METER
- Last UpdatedMar 20, 2025
- 2 minute read
The METER() function returns the delta change of the value of a stream or array of streams. This works both for tags without rollover, and tags that reset upon reaching a rollover value.
If an expression includes a single tag, the rollover value defined in the AVEVA Historian will be used. If an expression includes multiple tags, or performs an operation on a tag, a rollover value of 0 is assumed. For example, the following would use the Historian-defined rollover value:
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METER( Tag1, hour)
The following would assume a rollover value of 0:
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METER( Tag1 + Tag2, hour)
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METER( Tag1 + 5, hour)
Otherwise, the METER function works similarly to counter retrieval mode. For more details about rollover, delta change, and common use cases for this function, see Counter retrieval.
Syntax
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Format |
Stream = METER(Stream or ArrayOfStreams) |
Arguments |
Stream - A time-ordered vector of values. ArrayOfStreams - An array of streams. See Selecting an array of streams. |
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Description |
Returns the delta change in the stream or array of streams during the query period. The query period is based on local time. |
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Format |
Stream = METER(Stream or ArrayOfStreams, TimeInterval) |
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Arguments |
Stream - A time-ordered vector of values. ArrayOfStreams - An array of streams. See Selecting an array of streams. TimeInterval - The time interval over which the delta change is calculated. |
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Description |
Returns the delta change in the stream or array of streams over the specified time interval during the query period. The query period is based on local time. The returned start time is rounded down to the time interval's unit. For example, if the interval is hourly, the time stamps of all values end with "00:00.000". |