PT100/1000 input module for the FX5 rack
The FX5-4AD-PT-ADP is a 4-channel analog input module that reads PT100 or PT1000 RTD temperature sensors directly, resolving to 0.1°C across a -200 to +850°C span. Each channel converts at approximately 85 ms, which sets the practical scan-rate ceiling for a multi-channel temperature loop — if you need faster updates per point, budget for a separate module per sensor or accept the aggregate update time. The module occupies zero I/O points on the FX5 backplane, so it does not eat into the CPU's maximum I/O count — useful when the rack is already dense.
Isolation and wiring considerations
Photocoupler isolation sits between the input terminals and the CPU module, but there is no channel-to-channel isolation — adjacent input channels share a common reference. For cold-storage or freezer applications where sensor runs cross different grounding potentials, the non-isolated channel architecture means you keep the PT100/1000 returns on a common rail and verify the ground loop is not driving offset error at 0.1°C resolution.