Re: [foxboro] just a tip

At 04:28 PM 5/18/04 -0400, Jaime Claramunt R. (Inforsa) wrote:

 >hey list,
 >
 >does anybody have a tip for this ...
 >we have some flowmeters (AIN) that still indicates some when there is no
 >flow...
 >this is used then in ACCUM blocks, and I want to find the way to indicate
 >this block to accumulate only values over a low limit...with limits ?
 >clamping ? (without hold ...)

I don't understand your "without hold ..." comment, but am going to 
toss out my solution anyway. Here goes....

For some reason, the SCI of 7 (low flow cut-off) doesn't work for me, 
even though it's a pretty plain-jane mass meter sending 4-20mA signal 
through an FBM 4. My solution: I tie the close limit switch of the 
block valve going to this meter to the HOLd parameter of the ACCUM 
block: valve closes, ACCUM goes into hold and stops accumulating. 
(Yeah, I know, one of these days the limit switch is going to fail and 
somebody will have to fiddle with the ACCUM block, but it works well for now.)

Hope this helps.

Duc

 
 
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