EU = Input Counts x (( Max counts - Min Counts)/Range)
You will need to check to see if the DP uses an internal Square Root Extraction, or if you need to do this prior to the scaling calculation.
Otherwise, need to know orifice size to perform the calculations, and why use a DP meter when a mag meter would be far better and requires less effort ot install, setup and calibrate.
with best regards,
what is the source of the differential pressure?
oriffice plate? or column weight?
you might laugh but probably the most "accurate" factor in your basic conditions is just measure 55 gallons and get a factor and that's it
remember that you need to get sure that the dp and the transmitter are in the right range because you could be on 20 Ma or close to 4 all the time,just because of the right selection of the dp source
if you plan something more sophy call me 661 665 0999
follow this link: http://www.rosemount.com/products/pressure/m3051ssl.html
Use this website www.clabberhead.com you will need to know the bore of the orifice plate you are measuring the DP across. The internal diameter of the pipe, you will find this from ppipe table by comparing it to the pipe specification, normally marked on the PID's. Basically the DP is equal to the (square of the mass flow)/((square of (pipe CSA X square of beta ratio))x density).
now we assume density, internal area and beta ratio are all constants then flow squared is proportional to DP.
so to get linear flow reading we must sqare root DP either at the transmitter or ar the PLC but not at both.
use table below for quick calibration of a transmitter with square root extraction.
%flow percentage 0f DP rage applied mA signal
0 0 4
10 1 4.16
20 4 4.64
30 9 5.44
40 16 6.56
50 25 8
60 36 9.76
70 49 11.84
80 64 14.24
90 81 16.96
100 100 20
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