Function description
Operating Manual PSSu K F EI
1003303-EN-03
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4.5.1
Safe speed monitoring - SSM
The "Safe speed monitoring" function (SSM) monitors whether the current speed exceeds a
limit value.
A tolerance range may also be set for the limit values used to monitor the speed. This toler-
ance range modifies the set limit values. As a result, one-off or periodic overshoots that ex-
ceed the limit values can be tolerated.
Activate the monitoring function by:
}
The monitoring function does not need to be activated. Monitoring starts as soon as the
module is ready for operation.
Reaction:
}
If the configured limit value, plus the configured tolerance, is violated:
– a 1/0 pulse edge at SSM_Enable
– the local outputs switch off, depending on the configuration. Further information is
available in PAS4000's online help.
The following values can be configured for the tolerance range:
}
Tolerance time (t1), which takes into account the length of the overshoots (maximum time
for which the limit value may be exceeded)
}
Tolerance period (t2), which takes into account the oscillation period (minimum time that
must elapse between one limit value overshoot and the next)
}
Tolerance amount as % (Tol), which takes into account the amplitude of the overshoots
(maximum permitted percentage by which the configured limit values may be exceeded)
}
Hysteresis as % (Hys), prevents the outputs from bouncing if there are fluctuations
around the response value. The hysteresis takes effect when the output is switched on:
– Switch-on value = Switching threshold – Hysteresis
