Hi Alex,
I agree that omget is not the best way to get data but it works and the
scripts are easy to alter. When I first cooked up this scheme two years ago
I could not get any Foxboro people to commit to what a "reasonable" number
of omgets were and how far apart they should be spaced.. At one time I had
a script that called omget three times, with about 25 values per omget. I
slept 2 seconds between calls, and the best advice from Foxboro was "see if
it causes a problem". I never saw any problems, and no perceptible loading
on the system.
My current script still calls omget three times, but only reads 14, 22,
and 12 values. I still sleep 2 seconds between omgets, and this has been
running every two minutes for the last few years.
I am using the regular Historian Report Scheduler to run a report after
shift changes, and every morning to pick up the shift & daily numbers.
These values are basically "static", so omgetting them would be a waste.
These static values are in a separate text file & get mixed in with the live
values when my perl script generates a new html document.
I really should write a program to read the live data, but it always seems
to get pushed to the back burner.
Stephen Murray
Original Message -----
From: Johnson,Alex <[EMAIL PROTECTED]>
To: Foxboro DCS Mail List <[EMAIL PROTECTED]>
Sent: Monday, March 13, 2000 12:27 PM
Subject: RE: Browser access to Foxboro graphics.
>Re: a simple script to "omget" about a hundred key values and write them to
>a text file
>
>I would not recommend the use of "omget" for this type of service as a
>general solution. Omget uses unoptimized getval calls to retrieve the data
>from the process.
>
>These calls generate a broadcast message for each value. Broadcast messages
>of this sort can cause significant performance problems in larger systems.
>One more than one large system, I've seen significant problems due to high
>and generally unnecessary broadcast traffic.
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