Re: What's wrong if a PV with DISA=1 still processes?

[Andrew Johnson <anj@aps.anl.gov>]

Hi Dayle,

Dayle Kotturi wrote:
> I am using SNL to manage the operational mode of a phase and amplitude ctrllr.
> Mode is either CALIBRATING or RUNNING.
> When RUNNING, I attempt to disallow changes to gain setting via entry{}
> clause of state RUNNING where I set DISA to 1 for the gain PV.
> I can see DISA field is set correctly to 1 via dbpr.
> On the EDM GUI, however, I am still able to change the gain.
> The gain is a longout record.
>
> From the doc, I understand that when DISA==DISV==1, processing should
> not occur. Why does it?

Are you sure that your gain is actually being sent out to the hardware 
when DISA==DISV?  What disabling the record means is that the record's 
process routine will not run, thus no device support output or alarm 
checking, DRVH/DRVL clipping etc.  However this does not stop CA from 
being able to write to the record's modifiable fields, nor any CA 
monitors from seeing those updated field values (since a ca_put 
automatically causes a monitor event on the field that is changed).

HTH,

- Andrew
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