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Entry type: FAQ Entry ID: 49054152, Entry date: 04/06/2011

How do you avoid a STOP of the Technology CPU when stopping or interrupting a path object that is being moved by MC_MovePath (in S7 Technology V4.2)?

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Using the MC_MovePath block a path object is moved along a base point table that has been defined previously with MC_PathSelect.
Depending on the application, it might be necessary to stop the path motion of MC_MovePath, for which case the MC_GroupStop block is provided.

When using the MC_GroupStop block, the CPU might go into STOP mode if the conditions below coincide.

  • Firmware version of the integrated technology is V4.1.5 (with S7 Technology V4.2).
  • There is path motion with MC_MovePath.
  • The path motion is in the last segment of the base point table.
  • MC_GroupStop is called to stop this path motion.

Therefore, you should only use MC_GroupStop to stop a MC_MovePath motion after checking that the path motion is in the last segment.

Instead of MC_GroupStop you can proceed as follows to stop a path motion of MC_MovePath.

  • Interrupt motion
    If the path motion is to be interrupted and continued later, then the MC_MovePath block must be interrupted with the MC_GroupInterrupt block. The path object is then brought to a halt in accordance with the dynamic values parameterized on the block. The path contour is not left here! The path motion can be continued again using the MC_GroupContinue block.
  • Stop motion
    You also use the MC_GroupInterrupt block to stop the path motion. When this job has been completed (output DONE has been set), you call the MC_MoveRelative command with DISTANCE=0 for just any one of the axes in the path group. This dissolves path group and interrupts the MC_MovePath without performing a motion.
    An alarm is reported in the path object, which can be acknowledged with an MC_Reset.

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