11.03
3 Safety-Related Functions
3.5 Safely-reduced speed (SG)
© Siemens AG 2003 All Rights Reserved
SINUMERIK 840D/SIMODRIVE 611 digital SINUMERIK Safety Integrated (FBSI) - Edition 11.03
3-99
n
n act
a)
b)
c)
t
1
t
2
SG_03.DS4
SG
t
t
6
t
3
t
4
t
5
Error
Limit value
exceeded
Commencement
of stop reaction
t
7
not to scale
Fig. 3-16
Timing when the limit value is exceeded with active SG
Table 3-24
Explanations of the Fig.
Time Explanation
t
1
Position control clock cycle defined by the following MDs:
MD
10050:
$MN_SYSCLOCK_CYCLE_TIME
MD
10060:
$MN_POSCTRL_SYSCLOCK_TIME_RATIO
t
2
Monitoring clock cycle defined by the following MDs:
MD 10090: $MN_SAFETY_SYSCLOCK_TIME_RATIO
For 611 digital:
MD1300: $MD_SAFETY_CYCLE_TIME
t
3
Time between an error occurring and a limit value being violated
t
4
Time until the violation of a limit value is detected (maximum 1.5 monitoring clock cycles)
t
5
Response time required to initiate the configured stop response (maximum 2.5 monitoring clock cycles)
t
6
Time until the stop response sequence starts (time = 0, depends on configured stop response, refer to
Chapter 2, "Stop responses")
t
7
Time required to bring the axis to standstill.
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 start-up to determine the distance it travels between violation of the limit value
and coming to a standstill.
3.5.5 SG-specific
stop
responses
Using the configurable SG-specific stop response, a suitable braking behavior
can be set for every SG stage in-line with the application when the particular
speed limit value is exceeded.
Example of possible setting:
Level SG2 is active with configured stop response STOP C in the setting-up
mode and level SG4 is active with configured stop response STOP D in the
automatic mode.
The function is active whenever MD 36961/1361:
$MA_/$MD_SAFE_VELO_STOP_MODE = 5.
Configurable
SG-specific stop
responses
Activating
