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2500 Humidity Generator

The Model 2500 Benchtop Humidity Generator is a self-contained system capable of producing atmospheres of known humidity’s using the fundamental, NIST proven, “two-pressure” principle. This system is capable of continuously supplying accurately known humidity values for instrument calibration, evaluation, and verification, as well as for environmental testing. Simply apply power and the 2500 will power-up ready to generate. Humidity setpoint values are input by the operator from the front panel keypad and are limited only by the range of the 2500 humidity generator.


  • 0.5 %RH Uncertainty *
  • Traceable to NIST
  • Self Contained and Mobile
  • Automated Control of User Setpoints
  • 2500 ControLog® Automation Software
  • HumiCalc® with Uncertainty Software
  • Computerized Internal Transducer Calibration
  • Low Noise Air Compressor with Air Dryer
  • RS-232C Serial Interface

Key Specifications

  • Relative Humidity Range: 10 to 95%RH
  • Relative Humidity Resolution: 0.02 %RH
  • Relative Humidity Uncertainty: (@ Pc Tc *) 0.5 %RH
  • Chamber Temperature Range: 0 to 70 ºC
  • Chamber Temperature Range: (Optional) –10 to +70 ºC
  • Chamber Temperature Resolution: 0.02 ºC
  • Chamber Temperature Uniformity: ** ±0.1 ºC
  • Chamber Temperature Uncertainty: * 0.06 ºC
  • Chamber Pressure Range: Ambient
  • Gas Flow Rate Range: 5 to 20 l/m

* Represents an expanded uncertainty using a coverage factor, k=2, at an approximate level of confidence of 95%.

** When operated at temperatures within 10 ºC of room ambient temperature.

Typical Applications

The fluid jacketed test chamber can accommodate humidity sensors, hygrothermographs, chilled mirror hygrometers, and various material samples for environmental testing. Virtually any humidity and temperature point may be generated, for any length of time, within the operational limits of the generator. The output of the device under test may then be compared with the generator’s printed data for analysis.

Humidity Sensors And Chart Recorders

Insert humidity probes through the two inch port in the side of the chamber or place hygrothermographs into the chamber and you can: determine humidity calibration accuracy and characterize humidity sensitivity by subjecting the sensing system to a variety of humidity levels; perform operational checks such as the sensing systems capability to correctly calculate and display other humidity parameters; determine the repeatability, stability, hysteresis, and drift characteristics of various humidity sensing systems.

Chilled Mirror Hygrometers

Install the actual chilled mirror head into the chamber or insert a sample tube through the test port and draw a sample through the chilled mirror head and you can: verify mirror temperature measurement accuracy (calibration) when the hygrometer is in thermal equilibrium with its environment; perform operational checks of the heat pump and optical components before and after mirror cleaning and balancing; determine whether the hygrometer is controlling the mirror deposit in the liquid phase or ice phase when operating at dew and frost points below 0 °C; determine if the hygrometer is correctly calculating other humidity parameters; determine the hygrometer’s repeatability, stability, and drift characteristics.

Environmental Testing

The 2500 can serve as a test bed for evaluation and R&D of humidity sensors, humidity sensing systems, and humidity sensitive products, e.g., polymers, composites, film, magnetic medium, blood gas analysis, pharmaceuticals, soil hydrology, consumables, electronics, optics, etc. Depending on the temperature and humidity being generated, the 2500 may operate continuously from hours to months. With continuous generation of a nominal 50 %RH at 21 °C, the reservoir will last about two weeks between refills.