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WetBoss - Relative Humidity Sensor


WetBoss - Relative Humidity Sensor - Environmental Sensor

WetBoss Relative Humidity SensorWetBoss Relative Humidity Sensor
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WetBoss Relative Humidity Sensor -- Sensing humidity may seem easy, reflecting back on the original horsehairs and the like, but indeed, precise monitoring of RH is anything but easy. There is a fair amount of snake-oil in the industry, i.e. specs boasting of 0-100% ranges, knowing full well that the very low and very high ends are only estimates, and shrouded by the 5% FS tolerance.

The mystique deepens when one discovers the virtual impossibility of reliably field recalibrating an RH sensor. Recognizing that the only way to assure continued accuracy, Rel-Tek engineered a field replaceable sensor head that can be simply plugged in without having to recalibrate the unit. In essence, the factory calibration follows the head, not the base unit. We make no bones about it, our unit is dependable between 5-95%. And, we can assure continued accuracy throughout the entire life of the product.

Thus, the WetBoss*100 has evolved over a dozen years into an honest, dependable, quality product that does the job without a whimper. Every year or so you can replace the sensing head -- a five minute job -- returning the sensor to its factory new calibration. Powered by 12-30VDC, 4-20ma, 2-wire hookup. It is MSHA classified for hazardous methane areas. A digital meter can be purchased for front panel mounting to continuously display the RH reading in 1/2" high characters. The WetBoss*100 is US-manufactured and serviced. Rely on Rel-Tek for the best solutions.

Spec: 5-95% RH, 4-20ma, 2-wire transmitter

Technology: Capacitance detector

The WetBoss*100 senses ambient relative humidity (RH) and transmits a linear 4-20ma analog signal for remote readout. It consists of an electronic module and a sensor module, mounted in a 5x5x2" plastic housing supplied. The WetBoss*100 is powered by the signal current flowing in the current loop. The 2-wire hookup simplifies installation and checkout. The signal current range corresponds with 0% and 100% RH, factory adjusted at 60-80F. Special circuitry maintains the 4-20ma signal accurate over a wide range of input voltages and line-plus-termination resistances, Transmission range can be as far as several kilometers, depending on voltage drop conditions around the circuit. Required input voltage is 10-30VDC at sensor terminals.

The effective range of the WetBoss*100 is 5-95% RH, with accuracy of +/- 5% RH over an ambient temperature range of 0-70C, 32-150F. Storage temperature is -25 to +70C, -13 to 150F). Storage humidity range is 0-100% RH, without condensation. Temperature dependence of RH readout is about +0.1% RH per degree C. Unit is calibrated at normal ambient conditions 22C (72F). A calibration adjustment pot is provided. Electronic circuits are potted in epoxy for protection against physical damage, water and dust intrusion. Interchangeability of sensing modules is normally within +/- 5% RH. Time constant in still air is about 10 minutes. An optional dual-screen dust filter protects the humidity sensing element from accumulations of dust, mud, etc. The filter is replaceable.


Item Code Catalog
WetBoss*100 (complete) 7.1900 WB100
add digital meter, installed add -D
Relay Module, 2 thresholds; in separate box RM420i
Filter assembly WB-FLT/A
RH calibration kit KAL-KIT/RH

The WetBoss is US/MSHA classified G, issue #49 for use in hazardous methane areas when properly powered through intrinsic safety barriers. Unit is also covered under MSHA MultiBoss evaluation file, Classes G, H and L, issues 95, 32 and 64, respectively - as well as in Canada NRCan(EMR) #1053 - for use in hazardous (methane and natural gas).

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WetBoss is a registered Rel-Tek trademark.