12 Functional Descriptions 09.95
12.19.4 Temperature compensation TC
Data format of user DB
• Length in words: Always value 7 in KF format
• Axis number: Values 1 to 30 in KF format
• Absolute TC value K
TCabs
: With sign, in units (MS), in KF format
(value range ±1 073 741 823)
• Coefficient tan ß: With sign, with significance 2
-31
in KF format
(value range -1....+1)
The following table gives an example description of the data format of tan ß
ß tan ß (tan ß) · (2
31
–1)
(dec.)
(tan ß) · (2
31
–1)
(hex.)
0 0 0 0000:0000
30 0.577 1 239 850 262 49E6:9D16
45 1 2 147 483 647 7FFF:FFFF
-30 -0.577 -1 239 850 262 B619:62EA
-45 -1 -2 147 483 647 8000:0001
• Reference point P
0
: With sign, in units (MS), in KF format
(machine reference system, value range ±1 073 741 823)
The values K
TCabs
, tan ß and P
0
can be entered as the result of a floating-point calculation,
followed by a fixed-point format conversion.
12.19.4.4 Activation of function
• TEMPERATURE COMPENSATION option must be available.
• Transmission of applicable compensation values via command channel to the NC
(cyclically or as a function of the NC PLC interface). Please refer to Interface Description,
Part 1, Signals, for more detailed description of command channel.
Caution:
Since the compensation values are immediately included in the calculation for the position
control, the surface quality may suffer if an axis is traversing and the change in compensation
value between two transmissions is too large.
12–190
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SINUMERIK 840C (IA)