Re: [foxboro] FW: parameter state at CP boot

The problem is directly associated with batching operations, not continuous
control (AIN-PID-AOUT).  My facility uses GDEV blocks for ON-OFF valves and
pumps, which leads to potentially undesirable valve and pump state when a
CP boots.


Steve Shimp
Maintenance & Systems Engineer
ExxonMobil Paulsboro Lube Plant
phone: 856.224.5059      cell: 609.820.8501      fax: 856.224.5030
email:  steve.shimp@xxxxxxxxxxxxxx

foxboro-bounce@xxxxxxxxxxxxx wrote on 01/30/2006 10:11:09 AM:

> Dirk,
>
> Are you using PID type blocks to AOUT to ECB and then to a valve?
>
> If you configure the FBM's ECB for fail safe, and you set the AOUT =
> PRIBLK true (1) then on recovery of a failure, either the field bus =
> fails or the CP reboots, your PID (I assume you set it to initialize in =
> Manual) will hold its output at whatever you selected for the ECB =
> failsafe value, regardless
> of the value for PID.OUT in your checkpoint file.
>
> If you have blocks between the PID and the AOUT, you need to back =
> propagate status bits so that you can still set AOUT.PRIBLK true.
>
> If you are talking about ON-OFF valves controlled by PLB, you need to do
=
> a lot of coding to make this happen, but it can be done.
>
> Regards,
>
> Terry
>

 
 
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