The function for forward/backward motion on the path permits backward motion along the originally programmed path by means of a real-time signal when the NC program is active. Backward motion is terminated by resetting the real-time signal. Forward motion then resumes.


Different modes are possible with forward/backward motion and they can be set over the PLC interface. They include suppressing the synchronisation of M/H functions or skipping program sections from backward motion. Restrictions must be observed for certain functions for backward motion. They are described in detail in the section "Known restrictions".

Forward/backward motion on the path can be used for:


The exact response for forward/backward motion can be configured in the start-up and channel parameters. A complete list of parameters described in this document is contained in the chapter Parameter.


In the NC program the command #OPTIONAL EXECUTION... marks a sequence of NC blocks as non-executable in forward/backward motion mode.