Siemens sinumerik 840D sl Function Manual page 155

Entering gantry trip limits
For the monitoring of the actual position values of the synchronized axis in relation to the
actual position of the leading axis, the limit values for termination, as well as for the leading
and synchronized 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 trip limit for 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 the digital 611D 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 leading and
synchronized axes are set to the same dynamic response value.
To ensure the best possible synchronism, the leading axis and synchronized 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.
The following control parameters must be set to the optimum axial value for both the leading
axis and the synchronized axis:
• MD32200 $MA_POSCTRL_GAIN (KV factor)
• MD32620 $MA_FFW_MODE (feedforward control parameter)
• MD32610 $MA_VELO_FFW_WEIGHT (feedforward control factor for acceleration/speed)
• MD32650 $MA_AX_INERTIA (inertia for torque feedforward control)
• MD32800 $MA_EQUIV_CURRCTRL_TIME(Equivalent time constant current control loop
• MD32810 $MA_EQUIV_SPEEDCTRL_TIME (equivalent time constant speed control loop
References:
/FB2/ Function Manual, Extended Functions, Compensations (K3)
The following control parameters must be set to the same value for the leading axis and
synchronized axis:
• MD33000 $MA_FIPO_TYPE (fine interpolator type)
• MD32400 $MA_AX_JERK_ENABLE (axial jerk limitation)
• MD32410 $MA_AX_JERK_TIME (time constant for the axial jerk filter)
Special functions: Gantry Axes (G1)
Function Manual, 11/2006, 6FC5397-2BP10-2BA0
for feedforward control)
for feedforward control)
Detailed description
2.3 Start-up of gantry axes
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