Siemens SINUMERIK 840D sl Function Manual page 147

Synchronous axis
The axes of the gantry grouping, which are traversed by the NC in synchronism with the
leading axis, are known as synchronous axes. From the point of view of the programmer and/
or operator, the synchronous axes "do not exist".
Gantry axes
The axes of a gantry grouping, leading axis and synchronous axes are generally called gantry
axes.
Synchronism difference
The synchronism difference is the deviation of the axial actual value of the synchronous axis
from its ideal position referred to the actual value of the leading axis. The NC continually
monitors the synchronism difference. In order to prevent any damage to the machine, the
gantry grouping is stopped when a parameterizable limit value is exceeded.
Definition of a gantry grouping
Axes belonging to a gantry grouping, are defined as follows:
MD37100 $MA_GANTRY_AXIS_TYPE[<axis>] = <type><number>
The input is decimal-coded:
10th decimal place
<type>
A maximum of 8 gantry groupings can be defined.
A gantry grouping can have a maximum of 2 synchronous axes.
Supplementary conditions
The following supplementary conditions apply to a gantry grouping:
• A gantry grouping must not contain a spindle.
• A synchronous axis must not be a concurrent POS axis.
• A synchronous axis must not belong to a transformation.
• A synchronous axis must not be a following axis of another axis coupling.
• A synchronous axis must not be a leading axis of another axis coupling.
NOTICE
Drive optimization
At a SINAMICS S120 drive unit, a maximum of 3 drives can be optimized or measured at the
same time (speed controller optimization/function generator). Therefore, for a coupling with
more than 3 coupled drives at the same time, we recommend that these are distributed over
several drive units.
Special Functions
Function Manual, 09/2011, 6FC5397-2BP40-2BA0
1st decimal place Range of values
0, 1
<number> 1, 2, 3, ... max.
number
G1: Gantry axes
2.2 "Gantry axes" function
Meaning
0: Leading axis
1: Synchronous axis
Number or identifier of the
gantry grouping
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