Re: Naming bits in an mbbiDirect record

[André Favoto via Tech-talk <tech-talk at aps.anl.gov>]

I did open an issue some time ago requesting that feature: https://github.com/epics-base/epics-base/issues/846

It would be very convenient to have a way to set a label for each bit inside the record.

As a workaround, we have separate PVS like "NameBit1", "NameBit2", etc, which works, but it is as much of a pain as mapping individual bi records.

Having a binary PV for each bit kind of defeats the purpose of using mbbiDirect structure IMO.

There is, of course, the concern of having the individual bit severities that Ralph mentioned on the issue above.

But having one does not block the other, and I don't see how adding labels to the bits would change in any way the severity/alarm handling.

If one needs individual severities/alarms for each bit or combinations of them, then I agree that mapping to separate records is the correct approach.

Best Regards,

André Favoto

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From: Tech-talk <tech-talk-bounces at aps.anl.gov> on behalf of Ralph Lange via Tech-talk <tech-talk at aps.anl.gov>
Sent: Friday, September 4, 2026 08:59
To: EPICS Tech Talk <tech-talk at aps.anl.gov>
Subject: Re: Naming bits in an mbbiDirect record

 

No, not inside the mbbiDirect.

To get the single bit description (and alarm severity/status, and value strings, ...) add a biRecord for each bit and point its input link to the appropriate bit field of the mbbiDirectRecord. If you make that input link CP or CPP, the single bit record will only process when the value of that bit changes.

Cheers,
~Ralph