Desync Handling¶
Synchronous axes can be configured to automatically stop or turn the servo off if any of the sync axes becomes desynchronized.
A slave axis may become desynchronized for several reasons, including:
The slave axis servo was commanded to turn off.
The slave axis encountered an amp alarm, and the servo was turned off.
The slave axis has lost communication.
A software emergency stop was executed.
The slave axis touched a limit switch (when Sync LS is set to FALSE).
The Master Desync Type parameter is set for the master axis and determines how the master axis responds when the slave axis becomes desynchronized.
The Slave Desync Type parameter is set for the slave axis, and determines what the slave axis does when the master axis servo turns off. If this parameter is set to the default value of NoAction, the slave axis will remain synchronized with the master axis when the master axis servo turns off (if the master axis is moved while in the servo off state, the slave axis will follow the motion of the master axis).
In a gantry system or any scenario where misalignment between the master and slave could lead to significant damage, Master Desync Type and Slave Desync Type should not be left as its default value (NoAction). .
For desync handling of Sync Group, please refer to Desync Type section of Sync Group page.
The following are two sample configurations for desync handling.
Configuration 1: Turn both the master axis and slave axis servos off when the limit sensor is on for either axis.
Set Master Desync Type of the master axis to ServoOff.
Set Slave Desync Type of the slave axis to ServoOff.
Configuration 2: Stop both the master axis and slave axis servos with the same deceleration when the limit sensor is on for either axis. (Note that the servo hardware parameters must be configured to not stop the axes or turn the servos off when the limit sensor is on.)
Set LS Dec of the master axis to the deceleration rate.
Set LS Dec of the slave axis to the deceleration rate.
Set Master Desync Type of the master axis to Dec.
Set Slave Desync Type of the slave axis to NoAction.
Set Master Desync Dec of the master axis to the deceleration rate.
The Slave Desync Type only applies when the master axis is desynchronized, which only occurs when the master servo turns off. Because this case is irrelevant, the Slave Desync Type is set to NoAction.
All three deceleration rates above must be the same to synchronize the deceleration of the axes when a limit switch sensor turns on.
Alternatively, the following configuration can be used to prevent desynchronization due to the limit sensor detection.