ABB SM500F User Manual page 107

SM500F
Field mountable paperless recorder
IM/SM500F Rev. Z
Note. Delayed process alarms only – see Fig. 7.15, page 103.
Set the value, in engineering units, at which the alarm is to activate.
Set the hysteresis value in engineering units and the delay time in
seconds.
The delay time is the period of time for which alarm activation is delayed
after the enable signal is switched on. Once the delay time has expired,
the alarm operates in the same way as a standard High/Low process
alarm.
Note.

Rate alarms only – see Fig. 7.14, page 102.

A Rate alarm remains active until the rate has been within limits for
at least one complete Alarm Period.
Set the minimum or maximum amount of deviation allowed within the
Rate Alarm Period before the alarm is activated.
Set the time period over which the deviation is measured. For High Rate
alarms, the alarm becomes active if the value changes by more than the
deviation value within the alarm period. For Low Rate alarms, the alarm
becomes active if the channel value changes by less than the deviation
within the alarm period.
Set the filter time to be used to reduce the number of spurious alarm trips.
The source signal is averaged over the filter period prior to the rate alarm
being determined.
7 Configuration
105