Siemens SINUMERIK 840D sl Function Manual page 347

The NC then executes a block change or considers the positioning motion to be completed,
but still leaves a setpoint applied to the drive actuator to allow the clamping torque to take
effect.
The fixed stop monitoring function is activated as soon as the stop position is reached.
Monitoring window
If no fixed stop monitoring window was programmed in the block or from program start, then
the value set in the machine data:
MD37020 $MA_FIXED_STOP_WINDOW_DEF
(Default for fixed stop-monitoring window)
is entered.
If the axis leaves the position it was in when the fixed stop was detected, then alarm 20093
"Fixed stop monitoring has responded" is displayed and the "Travel to fixed stop" function
deselected.
The window must be selected by the user such that the alarm is activated only when the axis
leaves the fixed stop position.
Enabling the fixed stop alarms
With the machine data:
MD37050 $MA_FIXED_STOP_ALARM_MASK
enabling the fixed stop alarms can be established as follows:
MD 37050 = 0
MD 37050 = 2
MD 37050 = 3
All other permissible values of 7 or less do not suppress any alarms.
Using the parts program command NEWCONF a new setting can be activated.
Fixed stop is not reached
If the programmed end position is reached, without detecting the state "fixed stop reached",
then depending on the state of the machine data:
MD37050 $MA_FIXED_STOP_ALARM_MASK (Release of fixed stop alarms)
the alarm 20091 "Fixed stop not reached" is output.
Function abort
If the "Travel to fixed stop" function is aborted owing to a pulse cancellation command,
cancelation of PLC acknowledgments or a Reset in the approach block, the display or
suppression of alarm 20094 can be controlled via machine data:
MD37050m $MA_FIXED_STOP_ALARM_MASK
can be controlled.
Basic logic functions: Travel to fixed stop (F1)
Function Manual, 11/2006, 6FC5397-0BP10-2BA0
Fixed stop not reached (suppress Alarm 20091)
Fixed stop not reached (suppress alarm 20091) and fixed stop aborted
(suppress alarm 20094)
Fixed stop aborted (suppress alarm 20094)
Detailed Description
2.1 General functionality
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