Re: [Pvmanager-devel] alarm limits will not always work

[Andrew J. <an...@ap...>]

On Friday 10 September 2010 05:06:26 Marty Kraimer wrote:
> Without knowing the severities and algorithm for computing value alarms
> a client can not handle all possibilities.
>
> A simple example is:
>
> record A gives values to none of the value alarm fields, i.e. it does
> not raise value alarms
>
> record B requires that the value be positive or it raises a major alarm.
> It only sets LLSV=MAJOR_ALARM. Think is a pipe with a check valve. A
> negative flow indicates a broken check valve.
>
> record C requires that the value be negative. It sets HHSV=MAJOR_ALARM
>
> A caV3 client can not distinguish between these cases.

Note that in R3.14.11 we changed the get_alarm_double() routines of most of 
the analog record types (ai, ao, calc, calcout, dfanout, sel, sub) to return 
NAN for the relevent level when the associated xxSV field is NO_ALARM.  This 
doesn't solve the whole problem, but it allows a V3 client to distinguish 
between /some/ of the cases (we obviously decided this was better than doing 
nothing at all).

- Andrew
-- 
The best FOSS code is written to be read by other humans -- Harald Welte