DT722 User`s Manual
Contents
1. A d Michell Instruments is concerned with the protection of the environment It is our commitment to reduce and eliminate from our operations wherever possible the use of substances which may be harmful to the environment Similarly we are increasingly using recyclable and or recycled material in our business and products wherever it is practical to do so To protect natural resources and to promote material reuse please separate batteries from other types of waste and recycle responsibly If batteries are not properly disposed of these substances can cause harm to human health and the environment The product that you have purchased may contain recyclable and or recycled parts and we will be happy to provide you with information on these components if required WEEE And RoHS Compliance The Waste Electronic and Electrical Equipment WEEE Directive and the Restriction of Hazardous Substances ROHS Directive place rules upon European manufacturers of electrical and electronic equipment The directives aim is to reduce the impact that electronic devices have on the environment Michell products are currently exempt from the RoHS directive however all future products will be developed entirely using compliant materials Furthermore Michell is taking active steps to remove non compliant materials and components from existing products wherever possible Michell is in full compliance with the WEEE Directive Registration No WEE JBO235V2. DT722 RH amp Temperature Transmitter Duct Mount User s Manual 97332 Issue 1 December 2012 Please fill out the form s below for each instrument that has been purchased Use this information when contacting Michell Instruments for service purposes mm p e PT mm p me p nn TIT mm p e PT me f me p nn Em e PT me f me nn L B MICHELL Instruments DT722 For Michell Instruments contact information please go to www michell com 2012 Michell Instruments This document is the property of Michell Instruments Ltd and may not be copied or otherwise reproduced communicated in any way to third parties nor stored in any Data Processing System without the express written authorization of Michell Instruments Ltd DT722 User s Manual Contents EE EB V EISCEEI A T EE V terdi d EEN V Repair and Maintenance EE V e e e EE V Se Eere nU ATT V EE a A EEEEHEIE T vi MV EAMG EA Vi t INIRODUCTION aa ie rennen 1 LE E A EE SEE Re 1 2 INSTALLATION E 2 Zaks TEISERRIE CONTENT nen Rn EEE 2 3 CALIBRATION AND ADJUSTMENT PROCEDURE uz222422220020nnnn nn nn nn nn nn nun nn nn n nn nn 3 3 1 Calibration and Adjustment nennen 3 Figures Figure 1 Ee H Figure 2 Ee EE 2 Figure 3 CE E E E A EE OE T eT ere ee J Figure 4 Ree ee 6 Figure 5 EE 7 Appendices Appendix A Technical Specifications ssc c c ee eee ee ee eee eee 5 Appendix B EC Declaration of EE 9 Appendix C Quality
3. Recycling amp Warranty Iotormmatton NEEN 11 C i Py CU ON EEN 11 C 2 WEEE And ROHS EE 11 ORG Manufacturing Quality a i 11 C 4 Calipration Led We EE 12 C 5 PRO CLI POC EE 12 C 6 dE el 12 Appendix D Return Document amp Decontamination Decaraton uk 14 Appendix E Recommended Practices in Humidity Measurements ccccceccseeeeeeseeeees 16 IV 97332 Issue 1 December 2012 DT722 User s Manual Safetv The manufacturer has designed this equipment to be safe when operated using the procedures detailed in this manual The user must not use this equipment for anv other purpose than that stated Do not applv values greater than the maximum value stated This manual contains operating and safetv instructions which must be followed to ensure the safe operation and to maintain the equipment in a safe condition The safetv instructions are either warnings or cautions issued to protect the user and the equipment from injurv or damage Use competent personnel using good engineering practice for all procedures in this manual Electrical Safetv The instruments are designed to be completelv safe when used with options and accessories supplied bv the manufacturer for use with the instrument Toxic Materials The use of hazardous materials in the construction of this instrument has been minimized During normal operation it is not possible for the user to come into contact with anv hazardous substance which might be employed in the cons
4. W Customers may be required to return certain instruments for treatment at the end of their working life June 2010 Manufacturing Quality Michell Instruments Ltd is registered with the British Standards Institute for Quality Assurance to BS EN ISO 9001 2008 Rigorous procedures are performed at every stage of production to ensure that the materials of construction manufacturing calibration and final test procedures meet the requirements laid down by our BSI approved Quality System Please contact Michell Instruments www michell com if the product does not arrive in perfect working order Michell Instruments 11 APPENDIX C DT722 User s Manual C 4 C 5 C 6 Calibration Facilities Each unit has an internal reference which is calibrated against our working factory standard and is traceable to VSL in The Netherlands and National Physical Laboratory NPL in the UK Calibration Certificates In addition to the normal calibration procedure each internal reference transmitter can be supplied with its own VSL or NPL traceable calibration certificate Return Policy If a Michell Instruments product malfunctions within the warranty period the following procedure must be completed 1 Notify a Michell Instruments distributor giving full details of the problem the model variant and the serial number of the product 2 If the nature of the problem indicates the need for factory service then the instru
5. basis Any transportation costs for the return of a warranty claim shall reside with the Customer 12 97332 Issue 1 December 2012 DT722 User s Manual APPENDIX D Appendix D Return Document amp Decontamination Declaration Michell Instruments 13 APPENDIX D DT722 User s Manual Appendix D Return Document amp Decontamination Declaration Decontamination Certificate IMPORTANT NOTE Please complete this form prior to this instrument or any components leaving your site and being returned to us or where applicable prior to any work being carried out by a Michell engineer at your site Address Reason for Return Description of Fault Has this equipment been exposed internally or externally to any of the following Please circle YES NO as applicable and provide details below Please provide details of any hazardous materials used with this equipment as indicated above use continuation sheet if necessary Your method of cleaning decontamination Has the equipment been cleaned and decontaminated NOT NECESSARY Michell Instruments will not accept instruments that have been exposed to toxins radio activity or bio hazardous materials For most applications involving solvents acidic basic flammable or toxic gases a simple purge with dry gas dew point lt 30 C over 24 hours should be sufficient to decontaminate the unit prior to return Work will not be carried out on any unit that does not have a complete
6. but not instruments unless designed for this The lower the moisture content to be measured the more dramatically the required drying time multiplies Avoid hygroscopic materials At low humidity anything much below a dew point of 0 C the amounts of water given off by organic and porous materials can dramatically affect the value of humidity The lower the level of moisture the more significant the effects Choose impermeable materials to avoid inward diffusion of moisture through sampling tubes and enclosures Steel and other metals are practically impermeable PTFE Teflon is only slightly permeable and will usually be satisfactory for dew points above 20 C and sometimes below this level Materials such as PVC and rubber are relatively permeable and so totally unsuitable at low humidity and not really satisfactory in any humidity range Surface finish of pipework is important for very dry gases Even the tiny quantities of water adsorbed on the surfaces of non hygroscopic materials can have significant effect Polished or electropolished steel is recommended for the best results Clean environments are always best for humidity measurements but this is especially critical at very low humidity Even fingerprints harbour water High purity cleaning agents are recommended Analytical Reagent AR quality solvents for oil based contaminants and purified water distilled or de ionised for salts Cleaning should be followed by th
7. d decontamination declaration Decontamination Declaration I declare that the information above is true and complete to the best of my knowledge and it is safe for Michell personnel to service or repair the returned instrument rn a MICHELL FO121 Issue 2 December 2011 Instruments 14 97332 Issue 1 December 2012 DT722 User s Manual APPENDIX E Appendix E Recommended Practices in Humiditv Measurements Michell Instruments 15 APPENDIX E DT722 User s Manual Appendix E Recommended Practices in Humidity Measurements The following text is reproduced with kind permission from the National Physical Laboratory It is originally published in the booklet A Guide to the Measurement of Humidity Definition of Relative Humidity Relative Humidity The ratio of the actual vapor pressure to the saturation vapor pressure over a plane liquid water surface at the same temperature expressed as a percentage This is commonly understood when the term X percent relative humidity is used For actual vapor pressure e and saturation vapor pressure e e relative humidity in x 100 e S USAGE The phrase relative humidity is commonly abbreviated RH although this is not a recognized abbreviation Values of relative humidity are commonly expressed in units of percent relative humidity RH Recommended practices in humidity measurements General practical recommendations e Where relative humid
8. e used or filters emploved Oscillations in pressure due to pumping can sometimes be reduced or buffered using a needle valve or a reservoir of large volume e Special treatments such as filtration can change the amount of moisture in a gas Some drving agents take out other gases too e When sealing anv sensor or probe into a port or manifold in a duct or chamber leaks through the probe or electrical cable should be considered These are not alwavs sealed against passage of ambient air e Where sampling involves a step change in temperature pressure or gas flow rate relative to the process being sampled results mav need to be converted or interpreted For example pressure dew point will differ from the value found after expanding the gas sample to atmospheric pressure Care should be taken to distinguish between gauge and absolute values of pressure Dew point in general The measuring environment and all parts of the sampling pathway must be kept above the dew point if condensation is to be avoided Electrical trace heating or other heating methods should be used if necessary An excess temperature of 10 C above the dew point is usually a safe margin e For measurements in the region below 0 C it must be clear whether the condensate is dew or frost Failure to distinguish between these can result in errors of about 1 C for every 10 C below zero Michell Instruments 17 APPENDIX E DT722 User s Manual Relative humidit
9. idity lt 2 RH 5 95 RH Accuracy at 25 C 77 F S S Stability RH Sensor 1 RH year Response time RH Sensor lt 10 sec typical for 90 of the step change Electrical Specifications Output Signal 4 20 mA Supply Voltage 8 to 32 V DC Supply Voltage Influence 0 01 RH V typical Operating Specifications Operating Humidity i Probe Housing Storage 10 to 9590 RH non condensing Operating Temperature Probe 40 to 150 C 40 to 302 F Housing 20 to 70 C 4 to 158 F Storage 230 to 75 C 22 to 167 F Mechanical Specifications Ingress Protection IP65 NEMA 4 level Housing Material Stainless steel Refer to Figure 4 Dimensions Weight 200mm 800g 7 87 28 2202 300mm 900g 11 81 31 750z 500mm 1040g 19 69 36 680z 900mm 1412g 35 43 49 800z 1500mm 1970g 59 05 69 480z Electrical Connections 5 pin M12 Michell Instruments 5 APPENDIX A DT722 User s Manual Dimensions 120mm O 78mm 3 07 0 47 lil 38 0mm 1 49 4 x HOLE 5 5 mm 0 21 19 05mm 0 73 200 0 mm 7 87 300 0 mm 11 81 500 0 mm 19 68 900 0 mm 35 43 1500 0 mm 59 05 B18 5mm 0 73 Figure 4 Dimensions 6 97332 Issue 1 December 2012 DT722 User s Manual APPENDIX A 80 0mm 3 15 68 0mm 2 6 T B ss mmm rm 4 x HOLE 5 5 mm 0 21 This drawing is actual size and can therefore be photocopied and u
10. itv is of interest a direct measurement of relative humiditv is usuallv best Where an absolute measure of humiditv is needed choose dew point vapor pressure or similar measurements e Establish the measurement requirements at the purchasing stage in order to have the right instrument for the job o Allow hygrometers to equilibrate in any new environment This is particularly necessary after changes in temperature due to transportation or storage Depending on the instrument and on how great the change in conditions this may require from only a few minutes to many hours o Follow Michell Instruments care instructions for the instrument Some instruments need routine cleaning or other maintenance Before using anv solvent cleaner check with Michell Instruments that this will not harm the sensor or other materials of construction e Wherever possible ensure that hvgrometers are calibrated under the conditions of use i e at similar values of humiditv and temperature and if relevant in similar conditions of pressure airflow etc e Keep a record of calibrations and anv adjustments to the hvgrometer This will show the long term stabilitv of the instrument and allow the associated uncertaintv to be assessed e Check instruments if possible at intervals between calibrations bv comparison with another stable instrument to monitor for long term drift Routine checks are also useful before and after subjecting an instrument to transpor
11. ment should be returned to Michell Instruments carriage prepaid preferably in the original packaging with a full description of the fault and the customer contact information 3 Uponreceipt Michell Instruments will evaluate the product to determine the cause of the malfunction Then one of the following courses of action will be taken e If the fault is covered under the terms of the warrantv the instrument will be repaired at no cost to the owner and returned e If Michell Instruments determines that the fault is not covered under the terms of the warrantv or if the warrantv has expired an estimate for the cost of the repairs at standard rates will be provided Upon receipt of the owner s approval to proceed the product will be repaired and returned Warrantv Unless otherwise agreed the Supplier warrants that as from the date of deliverv for a period of 12 months the goods and all their component parts where applicable are free from anv defects in design workmanship construction or materials The Supplier warrants that the services undertaken shall be performed using reasonable Skill and care and of a quality conforming to generally accepted industry standards and practices Except as expressly stated all warranties whether express or implied by operation of law or otherwise are hereby excluded in relation to the goods and services to be provided by the Supplier All warranty services are provided on a return to base
12. orough drying by a clean method Sample tubing should be as short in length as possible The surface area should be minimised by using the narrowest tubing that the flow conditions will permit Avoid leaks Minimising the number of connections elbows tees valves etc helps with this Adequate flow of the gas sample should be ensured to minimise the influence of sources of stray water in the flow path Dead ends should be avoided as they cannot easily be flushed Back diffusion of moisture should be minimised e g by fast flow rates of gas long exhaust tubes after the sensor or by valves which isolate the low humidity region from ambient air 18 97332 Issue 1 December 2012 DT722 User s Manual APPENDIX E Practical recommendations for specific tvpes of hvgrometer Relative humiditv capacitive sensor Care should be taken to avoid mechanical shock impact or thermal shock sudden temperature changes Sensors should be protected from steam or water sprays and from direct sunlight e Where a sensor is at risk of exposure to dust droplets or the occasional knock during handling the appropriate guard or filters for the sensor head should be used e Anv temptation to breathe on the sensor or to wave it over cups of tea etc should be resisted Filters and saturation guarding mav protect the sensor but these actions carrv a risk of damage bv condensation or other contamination e Protective filters can slo
13. ration interval time Under normal ambient conditions 0 to 50 C 0 to 70 RH and for accuracy of 2 RH an annual calibration is recommended For accuracy of 5 RH a calibration is recommended every five years For environments with airborne chemicals or of high humidity and high temperature conditions more frequent calibration is recommended A humidity generator Michell Instruments S503 S904 or Optical used in combination with a general reference handheld hygrometer is ideal for a quick and accurate calibration For more information on the S503 S904 or Optical humidity generators please contact Michell Instruments see www michell com for contact details 3 1 Calibration and Adjustment For recalibration and adjustment of the product please contact Michell Instruments see www michell com for contact details CONNECTIONS CONNECTOR CABLE SUPPLY 4 8 32 Vdc OUTPUT 2 Temp 4 20 mA max 500 ohm i DO NOT CONNECT for calibration only RER ER OUTPUT 1 RH 4 20 mA max 500 ohm Temp PINS DO NOT CONNECT for calibration only i Figure 3 Connections Michell Instruments 3 APPENDIX A DT722 User s Manual Appendix A Technical Specifications d 97332 Issue 1 December 2012 DT722 User s Manual APPENDIX A Appendix A Technical Specifications Performance Measurement Range RH 0 100 RH Measurement Range T 40 to 150 C 40 to 4302PF Accuracy at 25 C 77 F O OEO Hum
14. sed as a template when mounting the instrument Figure 5 Template Michell Instruments APPENDIX B DT722 User s Manual Appendix B EC Declaration of Conformity 8 97332 Issue 1 December 2012 DT722 User s Manual APPENDIX B Appendix B EC Declaration of Conformitv EC Declaration of Conformitv d MICHELL instruments Ce Manufacturer Michell Instruments B V Krombraak 11 4906 CR Oosterhout Netherlands We declare under our sole responsibility that the product DT722 RH amp Temperature Transmitter complies with all the essential requirements of the EC directives listed below 2004 108 EC EMC Directive Using the standards EN61326 1 2006 Electrical equipment for measurement control and laboratory use EMC requirements Group 1 Class B emissions and immunitv and has been designed to be in conformance with the relevant sections of the following standards or other normative documents EN61010 1 2010 Safety Requirements for Electrical Equipment for Measurement Control and Laboratory Use Part 1 General Requirements Peter Haakma Managing Director Michell Instruments B V Date of Issue November 2012 Michell Instruments 9 APPENDIX C DT722 User s Manual Appendix C Quality Recycling amp Warranty Information 10 97332 Issue 1 December 2012 DT722 User s Manual APPENDIX C Appendix C Quality Recycling amp Warranty Information C 1 C 2 C 3 e Recvcling Policv
15. sinks of water vapor should be avoided in anv sampling svstem Invasion of strav water can be minimised bv attention to leaks hvgroscopic materials droplets and condensation The lower the humiditv the more critical these precautions are e Hvgroscopic materials should be avoided Manv materials contain moisture as part of their structure particularlv organic materials whether natural or svnthetic salts or anvthing Which contains them and anvthing which has small pores Temperature changes can increase the tendencv of these materials to affect the humiditv of the surrounding air e Condensation in a sampling process can invalidate humiditv measurements bv reducing the water content of the gas being measured What is more condensed liquid mav alter the humiditv elsewhere bv dripping or running to other locations and evaporating there In these circumstances measurement results mav be misleading if hvgrometer location is not considered carefully e Water droplets or mist must be avoided These can result in overestimates of the humiditv of the air between the droplets Such results mav exceed 10090 RH or mav be impossible to interpret meaningfuliv Droplets of liquid also damage some electrical tvpes of humiditv sensor Filtering the air sample can eliminate droplets e If pumps are used for sampling gas these should be located after the hvgrometer to avoid contaminating the measurement environment Where possible oil free pumps should b
16. tation or other stress which might lead to a shift in its performance Where the check is against two or more instruments this is even better not only does this add confidence but in the event of one instrument drifting among a set of three it can be seen which reading is most suspect e Cleanliness of the environment will affect different hvgrometers in different wavs Dust and airborne droplets should be avoided or filtered out if possible Contaminants can come from the most surprising sources ordinarv urban pollution for example e The readings given by some types of hvgrometer are sensitive to gas type For any Instrument which reads in terms of mass per unit volume e g in grams per cubic metre it must be confirmed whether the calibration is valid for the gas in use 16 97332 Issue 1 December 2012 DT722 User s Manual APPENDIX E e Avoid using instruments in direct sunlight or near anv other source of heat unless thev are suitabiv shielded to prevent measurement errors Sampling in general o Relative humidity measurements should be carried out at a representative temperature Failure to allow temperature equilibration will lead to a false indication of the relative humidity e Variations in vapor pressure from place to place can occur where an environment is subject to anv addition or removal of water If so care must be taken over where to make a measurement in order to obtain a representative result e Sources and
17. truction of the instrument Care should however be exercised during maintenance and the disposal of certain parts Repair and Maintenance The instruments must be maintained either by the manufacturer or an accredited service agent Refer to www michell com for details of Michell Instruments worldwide offices contact information Calibration Michell Instruments recommends an annual calibration for an accuracy requirement of 2 RH under ambient conditions where temperature is 0 to 50 C 32 to 122 F and relative humidity is 0 to 7090 RH For environments with airborne chemicals or for high humidity and high temperature conditions more frequent calibration is recommended Safety Conformity This product meets the essential protection requirements of the relevant EU directives Further details of applied standards may be found in the product specification Michell Instruments V INTRODUCTION DT722 User s Manual Abbreviations The following abbreviations are used in this manual OC degrees Celsius OF degrees Fahrenheit DC direct current g gram s inch es Ib pound s mA milliampere mm millimeters percentage OZ ounce s RH relative humidity temperature Volts Warnings The following general warning listed below is applicable to this instrument It is repeated in the text in the appropriate locations Where this hazard warning symbol appears in the following sections it is used to indicate areas
18. w the response time of sensors This can be avoided bv removing any filter but the benefit must be weighed against the risk of damage to the sensor e Sensors should not normallv be submerged in liquids In the case of a resistive electrolvtic sensor water or other liquids would certainly damage the sensor beyond repair e Salt solutions are especially commonly used for calibration of electrical sensors and should be provided with traceability directly or via a calibrated hygrometer Protection of sensors from direct contact with salt or solution is most important as contamination would destroy or seriously impair the sensing element Michell Instruments 19 DT722 User s Manual NOTES 20 97332 Issue 1 December 2012 DT722 User s Manual NOTES Michell Instruments 21 MICHELL Instruments http www michell com
19. where potentially hazardous operations need to be carried out vi 97332 Issue 1 December 2012 DT722 User s Manual INTRODUCTION 1 INTRODUCTION The DT722 is a rugged industrial relative humiditv and temperature transmitter designed for process applications where accurate stable measurement and control of humiditv and temperature is required Figure 1 DT722 1 1 Features e Designed for accurate measurement in a harsh environment e Can withstand temperatures up to 150 C 300 F e Stainless steel housing e Calculated moisture signal output optional o Integral loop powered display optional e Stainless steel housing available e 0 to 100 RH 40 to 150 C operating ranges e Long term stability 1 RH over 12 months o M12 fast connector and cable gland Michell Instruments 1 INSTALLATION DT722 User s Manual 2 INSTALLATION 2 1 Electrical Connections Output 2 Temp 4 20 mA max 500 Q DO NOT CONNECT for calibration only Output 1 RH 4 20 mA max 500 Q Ines DO NOT CONNECT for calibration only Figure 2 Electrical Connections 2 97332 Issue 1 December 2012 DT722 User s Manual CALIBRATION 3 CALIBRATION AND ADJUSTMENT PROCEDURE Calibration certifications In addition to the normal calibration procedure each transmitter can be supplied with its own traceable calibration certificate Please ask Michell Instruments or your local distributor for more information Calib
20. y in general Due care must be taken of temperature The effect of temperature on humidity is highly significant Failure to take this into account can sometimes lead to errors so large that the measurement is meaningless In many situations the largest single source of uncertainty in a humidity measurement is the effect of temperature differences from place to place in the process room or chamber The importance of considering the temperature effects carefully cannot be overstated when relative humidity is the parameter of interest Care must be taken when expressing uncertainties changes or fractional differences in relative humidity For example the difference between 50 RH and 52 RH is 2 RH This can also be expressed as a difference of 4 of value It is important to distinguish clearly between these two kinds of statement Recommendations specific to ranges of measurements Ambient humidity Avoid using hygrometers near the body which is a source of heat and moisture Do not breathe close to the measurement High humidity above the ambient range Ample lines should be maintained above the dew point of the gas being measured to avoid condensation Electrical trace heating is often the most practical method Low humidity and very dry gases If possible prepare for measurements by flushing sample lines and hygrometers with dry gas or by evacuating to low pressure Drive off stray residual water by baking assemblies if possible
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