B&R X20BM36 X20 SafeIO Backplane Bus Base Module

Technical Overview

The B&R X20BM36 (X20BM36) is a high-integrity backplane bus base module integrated with hardware address coding switches, engineered specifically to support the B&R X20 SafeIO functional safety module portfolio. Developed for deployment in safety-critical industrial applications like emergency stop loops, light curtain curtains, and automated robotic cells, this specialized infrastructure hardware coordinates fail-safe communication routing and internal power delivery to eliminate network collisions and minimize safety-related plant downtime. The module provides the essential mechanical and electrical backplane interface that binds the functional safety electronics to the high-speed X2X Link safety network. Featuring a connected-through 24 VDC I/O power line, it supports a permissible contact load of 10 A to ensure reliable current distribution across multiple adjacent safety slices.

Technical Configuration

The internal electrical routing and physical addressing mechanisms of this safety bus base prioritize deterministic configuration and hardware abstraction:

• Integrated Node Number Switches: Outfitted with two physical rotary hexadecimal switches (x16 and x1) to hard-code unique network node addresses directly on the backplane, independent of the plugged-in functional electronics.

• SafeIO Keyed System: Specifically modified to accept and validate X20 functional safety slices (such as safe digital inputs or outputs), preventing standard non-safety modules from being accidentally inserted into the slot.

• Continuous Power Distribution: Incorporates a continuous, uninterrupted internal 24 VDC I/O power backbone capable of carrying high current levels through to adjacent system nodes.

• Extremely Low Power Overhead: Operates with an optimized internal bus power draw of just 0.13 W, preserving backplane power capacity for complex functional safety microcontrollers.

Technical Specifications

Industrial Application FAQs

• Why does a safety module require a specialized bus base like the X20BM36 instead of a standard X20BM11?

  The X20BM36 features unique mechanical keying slots and optimized internal trace routing designed specifically for the X20 SafeIO safety modules. Additionally, the integrated manual node switches allow the permanent assignment of a safety node ID to the physical slot location. This design ensures that if a safety electronic slice is replaced during maintenance, the safety loop retains its certified addressing parameters without requiring software re-commissioning.

• Can the 10 A internal power line be split to isolate safety outputs from safety inputs?

  No. The internal 24 VDC I/O power bus inside the X20BM36 is connected through continuously to maintain potential equalization across the rack segment. To set up separate power zones or execute safety-directed power isolation, you must place a dedicated X20 potential isolation module or power supply module upstream of the safety group.

• What happens if the rotary node number switches are left in the 0x00 position?

  Setting both hexadecimal switches to 0x00 switches the module to default automatic addressing mode. While functional in standard I/O segments, many certified functional safety configurations require manual, deterministic node identification. Always consult your safety application manual to ensure compliance with relevant safety integrity level (SIL) specifications.

Field Engineering and Installation Directives

SAFETY VALIDATION NOTICE: Modifying the rotary node number switches changes the hardware address of the safety node on the X2X Link network. Any change to these switches must be followed by a full system safety loop test and validation log update to verify that the safety PLC maps the intended physical device.

Bus Base Interlock and Alignment

Snap the X20BM36 bus base cleanly onto a standard 35 mm symmetric DIN rail. Slide the base firmly to the left to mesh its gold-plated side slide connectors completely with the preceding module. Ensure that both the top and bottom integrated plastic locking tabs engage with an audible click. Misalignment will degrade the 10 A continuous power contact, leading to localized thermal heating and intermittent safety network timeouts under full operational loads.

Slot Cleanliness and Protection

The module features an IP20 open-type finger-safe rating when an electronic slice is fully installed. If the X20BM36 must sit empty on the DIN rail during staged machine assembly phases, install a standard X20 slot cover over the exposed pins. This barrier prevents conductive airborne particles, metal shavings, and moisture from contaminating the backplane contacts and triggering an internal bus short circuit.