Siemens Sinumerik 840D sl Function Manual page 142

Safety functions integrated in the system/drive
6.3 Safe Stops A- -F
Remark:
When combined with "ESR managed from the control", theoretically the following
error is possible: Both monitoring channels (NCK and drive) trigger a STOP F;
however, a safety function is only active on the drive side (errors in the two SPL
channels, which are then most probably responsible for the STOP F). In this case,
the NCK does not trigger an ESR, because for the NCK no subsequent STOP B
can be identified. Conversely, this statement is also valid for the combination with
"ESR integrated in the drive" and a safety function is only active in the NCK. The
ESR integrated in the drive is then not started.
Example 1 - - delaying the transition from STOP F to STOP B
The speed characteristic of an axis for parameterized stopping is shown in
Fig. 6-7. In this case, the axis should continue 500 ms and then brake along the
parameterized ramp. A delay time of 2.5 s is selected until STOP B is initiated
($MA_SAFE_STOP_SWITCH_TIME_F).
v
Figure 6-7 Velocity characteristic of an SI axis when stopping with STOP F
The following actions take place at the following instants in time:
t1:
STOP F occurs, ESR is started
t2:
500 ms after t1, braking starts along the parameterized ramp
t3:
STOP B is initiated 2.5 s after t1. The axis is already stationary at this time, which
means that the pulses can be immediately cancelled.
Example 2 - - delaying the transition from STOP F to STOP B
The same parameterization as in Example 1 is shown in Fig. 6-8. However, when a
STOP F occurs, no monitoring function is active. At instant in time t2, a monitoring
function is activated. ESR is only started if there is a STOP F with active monitor-
ing function.
6-142
SINUMERIK 840D sl/SINAMICS S120 SINUMERIK Safety Integrated (FBSI sl) - - 10.2015 Edition
Continue to traverse (ESR)
t2
t1
Braking along a ramp
= stopping (ESR)
t3
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10/15
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