Re: [foxboro] AIN Block / Deadband

The DGAP block, as mentioned in other replies, is probably the best way, 
but since you said "simple", and I took it way more than literally <g>, 
I'll point out that the AIN block itself has an alarm deadband parameter, 
HLDB.  The logic is, I believe, that the alarm flag turns on when the 
analog value is greater than/less than the alarm trip point, and turns 
back off when the value is less than (trip pt - HLDB)/greater than (trip 
pt + HLDB).  The disadvantage is that HLDB applies to _all_ alarm trip 
points; the individual alarm deadbands are not independently adjustable 
(another little thing I miss from my brand "H" days :).
Corey Clingo
BASF Corp.






"Livingood, William" <wlivingood@xxxxxxx>
Sent by: foxboro-bounce@xxxxxxxxxxxxx
05/21/2004 08:48 AM
Please respond to foxboro

              To:  "'foxboro@xxxxxxxxxxxxx'" 
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         Subject:       [foxboro] AIN Block / Deadband






Based on the output from an AIN block, I am turning on/off equipment.  The
value from the AIN block sometimes lies right near the threshold for 
turning
on/off the equipment.  The result is that the value from the AIN block
"bounces" above and below the threshold causing the equipment to turn on 
and
off rapidly.  Looking at the AIN block documentation, they have a deadband
category (DELT01), BUT the documentation suggests that it is not 
functional.


Does anyone have a simple way to send the output of the AIN block through 
a
deadband feature?

~Bill





 
 
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