The option called "Positioning to Machine Zero After Homing" in the Compax3 family of servo drive/controllers is designed to make an automatic 'offset move' after locating the home location. This feature defaults to enabled (set to Yes in the configuration wizard of the C3 Servo Manager software).
Regardless of the type of homing algorithm selected this option may be used to do an offset from the established mechanical home location and depends on the "Machine Zero Offset" value for that offset distance.
When the "Machine Zero Offset" value is 0, the home location and the machine zero locations will be the same. After a successful homing the Actual Position will be at 0. No additional offset move is made regardless of the "Position to Machine Zero After Homing" setting as you are now at the 'machine zero' location.
When the "Machine Zero Offset" value is non-0, after a successful homing the Actual Position will be set to the "Machine Zero Offset" value. Then:
- If the "Positioning to Machine Zero After Homing" is set to Yes the axis will then make an 'absolute' offset move to the 0 location and Actual Position will be 0 when it is complete.
- If the "Positioning to Machine Zero After Homing" is set to No then the axis will not make an offset move and your Actual Position will reflect the Machine Zero Offset value.
These features are most useful if homing to a limit switch or a hard stop so that the zero location is not right on the limit or hard stop. They may also be useful if the home sensor cannot be physically located where the machine zero location needs to be mechanically and to avoid having to physically align the motor's index location (motor reference point - Z channel) with the desired mechanical home location.
Foot Note - The Machine Zero Switch Adjustment feature is not related to the aforementioned features but added here to for clarity. The Machine Zero Switch Adjustment can be used for the homing modes that use a home sensor and then the index pulse (motor reference point - aka Z channel). In cases where the index pulse happens to physically line up with the reference edge of the home sensor you could get a 1 rev variation in final home location due to sensor hysteresis or small motor settling variations and it sometimes finds the index pulse that lines up with the sensor edge and other times goes another full revolution to find the index channel. The Machine Zero Switch Adjustment creates a 'lock-out' zone around the home sensor edge to ensure it always finds the index channel at the same mechanical location (aka - won't see the index channel within the +/- value set in units of degrees around the sensor edge).