Product Description:

The X20HB1881 is produced by B & R Automation for the X20 Fieldbus Input Output Modules series. As a hub expansion module, it slots into an existing X20 backplane and redistributes optical fieldbus traffic so additional remote I/O stations can be attached without changing the control program. In factory lines or process skids where long distances and high-noise environments challenge copper links, this module extends deterministic communication through a fiber segment while remaining transparent to the master controller.

The signal path relies on a fiber-optic medium, giving high immunity to electromagnetic interference and ground-loop problems. It works with multimode cable, so standard glass fiber can be used for runs inside panels or along conveyor structures. A dedicated SC receptacle provides 1 fiber connector, and the module includes 1 hub port for regenerating and forwarding telegrams. Fiber transmission also avoids the potential for ground-loop currents that can disturb copper-based links in mixed-power cabinets. Non-condensing operation protects the optics, and moisture must stay below 95% RH to keep the ferrules clear. When mounted horizontally, the electronics tolerate ambient temperatures up to 60 °C, allowing placement near drives or power supplies inside compact enclosures.

For cold-start conditions, the module remains functional down to -25 °C, so outdoor cabinets can be energized without preheating. If the carrier is installed vertically, self-heating increases and the upper limit drops to 50 °C, which matters when racks are stacked closely. This lower vertical limit should be considered when the module is mounted beside drives or other heat-producing equipment. Reliable data flow is supported up to 2000 m above sea level, covering most inland production sites without reducing link performance.