Product Description:

The X20DO4F49 is a relay-based digital output module from B&R Automation, supplied within the X20 Fieldbus Input Output Modules series. Installed on a remote I/O slice, it interfaces a controller with external solenoids, indicator lamps, or interposing contactors by converting low-level logic signals into field-side switching actions. Its role in industrial automation is to provide electrically isolated, high-voltage-capable contacts so that a PLC can actuate AC or DC loads without routing large currents through the backplane.

Each channel can interrupt or conduct up to 2 A of alternating current, allowing the module to drive modest single-phase devices directly. The permissible mains potential reaches 240 VAC, which covers standard plant distribution levels for lighting and small actuators. When the load is direct current, the contact rating drops to 0.28 A to limit arc energy and contact erosion, while the voltage ceiling remains 250 VDC so that inductive valves or relays on rectified supplies can still be switched. Internally, the four relays are wired as 2 NO + 2 CO, giving designers a mix of normally open paths for straightforward on/off tasks and changeover contacts for signal inversion or redundancy circuits.

The module presents 4 individually isolated outputs that the CPU addresses by bit position within the fieldbus image. Its output function is classified as a Digital Output, meaning each relay follows the logic state without proportional control. Because the output type is a mechanical Relay, the channels are free from leakage current and can switch either polarity, which simplifies wiring of mixed loads. The mechanical design aligns with neighboring slices for consistent rail installation. Appropriate suppression on inductive loads helps extend contact life when kickback or inrush currents are present.