- Vytvoril D2000 Dev Team na okt 13, 2017
GETARCHROW action
GETARCHROW archIdent, locRecDstIdent, timeFromIdent_TmA, timeToIdent_TmA, stepIdent_Int, maxValsIdent_Int, statusIdent_Int [,archivInstance_Int]
archIdent | in |
Reference
to row of:
|
locRecDstIdent | out | Local variable of Record type - read result. |
timeFromIdent_TmA | in | Identifier of Absolute time type - interval beginning. |
timeToIdent_TmA | in | Identifier of Absolute time type - interval end. |
stepIdent_Int | in | Identifier of Int type - time step for archive values oversampling. |
maxValsIdent_Int | in |
Maximum number of values. If given interval contains more data, the action will trim off the data and return ERR_MORE_DATA warning in the parameter statusIdent_Int. |
statusIdent_Int | out | Read 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. |
Archive data read request contains reference to data by means of:
- Object of Historical value type (or item of structured historical value) - in this case, the object that is to be read is uniquely determined.
- Other system object (I/O tag, user variable, ...)
or item of local variable variable of Record type - in this case,
the system automatically search for the historical value that archives
the object determined by the request (e.g. if the request contains the
reference to I/O tag that has been archived, the system automatically
redirects the request to the historical value). If such historical value
doesn't exist, the action will be terminated and return the _ERR_ARCHIV_NOT_RUNNING
error.
The parameter archIdent can be defined by one of the following ways:
- Row of local variable of „typed
ALIAS“ type
Example:
ALIAS (structure definition) _lAT
SET _lAT AS SV.Struct
GETARCHROW _lAT[4] , ...
Individual read requests are ALWAYS addressed to items in given column of the structure SV.Struct (even if the column contains items of Object type).
- Row of object of Structured variable type
Example:
GETARCHROW SV.Struct[4] , ...
Request addressing is the same as described in the article 1.
- Row of local variable of Record type
Example:
RECORD (structure definition) _lRec
REDIM _lRec[10]
SET _lRec[4]^Item1 AS Sec
SET _lRec[4]^Item2 AS SysTime
SET _lRec[4]^Item3 AS M.MeranyBod
.....
GETARCHROW _lRec[4], ...
All the columns of the structure definition must be of Object type. Individual read requests are to be addressed to the objects the row items refer to.
If any item does not refer to object, the action is to be terminated and returns the ERR_NO_ASSIGNED_ALIAS error.
- Row of structured historical value
Example:
GETARCHROW H.Struct[4], ...
Individual read requests are to be gradually addressed to all items in given row. The object H.Struct cannot be a one-column historical value.
Read result is stored in the local variable _locRecDstIdent.
Result of every request is either one value or a sequence of values. Every
sequence of values is arranged by time in ascending order and stored row by
row in the respective column of the local variable
_locRecDstIdent. The structure type of the structured variables archIdent and
_locRecDstIdent must be the same (it ensures the same number of columns).
The action automatically resizes the variable _locRecDstIdent
to required number of rows (the number is given by the largest number of
values in the read result).
The parameters timeFromIdent_TmA and timeToIdent_TmA specify
the time
interval for reading 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.
Therefore, if the value is differing from 0,
the times of all values in the result structure is the same and every column
contains read values up to the last row. If the value is 0, the size of the
result structure is given by the maximum number of values read by one
request. Therefore, not all columns will contains values read from the
archive up to the last row.
If the parameter timeToIdent_TmA is higher than actual time and the parameter stepIdent_Int
is differ from zero,
oversampled values with future timestamps will be invalid.
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.
The variable statusIdent_Int indicates the success of reading the
action. If this variable acquires the value _ERR_NO_DATA(22), it means that
all archives, which were used when reading, do not contain any data. If at
least one of the archives contains data, the action returns _ERR_NO_ERR(0).
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