Honeywell RTD Input Module Model no :- 621-0025RC Origin :- USA Input Isolation :- 300VAC Peak Point to Point OR Point to GND IPC 620 RTD Input Module 8 Channels (RIM) The model 621-0025RC Resistance Temperature Detector Module (RTDM) is an input device that can read resistance sent from RTD probes. As the module reads the signals, an analog-to-digital converter within the RTDM changes the signals into binary counts. A Control Processor Module can then read the counts and determine how to control the process that the probe is monitoring. The RTDM is typically used in process and batch process applications that require precise temperature measurements for long periods of time. Reactors and ovens are examples of devices that the RTDM can monitor. The range of temperatures that the RTDM can measure is -300 to 900¦F (-184 to 482¦C).