Temperature / RH Probe

A precision relative humidity and temperature probe which connects directly to the XR440 Data Logger, no external power required. Uses two XR440 input channels, one for temperature (dry bulb) and one for %RH, Wet Bulb, or Dew Point (software selectable).  May also be used with other data acquisition systems, see electrical specifications for details.

• High Accuracy
• Long Term Stability
• Wide Temperature Range

The Temperature / Relative Humidity Probe is available with three leads lengths as detailed below:

For information on using the TRH-100 with other data acquisition systems, see TRH-100 Electrical Specifications below

TRH-100 Electrical Specifications

The following information is provided especially for customers interested in using the TRH-100 Probe with their own data acquisition equipment.

The TRH100 Probe requires 5 vdc excitation at 2 ma max.

Warm-up time (5 vdc power applied until output signal is stable) is 100 ms.

The probe has four 24 awg insulated leads with the following colors and functions:

Black	Signal return (ground)
White	5 vdc excitation
Green	Humidity output signal
Yellow (or Red)	30k ohm Thermistor

The Humidity output signal is typically 0.8 vdc at 0% RH and 3.9 vdc at 100%RH. Each TRH-100 probe ships with individual scaling values typed on a durable label bonded to the probe's cable. Convert the output voltage into %RH using these linear scaling values for ±2% RH accuracy from 0-95% RH.

The Thermistor output signal is a resistance that varies precisely with temperature. A resistance vs temperature table for this thermistor is found in the file 'C.rvt' in the Pocket Logger Software's main directory.

Temperature Compensation

The RH output signal should be temperature compensated.  This compensation is performed automatically by the PACE Pocket Logger Software. If you are not connecting the TRH-100 to a PACE Pocket Logger, use the following formula:

RHc = RH/(1.0546 - 0.00216 * T)

Definitions:

RH = %RH (not temperature compensated).

T = Temperature of TRH-100's temperature sensor in deg. C.

RHc = %RH (compensated for TRH-100 Probe temperature).

Note: Compensation is negligible (<1%RH) in typical conditioned office environments.

Installation

In moist environments, the TRH-100 Probe should be mounted with the stainless steel filter pointing down. This is to allow any water condensate to drain out the sensor and not collect inside the sensor where it could damage the electronic circuitry within the body of the probe.

Temperature / RH Module

TRH-200 Temperature / RH Module

Miniature module plugs into XR440 Data Logger, replacing the detachable terminal block. Uses two channels, one for temperature, and one for relative humidity / wet bulb / dew point. Same specifications as the TRH-100 Probe except for temperature and humidity range (see below). Two channels are available for other PACE sensors, 0-5 vdc or resistive signals.

Operating Temp: -40 to 60°C (-40 to 140°F)

Humidity Range: 0-90% R.H.

Size: 1.61" wide x 0.75" deep x 0.75" high (41mm x 19mm x 19mm). Adds 0.35" (9mm) to Pocket Logger's overall length.

Part No: TRH-200

Part No.	Module Size	Price
TRH-200		RM1,100.00.

Temperature, Humidity and Light Module

TRH-300 Temperature, Humidity and Light Module

Miniature module plugs into XR440 Data Logger, replacing the detachable terminal block. Uses three channels, one for temperature, one for relative humidity / wet bulb / dew point, and one for light. Same specifications as the TRH-100 Probe except for temperature and humidity range (see below). Built-in light sensor is similar to the PACE LS-100 Light Sensor. One spare channel is available for a PACE sensor, 0-5 vdc or resistive signal.

Operating Temp: -30 to 60°C (-22 to 140°F)

Humidity Range: 0-90% R.H.

Size: 1.61" wide x 0.75" deep x 0.75" high (41mm x 19mm x 19mm). Adds 0.35" (9mm) to Pocket Logger's overall length.

Part No: TRH-300

Part No.	Module Size	Price
TRH-300	1ft leads (0.3m)	RM1,350.00.