What is zero return and when would you perform it?

• A. A homing process that moves axes to their reference trigger; performed after installation or fault.
• B. A routine to back up programs before power down.
• C. A calibration for tool length after tool change.
• D. A health check of sensors with no axis movement.

Answer: (A)

Zero return is a homing procedure that establishes the machine’s reference positions by moving each axis to its home or reference trigger. When the home switches are reached, the controller defines the axis positions as zero (the machine origin) and uses this as the basis for all future moves and offsets.

You perform zero return after installing the robot or machine, after a fault or power loss that may have disturbed the coordinate system, or after maintenance that could affect axis positioning. Once the home position is re-established, jogging, programming, and tool/work offsets can be relied on with accurate, repeatable results. It isn’t simply backing up programs, tool length calibration, or a sensor check without movement.