Rate Row Edit: Alarming tab

The Alarming tab in the rate Row Edit dialog box allows you to set alarm conditions for the rate record being configured.

Support is provided for a number of alarm conditions for analog and flow rate points, including:

• Instrument failure checking

• High/Low operating-range checking

• HighHigh/LowLow operating-range checking

• Rate-of-Change (ROC) checking

• Creep Detection or instrument-deviation checking

• Flatline Alarming checking

Each of these alarm conditions can be configured and enabled or disabled independently. You can set the conditions in the point’s record, or in the point’s easy eXtended Operator Station (ezXOS) control panel via the Alarm Limits window in ezXOS.

Refer to the table below for field descriptions and instructions on how to configure the editable fields.

Important: When you configure or modify the alarm limits of a rate record associated with an almlimit record (identified in the Alarm Limit Set field), the system transfers settings from the following sections to the almlimit record as well as any analog, rate, or flowTotalConfig records also associated with that almlimit record:

• Level Alarming

• ROC Alarming

• Creep Alarming

• Flatline Alarming

• State Alarming Inhibit (Inhibits tab)

  Items	Description
  Enable Email Notification	Select to enable the record for email alarm notification. For further information on the items in this section, refer to Email Alarm Notification.
  Alternate Email Subject	Select if alarms associated with this point are AVEVA Enterprise SCADA-related alarms. When selected, the subject line of email messages sent to defined recipients comes from the "emailSubject" application record. If the "emailSubject" application record does not exist, the subject line defaults to SCADA Alarm. When not selected, the subject line comes from the "emailMeaSubject" application record. If the "emailMeaSubject" application record does not exist, the subject line defaults to Measurement Alarm. For further information, refer torefer to Email Alarm Notification.
  Email Alert Group	Enter or select the name of the alertGroup record containing the Controllers and/or Administrators who will receive messages about alarms associated with this point.
  Minimum Alarm Severity	Do one of the following: Select a Minimum Alert Severity. The application sends an email message when an alarm's severity level is equal to, or greater than, the minimum alert severity. No message is sent when an alarm's severity level is below the minimum alert severity. Select none to disable this field. Note: The system excludes Return-to-Normal alarms from the minimum alert severity filter.
  Return to Normal Alarms, All Off- Normal Alarms, HiHi, Hi, Lo, LoLo, User Hi, User Lo, Instrument Fail, ROC, Creep, Setpoint Creep, Flatline	Select the types of alarms that will generate email messages. Note: If you select yes for All Off-Normal Alarms: All the following Off-Normal alarm fields become unavailable. The system sends out emails for all Off-Normal alarm conditions, regardless of individual Off-Normal alarm settings.
  Paging Park Time	Enter the amount of time (in minutes) that the Field Operator has to respond to the alarm. After the time expires, the alarm message will become visible to the Controller.
  Paging Retry	Enter the number of retry, or reminder, messages that will be sent until the Field Operator acknowledges the alarm or the Paging Park Time expires.
  Annunciated Page	Select the Annunciated Page field to allow both the Field Operator and Controller to acknowledge the alarm. If this field is selected, the alarm will not be parked and will be visible to the Controller immediately.
  Instrument Fail Check	Select to generate an alarm when an instrument failure occurs. An alarm is only generated if the point is connected with a Remote Terminal Unit (RTU) capable of sensing instrument failures.
  Instrument Fail Deadband	Enter a deadband value to apply to the instrument’s lower and upper raw operating limits, as configured in the Minimum (EGU) and Maximum (EGU) fields on the Input tab.
  Alarm Deadband	Enter the deadband value for the rate point. This value controls the sensitivity of the High and Low alarms. For more information, refer to Deadbands.
  HiHi/LowLow Alarm Check	Select to edit the HighHigh and LowLow alarm limits. Refer to Alarm Limits for more information.
  Hi/Low Alarm Check	Select to edit the High and Low alarm limits. Refer to Alarm Limits for more information.
  HiHi Alarm Limit	Enter the HighHigh alarm limit for the rate point.
  Hi Alarm Limit	Enter the High alarm limit for the rate point.
  Lo Alarm Limit	Enter the Low alarm limit for the rate point.
  LoLo Alarm Limit	Enter the Low Low alarm limit for the rate point.
  User Hi Alarm Check	Select to edit the Administrator-defined Hi alarm limit. For further information on the items in this section, refer to User Configurable Alarm Limits.
  User Hi Alarm Limit	Enter the Administrator-defined Hi alarm limit for the rate point.
  User Lo Alarm Check	Select to edit the Administrator-defined Lo alarm limit.
  User Lo Alarm Limit	Enter the Administrator-defined Lo alarm limit for the rate point.
  Enable ROC Alarm	Select to enable the Rate of Change (ROC) alarm. If the ROC exceeds the Rate of change limit, an alarm is generated. Refer to Rate of Change Checks for more information.
  ROC Type	Select the type of ROC alarming to use. Options: baseline method. Use the baseline method of ROC alarming. custom method. Use the baseline method of ROC alarming with the additional fields below: Negative Rate of change limit Time Interval for ROC In the baseline method, the system calculates the ROC as the difference between the current and previous poll, divided by the difference in time between these consecutive polls. This yields a rate in engineering units (EGUs) per second, which the system then compares against the ROC limit. The system generates an alarm if either positive or negative ROC occurs. The custom method works to reduce nuisance alarms by allowing Administrators to specify the delta time between values, as opposed to the system calculating the ROC between consecutive polls. In addition, the custom method allows for different ROC limits for positive and negative ROC. The system calculates custom ROC by recording multiple poll cycles (up to 30) and calculating the ROC between values that are separated in time by at least the delta time value that you specify (Time Interval for ROC): ROC = (Current Value - Value at Delta Time ago) / Delta Time Where: Delta Time = Time Interval for ROC. It is best to set the Delta Time to a multiple of the poll cycle time. For example, if poll cycles are 10 seconds, set the Delta Time to a value divisible by 10. Note: Baseline alarms are not persistent. However, Custom ROC alarms are persistent. Subsequent to a Custom ROC alarm, the system continues to calculate the ROC each poll using the above method, and maintains the alarm state so long as the ROC over the Delta Time exceeds limits. For custom ROC alarms, once the limit is no longer exceeded, a return-to-normal alarm will be generated.
  Rate of change limit (Units/Sec)	Enter the maximum allowable ROC (EGUs per second).
  Negative Rate of change limit (Units/Sec)	Enter the maximum, negative allowable ROC (EGUs per second).
  Time Interval for ROC (sec)	Enter the time interval over which the system should calculate the ROC.
  Creep Detection	Select to enable the Creep Detection alarm. If the value creeps out of its calibrated state by a value that exceeds the Deviation Alarm Limit, an alarm is generated. Refer to Creep Detection for more information.
  Deviation Alarm Limit	Enter the maximum deviation value (EGUs) that is acceptable before calibration deteriorates.
  Flatline Alarming	Select to enable Flatline Alarming. If the rate value does not change within the Timeout value (min), an alarm is generated.
  Timeout value (min)	Enter the maximum about of time (minutes) that can pass without the rate value changing.
  Enable Realarm (0-255 mins)	Enter the number of minutes after which an acknowledged alarm should re-alarm. Note: An entry of 0 disables the Re-Alarming functionality. For further information, refer to Re-Alarming.
  Alarm Suppression	Select to open the Alarm Suppression (Almsuppression) Table Edit dialog box, and configure almsuppression records associated with this record.
  Alarming on-delay	In this section, set the on-delay time in seconds for the desired alarm levels. When an alarm condition occurs, AVEVA Enterprise SCADA waits this many seconds before generating an alarm. For further information, refer to On/Off Delay enhancement.
  Alarming Off-delay	In this section, set the off-delay time in seconds for the desired alarm levels. When a return to normal condition occurs, AVEVA Enterprise SCADA waits this many seconds before generating a Return-to-Normal alarm. For further information, refer to On/Off Delay enhancement.
  Maximum period of time (min)	Enter the maximum allowable park time for alarms associated with this point. For further information, refer to Alarm Parking.
  Enable Alternate Alarm Limit	Select to enable alternative alarm limits and edit the Alarm Limit Set field. For further information on the items in this section, refer to Alternate Alarm Limits.
  Alarm Limit Set	Select (...) and select the desired alarmlimitset record from the Alarmlimitset Select dialog box.
  Enable Reasonability Alarming	Select to enable the point for Rate Reasonability checking, and configure the limit that the application compares against the point's incoming flow rate. For further information on the items in this section, refer to Rate Reasonability.