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<== Date ==> <== Thread ==>

Subject: aSub, EFLG, and array length changes
From: Michael Davidsaver <mdavidsaver@bnl.gov>
To: "tech-talk@aps.anl.gov" <tech-talk@aps.anl.gov>
Date: Tue, 02 Oct 2012 15:17:39 -0400
All,

I've come across an unexpected behavior with monitors on the VAL* fields of the aSub record. It seems that the default is to post monitors only on change (EFLG="ON CHANGE").

Unfortunately, the calculation to determine if the value has changed doesn't work correctly in some cases. The issue is that while the previous values are saved, the length of the previous values are not. So the comparison test uses the same length (NEV*) for VAL* and OVL*. Thus, if the change is that the array gets smaller, but the remaining values are unchanged, then no monitor is posted.

The obvious solution is to add another set of fields to track the number of element in the old value. Does this seem reasonable? Also, how to express "the number of element in OVLA" in 4 characters or less?


Michael


Replies:
Re: aSub, EFLG, and array length changes Andrew Johnson

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