Siemens sinumerik 840D sl Function Manual page 141

The control performs a plausibility check on the axis definition.
Components
The "gantry axes" function can be subdivided into the following functional units:
1. Setpoint generation of synchronized axis
2. Monitoring of actual value difference
3. Referencing and synchronization of leading axis and synchronized axes
Setpoint generation of synchronized axis
From the point of view of the operator, all coupled gantry axes are traversed as if only one
axis, i.e. the leading axis, were programmed in the NC. Analogously, only the leading axis is
programmed in the part program. The commands and traverse requests from the operator,
the PLC interface or via the part program therefore apply in equal measure to all axes in the
gantry grouping.
When the "gantry axes" function is active, the synchronized axis setpoint is generated
directly from the setpoint of the leading axis in all operating modes.
Note
The dynamic control response of the leading and synchronized axes must be set identically.
Monitoring of actual value difference
The position actual values of the leading and synchronized axes are continuously compared
with one another in the interpolation clock cycle and monitored to check that they are still
within the permissible tolerance range.
Machine data can be set to specify the following limit values for alarm output and termination
of the traversing motion for specific axes:
Gantry warning limit
The "warning limit exceeded" signal will be relayed to the operator when the position actual
value difference of the gantry warning limit is exceeded:
MD37110 $MA_GANTRY_POS_TOL_WARNING (gantry warning limit)
In addition, the following interface signal will be output to the PLC:
DB31, ... DBX101.3 (warning limit exceeded)
Special functions: Gantry Axes (G1)
Function Manual, 11/2006, 6FC5397-2BP10-2BA0
Note
Each axis in the gantry grouping must be set so that it can take over the function of the
leading axis at any time, i.e. matching velocity, acceleration and dynamic response
settings.
Detailed description
2.1 "Gantry axes" function
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