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GETARCHARR action


Function
Reading a value block of specified historical values within given time interval.
Declaration
 GETARCHARR archIdent, locVarColValueIdent_Rec, [locVarColFlagsIdent_Rec], timeFromIdent_TmA, timeToIdent_TmA, stepIdent_Int, maxValsIdent_Int, statusIdent_Int[, archivInstance_Int]

Parameters
archIdent in Reference to one value of historical value, reference to object or item identifier of Structured variable type object (note: values of object or item must be 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.

locVarColValueIdent_Rec out Reference to column of a RECORD type local variable for result values
locVarColFlagsIdent_Rec out Optional parameter. Reference to column of a RECORD type local variable for archive flags (Integer type).
timeFromItemIdent_TmA in Identifier AbsTime type for the interval beginning.
timeToItemIdent_TmA in Identifier of AbsTime type for the interval end.
stepIdent in Identifier of Int type - time step for the oversampling of values in the archive.
maxValsIdent_Int in Maximal number of values. If more values is in the required interval, they will be trimmed and the action returns the warning _ERR_MORE_DATA in the identifier statusIdent_Int.
statusIdent_Int out 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.

Description
The action reads values of the historical value archIdent within the time interval from timeFromIdent_TmA to timeToIdent_TmA with the steps stepIdent_Int (given in seconds). Maximal number of values is given by the identifier maxValsIdent_Int. See reading the values.

The parameter stepIdent_Int defines the oversampling (in seconds) of read values. If it is equal to 0, reading is not to be oversampled.

If the parameter archIdent is the reference to an object of Historical value type, the action performance is described above. If the parameter is the reference to an object (not of Historical value type) or a structured variable item that is not of Object type, the system is attempting to find an object of Historical value type that archives values of the object (item).
If the parameter archIdent is the reference to a structured variable item that is of Object type, the item "points" to an object in the system. If the object is of Historical value type, the action will read data from it. If it is not, the system is attempting to find an object of Historical value type that archives values of the object.

The return code statusIdent_Int can get one of the following values:

  • _ERR_TRANS_ABORT
  • _ERR_TRANS_ERROR
  • _ERR_TRANS_IGNORED
  • _ERR_NO_ERROR
  • _ERR_NO_DATA - no data within given interval
  • _ERR_MORE_DATA - more data than maxValsIdent_Int within given interval
  • _ERR_OBJECT_IS_NOT_IN_ARCHIVE

The error _ERR_MORE_DATA has only informative character and the required number of data is available. If the value of the identifier stepIdent_Int = 0, then values from the given interval are not be oversampled.

locVarColValueIdent_Rec - is the reference to an item of a RECORD type local variable. The action, after successful reading of values, resizes the array (internally the action REDIM) to the required number of rows and in sequence (from 1...) assign a value from the archive to the given item. Likewise locVarColFlagsIdent_Rec - is the reference to an item in a local variable of RECORD type. The item must be Int type. Analogous to the previous parameter, the action will resize the array (the sizes will be equal) and assign flags from the archive to the given item in each row (see the action GETARCHVAL). The parameter is optional and it can be omitted. An item for data from the archive and an item for archive flags may be from the same local variable.

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.


Example
The example assumes the existence of the object SD.ArchDemo of Structure definition type, that contains the following items: 

Structure definition items
Item name Item type
Text Text
Value Real number
Flags Integer

Reading values from the archive. Values and archive flags are in two various arrays.
 
 TIME _timeFrom
 TIME _timeTo
 INT _maxVals
 INT _step
 INT _status 
 RECORD (SD.ArchDemo) _locAValArr
 RECORD (SD.ArchDemo) _locAFlagsArr
 
_timeTo := %StrToTime("10:00:00 31-12-1999")
 _timeFrom := %StrToTime("09:00:00 31-12-1999")
 _maxVals := 100
 _step := 0
 GETARCHARR H.ArchObj, _locAValArr^Value, _locAFlagsArr ^Flags, _timeFrom, _timeTo, _step, _maxVals, _status
IF (_status = _ERR_NO_ERROR) | (_status = _ERR_MORE_DATA) THEN
   ; data are loaded 
 ELSE
   ; an error occurred
 ENDIF 

 
Seeing that the number of values and archive flags is always equal, the previous example should be implemented with the reading of values and flags into one array.
 
 TIME _timeFrom
 TIME _timeTo
 INT _maxVals
 INT _step
 INT _status 
 RECORD (SD.ArchDemo) _locAValArr
 
_timeTo := %StrToTime("10:00:00 31-12-1999")
 _timeFrom := %StrToTime("09:00:00 31-12-1999")
 _maxVals := 100
 _step := 0
GETARCHARR H.ArchObj, _locAValArr^Value, _locAValArr^Flags, _timeFrom, _timeTo, _step, _maxVals, _status
IF (_status = _ERR_NO_ERROR) | (_status = _ERR_MORE_DATA) THEN
   ; data are read
 ELSE
   ; an error occurred
 ENDIF 

 
Reading data from structured historical value.
 
 TIME _timeFrom
 TIME _timeTo
 INT _maxVals
 INT _step
 INT _status
 INT _row
 
 RECORD (SD.ArchDemo) _locAValArr
 
 _timeTo := %StrToTime("10:00:00 31-12-1999")
 _timeFrom := %StrToTime("09:00:00 31-12-1999")
 _maxVals := 100
 _step := 0
 _row := 4   ; row 4
 
 GETARCHARR (H.StructArchObj\HBJ, _row, 5) _locAValArr^Value, _locAValArr^Value, _timeFrom, _timeTo, _step, _maxVals, _status
 IF (_status = _ERR_NO_ERROR) | (_status = _ERR_MORE_DATA) THEN
   ; data are read
 ELSE
   ; an error occurred
 ENDIF 

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