Boundary Conditions - Siemens SINUMERIK 840D Function Manual

11.4

Boundary conditions

Alarms
Only axes with active drive control display drive alarms.
Position control loop
The drive train, and therefore also the position control loop, are disconnected while the setpoint
is being switched over. In order to avoid instability, the setpoint is only switched over at standstill
- and once all controller enable signals have been cleared (deleted).
When using a single drive, only one control loop can be closed at the same instant in time. Axes
without drive control are operated with open position controller and tracked positions.
Reference points
The use of load-side encoders does not affect the axis-specific reference points of a setpoint
switchover.
However, the mechanical reference to the load can be lost following setpoint switchover for a
load-side position derived solely from the motor encoder. These types of axis must be
referenced again after every setpoint switchover.
Parameter set switchover
A setpoint exchange is not performed if one of the following states is present:
● A parameter set changeover in one of the two machine axes has not completed.
● The parameter sets of the two machine axes are not the same.
Note
If, due to secondary conditions, a setpoint switchover is not performed, then a message is not
displayed.
"Parking" state
If an axis is in the "Parking" state, this state can only be canceled if this axis assumes drive
control.
Service display drive
The "Drive service display" HMI diagnostics screen does not take into account the changes in
assignments between machine axes and the drive.
Commissioning via SinuCom NC
The "SinuCom NC" commissioning tool can only be used to commission the setpoint
switchover via the expert list.
Safety Integrated
A detailed description of the supplementary conditions for setpoint switchover in conjunction
with Safety Integrated is available in:
Axes and spindles
Function Manual, 06/2019, A5E47437747B AA
S9: Setpoint switchover
11.4 Boundary conditions
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