Siemens SINUMERIK 840D sl Function Manual page 136

Safety functions integrated in the system/drive
7.4 Safe Acceleration Monitor
Figure 7-12
Table 7-5 Explanation of the diagram
Time Explanation
t Position control clock cycle, defined by the following MD:
1
MD10050 $MN_SYSCLOCK_CYCLE_TIME
MD10060 $MN_POSCTRL_SYSCLOCK_TIME_RATIO
t Monitoring clock cycle, defined by the following MD:
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 that is required to introduce the 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
typical 2 ms, maximum 3 position controller clock cycles + 8 ms)
(
t Time required to bring the axis to a standstill.
7
This time and thus the residual distance traveled by the axis is determined by the axis design (motor, mass, friction, ...).
Note
During "normal" operation, speed overshoot should not unintentionally initiate the SBR. Speed
overshoot should therefore be checked by making the appropriate measurements.
136
Timing when the actual stop limit value for SBR is exceeded
Function Manual, 12/2017, 6FC5397-4BP40-6BA1
Safety Integrated