What's the best way to hold a PI tag value from 0400 - 0700 every Thursday? This is because every Thursday morning there is a water wash and the system is re-routed to a line that does not have a flow meter. This throws off the value.
If the desire if to keep the last value before 4:00 AM on Thursday and not have any new values until 7:00 AM, I would write an analysis that is event triggered on the flow tag, and if the time is NOT between 4:00 and 7:00 AM on Thursday, use the flow value as the output value, else no output. This will require a new 'output' tag for the flow.
And, if AF is not in use or not desirable, it can be done with an event based PE as well.
Eugene Lee's suggestion of writing a program will work if you can't use another output tag.
Could you please provide more information on this request and functionality you would like to achieve?
I would advise writing a program to delete the values from 0400 to 0700 every Thursday and trigger that program weekly at maybe 0701 Thursday etc.
I would go with Tim's method. Although programmatic methods to do this give you the most flexibility, having a second tag will mean you haven't lost data if the time every changes or the water wash cycle does not start due to a fault
Thanks to all of you for the help!
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