Product Description:

The X20BM05 is a power supply bus module developed by B&R Automation for the X20 Fieldbus Input Output Modules series. It couples the rack’s system voltage to the internal backplane while forwarding fieldbus signals, so downstream slices share one electrical and communication path. Because the bus module is separate from the neighboring electronics slices, control and signal modules can be arranged as needed without changing the basic power feed location. In a controller cabinet, it serves as a compact interface between decentralized I/O assemblies and the central CPU.

The module operates from a nominal supply of 24 VDC and draws only 0.13 W from the bus, which helps limit heat buildup in densely populated racks. It supports manual or automatic addressing, so the node can be assigned locally or by the control system. The backplane contacts are rated for 10 A, which is suitable for feeding higher-current output slices on the same carrier. The housing provides IP20 protection against accidental finger contact, and a connector pitch of 12.5 + 0.2 mm helps keep module alignment consistent during installation. Supported voltage groups also allow separate power domains to share the same mechanical carrier without cross-connecting their loads.

For high-altitude installations, the component can be used up to 2000 m, and above that elevation the permissible ambient temperature must be reduced by 0.5 °C/100 m. Carrier rails can be mounted in horizontal or vertical orientations, which gives more freedom when arranging the cabinet layout. The internal I/O supply is interrupted on the left side, which helps isolate power sections on the carrier and prevents downstream faults from feeding back through this unit. A node number switch is also included, allowing bus IDs to be set directly on the module without software access.