Siemens SINUMERIK 802D sl Function Manual page 89

The "Gantry trip limit exceeded" IS is also output if the gantry grouping is jammed (no servo
enable, gantry grouping in "Hold" state).
The monitoring functions are deactivated while the grouping is operating in "Follow-up"
mode.
Extended monitoring
An extended monitoring function can be activated with the following machine data:
MD37150 GANTRY_FUNCTION_MASK (gantry functions)
Referencing and synchronization of gantry axes
As the example "Gantry-type milling machine" shows, the forced coupling between gantry
axes must remain intact in all operating modes as well as immediately after power ON. In
cases where an incremental measuring system is being used for the leading or the
synchronized axis, the reference point must be approached while maintaining the axis
coupling immediately after machine power ON.
After every axis in the gantry grouping has approached its reference point, any misalignment
that may exist between the axes must be eliminated (this is known as the gantry
synchronization process). As soon as this has been carried out, the following interface signal
is sent to the PLC:
V390x 5005.5 (gantry grouping is synchronized)
The operational sequence for referencing and synchronizing gantry axes is described in
detail under the topic "Referencing and synchronizing of gantry axes".
Closed-loop control
The dynamic control response settings for the coupled gantry axes must be identical (see
Start-up of gantry axes (Page 99)). This ensures that in normal operation, the leading and
synchronized axes move in positional synchronism, even during acceleration and braking.
Load effects are compensated by the appropriate drive of the leading or synchronized axis.
Disturbance characteristic
When a disturbance occurs which causes shutdown of one gantry axis owing, for example,
to cancellation of the controller enabling signal (example: EMERGENCY OFF), the coupled
gantry axes are also shut down.
Separation of forced coupling
In certain situations (e.g. one gantry axis is no longer referenced owing to an encoder
failure), it may be necessary to correct or reduce the misalignment between the gantry axes
prior to referencing. To do this, it must be possible to traverse the leading or the
synchronized axis manually in the uncoupled state.
Turning, Milling, Nibbling
Function Manual, 11/2012, 6FC5397-1CP10-5BA0
Gantry axes (G1)
6.2 "Gantry axes" function
89