t Dewpoint Tra n s mit d i br Hy T USER’S M A D H Xe n t a u AL U N er poration r o rC
HDT User’s Manual When calling your representative for technical support, please have your serial numbers available. The Sensor and Instrument Serial Numbers are engraved on them. Sensor Serial No.: _______________ Instrument Serial No.
HDT User’s Manual Xentaur reserves the right to change or modify the product specification and / or appearance at any time without notice. Therefore, the information in this document is subject to change without notice and does not represent a commitment on the part of Xentaur Corporation.
HDT User’s Manual Examine the HDT package for damage or mishandling. If any damage is evident notify the carrier and request an inspection. Unpack the box, it should contain: The HDT with sensor in desiccant container, a mating connector, and this manual. PLEASE READ THIS MANUAL IN WHOLE, PRIOR TO INSTALLING OR REMOVING THE SENSOR FROM ITS SHIPPING CONTAINER. This manual is organized in three sections: Section 1 is an overview of the HDT. Section 2 describes the sensor and sampling techniques.
HDT User’s Manual Warranty Xentaur instruments are 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. The equipment must be determined by Xentaur to have been defective for the warranty to be valid.
HDT User’s Manual HDT User’s Manual Table of Contents 1.0 Overview of the HDT ...................................................1 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 2.
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Section 1: Introduction 1.0 Overview of the HDT The HDT is a microprocessor based 4-20mA loop powered (2 wire) hygrometer, for measuring moisture content in gases or liquids in a wide range from -100°C to +20°C dewpoint in gases; and 0 ppmW to 1000 ppmW in liquids. The measurement is transmitted by varying the current drawn (4-20mA) from the power supply. The current varies linearly proportional to the selected measurement units.
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Section 2: Sensor and Sampling Techniques 2.1 Precautions using the sensor The Xentaur HTF™ Al2O3 sensor is designed and field proven to be highly reliable, rugged and maintenance free. However the user should consider the following precautions: • • • • • • • • • To avoid the need for prolonged dry-down (when expecting to measure dewpoints dryer than -65ºC), do not expose the sensor to room air longer than necessary (1 - 2 minutes).
HDT User’s Manual 2.2 Sensor Technical Specifications Type: .................................Hyper Thin Film high capacitance Al2O3. 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). XTR-60 ..........................-76°F to +68°F (-60°C to +20°C). XTR-LQ.........................for use in liquids. Capacitance:......................15nF to 200nF. Accuracy: ..........................±5.5°F (±3°C).
Section 2: Sensor and Sampling Techniques (water, oil etc.), and particulates. The sintered stainless steel sensor encapsulation protects from particulates larger than 100 microns, finer particulates (e.g. from degraded desiccant or rust) should be filtered with a particulate filter with suitable capability, do not use hygroscopic filter materials. 2.3.
HDT User’s Manual or removing the sensor.
Section 2: Sensor and Sampling Techniques Refer to the ESS literature for more information. If the resources to make your own sample system are available, the following two diagrams may be used as a guideline to configure a simple system.
HDT User’s Manual • ppm readings are computed for a pressure of one atmosphere (1 bar); and have to be corrected using a pressure nomograph, or calculator if the sensor is measuring at different pressures. If readings at line pressure are necessary, it is recommended to measure at ambient pressure and to use our dewpoint calculator to obtain the dewpoint at line pressure. Please make sure that: • The sample is taken from the upper surface of the main gas line. This avoids problems with contamination.
Section 2: Sensor and Sampling Techniques • • If filters are used upstream of the sensor, make sure these contain non-hygroscopic filter materials only. If pressure regulators, shut off valves etc. are used upstream of the sensor, make sure these do not contain rubber or other hygroscopic materials. 2.
HDT User’s Manual Troubleshooting unexpected readings (table spans 2 pages) Symptom Reading is not changing Possible Cause Condensation in sample system. Slow Response Dry Reading 1. Water vapor in the system. 2. Flow rate too low. 3. Sample pipe too large and/or too long. 4. Unsuitable sample pipe material. 5. Leaks 6. Hygroscopic materials in sample system faulty sensor. Leak in system or use of unsuitable pipe. Wet Reading Comparison of readings with manual cooledmirror instrument. 1.
Section 2: Sensor and Sampling Techniques Troubleshooting unexpected readings (continued from previous page) Symptom Diagnostic/Remedy Reading is not changing Condensation will occur if the temperature of the sample system, at any point is below (colder) the dewpoint temperature of the sample gas. Once having formed, the sample reaching the sensor will have a dewpoint equal to the temperature of the condensation, regardless of the dewpoint of the sample at the sample point.
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Section 3: Instrument 3.1 Precautions using the HDT The HDT uses state-of-the-art microelectronics to provide a miniature full functioning transmitter. The user should consider the following precautions when using any sensitive electronic device. • Do not install the unit near heat sources such as radiators or air ducts. • Do not install the unit in places subject to extreme mechanical vibration or shock. If this is not avoidable, use resilient mounting. If in doubt, call your representative.
HDT User’s Manual HDT and its wiring as practical. 3.2 Instrument Technical Specifications Enclosure: ...........................Stainless Steel. Dimensions & Weight:........~1.25”Dia. x ~5.68” long including sensor & connector (see appendix C) 0.5lbs. Pressure operating range:....Standard: ...........500 PSI (34 bar). Optional:5,000 PSI (340 bar). Operating Temperature: ......-22°F to 185°F (-30°C to +85°C). Mechanical connections:.....14mm x 1.
Section 3: Instrument ing DPT.00.D.7042. refer to appendix E 3.3 Installation 3.3.1 Mechanical Installation The HDT has two thread sizes (refer to Appendix C) for mounting to the sample cavity (consult the sensor installation section) where the dewpoint will be measured. Various adapters are available for direct connection into existing system openings. Ask your representative for a Sample Cell, if you do not have the ability to provide an appropriate sample cavity mounting.
HDT User’s Manual cooldown time. When selecting the power supply voltage do not neglect the voltage drop across any current measurement resistor and wiring in the loop. The connector is an Industrial Standard 9.4 mm, 4 pin connector. IP65 NEMA 4X. Please observe connector polarity when plugging in the HDT cable. Please align the wider earth ground pin (marked ) to the wider slot on the connector (marked ). Note that the wider slot is on the same side of the connector as the cable grip stem.
Section 3: Instrument Various strategies for interfacing with the HDT are shown in Appendix D. Please observe good electrical safety and grounding practices when connecting any electrical equipment; connecting one end (e.g. negative) of the power supply to earth ground is advisable. After the installation is complete, proper detection by the user’s equipment of the 4-20mA output, may be verified by confirming the measurements in the first few seconds after power up refer to Appendix A. 3.
HDT User’s Manual Symptom (more than 25 sec after powerup) Possible cause Current Loop Pin 3 Instrument failure High impedance Fixed at ~3.8mA Fixed at 21mA ‡ 4 to 20 mA Fixed at 4mA Intermittent (0V-3V) 1200 baud RS-232 data EEPROM checksum failure High impedance Cycle power, if problem persists return instrument Loop voltage insufficient Check power supply's capability to maintain at least 5V at 20 mA. see appendix A 1. open sensor 2.
page 19 0 4 10 20 0 ~3.5mA for 4 sec 4 4.5mA for 8 sec 8 12 16 20 If the HDT is in Polling Mode, then the loop test is bypassed the HDT begins measuring and loop goes to 4mA within 5 seconds of powerup. Data is obtainable only through the HART digital interface. EEPROM Checksum Fault (stay at ~3.8mA) 4.
page 20 0 power on high impedance high impedance high impedance high impedance 4 8 12 16 idle 20 24 28 32 Response Code byte 2, bit 6 PIN 3: Float =0, Ground =1 On the next HART message HDT pulls pin 3 to 3.
Appendices Appendix C: HDT Mechanical Drawing page 21
stainless steel sintered filter connected to loop negative Voltage Regulator 4/20mA Bell 202 modem page 22 0.001µF 10KΩ Housing shield 28V 100mA resetable fuse Xentaur Hybrid Dewpoint Transmitter Loop Power 5V-28V DC, will draw 4/20mA ( pin1= +VE; pin2= -VE ) Stainless Steel mounting threads and housing are electrically connected to the wider pin marked with the ground symbol " ". They are isolated from the current loop and sensor. µP 47Ω RFI filter 4/20mA loop 4/20mA loop C ma x.
Appendices Appendix D: HDT Block Diagram & Connections (cont) Hookup strategies from preliminary manual Suggested relay hookup page 23
pin GND Cable typically 20-60pF/ft. 3 4 Customer or vendor provided equipment E.g. Xentaur XDT, Panel Meter, DCS, etc. Control Equipment 2 Revisions Description Date Imax & Ci updated 3/7/05 per graph B3 and new capacitor C19 Pmax Vmax 6/8/05 The Associated Apparatus must be a linear output device. Control equipment connected to Associated Apparatus must not use or generate more than 250VRMS. Associated apparatus manufacturer’s installation drawing must be followed when installing this equipment.
pin 2 pin GND Cable typically 20-60pF/ft. 3 4 1 2 Revisions Description Date Imax & Ci updated 3/7/05 per graph B3 and new capacitor C19 Pmax Vmax 6/8/05 Customer or vendor provided equipment E.g. Xentaur XDT, Panel Meter, DCS, etc. Control Equipment 2 Rev Approved BB BB The Associated Apparatus must be a linear output device. Control equipment connected to Associated Apparatus must not use or generate more than 250VRMS.
pin 2 pin GND Cable typically 20-60pF/ft. ground shield opptional 3/7/05 6/8/05 Revisions Description Date Div/Zone 2 drwng Div2 Grp E Control Equipment Rev Customer or vendor provided equipment E.g. Xentaur XDT, Panel Meter, DCS, etc. Loop Power 5-28VDC UNCLASSIFIED AREA 1 2 page 26 WARNING - Substitution of components may impair suitability for Division 2, Zone 2 use. WARNING - To prevent ignition of flammable or combustible atmospheres, disconnect power before servicing.
Appendices DECLARATION OF CONFORMTY ATEX 0539 We declare under our sole responsibility that the following products: Xentaur dewpoint sensors series XTR to which this declaration relates, are in conformity with the protection requirements of Council Directive: 94/9/EC (ATEX Directive) on the approximation of the laws of the Member States concerning equipment and protective systems intended for use in potentially explosive atmospheres, and 89/336/EEC (EMC Directive) as amended by 92/31/EEC and 93/68/EEC
HDT User’s Manual Appendix G: Current vs. Dewpoint The current being drawn by the HDT, varies with the dewpoint being measured by the HDT. To use the current to calculate the value of the dewpoint measurement, one must know the settings of the low and high ends of the analog output range, then: (I – 4) × (H – L) D = ---------------------------------------- + L 16 where: I = current drawn by HDT loop in mA.
Appendices vide a useful output. Consider an example where the area of interest to be monitored is 10 to 100 ppmV, and the analog output is set up with the factory defaults of -100°C to +20°C (which is 0.014 to 23612 ppmV); then the current loop output will vary only from ~4.1 to ~4.2 mA in the area of interest (consult with the graph on the following page). In most instances this would be an unacceptable output for proper monitoring of the measurement.
HDT User’s Manual 10000 1000 Relationship of 4-20mA output and instrument reading in ppmV or LBS 100 ˚C g Hi h AO n ra 00 ge 10 w Lo AO n ra 100 1 1.97 LBS = -50˚C = 38.83 ppmV ge 4.5mA 8mA 12mA 4.1mA 0.1 10 20mA 5mA page 30 Lo w ra n 4/20 mA output AO Hi 5˚ C 5. -6 AO = ra n 0.56 LBS = -60˚C = 10.66 ppmV = gh ge C 5˚ 8. -3 Instrument reading in ppmV = -1 1000 49.3 LBS = -20˚C = 1019.
Appendices Appendix H: Uncertainty in LBS & ppmV calculations 48 44 38 34 1000 900 800 700 29 600 500 19 400 15 300 10 200 5 100 90 80 70 60 2.5 50 40 30 1 20 0.5 10 9 8 7 3˚C 6 0.1 nt + 5 4 poi Dew poi Dew 3˚C nt - 0.25 3 2 0.05 1 0.9 0.8 0.7 0.6 Measured Dewpoint ˚C page 31 -80 -75 -70 -65 -60 -55 -50 -45 -40 -35 -30 -25 -20 0.
% of step change page 32 Time (minutes) 0 5 10 15 20 25 30 35 40 45 50 55 60 65 65% of step change 70 75 80 85 90 95 95% of step change 100 105 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 Response Time of Xentaur Al2O3 Sensors to a Step-change (DOWN) from -39.4 ˚C(dp) at time 0, to -62.
Appendices Appendix J: Return Authorization Request 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.
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