Re: [foxboro] Foxboro's programming
- From: joseph wu <josewusan@xxxxxxxxx>
- To: foxboro@xxxxxxxxxxxxx
- Date: Tue, 26 Sep 2006 05:21:47 -0700 (PDT)
GDEV block provides two independent outputs. As a matter of fact, it is the
most powerful digital control block Invensys has ever designed. I have used
exclusively GDEV block for all pumps, valves or motors.
It has numerous feedback and confirm and interlock features which is worth
your time to look into it.
The output can be directly sent to the FBM and accept input from FBM for
confirmations.
Try it and you may like it (like I do!)
Joe Wu
Dow Chemcial DCS support
brad.s.wilson@xxxxxxxxxxxxxx wrote:
>>>
At it's simplest, a motor or valve is programmed with an AOUT (analog out)
or COUT (contact out) block. There are more complex blocks like MTR, VLV,
and a number of variations on that theme that provide things like an alarm
after a given time if a feedback or limit switch isn't reached.
<<<
One type of valve operation we have is a 2-stage ball valve. We have the
valve open full, but close halfway (to prevent hammer), then close fully.
We built these years ago using CALC & CINs. In effect, there are 2
solenoids - solenoid A is full-pressure & solenoid B is lower-pressure
instrument air. The limit logic obviously expects no limits in the halfway
position.
I'm surprised that GDEV has never had the ability to control the outputs
independently. Has Foxboro ever considered this?
Brad Wilson
Process Control Engineer
ExxonMobil Chemical Co
Edison Synthetics Plant
732-321-6115
732-321-6177 fax
Brad.S.Wilson@xxxxxxxxxxxxxx
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