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RH CAL 

Relative Humidity Calibrator

 

      

  OPERATORS MANUAL

 

 

 
 

 

 

 

 
 

399 River Road 

●  Hudson, MA USA 01749 

  Tel. [508] 263-5900 

● [800] 276-3729 ● Fax [508] 486-9348  

                                                                                     E-mail [email protected] 

● www.edgetechinstruments .com 

 

 

 

 

 

 

                                 

Rev. A  

March 2011

Summary of Contents for RH CAL

Page 1: ...Relative Humidity Calibrator OPERATORS MANUAL 399 River Road Hudson MA USA 01749 Tel 508 263 5900 800 276 3729 Fax 508 486 9348 E mail h2o edgetechinstruments com www edgetechinstruments com Rev A Mar...

Page 2: ...ents Inc s Commitment to Quality 9 6 0 N I S T Traceability What does It Mean 10 7 0 Glossary 11 8 0 Installation 12 8 1 Unpacking 12 8 2 Wiring Connections 12 8 3 Water Fill 13 8 4 Air Connection Opt...

Page 3: ...eory of Operation 30 13 2 Automatic Balance Cycle 31 13 3 Care and Maintenance of the Sensor 32 14 0 Maintenance 33 14 1 Routine Maintenance 33 14 1 1 Mirror Cleaning Schedule 33 14 1 2 Cleaning the M...

Page 4: ...on 16 11 1 The Information Display 18 12 1 Keypad 21 12 2 Changing the RH Setpoint 22 12 3 Changing the AT Setpoint 22 12 4 Selecting Dew or Frost 24 12 5 Locking In the Changes 25 13 1 Chilled Mirror...

Page 5: ...NIST Traceable Optical Chilled Mirror primary measurement technique the RH CALIBRATOR was developed for precise calibration of RH Sensors and Transmitters as well as laboratory and research applicatio...

Page 6: ...setup and operation of the control unit can be programmed via the front panel keypad or the RS 232 serial port LCD Graphics Display Displays three parameters simultaneously time date operational stat...

Page 7: ...cycle Serial Port The RS 232C serial port can be used to remotely program setup parameters initiate an ABC cycle or output data to a local or remote terminal printer or computer The data output funct...

Page 8: ...r other literature ii the items have not been misused or abused in any manner or repairs attempted thereon iii written notice of the failure within the warranty period is forwarded to Edgetech Instrum...

Page 9: ...want you to be entirely satisfied with your instrument The information contained in this manual will get you started It tells you what you need to get your equipment up and running and introduces its...

Page 10: ...RH Dew Point is a fundamental measurement of humidity It is not affected by temperature In addition the chilled mirror dew point sensor in your RH CAL provides a primary rather then a secondary measur...

Page 11: ...just before the ABC cycle Hysteresis The tendency of a sensor to give one set of readings when going up and a different set of reading when going down Mirror A small metallic reflective surface withi...

Page 12: ...ipping Plug should be installed to prevent water leakage 8 2 WIRING CONNECTIONS Connect the RH CALIBRATOR to a grounded instrument quality power source of between 100 to 240 VAC 50 60 Hz There are no...

Page 13: ...face In case of overfill draw the excess water into the syringe and bring the water level below the clear portion of the fill tube Total capacity of the Saturator is approximately 40 ml 2 3 full syrin...

Page 14: ...14 9 0 BASIC BLOCK DIAGRAM THEORY OF OPERATION Figure 9 1 Basic Block Diagram...

Page 15: ...ontrol the sensor mirror temperature which tracks the Dew Point up and down as it changes An Air Temperature AT sensor is also installed in the Test Chamber Mounted in each of these sensors is a preci...

Page 16: ...T 6 DIGITAL OUTPUT 8 ON OFF SWITCH Figure 10 1 RH CAL Panel Description 1 Air Inlet Sample In Brings in room air for use in the system An Instrument Air line may also be connected 1 4 inch compression...

Page 17: ...Analog Output Can be programmed to provide information for Dew Point Air Temperature or Percent Relative Humidity User may select either 0 to 5 VDC or 4 to 20 ma 8 ON OFF Switch Turns Power ON or OFF...

Page 18: ...and allowing calibration points to be easily programmed NOTES 1 The RS 232 Serial Port along with a computer or terminal may also be remotely used for the same purpose 2 All programming is in non vol...

Page 19: ...e dew layer on the chilled mirror surface The right hand vertical bar indicates the mirror itself and the white bars show the actual dew layer The layer can be seen to vary in thickness as the control...

Page 20: ...rd indicating that the fans and vacuum pump are operating 12 1 SYSTEM STATUS The status of the RH CAL control systems may be seen in the upper right corner of the Display When first turned on it will...

Page 21: ...put indicates MAX HEAT During an ABC cycle MAX HEAT MAX COOL does not function Figure 12 1 Keypad NOTE Turning on MAX HEAT turns off MAX COOL and vice versa Both cannot be activated simultaneously COO...

Page 22: ...R key to accept the new setting and the ESC key to exit the menu Figure 12 2 Changing the RH Setpoint RH SETPOINT AT SETPOINT OR SERIAL PORT ON OFF The RH SETPOINT AT SETPOINT and SERIAL PORT all have...

Page 23: ...the range are programmable The output is factory set at 0 5 VDC 4 20ma output can be selected from the main circuit board inside the RH CAL See the Maintenance section ABC CYCLE The Automatic Balance...

Page 24: ...in chilled mirror dew point sensor will maintain a thin layer of dew on the surface when it is measuring a dew point mirror temperature above freezing It will maintain a thin layer of frost on the sur...

Page 25: ...nside the chamber run the sensor cables through the supplied rubber seals If a longer sensor or an entire RH transmitter is being calibrated insert the measuring portion of the RH sensor into the cham...

Page 26: ...such as with a PC or Terminal a communication or terminal emulation software package is needed on the PC There are many inexpensive communication programs readily available Two such programs are Hype...

Page 27: ...e displayed on the computer terminal screen Start an ABC Cycle This command initiates an ABC cycle at any time The cycle is the same as a programmed ABC cycle Type the letters AB and press the ENTER k...

Page 28: ...onds Type the letter O and press the ENTER key Enter the desired interval in seconds and press ENTER Poll for Output This command requests the RH CALIBRATOR to send serial data at any time and is inde...

Page 29: ...ssed in 24 hour military time Enter the desired time with colon delimiters Examples 00 00 00 12 midnight 23 59 59 11 59 59 pm Units F C The RH CALIBRATOR can display temperature in either Degrees C or...

Page 30: ...ting in a reduction of light as seen by the direct photodetector and an increase in light as seen by the scatter photodetector These signals are next sent to a servo amplifier which controls power to...

Page 31: ...on the surface The amount of light received from the dry mirror is then measured and a correction in the servo loop is made normalizing the system balancing and compensating for the contaminant layer...

Page 32: ...imizes the requirement for mirror cleaning eventually the system will have to be shut down and the mirror cleaned A CLEAN MIRROR indication displayed at the end of the ABC cycle tells the user when cl...

Page 33: ...een routine mirror cleanings can be easily achieved However if the sample contaminants are particularly high more frequent mirror cleanings may be required When cleaning is required clean the mirror s...

Page 34: ...rror The only service that can be performed in the field is to lift the Panel and check for a loose connector in the mirror control system or call the Factory 14 1 3 DRYER TUBE MAINTENANCE When the Dr...

Page 35: ...ed syringe add clean distilled water up to the level of the panel surface no higher If excess water is seen use the empty syringe to remove the excess Replace the reservoir cap firmly If necessary rep...

Page 36: ...e required fuse value is 3A 3AG 250VAC Slo Blo For power line voltage between 150 to 240 VAC the required fuse value is 1 5A 3AG 250 VAC Slo Blo For European use Use Type T fuses For nominal 230 VAC t...

Page 37: ...37 Figure 14 5 DIP Switch Configuration SWITCH NUMBER Where O Open C Closed OUTPUT 1 2 3 4 4 2O mA C O C O 0 20 mA O C C O 0 24 mA O O C O 0 5 VDC C C O C...

Page 38: ...nt and Ambient Temperature Accuracy 0 2 C 0 36 F nominal Dew Frost Point and Ambient Temperature Sensors 3 wire Platinum Resistance Thermometer PRT 100 ohms at 0 C nominal Precision 0 1 degrees C or F...

Page 39: ...pin D sub miniature connector female RS 232C compatible Half Duplex Protocol N81 Baud Rates 2400 4800 9600 19200 Functions Timed output of date time Dew Frost Point Ambient Temp and RH Programmable Ou...

Page 40: ...52 4W x 43 7D x 21 7H cm 20 5 8W x 17 3 16D x 8 9 16H in Power Requirements 100 to 240 VAC 50 60 Hz 150 Watts maximum Fuse For U S Operation 100 150 VAC Operation 3A 3 AG 250 VAC Slo Blo 150 240 VAC O...

Page 41: ...Notes...

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