Experimental Physics and
Industrial Control System

Ian Smith <[email protected]> · Wed, 14 Feb 1996 15:54:37 +0000 (GMT)

Hi, 

thanks for the reply:

On Tue, 13 Feb 1996, Marty Kraimer wrote:

> > 1: I can't monitor the PACT leg with either probe or cau etc, nothing can 
> >    connect to it, so it is impossible to verify its operation.
> > 
> 
> I think that what you mean is that db_post_event is not called for
> this field. It is possible to look at PACT with cau, probe, etc.
> The problem is that  monitors are never triggered.

I couldn't get probe to connect.  In an attempt to put a copy of the error 
message here I tried just now to connect with probe, and today it did 
connect(??).  So yes you can use probe etc to connect to the PACT field, 
but as you point out you won't see any change in value.

> I would image that what you want is to detect records that are stuck,
> i.e.PACT is true forever. 

In my particular case I'm doing something else; if you imagine a pipeline 
of records with the first one activating every 10 secs and the rest 
passive but with FLNK daisey chained.  Just occasionally a subroutine record 
half way down takes longer to process than 10 seconds, so its PACT field is 
used to stop the first record starting up again until the pipeline has 
completed.

No doubt a call back solution could implemented, but I thought it easier 
to use the PACT and SDIS fields.  It does work, I just couldn't prove it!

> > 2: If the record is actively processing, say every 10 seconds, then it 
> > seems to count the number of times it should have activated whilst it is 
> > disabled and then, when it is re-enabled, it seems to process n 
> > times without a 10 second wait between each. Ie, if it was disabled for 60 
> > seconds then when it is re-enabled, it processes at least twice, perhaps 
> > 6 times, instantaneously.  The record behaves itself if it is passive.
> > 
> 
>This is called "Cached Puts"
> 
Yes, that fits, the records process so fast (compaired with us humans) 
that it was difficult to tell if it was 6 times or twice.

I'm not sure what to suggest for the dillema this has exposed, but thanks 
for confirming the behaviour of the database.

cheers

Ian A Smith			Telephone: +44 (0) 131 668 8257
Royal Observatory		Fax:       +44 (0) 131 668 1130
Blackford Hill			Web:       http://www.roe.ac.uk/
Edinburgh
EH9 3HJ
UK

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System