Introduction

Pantech Instrument�s Model 902 is an extended version to its predecessor model 901. Model 902 is a Humidity Transmitter + RTD sensing element. The Sensing + Transmitter circuits not only senses the %RH value , but also does convert it into 2-wire 4-20 mA DC signal, for use of the higher instrumentation or controlling layers. The load capacity of this 4-20 mA DC signal is 600 ohms. Model 902 series is often ideally suited for low drain, battery operated systems. The basic HUMIDITY sensor inside the probe gives quality RH ( Relative humidity ) sensing performance in a competitively priced package. The RH sensor is a laser trimmed, thermoset polymer capacitive sensing element with on-chip integrated signal conditioning. The sensing element�s and transmitter PCB�s multilayer construction provides excellent resistance to most application hazards such as wetting, dust, dirt, oils and common environmental chemicals. For TEMPERATURE measurement, a miniature but high quality RTD is installed inside the basic sensor. The model is a fully configurable one, microprocessor based type. The model incorporates low drift operational amplifiers and industrial grade componenets. Burn in of each module ensures a long trouble free operation