Archiving is used for saving measured points or calculated points. These points can be archived in two ways:
1. Periodical archiving
2. Archiving at value change
Only value changes are recorded in the archive
1. Primary archiving
2. Archiving using a statistical function
3. Archiving using an entered expression
4. Archiving using a filled script
An object in CNF describing the source of archived data and their archiving and processing method. Archived values parent is a SELF.ARC process.
More information about archiving at documentation.
In the following preview, we will archive a calculated point using primary archiving.
Creating the statistical archiving
Creating an archive using the statistical function can use, for example, implemented functions: average, weighted average, integral, sum, maximum, minimum, etc.
- Progressive - calculation is made continuously. Result values are calculated according to a definition and are available automatically (based on the system utilization).
- On demand -calculation is made and the results are recorded to the archive on demand. A calculation request can be generated with a Tell command RECALC v SYSCONSOLE action.
- At reading - calculation is made according to a read request. The advantage of this method is that values are not recorded to the archive and do not take up any space. For such an archive object, there exist no options to make patch recalculation in case of delayed value recording to the archive. A disadvantage is that each read request from the archive requires loading source data and performing calculation.
In the following preview, we will archive using the statistical feature. Only archived values can be archived by the feature.