Siemens SINUMERIK 840D sl Function Manual page 760

Interaction with other functions
12.10 Response of Safety Integrated when the communication fails
If a pulse suppression delay is parameterized using
$MN_SAFE_PULSE_DIS_TIME_BUSFAIL, after a communication failure, the SGA of all axis-
specific SI monitoring channels are first left in their old state. All SGAs are deleted after this
delay time has expired. The axis-specific monitoring functions are no longer processed
immediately after communication fails as the basis for the monitoring functions, the safe actual
value, is no longer available.
In the following cases, in the event of a communication failure, the axis-specific NCK-SGA are
immediately deleted, even if a delay time is parameterized in
$MN_SAFE_PULSE_DIS_TIME_BUSFAIL:
● An external STOP A is selected
● A test stop is selected
● Function SBH is selected - or will be selected
● An SG stage is selected or will be selected, where it was previously explicitly specified that
in this SG stage no ESR should be performed in the event of a communication failure (e.g.
SG stage to protect persons), (see MD36963 $MA_SAFE_VELO_STOP_REACTION or
MD36961 $MA_SAFE_VELO_STOP_MODE).
Since the NCK monitoring channel is assigned to the switch-off signal path of the Motor Module,
the Motor Module must also know whether, in the event of communication failure, the pulses
should be canceled with a delay. The NCK cyclically provides the Motor Module with this
information. If the Motor Module detects a communication failure, dependent on the latest
information of the NCK, it starts its delay timer with the parameterized time from p9897 and
then independently deletes the pulses.
Behavior of the drive monitoring channel
The drive monitoring channel, just like the NCK monitoring channel, delays its pulse
cancellation by the parameterized time. However, in addition it also keeps the monitoring
functions active, which were active at the time of the failure. The drive can continue to monitor
as it still has the correct actual value.
In the following cases, communication failure immediately triggers pulse cancellation, even if
a delay time has been configured:
● The SBH function is selected.
● An SG stage has been selected, where it has been previously defined that in this SG stage
no ESR should be performed in the event of communication failure (for example - SG stage
to protect persons).
ESR executed in the drive when communications fail
Note
In the event of a communication failure between the NCK and Control Unit, only an ESR
executed independently in the drive is possible, which must be initiated from the Control Unit
itself.
The precondition in this case is that pulse cancellation is delayed.
Example
760
Function Manual, 12/2017, 6FC5397-4BP40-6BA1
Safety Integrated