%ARC_GetValue function

Function
The function gets the value of the specified object of Historical value in defined time.
Declaration
REAL %ARC_GetValue(
        in archObject
   TIME in time
   BOOL in exact
 )

Parameters
archObject Name of object of Historical value type.
time Archiving time.
exact The parameter is important in periodical archiving - defines the behaviour of the function if the archive database does not contain a value with the time specified by the parameter time.
Possible values:
  • @TRUE - the function returns invalid value,
  • @FALSE - the function retrieves the value with nearest older time.

Example
The statement in the example below calculates the difference between current value of the object H.Arc1 and its value a minute ago.
 
(H.Arch1 - %ARC_GetValue(H.Arch1, %NewTime(@EvalTime,0,0,0,-60),  @FALSE)

Note
The system constant @EvalTime - more information.

Functions for calculated historical values
Function arguments - types