The Creep alarm calculation types can only be implemented with the CygNet Enhanced Point Scheme. See Understanding the CVS Metadata File for more information about the elements and attributes that define the CygNet Enhanced Point Scheme.
For more information, see Alarm Calculation Types.
See the following subsections for details:
Note: The Calculation Parameters are user-provided.
The Creeping Average alarm uses the Creep Average (CREEP_AVG) calculation. On each update, the system will calculate the average from the newest value older than the time interval to (and including) the previous value. The system compares the difference between the average and the update, and sets the alarm bit if the difference is more than the threshold.
The following image shows the area of an Analog Alarm Settings page of a PNT Editor with an enabled Creeping Average alarm.
Calculation Parameters
Preliminary Calculations:
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Sum = sum of previous values within time interval + newest value older than time interval
Count = number of summed values
Average = Sum/Count |
Equation
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ABS(Average Value - Current Value) = difference in value |
Example
In this example, the Creeping Average bit is set because the difference of the average (183.51) and the current value (105.2) is greater than the calcparm1 value of 10.
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Sum = 917.59 Count = 5 Average = 183.51
183.51 (Average) - 105.2 (Current) = 78.318 (value is greater than calcparm1 value of 10) |
The Creep (Value) alarm uses the Creep Value (CREEP_VAL) calculation. On each update, the system calculates the change in value between the current value and the newest value older than the time interval. There is a comparison made between the difference and the calcparm1 value, and if the difference exceeds the threshold, the alarm is set.
The following image shows the area of an Analog Alarm Settings page of a PNT Editor with an enabled Creep (Value) alarm.
Calculation Parameters
Equation
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ABS(Current Val - Newest Val Older than Time Intvl) = difference in value |
Example
In this example, the Creep (Value) bit (CONFIG12) is set because the difference in value between the current value (16.25529) and the newest value older than the time interval (1) is greater than the calcparm1 value of 10.
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16.25529 - 1 = 15.25529 (more than the max change of value allowed, so alarm bit is set) |
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