The ACI Transmitter Rigid Averaging Series features a two-wire, 4 to 20 mA loop-powered output signal with an optional 3-Wire voltage output signal available. The Rigid Averaging sensors are designed to be installed in small to medium size ducts to give you a better average compared to that of a single point sensor. All transmitters include Zero and Span adjustments for field calibration and are calibrated using NIST Certified Calibration equipment. ACI recommends the use of an 18 to 22 AWG shielded cable for all temperature transmitter installations to help eliminate the possibility of noise being introduced onto the signal lines. The 1K Ohm Rigid Averaging sensor assemblies include a continuous sensing element that covers the entire length of the stainless steel probe and are manufactured using colored Etched Teflon lead wires to differentiate between the sensor types. All units are hermetically sealed using our epoxy material to eliminate the effects of moisture on the sensors. The Rigid Averaging transmitters include a foam pad to properly seal the duct and limit vibration once installed. Optional NEMA/IP rated weather proof enclosures are available as specified on the back of the product data sheet. For best accuracy, ACI recommends the use of the A/TTM Series Matched transmitters with a 3 or 5 Point NIST Calibration Certificate, since they include a second calibration process in which the RTD and transmitter are calibrated together as a system. On larger ducts, ACI’s bendable copper averaging transmitter should be used for better coverage and control of the air inside of the duct.