46
SI-Safety Installation & Operating Manual
Issue Number: 1
5.4
Response times for fault distance monitoring
To calculate the worst case scenario, use the following calculations:
System speed at scanning time: V(t)
System speed for module response: VA(t)
Threshold value for monitoring (SLS or SCA): VS = constant for all t
Configured filter value: XF = constant for all t
Max. Possible acceleration for the application: a
F
= constant for all t
Retardation after disengagement: a
V
= constant for all t
Scanning time for occurrence of a worst case event: T
fault
Module response time: T
response
For the worst case scenario, it is assumed that the drive unit initially moves at a speed
of v(k), precisely in line with the configured threshold of V0, then accelerates at a
maximum possible value of a0.
Figure 5-1 Characteristics of drive unit with and without linear ramp and
overspeed distance
s m. Overspeed
Distance (m)
s without Overspeed
Distance (m)
Vm. Overspeed
Distance (m/s)
V without Overspeed
Distance (m/s)
T
Fault
T
Response
T
Response
XF
V
a2
V
a1
V
s
Summary of Contents for unidrive m
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