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Block for flow compensation

Created by: DJB at: 6/13/2008 8:16 AM (6 Replies)

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6/13/2008 8:16 AM	Rate (0)
DJB Posts: 12 Rating: (0)	Hi , What is the standard block available in PCS 7 for volumetric / mass flow calculation from Differntial Pressure value ( obtrained fron standard DP transmitter) . The required compensation for pressure and temperatureshall also be taken care . In other words , I am looking for standard block from PCS 7having the following I/O : Inputs : 1. Differential pressure value from standard orifice and DP transmitter. 2. Temperature value from temperature transmitter 3. Gauge pressure value from gauge pressure transmitter. Output : 1. Volumetric flow rate 2. Mass flow rate. If available , where can I get the blocks from ??
DJB Posts: 12 Rating: (0)
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6/13/2008 9:18 AM	Rate (0)
Mario Braganca Posts: 124 Rating: (17)	Hello DJB There is no Standard Block for this. But ifyou know the formulas you can create your own block with SCL. I don't work directly with instrumentation but it seems to methatmanypeople useFlow Transmiters with embedded calculation. I remember to see parameters in PDM like these (mass or volume flow measurement). So it's just a matter of adjusting the parameters in a PA Transmiter. But ifyou really need to calculate application, than SCL can be used. Regards
Mario Braganca Posts: 124 Rating: (17)
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6/13/2008 11:14 AM	Rate (0)
Pandiani Bronze Member Joined: 10/31/2005 Last visit: 9/4/2024 Posts: 366 Rating: (31)	Hi DJB, as Mario said, you can calculate temperature and pressure compensation if you know formulas. However, I found this very tricky part. You can use approximated formulas for gas flow: Qcomp = Qdp * sqrt(Pcomp * Tcomp) where Pcomp = Pref/Pa for volumetric flow where Pref is designed abs pressure and Pa is actual absoulte pressure from transmitter. Pcomp= Pa/Pref for mass flow. On the other handm for temperature is different: Tcomp = Ta/Tref from volumetric and Tref/Ta for mass flow. I found these formulas as approximation formulaswhich is used by Honeywell SMV multivariable transmitter. You can see more in attached file... I hope this helps Attachment SFC part of Manual 34-ST-11-14F.pdf (938 Downloads)

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6/13/2008 11:40 AM	Rate (0)
DJB Posts: 12 Rating: (0)	Thanks Pandiani for ur valuable input . I also got similar formulas from a Siemens source ...see this ... Attachment AD353-124r1.pdf (955 Downloads)
DJB Posts: 12 Rating: (0)
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6/13/2008 2:43 PM	Rate (0)
Pandiani Bronze Member Joined: 10/31/2005 Last visit: 9/4/2024 Posts: 366 Rating: (31)	You're welcome DBJ. There is also one add in package for PCS7 , it is called PS (for power generation). In it you have steam, water and gas flow correction blocks that have built in lookup tables. I assume you'll need to paid for it. Try and see if these formulas will help ou. Regards

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6/18/2008 11:57 AM	Rate (0)
Deleted User Posts: 767 Rating: (69)	Ablock for DP flow calculation on the basis of static pressure, temperature and DP is also available in CIS_CK library by I&S IP PEP departmrnt of Siemens. I think I can email it to you for testing purposes...jut mail me on shahiiee@hotmail.com.
Deleted User Posts: 767 Rating: (69)
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4/23/2014 7:36 AM	Rate (0)
GrasserF Posts: 340 Rating: (6)	new question is splittet to calculate mass flow, I get this block for PCS7
GrasserF Posts: 340 Rating: (6)
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