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

Subject: Re: portable ca server
From: Benjamin Franksen <[email protected]>
To: [email protected]
Date: Mon, 27 Aug 2001 18:42:12 +0200
Kay-Uwe Kasemir wrote:
> 
> First the part that got me confused and I know from emails that I'm not the only one:
> lopr, hopr, hihi, ... are epics record fields.
> CA talks about display limits, alarm limits, ...
> That's different.
> 
> When you ask an ai record fred for "fred",
> the value is the VAL field, display limits are HOPR, LOPR,
> alarm limits are HIHI, LOLO, warnings are HIGH, LOW, ...
> So for ai, the "upper display limit" is the HOPR field?
> Yes for the VAL fiels, No for the HHSV fields:
> It's enumerated, ai.HHSV has values NO_ALARM, MINOR, MAJOR, INVALID
> and display limits could be NO_ALARSM and INVALID.
> I don't know what record fields are used for display limits etc.
> when you attach a channel to e.g. the HIHI field,
> you want e.g. control limits that allow for putting up
> a slider that's useful for adjusting the HIHI field.
> Read the record ref manual of the EPICS base sources
> if you have to know what e.g. the high/low display limits
> are for each field.

It also depends on the request type. If the request's base type is
DBR_ENUM (and this is the default "native" type for DBF_MENU fields like
HHSV), there is no such attribute "display limits" or "alarm limits" for
the corresponding _GR_ and _CTRL_ requests. So the questions appears
only if the value is requested as e.g. DBR_GR_LONG and a reasonable
choice for e.g. HHSV field would indeed be NO_ALARM as lower and INVALID
as upper limit.

Unfortunately, the EPICS runtime database does not do so. Instead, these
attributes field are set to 0 in case of a menu field.

Ben
-- 
Berliner Elektronenspeicherring-Gesellschaft für Synchrotronstrahlung
(BESSY) GmbH, Control System Group
Albert-Einstein-Straße 15, 12489 Berlin, +4930 6392 8462, www.bessy.de


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Re: portable ca server Kay-Uwe Kasemir
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Re: portable ca server Kay-Uwe Kasemir

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