HEIDENHAIN TNC 426 CB, Техническое руководство

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December 2001 Display and Operation 6 – 223
6.13.1 Machine Datum
The machine is built with a fixed machine datum . All referenced displays and
positioning blocks refer to this machine datum.
In the MANUAL OPERATION and ELECTRONIC HANDWHEEL modes you
can define the
workpiece datum with the “datum setting” function. NC
programming blocks are entered with respect to the defined datum.
Other datums:
n
If the user programs M91 in an NC program, the NC programming block
refers to the machine datum.
7 7 7 7 In MP960.x, enter the distance between the machine datum and the scale
reference point.
n
All NC programming blocks are referenced to the machine datum.
7 7 7 7 With MP7295, disable the “datum setting” function for specific axes.
n
NC program block values are defined with respect to fixed positions of the
machine if the user programs M92 in the NC program.
7 7 7 7 In MP950.x, enter the distance between the machine datum and the
machine-referenced position.
The datum can be set either only by the Datum Setting soft key or only by the
soft key plus the axis keys:
7 7 7 7 With MP7296, define how the datum should be set.
To change the datum in the OEM cycles:
7
7 7
7 Press the MOD key.
7 7 7 7 Enter the code number 555 343.
7 7 7 7 Enter: FN25: PRESET <axis>/<value to be converted>/<new datum>.
Note
M91 and M92 are active only in the block in which they are programmed.
<Axis> Axis for which the datum is to be set
<Value to be
converted> Coordinate in the active coordinate system to which
the datum is to be set, or the number of the
Q parameter that contains this coordinate
<New datum> Desired value of the datum