Store Home Position
Overview
The home position value can be saved in the Object Dictionary. When this feature is configured, it is also stored in the configuration file each time homing is performed. After a power cycle or if the configuration needs to be reloaded, the homing value can be restored so the drive can be referenced without repeating the homing procedure.
Restoring the home value after a power cycle or config reload should be done with absolute position encoders on the output shaft (dual loop setups, multi-turn encoders with battery, single-turn encoders on torque motors).
Note: Incremental encoders or setups where a gearbox is after the absolute encoders homing position should not be used for restoring the home position.
Usage
On the first power on, the position of each of the axes is random, given the mechanical mounting of the motor.
The master controller enters OPMODE HOMING and reads bit 12 (Homing Attained) of the statusword. On each axis, the value of bit 12 is zero, which means the axis is not referenced.
Note: The axes need to be homed before the master allows turning on CSP
-
Choose the homing method and run the homing process.
-
When the axis is homed, the homing value is updated in the subindex 2005:1 Home Position and bit 12 of the statusword is set to 1 by the firmware.
-
Change the parameter Restore Home Position on Startup to Yes.
-
The values of the objects Home Position and Restore Home Position on Startup must be saved to the config file (for example, by clicking "Save To Device" in OBLAC Box).
After power cycling the drives, the controller goes into OPMODE HOMING and reads the value 1 in bit 12 for each drive, indicating that they don’t need to be homed anymore.
Upon start-up, the firmware references the axis with the value stored in subindex 2005:1 Home Position.
Parameters
| Object ID | Name | Description |
|---|---|---|
| 0x2005:1 | Home Position | Encoder value at home position |
| 0x2005:2 | Restore Home Position when loading configuration | Flag that shows if the home position saved in `0x2005:1` is valid. |