adccommunitymod (AutomationDirect) asked a question.
differential transmitter
Created Date: May 15,2010
Created By: pachex76
**** This post has been imported from our legacy forum. Information in this post may be outdated and links contained in the post may no longer work.****
hello guys i need help doing a differential pressure transmitter on using a 205dl with a 260 cpu. my module is a 8 channel a is 12bit. i want to use the differential transmitter to meter the water flow. i calibrate the dp 0 =4ma and 100 in h20= 20ma. my orifice place is 3.9861 and my factor is 1087.7. In another words i need to be able to see the total flow
Created Date: May 16,2010
Created by: KPrice
pachex76, as a place to start, I'll assume this is a packaged, calibrated flow meter with the pipe sections, taps, and orifice plate. The calibration will provide a given accuracy over a given flow range.
To find the of the delta P:
Let V2000 = scaled delta P, 0-100 BCD
Let V2006 = square-root delta P, 0-1000 BCD w/ 2-implied dec point
LD V2000
BIN
BTOR
SQRTR
MULR R100
RTOB
BCD
OUTD V2006
This value would be multiplied by a factor based on pipe size, orifice plate, pipe taps, density, from the calibration from the manufacturer. Is this your value of 1087.7? What are your units? What is your flow range? The installation would also require straight pipe lengths upstream and downstream, and horizontal pipe.
You could also setup ladder logic to compare the measured flow to the given flow range and indicate if you are in or out of the flow range. Did you have a question on scaling?
Created Date: May 16,2010
Created by: KPrice
pachex76, a better idea, for more resolution, and this includes the scaling:
Let V4000 = analog input 0-4095 BCD (represents 0-100 delta P)
Let V2006 = square-root delta P, 0-1000 BCD w/ 2-implied dec point (0-10.00 sqrt delta P)
LD V4000
BIN
BTOR
MULR R100
DIVR R4095
SQRTR
MULR R100
RTOB
BCD
OUTD V2006
Created Date: May 20,2010
Created by: pachex76
differential transmitter
thanks for your help kprice, am not clear when u said what units, and i want to use the transmitter to monitor water flow. My under question is what is better to use bcd or real number if on using a micro c-more. Is their a way to use real number with a micro c-more because on struggle-ling to send real number to the c-more.
on using your scaling, here what i think if is right
LD 2000 CHANNEL 1
BIN
BTOR
MULR R100
DIVR R4095
SQRTR
MULR R100
OUT V6002
LDR V6000 = 1087.7 METER FACTOR
MULR V6002
OUTD V6006 THIS TO BE MY INST FLOW
Created Date: May 20,2010
Created by: KPrice
pachex76, almost.
LD 2000 CHANNEL 1 (0-4095 BCD/0-100 delta P)
BIN
BTOR
MULR R100
DIVR R4095
SQRTR
..............(Do not need MULR R100, previously for adding 2-dec pt to BCD value)
OUTD V6002 (Sqrt delta P, 0-10.000 Real) (NEED OUTD instruction, Real requires 2 V-memory locations)
LDR V6000 = 1087.7 METER FACTOR
MULR V6002 (Sqrt delta P, 0-10.000 Real)
OUTD V6006 THIS TO BE MY INST FLOW (Flow, 0-10877.000 Real)
You can convert the Real to BCD if it's easier to work with in the Micro:
LDR V6006 (Flow, 0-10877.000 Real)
RTOB
BCD
OUTD V3000 (Flow, 0-10877 BCD w/no implied dec pt.)
I was just curious about your units for pressure and flow. In my work, I'm used to "psi " or "inch w.c. " for pressure, and "GPM " (gallon per minute) for flow. With a number like 10877, you must be using other units, right?
Created Date: May 21,2010
Created by: pachex76
differential transmitter
kprice, yes am using bpd for my units and again thanks for your help
Created Date: May 15,2010
Created by: pachex76
hello guys i need help doing a differential pressure transmitter
on using a 205dl with a 260 cpu. my module is a 8 channel a is 12bit.
i want to use the differential transmitter to meter the water flow. i calibrate the dp 0 =4ma and 100 in h20= 20ma. my orifice place is 3.9861 and my factor is 1087.7. In another words i need to be able to see the total flow