HEIDENHAIN TNC 306 Technical Manual - Manual (Page 176)

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TNC 406/TNC 306 6 Display and operation 4 3/97
6 Display and operation 4
Machine parameters and PLC-markers can be used to influence the control behavior for certain
functions. All machine parameters and PLC markers which influence the display and the operation of
the control, and those for which there is no separate section in this manual, are described in the
section "Display and operation" .
The VDU-screen displays can be changed by machine parameters and PLC-markers.
6.1 Setting the machine datum point
A workpiece datum point can be defined in the operating mode "Manual operation."
NC positioning blocks normally refer to the set datum point (workpiece datum point). If a positioning
block is to be referenced to the reference point of the encoder instead of the set datum point, this
can be achieved with M91.
The distance from the machine datum to the scale datum is entered in machine parameter MP960.x.
All REF-related displays and positioning commands refer to the machine datum.
A third datum point can be defined in machine parameter MP950.X. If a positioning block is to be
referenced to this datum point, this can be achieved with M92.
M91 and M92 are effective only for the block in which they are programmed in (non-modal). The
workpiece datum, once set, will not be lost.
M91 and M92 are non-modal.
RM
RM
RM
Workpiece datum
Scale datum RM = Reference mark
Machine datum