Beckhoff Automation KS2521 Pulse Train I Module

Beckhoff KS2521 is a one-channel pulse train output terminal that generates precise differential RS-422 pulses on two 24 V tracks (A/B) to drive stepper or motion devices from the Beckhoff K-bus. Pulses can be created by the PLC or by an associated I/O module, and the module supports incremental encoder simulation for testing or closed-loop setups. Key specifications include a frequency range from 100 Hz up to 500 kHz (default 50 kHz), a 50% duty factor, and a ramp calculation of 2 ms per step, with an output cycle time of 1 ms synchronized to the K-bus and a dead time of 0.6 ms after each K-bus cycle. The device presents a 24-bit output process image (16 bits of output data, 8 bits of control) and a 24-bit input process image (16 bits of input data, 8 bits of status), with two inputs available at +T and +Z. Electrical isolation is 500 V between the K-bus/field voltage and the I/O, and current consumption from the K-bus is typ. 50 mA with a worst-case 120 mA (load-dependent). The KS2521 weighs roughly 50 g and is rated for an ambient operating range of 0 °C to 55 °C. This module is part of Beckhoff’s KL2521/KS2521 family, offering a compact, plug-in pulse train solution for high-speed motor control, encoder simulation, and precise frequency signaling in automation projects.