Re: [foxboro] Check against entering ridiculous values

It is unfortunately hard to implement this, but...
The PIDA block has a couple of features that may help:

1) Setpoint high and low limits (SPCLMP, SPHLIM, and SPLLIM)
2) Setpoint ramp rate option (eliminates bumps due to setpoint changes)
(SPROPT, SPRATE, SPRAMP)


Regards,
 
Alex Johnson
Invensys Systems, Inc.
10900 Equity Drive
Houston, TX 77041
713.329.8472 (voice)
713.329.1700 (fax)
713.329.1600 (switchboard)
alex.johnson@xxxxxxxxxxxxxxxx

-----Original Message-----
From: foxboro-bounce@xxxxxxxxxxxxx [mailto:foxboro-bounce@xxxxxxxxxxxxx]
On Behalf Of Adam.Pemberton@xxxxxxxxxxxx
Sent: Sunday, October 15, 2006 7:04 PM
To: foxboro@xxxxxxxxxxxxx
Subject: [foxboro] Check against entering ridiculous values

We had an incident on Saturday where an operator accidently entered a
very low setpoint (5kPa when it should be >2200 kPa) on the pressure
control for one of our Autoclaves. This caused the vent valve to open to
100% and the clave to rapidly depressurize. This is a potentially
catastrophic incident since high venting in an Oxygen rich environment
can cause a major fire.
 

We are at the final stages of a migration from Display Manager to
FoxView. In order to help these guys with the transition, we have
provided them with one Exceed XTerm running Display Manager off our
engineering development AW.

 

This incident illustrated a number of issues :

   - The operator claimed that the FoxView workstation he was working on
(Blade 150) locked up and he had to move to Display Manager on the Xterm
to correct the erroneous value.

   - We have disabled the arrow keys on FoxView while we wait for 9.0.2.
Using the arrows on some parameters gives very large changes.

   - We need a good way to prevent ridiculous values being entered in
situations such as this.

 

My question from all this is what have people in this group done to
resolve the issue of preventing operators from entering dangerous
values? One suggestion was to have a popup appear if the change is
greater than 200kPa (for example). Is there an easy way of doing this?

All our workstations are Sun Blade 150's or PC's running Exceed (usually
V7). I/A is version 7.1.1. FoxView is version 9.0.1

 

Adam Pemberton
Site Electrical & Control Systems Engineer
Lihir Gold Limited

Ph: +675 9865 655
Fax: +675 9865 666
Mob: Nogat
Postal:
   Australia: GPO Box 905, Brisbane, QLD 4001
   PNG: PO Box 789, Port Moresby, NCD

 


 
 
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_______________________________________________________________________
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