Using the PDM-75 Portable DewMaster Chilled Mirror Hygrometer

The Model PDM-75 is an acronym for “Portable DewMaster”.  It is a portable, multi-function, optical chilled mirror hygrometer designed to accurately measure the moisture content in gases.  It offers precision dew point measurement in a robust, transportable carrying case.  The PDM-75 uses the chilled mirror (CM) dew point temperature condensation principle to determine the water vapor concentration in gas mixtures, and a precision platinum resistance thermometer to measure the mirror temperature. The CM uses a thermo-electric device to control the temperature of the mirror in determining dew point. Since it is a direct measurement of dew point and thus a Primary Standard Measurement Technique. The PDM-75 is highly regarded by calibration technicians and manufacturing facilities for its portability, accuracy, quick dry down, fast response in detecting upset conditions and long life characteristics.

The PDM-75 may be fitted with a precision air temperature sensor (needed to determine RH), pressure transducer, and a wide range of either local or remote chilled mirror sensors.

Two main types of chilled mirror sensors are available for the PDM-75: the remote mounted D-Probe featuring a two stage air cooled chilled mirror or the S-Series sensor- available in both local and remote mount configurations.  Depending on the desired measurement range, the SSeries sensor is available in Two or Three stage chilled mirror configurations.  To accommodate different cooling thresholds, the S-Series sensor may be air cooled, fan cooled or liquid cooled. In contrast, the D-Probe is only available as a Two-Stage chilled mirror. But since it is configured as a probe, it may be used in a wide array of applications including ambient air monitoring, insertion into glove boxes, HV AC ducts, environmental test chambers, circulation pipes, refrigerated storage rooms, engine test filter rooms.


Troubleshooting Dryer Systems

Diffusion Furnaces

Product Drying Chambers

Environmental Testing

Food Packaging

Medical Packaging

Heat Treat/ Annealing Ovens

Chemical Reactors

Data Center Air Makeup

Fuel Cell Testing

Compressed Air Systems

Pharmaceutical Powder Drying

The PDM-75 offers many standard features including:

  • PRIMARY STANDARD MEASUREMENT:  Chilled Mirror measurement technique

  • NIST Traceable calibration certificate

  • Automatic Balance Cycle (ABC) automatically re-standardizes and corrects for contaminants

  • Programmable Balance Cycle: ABC at programmed intervals or MABC (Manual ABC)

  • Real Time Clock with date

  • Two selectable Analog Outputs (4-20 mA , 0-20 mA, 0-5 VDC, 0-10 VDC scaleable)

  • RS-232 Serial Interface

  • Two programmable electrically isolated alarm relays

  • Integral Flowmeter for control and viewing sample flow

  • Universal VAC Power Input

BENEFITS of the Edgetech Instruments PDM-75:

  • Portable unit great for troubleshooting and convenient measurements

  • The CM Sensor is a direct, Primary Standard measurement method, NIST traceable

  • Improve your quality control: Excellent Precision and Stability

  • Reduce Maintenance Costs: Chilled Mirror is robust, long Life with no moving parts

  • Rapid dry-down time in comparison to other technologies

  • Eliminate Scrap or Lost Time: Fast response in responding to upset process conditions.

Edgetech Instruments Inc.

An ISO 9001 Certified Company

399 River Road . Hudson . MA . 01749

Main: +1 508-263-5900  .  Fax:+1 508-486-9348

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