Product Description:

The X20DI2371 is a digital input module manufactured by B & R Automation for the X20 Fieldbus Input Output Modules series. As a two-channel unit, it captures 24 VDC control signals from sensors or switches and conveys their states to the host PLC, allowing basic on/off condition monitoring in distributed automation nodes. It is intended for straightforward discrete signal acquisition rather than analog measurement. The module fits small distributed stations where selector contacts, limit switches, and proximity sensors are read directly at the machine.

This module accepts a nominal control level of 24 VDC and evaluates exactly 2 input points that follow the IEC 61131-2 Type 1 characteristic. A sink-type input circuit references the sensor return to the module’s common, while a 3-wire connection scheme routes field supply, signal, and ground in one connector. Transitions are debounced by a hardware filter capped at ≤100 µs, so brief electrical noise is ignored. Logic HIGH is registered above 15 VDC and LOW below 5 VDC, giving clear switching margins. Each channel is galvanically separated from the internal bus by 500 Veff, protecting the backplane against field faults. Overall bus power demand is only 0.12 W, and the logic side draws an additional 0.29 W from the internal I/O rail. The housing carries an IP20 rating for placement in enclosed cabinets, and all inputs are short-circuit proof to prevent damage from wiring errors.

For peripheral devices, the module sources up to 0.5 A through its auxiliary terminals, and the combined sensor load may not exceed 12 W. At that current limit, the feeder path introduces a maximum drop of 2 VDC, which helps maintain adequate headroom for proximity switches and optical emitters placed several meters away. This arrangement suits compact machine panels that use shared field power and still need reliable signal pickup from nearby sensors and switches.