Start-Up Of Gantry Axes - Siemens SINUMERIK 840D Function Manual

G1: Gantry axes

9.4 Start-up of gantry axes

9.4 Start-up of gantry axes
General
Owing to the forced coupling which is normally present between guide and synchronous gantry
axes, the gantry grouping must be started up as if it were an axis unit. For this reason, the axial
machine data for the guide and synchronous axes must always be defined and entered jointly.
If the synchronous axis is overloaded due to a weaker dynamic response than the guide axis,
alarm 10656 is displayed.
Special points to be noted with regard to starting up gantry axes are described below.
Traversing direction
As part of the start-up procedure, a check must be made to ensure that the direction of rotation
of the motor corresponds to the desired traversing direction of the axis. Correct with the
following axial machine data:
MD32100 $MA_AX_MOTION_DIR (traversing direction)
Entering gantry trip limits
For the monitoring of the actual position values of the synchronous axis in relation to the actual
position of the guide axis, the limit values for termination, as well as for the guide and
synchronous axes, should be entered corresponding to the specifications of the machine
manufacturer:
● MD37120 $MA_GANTRY_POS_TOL_ERROR (gantry trip limit)
● MD37130 $MA_GANTRY_POS_TOL_REF (gantry shutdown limit when referencing)
Note
The control must then be switched off and then on again because the gantry axis definition
and the trip limit values only take effect after power ON.
Response to setpoint changes and disturbances
Since digital drives respond well to disturbances and setpoint changes, there is no need for a
compensatory control between the gantry axes. However, the gantry axes can only operate in
exact synchronism if the parameters for the control circuits of the guide and synchronous axes
are set to the same dynamic response value.
To ensure the best possible synchronism, the guide axis and synchronous axis must be
capable of the same dynamic response to setpoint changes. The axial control loops (position,
speed and current controllers) should each be set to the optimum value so that disturbances
can be eliminated as quickly and efficiently as possible. The dynamic response adaptation
function in the setpoint branch is provided to allow differing dynamic responses of axes to be
matched without loss of control quality.
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Axes and spindles
Function Manual, 06/2019, A5E47437747B AA