Effects When An Se Responds - Siemens SINUMERIK 840D sl Function Manual

Preconditions
The following prerequisites must be fulfilled for the "safe software limit switches" function:
● The "safe software limit switches" function must be enabled
● The axis/axes must have been safely referenced (user agreement)
● SGE "SE selection" must be supplied (configured) in both channels
Effectiveness of safe software limit switches
"Safe software limit switches" are only effective if the user agreement has been given.
During the time in which the measuring system of the machine axis is switched off, it is not
permissible that the axis is mechanically moved. Otherwise this results in an offset between
the last buffered actual position and the real actual position of the machine axis. This would
lead to an incorrect synchronization of the measuring system resulting in danger to personnel
and the machine.
If axis motion cannot be prevented mechanically in the shutdown state, either an absolute
encoder must be used or the axis must be referenced again with reference point approach
after switching on.
7.7.1

Effects when an SE responds

Monitoring software limit switches
The SE function does not predictively monitor the SW (software) limit switches. This means
that the axis stops after passing the limit position. The distance traveled after the SE is
dependent on:
● How the function was parameterized (monitoring clock cycle, stop response, ...)
● The actual speed
● The design of the axis
Configurable stop responses
When a "safe software limit switch" is passed, then a stop response, which can be configured
using the following machine data, is generated:
for 840D sl:
MD3696: $MA_SAFE_POS_STOP_MODE
for SINAMICS S120:
p9562 SI Motion SLP (SE) stop response (Control Unit)
The user can select either STOP C, D or STOP E.
Safety Integrated
Function Manual, 12/2017, 6FC5397-4BP40-6BA1
WARNING
WARNING
Safety functions integrated in the system/drive
7.7 Safe software limit switches (SE)
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