Siemens SINUMERIK 840D sl Function Manual page 348

Detailed Description
2.1 General functionality
Abort without alarm
The travel to fixed stop can be aborted by the PLC in the approach block without triggering
an alarm (for example, when the operator actuates a key), if in the machine data:
MD37050 $MA_FIXED_STOP_ALARM_MASK
the alarm 20094 is suppressed.
The Travel to fixed stop function is deselected in response to both "Fixed stop not reached"
and "Fixed stop aborted".
Interrupts
If the fixed stop position is not reached when the function is active, alarm 20091 "Fixed stop
not reached" is output and a block change executed.
If a travel request (e.g. from the part program, the PLC, from compile cycles or from the
operator panel) is provided for an axis after the fixed stop has been reached, the alarm
20092 "Travel to fixed stop still active" is output and the axis is not moved.
If an axis has reached the fixed stop and is then moved out of this position by more than the
value specified in
SD FIXED_STOP_WINDOW (Fixed stop monitoring window)
from the position, then the alarm 20093 "Standstill monitoring has triggered at the stop" is
given, the function "Travel to fixed stop" for this axis is deselected and the system variable is
set $AA_FXS[x]=2.
No termination during alarm
"Travel to fixed stop" remains active from now on for alarms,
if the bit values in the machine data:
MD37052 $MA_FIXED_STOP_ALARM_REACTION
were set.
IS "Mode group ready" (DB11, ... DBX6.3) remains active.
Alarm suppression after new programming
Travel to fixed stop can be used for simple measuring processes.
For example, it is possible to carry out a check for tool breakage by measuring the tool
length by traversing onto a defined obstacle. To do so, the fixed stop alarm must be
suppressed. When the function for clamping workpieces is then used "normally," the alarm
can be activated using parts program commands.
12
Basic logic functions: Travel to fixed stop (F1)
Function Manual, 11/2006, 6FC5397-0BP10-2BA0