Re: [foxboro] CALC Block
- From: Kevin FitzGerrell <fitzgerrell@xxxxxxxxxxxxxxx>
- To: foxboro@xxxxxxxxxxxxx
- Date: Sun, 25 Jan 2004 19:04:16 +1300
Omprakash,
There's lots of ways to do this (if I am understanding what you want
correctly). Just how you implement it really depends on what you are trying
to achieve and what the characteristics of your measurement are.
A few include:
To get an update every minute, run the CALC block once a minute. RI 01 is
the AIN block.
IN RI01
IN M01
SUB
OUT RO01
IN RI01
STO M01
This can be improved by running more frequently and storing multiple
values -- effectively an internal dead-time block. Filtering or averaging
multiple values may be a good idea too if the AIN block output is not
smooth.
If you want results continuously, configure a DTIME block for a 1 minute
deadtime and feed the AIN block to it. Then your calc block just needs to
calculate the difference between the AIN block output and the output of the
DTIME block. Again, consider averaging multiple values or filtering the AIN
output if it is not smooth.
If you want change of weight per minute over a longer period, configure the
DTIME block for a longer time (or daisy chain multiple DTIME blocks).
Configure the output to interpolate rather than step. Use the calc block to
rescale the result in change of weight/minute.
If appropriate, consider what to do in the event of batch events -- ie, if
you have a tank on a load cell and you want to measure product flow as
change in weight per minute, what do you want the result to show while
filling the tank?
Was there an attachment (image)? List doesn't pass images.
Regards,
Kevin FitzGerrell
Systems Engineer
Foxboro New Zealand
+64 9 573 7690
----- Original Message -----
From: "Omprakash" <omprakash@xxxxxxxxxxxx>
To: <foxboro@xxxxxxxxxxxxx>
Sent: Sunday, January 25, 2004 1:58 AM
Subject: [foxboro] CALC Block
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> Hi List
> =20
> I would like to calculate change of weight (AIN block) per minute using
> CALC/CALCA block Any help?
> =20
> Regards, =20
> =20
> G.R.OMPRAKASH
> Instrument & Control Engineer
> Jubail Chemical Industries Company (JANA)
> PoBox:10661, Jubail Industrial city 31961
> Jubail, Saudi Arabia
> =20
> Phone: +966 3 3585002 Ext 323
> Fax : +966 3 3583192
> Mobile +966 5 3965289
> email: omprakash@ jana-ksa.com=20
> =20
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