DSC: Alarm time delays

[JKSH]

Hello,

How can I make the DSC alarm tolerate transient spikes? e.g. trigger an alarm event if the temperature has exceeded the HI level for over 5 seconds, but ignore it if the HI level was only exceeded for 1 second.

Thanks!

[Esteban_B]

Hi JKSH,

Please take a look at the Help File for the Alarming Page of the shared variables, under alarms, the Deadband/Time option seems  to be the one you are looking for:

Deadband/Time—Sets the Deadband or Time of the alarm.

• Deadband (%)—Sets the alarm deadband as a percentage of the full scale range. The Share Variable Engine (SVE) does not clear an active alarm until the percentage difference between the new value and the previous value equals or exceeds the deadband. If you set the Deadband/Time too high, the SVE might not clear the alarm.
• Time (ms)—Sets the amount of time, in milliseconds, in which the shared variable value must change at least the value of Change to go into an alarm state.

[JKSH]

Hi Steve,

The "Time" option only applies to "Rate of Change" alarms, i.e. trigger an alarm if the variable changes by a magnitude of Change (or more), within a period of Time.

I'm looking for a way to trigger an alarm if the variable exceeds a level for more than a specified period, but not if it exceeds that level for only a short instant.