Experimental Physics and
Industrial Control System

"Ned D. Arnold" <[email protected]> · Thu, 09 Jan 1997 08:00:28 -0600

>Operator response is a high priority requirement for all screens, and there
>are too many to keep up all the time.  To address your concern, and still
>keep the performance, there are two solutions:
>
>1) move name resolution off to another (redundant) process on Unix; probably
>   configurable so those who don't want to manage their namespace don't have
>   to.

>2) use the CA gateway to front most or all clients, and have the gateway
>   have LONG timeouts on dropping an unused channel.  This unloads most of 
>   the connect and monitoring load off of the ioc, making it more real
>   time

Here are a couple more options for those that find themselves "CPU
challenged"  ...

1) If the CAMAC device support does not support "I/O Intr" scanning
   of records, it should. In the Allen Bradley device support, one can
set 
   the binary records to I/O Intr and the records will only process when
that
   input (or any other on the same I/O card :{  ) changes. If these
   records happen to be linked to others, the # of records scanned per 
   second can be considerably reduced.

2) GO TO 3.13 IMMEDIATELY. There is this fantastic capability added in
   3.13 that allows records to only be processed when an input PV
   changes. All those records that have input links to records on other 
   ioc's can use this and they will only be processed when the source
   PV changes. With prudent use of the mdel field, record processing
   can be SUBSTSANTIALLY reduced (your mileage may vary due to your
   specific circumstances). The other BIG WIN is when an input record
   forward links to a large chain of records. IN 3.12, all records in
the
   chain are processed everytime. With prudent (hmm, this word seems to 
   come up alot) application of the new CP link attribute, each record
   will only get processed when its input value(s) change. Once again,
   your mileage may vary, but for large, heavily linked, heavily binary,
   periodically executed databases, the impact is likely to be
significant.

		Ned

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System