Specify when a Change in Value Triggers a Change in Point State

The following fields are displayed toward the bottom of the Alarm Limits section on the Analog Point tab:

• Hysteresis—Use to specify the amount by which the DNP3 SCADAPack point’s engineering value has to change for an alarm condition to clear. For further information, see Specify the Hysteresis - the Minimum Value Change that can Clear an Alarm in the Geo SCADA Expert Guide to Core Point Configuration.

  Hysteresis does not apply to Overrange and Underrange. When a point’s value returns from one of these conditions, the SCADAPack E outstation immediately generates an event at the limit value.

• Persistence into Alarm—Use to specify how long the point’s value has to transgress an Alarm Limit for before the outstation generates an event. If the point’s value returns from the transgressed state within this time, no event is generated.

  Enter the time in the OPC Time Format.

  Persistence into Alarm does not apply to Overrange and Underrange. When a point’s value returns from one of these conditions, the outstation immediately generates an event at the time that the limit is transgressed.

• Persistence out of Alarm—When the point’s value is returning from an Alarm Limit transgression, this property specifies how long the point’s value has to remain within the Alarm Limit before the outstation generates an event. If the point’s value transgresses the Alarm Limit within this time, no event is generated.

  Enter the time in the OPC Time Format.

  With the Overrange and Underrange conditions, the outstation generates an event once the point’s value has remained Overrange or Underrange for one tenth of the specified Persistence out of Alarm time.