HEIDENHAIN TNC 620 User Manual page 306

6
Behavior with M92 – Additional machine reference point
Refer to your machine manual.
In addition to the machine datum, the machine
manufacturer can also define an additional machine-
based position as a reference point (machine preset).
For each axis, the machine manufacturer defines the
distance between the machine preset and the machine
datum.
If you want the coordinates in positioning blocks to be based on the
machine preset, enter M92 into these NC blocks.
Radius compensation remains the same in blocks that
are programmed with M91 or M92. The tool length will
not be taken into account.
Effect
M91 and M92 are effective only in the blocks in which M91 and M92
have been programmed.
M91 and M92 take effect at the start of block.
Workpiece preset
If you want the coordinates to always be referenced to the machine
datum, you can inhibit presetting for one or more axes.
If presetting is inhibited for all axes, the control does not display the
SET PRESET soft key in the Manual operation operating mode.
The figure shows coordinate systems with the machine and
workpiece datum.
M91/M92 in the Test Run mode
In order to be able to graphically simulate M91/M92 movements,
you need to activate working space monitoring and display the
workpiece blank referenced to the defined preset.
Further information: "Showing the workpiece blank in the working
space (option 20)", Page 257
306
Testing and running | Miscellaneous functions for coordinate entries
HEIDENHAIN | TNC 620 | User's Manual for Setup, Testing and Running NC Programs | 01/2022