Experimental Physics and
Industrial Control System

"Mark Rivers" <[email protected]> · Tue, 12 Jun 2007 19:22:03 -0500

> The reason I'm asking is that in my application, only the 
> channel access 
> link causes "answr" to process, the database link doesn't, and we 
> couldn't agree on what was supposed to happen.

That is what is supposed to happen.  If you want a record to process
when its input changes then you must set the link to CP.

PP is what you set output links to if you want it to process the record
that the output is linked to.

Mark

> -----Original Message-----
> From: [email protected] 
> [mailto:[email protected]] On Behalf Of Mathias Steiner
> Sent: Tuesday, June 12, 2007 6:00 PM
> To: [email protected]
> Subject: Basic Question regarding input links
> 
> Learned Friends,
> 
> I have what I believe to be a very basic EPICS question.
> I'm new to ioc programming, so bear with me, please.
> 
> Let "a" and "b" be analog input records, passive, initialized to 1.
> On the same ioc as those two, define
> 
> record(calc, "answr")
> {
>    ...
>    field(INPA, "a.VAL PP NMS")
>    field(INPB, "b.VAL CP NMS")
>    field(CALC, "A+B")
>    ...
> }
> 
> As the ioc starts up, the value of "answr" is 2, as expected.
> 
> My question is this:
> When "a" is set to another value, does "answr" process?
> 
> Also, when "b" is set to a different value, does "answr" process?
> 
> In other words, does a change in the linked record lead to 
> processing of 
> the linking record, and does it do so for both database links and 
> channel access links?
> 
> The reason I'm asking is that in my application, only the 
> channel access 
> link causes "answr" to process, the database link doesn't, and we 
> couldn't agree on what was supposed to happen.
> 
> Cheers, and Thanks in advance,
> -Mathias
> 

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System