Siemens SINUMERIK 840D Description Of Functions page 113

11.03
Fig. 3-19
Table 3-42 Explanations of the diagram
Time Explanation
t Position control clock cycle defined by the following MDs:
1
For 840D: MD 10050: $MN_SYSCLOCK_CYCLE_TIME
MD 10060: $MN_POSCTRL_SYSCLOCK_TIME_RATIO
t Monitoring clock cycle defined by the following MDs:
2
For 840D:
For 611 digital:
t Time until passing limit position is detected (maximum 1 monitoring clock cycle)
3
t Delay until the configured stop response is output (maximum 2 monitoring clock cycles)
4
t Delay until the configured stop response takes effect (time = 0, depends on the configured stop response,
5
refer to Chapter 2, "Stop responses")
t Time required to bring the axis to standstill.
6
This time period and thus the residual distance traveled by the axis is determined by the axis design
(motor, mass, friction, ...) and the configured stop response (STOP C is faster than STOP D).
Note:
Each axis must be measured during commissioning to determine the distance it travels between the limit value being
violated and it coming to a standstill.
© Siemens AG 2003 All Rights Reserved
SINUMERIK 840D/SIMODRIVE 611 digital SINUMERIK Safety Integrated (FBSI) - Edition 11.03
n
a) Axis crosses limit position
n act
t
2
t
1
t
3
t
4
Timing when the software limit switch is passed
MD 10090: $MN_SAFETY_SYSCLOCK_TIME_RATIO
MD1300: $MD_SAFETY_CYCLE_TIME
3 Safety-Related Functions
3.6 Safe software limit switches (SE)
SE_01.DSF
t
not to scale
5
t
6
t
3-113