Pausing and resuming movements

 

By means of the MC_GroupInterrupt and MC_GroupContinue POUs, it is possible to pause the execution of the commanded move­ments and resume them later.

By executing MC_GroupInterrupt, a stop is executed that is true to the path, similar to a MC_GroupHalt. Then the state of the axis group is saved in a variable passed by the user (type SMC_AXIS_GROUP_CONTINUE_DATA). Now the axis group is in GroupStandby state and can be used as normal. It would be typical, for example, to jog the axis group.

Later, users can then resume the interrupted execution with MC_GroupContinue. Then it passes the saved data (type SMC_AXIS_GROUP_CONTINUE_DATA). For this to work without errors, the position of the axis group must agree with the position that it had after executing MC_GroupInterrupt. (See SMC_GroupGetContinuePosition.)

If a tracking movement is interrupted (a movement that was commanded relative to a dynamic coordinate system), then MC_GroupInterrupt halts relative to the dynamic coordinate system, not absolute like MC_GroupHalt. For example, if a workpiece is tracked on a rotary table, then MC_GroupInterrupt halts accurate to the path regarding to the workpiece. The axis group continues to follow the workpiece. Before resuming with MC_GroupContinue, the same position also has to be reached again regarding the workpiece.

Restriction: The interruption of a PTP tracking movement is currently still not supported (MC_MoveDirectAbsolute or MC_MoveDirectRelative).