EPICS Re: Automatic refresh of OPI

Experimental Physics and Industrial Control System

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

Subject:	Re: Automatic refresh of OPI
From:	Andrew Johnson <[email protected]>
To:	Iain Marcuson <[email protected]>, EPICS Tech Talk <[email protected]>
Date:	Tue, 12 Sep 2017 10:48:23 -0500

Hi Iain,

On 09/12/2017 08:39 AM, Iain Marcuson wrote:
> That solved the problem.  The Text Input widgets update with their new values

> The IOC holds the values e.g.  "start", "stepsize" and "end" parameters
> as separate PVs.  A fourth PV triggers Stream Device to write those three
> PVs over TCP/IP to the "backend hardware" in one transaction.

The fact that your widgets weren't updating automatically suggests to me
that those other PVs might not have been configured correctly, because
Text Input boxes should update automatically when they get a monitor
event from the IOC. The fact that yours aren't implies that somehow
their values are being changed (presumably by the hardware) without
triggering record processing, which would trigger a CA update event and
thus update the GUI automatically. Your approach might work fine with
CS-Studio, but a different GUI tool might not have the same ability, so
I don't recommend that you accept this as the right solution.

Is this a situation where those PVs can be updated from either the GUI
or the back-end hardware? There are techniques people have developed to
handle this correctly if it is.

- Andrew

-- 
Arguing for surveillance because you have nothing to hide is no
different than making the claim, "I don't care about freedom of
speech because I have nothing to say." -- Edward Snowdon

Replies:: RE: Automatic refresh of OPI Iain Marcuson

References:: Automatic refresh of OPI Iain Marcuson; Re: Automatic refresh of OPI Kasemir, Kay; RE: Automatic refresh of OPI Iain Marcuson

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