Siemens Sinumerik 840D sl Function Manual page 157

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Timing when the limit value is exceeded
When the safely reduced speed function is active, then the timing is as follows
when the limit value is violated:
Figure 6-14 Timing when the limit value is exceeded for SG
Table 6-13 Explanation of the figure
Time Explanation
t The position control clock cycle, defined by the following MDs:
1
MD10050 $MN_SYSCLOCK_CYCLE_TIME
MD10060 $MN_POSCTRL_SYSCLOCK_TIME_RATIO
t Monitoring clock cycle, defined by the following MDs:
2
for 840D sl:
MD10090 $MN_SAFETY_SYSCLOCK_TIME_RATIO
for SINAMICS S120:
r9500 SI Motion monitoring clock cycle (Control Unit)
t Time between an error occurring and a limit value being reached
3
t Time until a limit value violation is detected
4
(typical 1 monitoring clock cycle, maximum 1.5 monitoring clock cycles + 1 position controller
clock cycle)
t Response time required to initiate the configured stop response
5
(typical 2 monitoring clock cycles, maximum 2.5 monitoring clock cycles + 1 position controller
clock cycle)
t Time until the stop response that was initiated starts
6
(STOP A: typical 2 ms, maximum 3 position controller clock cycles + 8 ms)
(STOP B/C: typical 2 position controller clock cycles, maximum 2 position controller clock cycles)
(STOP D/E: typical 2 interpolation clock cycles, maximum 2 interpolation clock cycles + 2 monito-
ring clock cycles)
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SINUMERIK 840D sl/SINAMICS S120 SINUMERIK Safety Integrated (FBSI sl) - - 10.2015 Edition
n
Limit value
exceeded
b)
SG
Error case
a)
n act
t
3
t
Safety functions integrated in the system/drive
6.5 Safely reduced speed (SG)
c)
Start of the
stop response
t
1
t
2
not to scale
t
6
4
t
5
t
7
t
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