Re: [foxboro] Foxboro's programming
- From: brad.s.wilson@xxxxxxxxxxxxxx
- To: foxboro@xxxxxxxxxxxxx
- Date: Tue, 26 Sep 2006 06:08:00 -0500
>>>
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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