Product Description:

The X20BB82 is a base unit manufactured by B&R Automation for the X20 Fieldbus Input Output Modules series. Within an automation cabinet, this part provides the mechanical and electrical backbone that links individual I/O slices to the system bus and distributes supply power along the row. Its function is to hold a defined group of slice modules, manage their fieldbus connection, and pass 24 V DC power so that digital or analog signals from the machine can be collected and forwarded to a central controller.

The base draws only 0.70 W from the internal bus, which minimizes the load on the upstream supply rail. All electronics referenced on the carrier operate from a regulated 24 VDC nominal voltage, which is a standard level in low-power control cabinets. Physical alignment inside the backplane is fixed by an 87.5 mm (+0.2) pitch, helping terminal blocks and neighboring modules remain flush across the assembly. The unit provides 2 expansion slots, allowing auxiliary function modules to be added directly next to the base without additional wiring. The predefined structure of 1 base, 2 add-on, 1 supply simplifies layout because the sequence of elements and the resulting current path are already determined by the hardware.

The enclosure meets the IP20 protection rating, so live conductors are finger-safe, but the unit must still be installed in a closed control cabinet to avoid moisture and dust exposure. Signal routing through the internal connector can carry up to a 10 A permissible contact load, which is sufficient for the typical sensor and actuator currents handled by X20 slices. The carrier can be mounted in horizontal or vertical orientations without derating, which supports both compact panels and tall rack layouts. The package includes left and right end cover plates included, which seal the segment edges and help maintain touch protection across the entire node.