Scan State. Tag field "SCANST" allows a user to put a tag in “maintenance mode” by setting this field to a desired value. This applies to IO tags, Constant, Calculation and Accumulation point Tags. Only I/O tags have the “bad” states (4 to 7).
0 is normal.
Set this value to:
1 to disable writes to this tag.
2 to disable alarm checking.
3 to disable writes & alarm checking.
4 to show value as BAD, '*' (asterisks), with quality 0xf0f0.
5 to show bad and disable write.
6 to show bad and disable alarm checking.
7 to show bad, disable write and alarm checking.
"Restore Tag Scan Status Timeout” can be defined in SCADA node properties. If the kernel re-starts with in the timeout, the kernel restores previous SCANST for the tag. If the kernel stopped normally, the last value is restored, otherwise, the last on-the-minute value is restored.