Is it Possible to Not Use the Z Signal Channel for a Closed-loop Stepper Motor?

The core function of the Z signal is to provide a unique "absolute position reference point" per revolution. It acts as a mechanical home position; for every full rotation of the motor shaft, the Z signal outputs one pulse. Descriptions of encoder channels can also be found on the STEPPERONLINE website.

Stepper motor with Z signal:

Stepper motor without Z signal:

Situations where the Z signal is typically NOT required:

• Speed Control Mode: If you are only using the motor for speed control and are not concerned with absolute position, only the A and B phases are needed for speed feedback.
• Relative Position Control: If all your movements are based on "moving a relative distance from the current position after power-on," without needing to relate to an absolute coordinate in the mechanical world. For example, a simple material pushing device that only needs to perform reciprocating motion with a fixed stroke after each power-on, where the starting point can be any position.
• System Already Has Other Homing Methods: If your equipment is already equipped with reliable and convenient home position sensors (such as limit switches) and performs a homing routine after each startup, then the Z signal is not necessary. Often, homing with an external sensor is more precise and reliable than using the Z signal (because the Z signal only indicates the motor shaft's position, while an external sensor can directly detect the load's position).

Situations where the Z signal IS required:

• High Multi-Axis Synchronization Requirements: In multi-axis systems requiring strict synchronization of all axes at the start of each revolution. The Z signal can provide a common synchronization point for multiple motors.
• Preventing Multi-Revolution Cumulative Error: In applications requiring long-term continuous operation where any position error accumulation is unacceptable, the Z signal can serve as an "error correction benchmark" per revolution.
• As a Precise Intra-Revolution Home Position: When the "work home" of the load directly driven by the motor aligns with the Z signal position of the motor shaft, the Z signal can be used as a very precise and highly repeatable home signal, eliminating the need for an external sensor.

Summary: For most conventional closed-loop stepper applications, it is entirely feasible not to connect the Z signal, provided you can accept that the system needs to perform a homing operation after each power-on to establish an absolute coordinate system. Decide whether to use it based on your specific application's requirements for establishing a home position upon power-up. During actual wiring, you only need to correctly connect the encoder's A, A-, B, and B- signal lines to the driver; the Z and Z- lines can be left unconnected (please confirm this in your driver's manual).

Updated on: 26/09/2025