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

Subject: Re: [db] simple command ?
From: Benjamin Franksen <benjamin.franksen@helmholtz-berlin.de>
To: <tech-talk@aps.anl.gov>
Date: Sat, 7 Apr 2012 00:45:10 +0200
On Wednesday 04 April 2012 18:43:29 Pavel Masloff wrote:
> You are right - I want the record to automatically switch its value back to
> 0 after somebody sets it to 1. Time doesn't really matter. Imagine a
> pneumatic valve. I have two records two control it: cmd:valve_ON and
> cmd:valve_OFF. The reason I use two records instead of one is simply
> because there are two buttons on the front panel of my control cubicle. And
> the PLC logic is that it checks whether only one button is pressed at a
> time. This is local control. Yet, at the same time I want to remotely
> control my system by means of EPICS.

Beware, though: using the HIGH field causes the record to process (again) when
VAL gets reset to zero.

The bo machinery with all the extra processing, setting up timers etc seems to
be overkill for this commonly requested feature. I tend to use mbbo records
(one for each command) and let clients write to the PROC field (they can write
any value they like).

One feature that I miss with this solution: a (simple) way to make the VAL
field immutable, so chosing /which/ command is executed cannot be changed at
runtime. Any ideas how to do that except writing a new record type?

Cheers
Ben

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Replies:
Re: [db] simple command ? Tim Mooney
References:
[db] simple command ? Pavel Masloff
Re: [db] simple command ? Tim Mooney
Re: [db] simple command ? Pavel Masloff

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