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Xentaur XDT User Manual

Dewpoint transmitter
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  • Page 1 yyyyyyyyy yyyyyyyyy yyyyyyyyy yyyyyyyyy yyyyyyyyy yyyyyyyyy...
  • Page 2 Check the Internet for updates; the latest revision of this manual is available in Adobe Acrobat for- mat at: http://www.xentaur.com Document No.: XDO.01.D.0000 Rev.2.1 5/10/02 Copyright © 2000 by Xentaur Corporation Your Representative is: XDT User’s Manual...
  • Page 3 Swagelok, Cajon are trademarks of SWAGELOK Co. Acrobat is a trademark of Adobe Systems Incorporated Epson is a registered trademark of Seiko Epson Corporation Microsoft Windows is a registered trademark of Microsoft Corporation HTF is a trademark of Xentaur Corporation...
  • Page 4 XDT User’s Manual Examine the XDT package for damage or mishandling. If any damage is evident notify the carrier and request an inspection. Unpack the box, it should contain: The XDT, sensor in desiccant container, connec- torized cable, and this manual.
  • Page 5 XDT User’s Manual Warranty This instrument is warranted to be free from defects in workmanship and materials. Liability under this warranty is limited to servicing, calibrating, and replacing any defective parts of the instrument returned to the factory for that purpose. Fuses are specifically excluded from any liability. This warranty is effective from the date of delivery to the original purchaser.

  • Page 6: Table Of Contents

    XDT User’s Manual Table of Contents 1.0 Overview of the Dewpoint Transmitter model (DT) ...1 2. Sensor and Sampling Techniques ...3 2.1 Precautions using the sensor ...3 2.2 Sensor Technical Specifications ...4 2.3 Sensor Installation & Sampling Techniques...4 2.3.1 In-situ Installation ...5 2.3.2 Extractive Installation ...6...
  • Page 7 XDT User’s Manual Appendix D: Optional Sensor Fittings...41 Appendix E: DT Circuit Board Dimensions...42 Appendix F: Sensor/SpanCheck™ Theory of Operation ...45 Appendix G: Dewpoint Response time Analysis ...46 Appendix H: Sample Gas Filter Considerations...48 Appendix I: DT Grounding Considerations...49 Appendix J: Analog Output vs. Dewpoint...50 Appendix K: RS-232C Interface Protocol ...52...

  • Page 8: Overview Of The Dewpoint Transmitter Model (Dt)

    The measurement is displayed on the instrument’s custom LCD, can be transmitted by optional analog and digital outputs, and can control optional programmable relays. Four front panel but- tons provide the user with a rich feature set. The XDT’s advanced design allows it to be housed in a variety of enclosures.
  • Page 9 XDT User’s Manual...

  • Page 10: Sensor And Sampling Techniques

    2. Sensor and Sampling Techniques 2.1 Precautions using the sensor The Xentaur HTF™ Al sensor is designed and field proven to be highly reliable, rugged and maintenance free. However the user should consider the following precautions: • If the instrument is used to measure moisture in toxic, flammable, or explosive gases, the sam- ple outlet must exhaust to a safe place.

  • Page 11: Sensor Technical Specifications

    XDT User’s Manual 2.2 Sensor Technical Specifications Type: ...Hyper Thin Film HTF™ high capacitance Al Dewpoint range:...XTR-100: -148°F to +68°F (-100°C to +20°C) XTR-65: -85°F to +68°F (-65°C to +20°C). Capacitance:...15nF to 200nF. Accuracy: ...±5.5°F (±3°C) refer to appendix M for accuracy expressed in other units of measure.

  • Page 12: In-Situ Installation

    2.3.1 In-situ Installation In-situ installation is recommended only for measurements where the gas pressure is expected to vary little, the gas is expected to be free of contaminants, the gas temperature is within the operat- ing specifications of the sensor, and there is no chance of liquids coalescing. Examples of applica- tions suited for in-situ installations are: pure gases, output of desiccant dryers (for instrument air), glove boxes, etc.

  • Page 13: Extractive Installation

    XDT User’s Manual 2.3.2 Extractive Installation For extractive installations we recommend our sample system ESS, which may be equipped with a variety of features, such as: isolation valve, coalescing or particulate filter, pressure regulator, calibration sample injection or extraction port, pressure gauge, flow meter, weatherproof enclo- sure.

  • Page 14: Mechanical Installation

    inside these materials. • Try to run pipes to the sensor upwards, so that contaminants tend to fall back into the main line. • Keep the length of the sample line to the sensor as short as possible. • Use small diameter pipes (1/4” or 1/8” OD). •...

  • Page 15: Troubleshooting Unexpected Readings

    XDT User’s Manual 2.5 Troubleshooting unexpected readings If erroneous readings are suspected on a newly acquired instrument, compare the serial number engraved on the sensor sintered filter, to the label on the instrument. The two should be the same; if they are not, the instrument may not be calibrated with the installed sensor. To troubleshoot other problems, identify the unexpected reading category in the following table, and consider the possible causes and appropriate diagnostic action and remedy.

  • Page 16: Instrument

    3.1.1 Electromagnetic Compatibility Considerations The XDT has been designed and verified by testing to meet the requirements of the EC Council EMC Directive 89/336/EEC, for Industrial, Scientific & Medical equipment. The sensor ground is isolated from the AC ground, logic ground, 4-20mA loop return, etc.;...

  • Page 17: Instrument Technical Specifications

    XDT-PM panel-mount, DIN 43700 dimensional standard, optional NEMA 12 type protection gasketing available Dimensions & Weight:...XDT-OEM: 4.25” x 5.15” x 2.25”, 0.6 lbs (fully optioned) without cables. XDT-NEMA: 4.73” x 6.3” x 3.55”, 2.1 lbs (fully optioned) w/cables. XDT-PM: 5.67” x 2.84” x 2.95” DIN 43700 standard, 1.3 lbs (fully optioned) w/cables.

  • Page 18: Installation

    To achieve a good environmental seal the XDT-PM must be mounted onto a rigid flat panel with a cutout according to the specified dimensions, using the provided panel gasket and all four provided mounting brackets. The instructions listed below should be followed.

  • Page 19: Electrical Connections

    The XDT is typically provided to be field wired to operate from AC Mains Power of 100 to 250VAC, 50/60Hz, 10VA, the instrument has an internal 0.5A, 250V fast acting fuse. However the XDT can also be optionally ordered to operate from 15 to 30 VDC 0.5A, with an internal 0.5A 0.5A 250V AC LIVE 4.3mH...

  • Page 20: Ac Mains Electrical Power Connection

    3.3.2.1.2 Low Voltage DC Powered Option - Electrical Power Connection When an XDT is configured with the low voltage DC power option, it can be powered by apply- ing 15 to 30 VDC 0.5A, to the PS+ (#12) and RET (#11) pluggable screw terminals. The positive supply must be connected to PS+, while the negative or ground to RET.

  • Page 21: Interfacing To The Analog Output

    XDT User’s Manual dent relays corresponding to the HI and LO alarms. The relay contacts are rated at 10A 250VAC or 30VDC, instruments for use in division 2 Hazardous Areas have hermetically sealed relays rated at 3A 125VAC. Use wiring appropriate for the voltage and current that will be switched by the relays.

  • Page 22: Interfacing To The Rs-232 Option

    To connect the instrument to a Personal Computer a 3 conductor cable is required; with wires to be placed in the screw terminals of the XDT at one end, and with either a DB9 or DB25 female connector at the other end:...

  • Page 23: Display Conventions

    MODE button on top. There is also a connector provided which allows the use of external switches. The XDT-NEMA makes use of the circuit board mounted push-button switches, to access them one must open the cover of the XDT-NEMA enclosure.

  • Page 24: Operating State

    • With a front plate containing four membrane switches connected to the circuit board, provid- ing the operator with a easy to use interface. XDT (C) 1999 XENTAUR CORP. DEWPOINT TRANSMITTER MADE IN USA CAUTION...
  • Page 25 XDT User’s Manual parts per million by volume computed at the sensor pressure (more about pressure later). The LBS and G/M are density measurements, pounds of water per million standard cubic feet and grams of water per standard cubic meters, respectively, both in Natural Gas, they are computed accord- ing to data derived by IGT Research Bulletin 8, taking into account sensor pressure.

  • Page 26: Alarms

    XDT power loss, or in case of any other errors or failures which will cause the relays to de-energize.

  • Page 27: Start Calibration

    XDT User’s Manual 5. Push the MODE button. The display will show: the ‘DEWPOINT’ indicator means that we are changing the alarm trigger dewpoint 6. Push the UP or DOWN buttons until the display shows: 7. Push the MODE button. The display will show: indicates that we are changing the hysteresis of the alarm.

  • Page 28: Spancheck™ Mode

    3.4.4.3.1 SpanCheck™ Mode The instrument is calibrated at the factory with the sensor it is shipped with and does not need to be re-calibrated prior to installation. Instrument calibration is recommended in approximately 12 month intervals, and the XTR65W sensor should be re-calibrated after prolonged exposure to liquid water. Simply follow steps 1 - 7 of the procedure below, removing the sensor from the sample gas stream.

  • Page 29: Single Point Self Calibration, Manual Or Scheduled

    XDT User’s Manual The instrument will retain the calibration even if the power is turned off. Under certain conditions, an over (super) saturated sensor may need to be completely dried out before a calibration is performed. Symptoms of these conditions are a sensor that will not go through the SpanCheck™...
  • Page 30 point the waiting time may have to be increased - specially if the sensor was wet before the procedure is initiated. Consult with your representative to determine sufficient waiting time for your application. • Make sure the instrument is unlocked. Press the MODE button a few times until the display shows CAL.
  • Page 31 XDT User’s Manual DEWPOINT legends will also appear. Use the UP and DOWN buttons to modify this dew- point to match the dewpoint of the reference gas. Press the MODE button, the display will alternately show 720 / HRS / INTR, indicating that •...

  • Page 32: Viewing Serial Number Mode

    • The instrument will display the measurement using the newly acquired calibration values. The instrument computes the dewpoint from the measured capacitance of the sensor. The sequence of computations is as follows: • The capacitance is converted to percent of full scale (-100°C to +20°C dp), using the low dB, low dew, and saturated dB when performing SpanCheck values.
  • Page 33 XDT User’s Manual CAUTION: 2), 3), 4) and 5) are set at the factory and need only be modified when a sensor is changed. 2. Selecting the sensor type: In this mode the user can select the software matching the type of sensor installed in the instrument: 3&4Adjusting low end sensor attenuation and dewpoint: These modes are used to enter a data...
  • Page 34 a. Go to the CAL/ADJ mode and press the UP button, the display will show the current value, in the range of -1.99 to +1.99 followed by blinking horizontal lines, ignore the alternately dis- played dewpoint. b. Use the UP or DOWN buttons to modify the cal-adjust value as necessary. c.

  • Page 35: Resetable Audio-Visual Alarm Option (Nfpa Compliant)

    The compensation data will be retained even if power is turned off. 3.5 Resetable Audio-Visual Alarm Option (NFPA compliant) When the instrument is ordered with an Audio-Visual Alarm option, it is provided in the XDT- NEMA enclosure, outfitted with two front panel momentary push buttons in NEMA sealed rubber boots.

  • Page 36: Troubleshooting The Instrument

    Under these circumstances the unit display will be blank and the instrument will not draw any current when powered up. The user may replace the fuse with a comparable 0.5A, 250V fast acting fuse, to locate the fuse refer to the XDT mechanical drawing in Appendix Section 3: Instrument...
  • Page 37 XDT User’s Manual DISPLAY LO ERR HI ERR RAM write/read test failed. % ERR Unidentified power-up failure. C.S.F/ EEPROM Check Sum Failed. ERR/AD ERR/REF Reference voltage for A/D out of spec. LO/BAT LO RNG/ Instrument low temperature range TEMP HI RNG/...

  • Page 38: Maintenance

    The XDT-PM and XDT-NEMA instrument enclosures may be cleaned when necessary using a damp (moist) cloth.The XDT-OEM bare circuit board may be cleaned by blowing air across the circuit board. The sensor should not be cleaned as it may be damaged.
  • Page 39 XDT User’s Manual...

  • Page 40: Glossary

    0/24 mA ....range of current for the current loop (0mA=minimum reading, 24mA=maximum reading) 4/20 mA ....range of current for the current loop (4mA=minimum reading, 20mA=maximum reading) - preferred because less than 4mA can indicate a fault or open circuit, also there is at least 4mA available to power equipment...
  • Page 41 XDT User’s Manual used for the circuit (see 4/20) dB ..... see - decibel DB25 ....a style and size of connector - in this case with 25 pins DB9.
  • Page 42 impedance ....the ratio of voltage to current at a specified frequency measured in Ohms, a resistor of the same value would act the same as the mea- sured circuit in-hand micro-climate.
  • Page 43 XDT User’s Manual RG58 ....a type of coaxial cable - the letters/numbers refer to the electrical characteristic of the cable (resistance/capacitance per foot of length) RG6.

  • Page 44: Appendix A: Flow Diagram Of Operating State User Interface

    = faults Flash the relay NUMBERS Sensor CALCULATING CALIBRATION Reading TOO LOW 1 sec New calibration ignore error values are saved XDT User’s Manual Appendices appears when changing settings of locked unit View/Set Sensor Pressure Toggle 14.7 psi View/Set Pressure Confirm SpanCheck...
  • Page 45 XDT User’s Manual Appendices Flow Diagram Operating State User Interface (continued) Manual & Scheduled Self Calibration Flow diagram items not related to Self Calibration are shaded in gray. Power ON initialization and sign on message Toggle Pressure Correction HI/LO ˚C...

  • Page 46: Appendix B: Flow Diagram Of Set-Up State User Interface

    Test Analog Output by forcing it to Hi/Lo high, low or midpoint. (E. G. if Span is 4 to 20, Hi =20mA, Lo=4mA, Mid=12mA) Open cable at BNC connector XDT User’s Manual Appendices go to 4 min anywhere without Operating key press State Temp˚F...

  • Page 47: Appendix C: Sensor Mechanical

    Removable Sensor encapsulated in 100 sintered stainless steel, unscrew to remove. 5/16"-24 tension washer Viton A O-ring 3/4"-16 14mm x 1.25mm 2.230" cable with molded-on male BNC connector female BNC connector 3" min flats for 1 " wrench...

  • Page 48: Appendix D: Optional Sensor Fittings

    XDT User’s Manual Appendices Appendix D: Optional Sensor Fittings...

  • Page 49: Appendix E: Dt Circuit Board Dimensions

    XDT User’s Manual Appendices Appendix E: XDT Circuit Board Dimensions 2.125" Optional Key Pad 0.146" Connector 0.627" XDT (C) 1999 XENTAUR CORP. DEWPOINT TRANSMITTER 0.662" score line, break to fit in PM box CAUTION RELAY VOLTAGE 0.700" 0.350" 0.158" 4.250"...
  • Page 50 Appendix E (continued): XDT-PM Enclosure Mounting Dimensions Standard mounting (with clip-on compression brackets) Environmentally sealed mounting (with gasket and clip-on screw clamp mounting brackets) XDT User’s Manual Appendices...
  • Page 51 XDT User’s Manual Appendices Appendix E (continued): XDT-NEMA Enclosure Mounting Dimensions...

  • Page 52: Appendix F: Sensor/Spancheck™ Theory Of Operation

    (electrodes), thus the original factory measured values will always be valid. What may change is the pore volume, due to clogging with contaminants, residual oxidation, metal migration, etc. Thus to re-calibrate the sensor the XDT User’s Manual Appendices and the...

  • Page 53: Appendix G: Dewpoint Response Time Analysis

    XDT User’s Manual Appendices Appendix G: Dewpoint Response time Analysis Manufacturers of dewpoint sensors will make unbelievable claims of speed. But without support- ing data revealing the conditions under which the measurements were made, such as flow rate, temperature, the dewpoint at which the test was performed, and most importantly the units of measure.
  • Page 54 XDT User’s Manual Appendices Of course analyzing on a wet-up step will produce much faster results, because all sensors are fast on wet up, since Al (like most materials) adsorbs faster than it desorbs. Testing with a small step e.g. in the -10°C to 0°C dewpoint range will produce even faster results, and allow manufac- turers to make far-fetched claims of response time of 5seconds for a 90% of step change.

  • Page 55: Appendix H: Sample Gas Filter Considerations

    XDT User’s Manual Appendices Appendix H: Sample Gas Filter Considerations Sample treatment with pre-filtering may be a necessity in many instances. However the filter housing and element may affect the dewpoint reading and/or the response time of the system. Below is a graph comparing measurements from the same calibrated sensor with and without a filter utilizing a polycarbonate bowl.

  • Page 56: Appendix I: Dt Grounding Considerations

    AC power ground connection to XDT logic ground may be removed but this may cause a EMI problem. Please consult with your representative for information on optional isolated analog and RS-232 outputs.

  • Page 57: Appendix J: Analog Output Vs. Dewpoint

    Appendix J: Analog Output vs. Dewpoint The current output of the XDT, varies with the measured dewpoint. To use the current to calcu- late the value of the dewpoint measurement, one must know the settings of the low and high ends...
  • Page 58 Relationship of 4-20mA output and instrument reading in ppmV or LBS 20mA 12mA 4.5mA 4.1mA Instrument reading in ppmV Instrument reading in LBS of H2O / million cubic feet XDT User’s Manual Appendices 1000 10000 1000...

  • Page 59: Appendix K: Rs-232C Interface Protocol

    The characters sent or received are depicted in bold. Send refers to sending from the host com- puter to the XDT. Receive refers to receiving from the XDT into the host computer. The com- mands and arguments are shown in capital letters while place holders for choices are labeled with lowercase italic letters, with the allowed characters shown below, “nn”...
  • Page 60 The graphic mode may be chosen only for °C or °F, it will plot a graph of the measurement on printers which can respond to the Epson Graphic Commands, and have at least 80 character columns.
  • Page 61 XDT User’s Manual Appendices The printer should have at least 80 character columns, and it is best to use continuous form paper. “?” command Requests a single report of the measurement in the currently selected format. send:? The unit will respond in the format selected with the Data command, for example: receive: -59.3degC...

  • Page 62: Appendix L: Procedure For Exchanging Dt Sensors

    Through the following steps it is helpful to refer to Appendix A: Flow Diagram of XDT Set-Up State User Interface 1. Power up (or reset) the XDT while holding down the MODE key, in order to enter the Set-Up state. Make sure that the instrument in unlocked, refer to section 3.4.5.-10.

  • Page 63: Appendix M: Uncertainty In Lbs & Ppmv Calculations

    XDT User’s Manual Appendices Appendix M: Uncertainty in LBS & ppmV calculations Uncertainty of LBS & ppmV calculations due to +/-3 C measurement accuracy Calculated LBS H 2 O / mmscf Calculated ppmV...

  • Page 64: Serial Number

    Xentaur Return Authorization Number Request Form Xentaur must approve and assign a Return Authorization Number (RAN) to any instrument being returned. The RAN must appear on all paperwork and packaging. The issuance of a RAN does not automatically imply that the instrument is covered by our warranty. In order to serve you better and protect our employees from any potentially hazardous contaminants Xentaur must return unopened at the senders expense all items that do not have a RAN.

  • Page 66: Index

    Index Symbols °C ...17 °F ...17 AC power voltage ...10 accuracy °C,°F specification ...4 calculated lbs or ppmV ...56 adjusting low sensor attenuation and dewpoint ...26 alarms checking ...19 present setup ...19 relay contacts ...10 setting ...19 wiring ...13 ammonia ...3 analog output computation ...50 linearity ...50...
  • Page 67 Index copper tubing ...6 copyright ...i corrosive gases ...3, 20 CSA ...13 cUL ...4 current loop computations ...50 linearity ...50 load ...14 range setting ...27 span select4/20mA or 0/24mA ...27 testing ...27 wiring ...14 DC powered ...13 degrees Centigrade ...17 degrees Fahrenheit ...17 DEMKO ...4, 10 desiccant ...3...
  • Page 68 NPL ...1 oil ...3 operating state ...17 operating state flow diagram ...37 optionally ordered features/capabilities .1 outdoor installation ...9 outputs ...10 overview ...1 parts per million by volume ...17 password protection ...27 plastic tubing ...6 pluggable screw terminal ...12 pounds of H2O per million standard cubic feet ...17 ppm, ppmV ...17 precautions...
  • Page 69 Index voltage, mains supply ...10 warning labels ... iii warranty ...iv water ...3 weather proofing ...9 weight ...10 wiring ...9 alarm relay contacts ...13 analog output ...14 power ...12 requirements ...10 RS-232C ...15 sensor ...13...
  • Page 70 XENTAUR CORPORATION, 84F HORSEBLOCK ROAD, YAPHANK, NY 11980 U.S.A. TEL (631) 345-3434 FAX (631) 345-5349...

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