Siemens SINUMERIK 840C - Manual (Page 795)

12 Functional Descriptions 09.95
12.6.2 Functional description
For this reason, there is a transformation-specific value "Minimum velocity for Transmit"
MD 738, 748, ... . The value is entered in units [IS] / IPO cycle. Tests have shown the
value 10 to be a useful default value.
Because the feedrate is not reduced further after a certain distance between the contour
and the centre of turning, the maximum velocity of the rotary axis can be exceeded. The
NC therefore goes below the "Minimum velocity for Transmit" if the rotary axis velocity is
more than twice as large as the permissible value. After that, the rotary velocity is limited
to the maximum possible value.
This means there are no longer any velocity fluctuations of the rotary axis and the contour
error that arises because the real setpoint of the rotary axis lags behind the setpoint
calculated from the transformation is reduced. The magnitude of the contour error depends
on the input resolution, the maximum velocity of the rotary axis and the MD "Minimum
velocity for Transmit".
• Travelling through the transformation centre
With the new function the velocity of the rotary axis is always limited to the maximum value
independently of MD 5025.3.
It is also possible to travel through the transformation centre in JOG mode independently
of MD bit 5025.3.
12.6.3 The transformation data set
7 6 5 4 3 2 1 0
Bit No.
NC MD
5060
5061
5062
5063
5064
5065
5066
5067
5068
5069
Channel number of transformation
G function for transformation selection
Axis name 1st fictitious axis
Axis name 2nd fictitious axis
Axis name 3rd fictitious axis
Axis name 1st real axis
Axis name 2nd real axis
Axis name 3rd real axis
Axis name 4th real axis
Axis name 5th real axis
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SINUMERIK 840C (IA)