Flow meter scaling issue using flx3402 i/o card
Completed
Our customer connected 7 flow meter in Ewon flexy 102 with io card 4 to 20 mA they want to read different scaling ranges like
Canteen -0.1 to 5-meter cube / hour
Garden - 0.5 to 5
Sand filter - 5 to 10
Fire hydrant - 0.8 to 350
SFL - 2 to 10
Cooling tower - 2 to 5
by referred /ig-0030-00-flx-3402-io-8di-4ai-2do-extension-card.pdf this document I have used to get coefficient= max scale value-min scale value/max raw value - min raw value
example =5 - 0.5 / 65535 - 0
=4.5/65535
by using this coefficient value, the scale value does not occur perfectly.
when flow meter value shows I get 0.965354 by doing offset -0.9 in b 0 value reading but whenever value increasing not current flow meter value showing
see attached image for meter 7 raw value shows 13090 this means flow meter value is 0 but by doing scaling for 0 to 5 it shows 0.9 something. what I understood is when reading comes 4 mA means the raw value goes 13107.
kindly give solution for this issue.
Thanks & Regards
Mohana Priya
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Official comment
Resolution of the Ticket:
Here is the calculation for your reference.
The raw value is 0 to 65535 for 0 to 20mA and the theoretical raw value for 4 to 20 mA is 13107 to 65535.
As per your requirement (0.8 = 4mA = 13107) & (350 = 20mA = 65535)
Real Physical Conversion Value Formula
When configuring a tag under the IO server in the “Setup” mode of the Tag page, a conversion can be applied such as: Y = ax + b
X1 = 13107, X2 = 65535 & Y1 = 0.8 & Y2 = 350
After calculated the a & b value from the below formula
a = (Y2-Y1) / (X2-X1) & b = Y2X1 - Y1X2 / (X1-X2)
The final value for a = 0.0066605 & b = -86.5
Note: This formula and conversion are available in the FLX3402 manual please download to click on this LINK.
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Hi Mohana Priya,
I have created a support ticket for this request, you will hear from our support soon for further updates.
Best regards,
Prajnay0
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