CALCSTATFUNC archIdent, timeFromIdent_TmA, timeToIdent_TmA, statFuncIdent_Int, validPercIdent_Int, paramIdent, retValueIdent, statusIdent_Int [,archivInstance_Int]
|archIdent||in||Reference to one value of historical value or reference to object, values of which have been archived.|
Warning: If the parameter is the reference to an object archived several times, there is not specified which one of the historical objects is to be used.
|timeFromItemIdent_TmA||in||Identifier of AbsTime type - interval beginning.|
|timeToItemIdent_TmA||in||Identifier of AbsTime type - interval end.|
|statFunctIdent||in||Identifier of Int type - statistical function type.|
|validPercIdent||in||Identifier of Int type - validation criteria.|
|paramIdent||in||Identifier of Int or Real types - parameter for some types of functions.|
|retValueIdent||out||Identifier for calculation result.|
|statusIdent||out||Calculation (action) success.|
|archivInstance_Int||in||Optional identifier of Int type - identification of archive instance. If the parameter is not defined, the value 0 will replace it.|
The action executes calculation of the statistical function given by the parameter statFuncIdent_Int on the values represented by the historical value archIdent within the time interval given by the parameter timeFromIdent_TmA and timeToIdent_TmA . After successful execution of the action, the parameter retValueIdent contains a result value of the calculation. The parameter statusIdent_Intgets one of the following values:
Set of implemented functions is equal with the functions, which may be configured for statistical archive (except the FILTER and EACOAVG functions). For the individual functions, there are predefined local constants in ESL.
The parameter validPerctIdent_Int represents Validation criteria used during the evaluation of the statistical function. It can get values within 1 .. 100 (the error ERR_RANGE_ERROR occurs if the condition is broken).
For some statistical function, it is required to enter the parameter paramIdent according to the table:
|Statistical function||Parameter description|
Integral time units. For individual types, there are also established predefined local variables according to the table:
For the other statistical archive functions, the parameter paramIdent is not being evaluated.
Value of parameter archivInstance_Int defines the instance of archive which executes the request. If the parameter is not defined (or the value is 0), the active instance of archive will execute the request.
Note: When calculating CALCSTATFUNC action, a time limitation which is active in the computations of statistical archives and does not allow for calculation for future times, is no applied. With CALCSTATFUNC, it is therefore possible, for example, to calculate statistics over a script filled archive that has data in the future.
TIME _bt TIME _et REAL _retValue INT _retCode _bt := %StrToTime("8:01:00 16-10-2003") _et := %StrToTime("8:02:00 16-10-2003") CALCSTATFUNC H.ArchObj, _bt, _et, _STAT_F_SUM, 100, 0, _retValue, _retCode IF _retCode = _ERR_NO_ERROR THEN ; calculation done ELSE ; an error occurred ENDIF
If it is necessary to calculate statistics over a periodic archive (e.g. H.Period), it should be noted that the periodic archive has values only in multiples of the period. For example, if it were necessary to calculate the integral from the periodic archive and the beginning of the interval would not be multiples of the period, 0 would be integrated from the beginning of the interval to the first multiple of the period.
This feature can be circumvented by creating a on-change computed archive object (e.g. H.PeriodOnRead) that is computed on-read and that copies H.Period. Integral computed from H.PeriodOnRead archive will behave as expected.