
22.AUTOMATIC OPERATION NC FUNCTIONS B-63322EN/03
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22.6.4 Retrace
A tool can retrace the tool path along which the tool has moved. This
operation is referred to as retrace. In addition, a tool can move forward
again along the path that the tool has retraced. This operation is
referred to as re-forward.
The tool can then resume machining according to the program when it
returns to the position where it started retrace.
By using the retrace signal RVS, which is an input signal from the PMC
to the control unit, retrace and re-forward can be performed. Retrace is
performed when the retrace signal RVS turns to "1". Re-forward
operation is performed when the retrace signal turns to "0". In retrace, a
tool can retrace blocks that have been executed in the automatic
operation mode (memory command, tape command, manual data input),
but a limit is imposed on the number of blocks that can be retraced. For
detailed information, refer to the operator’s manual.
Whether to use the same federate as specified for normal operation or
use a feedrate dedicated to retrace can be determined by setting
parameter No. 1494.