HEIDENHAIN TNC 335 Technical Manual - Manual (Page 206)

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TNC 360 6 Display and Operation 4-109
6 Display and Operation
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 for which there is no separate section in this manual, are described in section "Display
and operation" .
6.1 Machine datum
In the operating mode ”Manual operation", a workpiece datum can be defined. NC positioning
blocks normally refer to this datum. If a positioning block should be referenced to the machine
datum instead of the workpiece datum, this must be programmed in M91. On the TNC 360 the
machine datum and scale datum point (= Reference point) are identical. All REF-referenced displays
and positioning movements (PLC positioning or M91) are referenced to the machine datum.
With MP950.x you can define an additional machine-referenced position. If you wish to reference to
this position in a positioning block, you must program it in with M92. MP950.x defines the distance
from this machine-referenced position to the machine datum.
M91 and M92 are active only in the blocks in which they are programmed.
RM
RM
RM
Workpiece datum
Scale reference point RM = Reference mark
Machine datum