IP3112-B318-0000 by Beckhoff

The IP3112-B318-0000 is a four-channel analog input module produced by Beckhoff within the IP Compact Box Units series. Designed for machine-mounted installation, the device converts 0/4-20 mA current signals from sensors into digital data that a controller can use for closed-loop control. By placing A/D conversion close to the transducer, it minimizes electrical noise and shortens wiring runs in distributed industrial automation systems.

Each input is galvanically isolated up to 500 V, protecting upstream electronics from field transients. The module tolerates a maximum differential offset of 35 V between each sensor pair and ground, so loops that share supply rails remain protected. A single sample is completed in 140 ms, a period that balances noise rejection with the cyclic update demands common in HVAC or utility monitoring. Ten programmable digital filters are available, and selecting one of the 10 modes lets the user balance response speed and ripple suppression. Converted values leave the A/D stage with a native resolution of 15 bits plus sign, allowing fine discrimination across the 20 mA span.

The differential front end presents an input resistance of 80 ?, ensuring loop integrity without placing an appreciable burden on powered transmitters. An external supply can provide up to 30 VDC to the connected transmitters. Four channels share a common internal ground and appear to the controller as a process image with four 16-bit inputs, simplifying PLC addressing through the PROFIBUS tee connector on the housing. After calibration, the absolute measurement drift remains within ±0.3% FS over the stated temperature range, maintaining accuracy when modules are mounted side by side. Screw-in M12 connectors simplify cable attachment, while the compact enclosure supports installation directly on the machine. This arrangement reduces the amount of sensor wiring that must be routed back to the control cabinet.