Dwyer WHT-31A Weather-Resistant Humidity/Temperature Transmitter is a reliable and accurate instrument for monitoring humidity and temperature. It has a drift of less than 1% RH/year and an accuracy of ±0.9°F @ 72°F for 4-20 mA output. It operates within a wide temperature range of -40 to 140°F and has a response time of 15 s. With its NEMA 3S (IP54) enclosure rating and ABS enclosure, it is designed to withstand harsh conditions. The transmitter utilizes a capacitance polymer sensor for humidity measurement and has a range of 0 to 100% RH. It is available in various power requirements and offers multiple output signal options. The electrical connections are made easy with a removable screw terminal block. The storage temperature limits are -40 to 176°F. With a repeatability of ±0.1% and hysteresis of ±1%, it provides stable and accurate measurements. The temperature sensor uses a solid-state band gap for 4-20 mA output and a 10K @ 25°C thermistor (Dwyer curve A) for passive output. The sensor accuracy for humidity is ±2% from 20 to 80% RH and ±3% from 10 to 20% and 80 to 90% RH.