Historian: At redundancy switch old value may be written again in new capsule

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• FAQ: Historian configuration general recommendations

  1. Recommendation on hardware: Storage Memory CPU - SSD (Solid-State Drive). - Disk space capacity as detailed in the attached Excel sheet outputs. - RAM required to load the archive data is about 4 times greater the size of the respective ARX files. ...

• Historian: At reload an old value is written again / received values with old external timestamp not discarded

  Description In the Service Engine, data from already closed archives is written to the current, open archive capsule in the Historian. This problem can occur: By project reload. If the PLC sends variable values with an external timestamp from the ...

• Under specific circumstances during redundancy switch-over a value received from the PLC on the standby server may be lost

  Summary With a redundant runtime on server and standby server that are both under heavy load the server, the runtime on the standby server may fail to record a value from the PLC if this value is received from the PLC after the server has failed and ...

• Archive configuration for best SQL evacuation performance

  The time required to evacuate data to a database increases linearly with the number of insert SQL statements. In earlier zenon versions, recorded values were evacuated to the target database sequentially using single-insert statements. From zenon 11 ...

• The length of CEL entry about String variable value changes is limited to 80 characters minus "old and new value"

  Summary If you use by String variable, for "Write set value", the "Logging in CEL" then the CEL entry is limited to 80 characters; minus length for new and eventually old value (option "old and new value"). Since introduction in the Chronological ...