Product Description:

The X20BM31 bus module is manufactured by B&R Automation as part of the X20 Fieldbus Input Output Modules series. It provides the internal power and data backbone that couples a fieldbus interface to the local stack of I/O slices, allowing sensors and actuators to share real-time signals with the controller over a single rail. By slotting this unit next to the chosen coupler, machine builders can create a seamless expansion path for additional digital or analog channels without extra wiring.

This module draws only 0.13 W from the backplane, so the system power budget remains largely unaffected even with many slices installed. A Double-Width housing means it occupies two standard X20 slots, creating space for the integrated bus circuitry while still aligning with neighboring modules. Field wiring lands on Push-In terminals, enabling toolless insertion and secure spring clamping of ferruled conductors. The keying contact is rated at 24 VDC, which helps prevent modules intended for other supply levels from being inserted into the row. For mechanical mounting, the housing snaps onto a TH35-7.5 DIN rail, matching the common 35 mm steel profile used in control cabinets. The bus module is intended for Overvoltage Category II installations, which are located downstream of the main distribution panel where transient energy is limited.

Each push-in terminal accepts a twin sleeve up to 2x 0.75 mm², so paired discrete conductors can be terminated without doubling in the clamp. The enclosure carries an ingress rating of IP20, which is suitable for clean, enclosed racks where no dripping water or dust clouds are present. In transport or service, the housing withstands shocks up to 15 g. During operation, it tolerates continuous vibration levels of 1 g, which suits cabinet-mounted applications on machines with moderate dynamic loads.