liquid is hygroscopic such as glycol the buffering effect described for desiccant dust may be so great that the sensor becomes too slow to use SADPmini Initial Configuration Each SADPmini is set up prior to despatch to the end users specification The following values will be preset e The specified sensor type is pre selected e The calibration data will be set to values that are applicable to the specified installed sensor The AutoCal value is set to match the installed sensor The clock will be set to the correct date and time GMT Moisture units set to C Dewpoint Pressure units set to barg pressure value set to 0 Security codes are set to 1000 No Single point calibrations Page 8 of 33 9 The Normal Display screen When the SADPmini is ON it displays the moisture level of the gas that the sensor is exposed too When the head is lowered the sensor is no longer exposed to the gas and is dried down by the desiccant in the head a El 4 9 1 44 Moisture Units PAS Pressure Value and units gt C Dewpoint ppm V gt 1 0barg HN E al Examples of the Main Display Screen The Display always shows the current moisture level that the internal sensor is exposed too
41. ue is displayed in the active moisture engineering units Once the new value is entered the SADPmini requires that another value be entered for the 20mA upper limit Once that new value is entered the SADPmini automatically reverts to the Exit option in the Setup Menu Note 1 The only way to leave this menu without altering any values is to press the key twice accepting the current values for both the upper and lower settings 2 The 4 20mA range settings are reset to full span whenever the moisture units are altered 3 The 4 20mA output should not be operated while the instrument is charging Page 11 of 33 11 1 4 AutoCal Description AutoCal allows the user of the SADPmini to ensure accuracy between laboratory calibrations by checking the span of the instrument and correcting for any deviation ACAL adjusts slope of curve New settings stored in SADPmini Inst Reading 100 The AutoCal facility uses the fact that each sensor is designed and manufactured to give no further increase in response when it reaches its maximum moisture level For example an SADPmini with a full scale value of 20 C dewpoint will read 20 C dewpoint when exposed to a gas with this moisture concentration and will continue to read 20 C dewpoint as the moisture concentration rises above 20 C dewpoint The SADPmini can therefore be adjusted to read 20 C dewpoint on any gas with a moisture concentration wetter than 20 C de
42. w the sensor to stabilise Start the AutoCal routine and enter the ambient moisture value into the SADPmini when asked to enter the AutoCal Value 14 2 Reference gas Connect the SADPmini to a reference gas raise the SADPmini head and ensure that a flow of 5 to 8 L M is obtained Allow the sensor to stabilise so that the gas surrounding the sensor in the SADPmini head is representative of the reference gas moisture value Start the AutoCal routine and enter the reference gas moisture value into the SADPmini when asked to enter the AutoCal Value 15 SADPmini 4 20mA Note The 4 20mA output should not be operated while the instrument is charging The 4 20mA signal gained from the SADPmini is loop powered only The connections are 4 20mA output CON066 connector Pin 5 Loop Power input CON066 connector Pin 9 Viewed from solder bucket side Loop Return CON066 ve Loop Supply Note See section 16 for details of CON066 assembly 15 1 SADPmini 4 20mA Circuit ve Loop Supply pin 9 ZVP4424A Loop Return pin 5 Page 23 of 33 15 2 Calculating Maximum Output Load Rex Rext Vexr 0 6 105 0 02 Examples VEXT 5V Rext 1150 Vexr 12V Rext 4650 Vexr 15V Rext 6150 VEXT 24V Rext 10650 Vextr 28V Rext 12650 16 RS485 Communications The RS485 Half Duplex communications signal is driven by a MAX3471 interface chip The SADPmini connections are RS485 B Connector Pin 7 RS485 A Connector Pi
43. wpoint ambient air for instance thus setting the span to match the original calibration AutoCal should be operated periodically every 2 to 3 months say or can be used to verify operation of the SADPmini if confirmation of an unexpected result is required Operation of SADPmini units with full scale values of 20 C or 0 C dewpoint 1 Select AutoCal from the Set up Menu 2 Follow the on screen instructions 1 e i Extend the desiccant head and press the 1 key 11 The SADPmini will display a moving bar until it assesses that the sensor has stabilised Up to 10 mins iii The SADPmini will now display the full scale value of the unit either 20 C or 0 C If the unit is being checked against a known moisture level such as from a moisture generator the scroll and A and W keys can be used to enter the known moisture level otherwise leave it set at the full scale value and press the 1 key iv The SADPmini will display a moving bar whilst the calibration data is modified Up to 5 mins v Close the desiccant head when instructed to do so and press the lt key vi The SADPmini will return to the Set up Menu with the EXIT option highlighted Pressing key again will return the instrument to operational mode Note Avoid carrying out the AutoCal procedure on a SADPmini with a full scale value of 0 C dewpoint on days when the ambient dewpoint may to be below this value for example a dry day when the ambi
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