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6.4.4 Compensation of thermal expansion
July 2013
To compensate thermal expansion, exact measurements of machine thermal
behavior as a function of temperature (e.g., the center of axis expansion, the
amount of the expansion) are necessary.
The temperatures measured by the Pt100 thermistors are copied into the PLC
words from IOconfig. Since the thermal expansion of the axes is largely
proportional to the temperature: you can directly determine the amount of
expansion by multiplying the temperature value by a certain factor.
Compensation:
Transfer the distance to be compensated to Module 9231. At the same
time, "lag tracking" becomes active. This means that the actual position is
offset by a certain value per PLC cycle until the complete value is
compensated.
In MP4070, enter the value for the offset per PLC cycle.
For gantry axes, the compensation value must be transferred separately for
each axis.
Heat compensation when using tilting axes is defined through machine
parameters or via the TEMPCOMP column of the kinematics table. See
"Temperature compensation with tilting axes" on page 741.
The actual value display does not change during compensation. As an
alternative, for axes 1 to 5 you can enter the value to be corrected in W576 to
W584.
MP4070
Compensation amount per PLC cycle for lagged-tracking
axis error compensation
Input:
0.0001 to 0.5000 [mm]
W576 - 584
Lag-tracking axis-error compensation
For axes 1 to 5
Input: –32768 to +32767 [1/10 µm]
6.4 Axis-error compensation
Set
Reset
PLC
PLC
659
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