AX5801 by Beckhoff

The AX5801 is a safety relay module developed by Beckhoff for its AX Digital Servo Drives series. Installed alongside a drive controller, it supervises the drive's power stage and issues redundant shutdown commands when a hazardous motion condition is detected. By integrating dedicated relay outputs with the drive's control circuitry, the module allows machine builders to meet stop-category requirements without adding external safety relays or complex wiring.

This module uses two connectors to interface with the drive logic and field wiring. The configuration includes one 4-pin connector and one 6-pin connector to separate supply, signal, and feedback lines. All mechanical contacts are positively driven contacts, so welded-contact faults can be detected through the complementary movement of the linked contact pairs. Internal electronics draw only 50 mA from the controller's auxiliary supply, keeping the load on the 24 V bus low. Two monitoring channels compare encoder-based status with relay feedback, and the safety loop is closed by a potential-free feedback contact for installations where reference potentials must remain isolated. The feedback path is wired in series and can carry up to 0.35 A, allowing it to energize typical control inputs without additional boosters.

Each of the module's two safety relays is driven by a coil rated at 24 V DC, and the overall switching capacity supports systems that require dual-channel interruption of the servo enable line. The functional core supports the safe stop categories STO and SS1, so motion can either be prevented or quickly ramped down while position information is retained for restart routines. Terminals accept conductors prepared to a strip length of 10 mm, ensuring full insertion depth for reliable clamping and consistent insulation clearances within a compact drive cabinet.