The ACI Relative Humidity with Temperature Transmitter Room Series utilizes a thermoset polymer capacitive sensing element with a factory applied hygroscopic fi­lter to deliver a proportional analog current or voltage output signal. The hygroscopic ­filter provides added resistance to moisture, dust, and other chemicals for greater long-term reliability. The RH Room transmitter features integral DIP switches for ­field selection of the proper output signal and supply voltage to meet your applications requirements. Each unit also contains 0%, 50%, and 100% test options to verify that the transmitter is both working and wired properly. Field calibration can be performed by using the increment and decrement calibration DIP switches without the need to replace the sensing element. These enhancements provide increased flexibility and outstanding long-term reliability. The temperature transmitter must be powered with 13.5 to 24 VDC power source and can be ordered as either a two-wire 4-20 mA or 3-wire voltage output sensor. The temperature transmitter is installed on the back of the enclosure and must be mounted over a single gang junction box in the wall. There are two styling options in this series which should satisfy most commercial decors. Both styles feature four-way air‑ow to minimize self-heating. NIST Calibration Certi­ficates are available for all RH TTM part series.