Experimental Physics and
Industrial Control System

Am 28.01.21 um 14:20 schrieb Zimoch Dirk (PSI) via Core-talk:
> One could of course change the check to if ((prec->drvl !=0 ||
> prec->drvh !=0) && prec->drvh > prec->drvl) But then in ao as well.
>
> It would change traditional behavior (which used to be documented
> wrongly in earlier EPICS releases) and potentially break existing
> IOCs where people use DLRH = DRVL != 0 and expect the limits to be
> ignored. It would also introduce a new "special case" because the
> record can then be fixed to any value except 0. Another option is to
> change the defaults from 0,0 to -verybig,+verybig.
>
> I think a poll would be needed.

-1

This makes a bad situation worse by complicating the rules. The problem
is the use of in-band exceptional values which is bad design and will
invariably hit you back sooner or later. Better fix: add a new field to
select whether to use or ignore DRVH/L.