Configure a rate point for Rate Reasonability checking

Follow this procedure to enable a rate point for Rate Reasonability checking and configure the limit that the application compares against the point's incoming flow rate.

Note: The Alarming tab in the rate Row Edit dialog box is opened through the rate table listing in the Advanced Database Editor (ADE). For general information on ADE, and further information on the rate table, refer to the Advanced Database Editor (ADE) Administrator documentation and RealTime tables, respectively.

To configure a rate point for Rate Reasonability checking

1. Navigate to the Alarming tab in the rate Row Edit dialog box.

   

2. Select Enable Reasonability Alarming.

3. In the Reasonability Limit field, enter the value to compare against the rate point's incoming flow rate.

   If the flow rate exceeds this value:

   • The rate point enters a Reasonability condition.

   • AVEVA Enterprise SCADA generates an alarm and logs an event.

     Valid values are from -100,000 to 250,000.

     Note: Ensure the value is above the expected, nominal flow rate. Otherwise, the rate point will immediately enter a Reasonability condition when you save the record, and the system will not have a last good flow rate available for use in processing software accumulator functionality.

4. In the Hold-off Time (minute) field, enter the length of time in minutes that the system should suppress a generated alarm.

   Valid values are from 0 to 15.

5. In the Hold-off Override Multiplier field, enter the value used in the equation that determines whether or not the system should cancel alarm suppression because of a large spike in a reported flow rate.

   Example:

   Assume the following:

   • Reasonability Limit = 1500

   • Hold-off Time (minute) = 10

   • Hold-off Override Multiplier = 2

     The rate point reports a flow rate of 2,000. As a result, the point enters a Reasonability condition. However, because of the Hold-off Time (minute) setting, the system does not immediately generate an alarm. Five minutes later, the rate point reports a flow rate of 3,200. Since this value exceeds the product (3,000) of the equation (Reasonability Limit) x (Hold- off Override Multiplier), the system cancels alarm suppression and immediately generates an alarm.

     Important: If you configure a rate point for Rate Reasonability checking, but then inhibit all Reasonability alarms for the rate point (as described below in Inhibit reasonability alarms), AVEVA Enterprise SCADA:

   • Will ignore any configured Hold-off Time (minute) and Hold-off Override Multiplier.

   • Will not generate an alarm when the rate point enters a Reasonability condition.

   • Will log an event when the rate point enters a Reasonability condition.