Analog input flexy card FX3402 4-20ma

duy27trong

• 18 de maio de 2020 14:13

Hi expert,
I'm using AI signal 4-20mA with data range temperature : 0 -100C .
I find the formula in manual but it just about 0 - 20 ma : like 0- 65535
How about scale ADC in 4-20 mA
Thanks you so much .

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  Tim Beaulieu

  • 18 de maio de 2020 14:19

  Hello,

  If I think if you want a scale from 4-20 instead 0-20, you should be able to do an offset of 4 with a scale of 4,095.9375 (65535/16)

  -TIm

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  duy27trong

  • 18 de maio de 2020 18:56

  i see . 0- 0, 20ma - 65535 .is this mean : 4ma -> 4*20/65535 = 0.001221

  temperature sensor : 4-20ma : 0- 100 oC:
  "> 0"> 0.001221
  ">100">65535.

  my understanding is right ?

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  Tim Beaulieu

  • 18 de maio de 2020 19:05

  if I understand right, do you mean that 4ma = 0 degrees celsius and that 20ma = 100 degrees celsius, I think that should be correct

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  duy27trong

  • 20 de maio de 2020 13:00

  yes. the sensor return : 4ma - 0oC , 20 ma - 100oC.IS this mean
  we will scale in flexy : 4ma --> 0.001221
  20ma -->65535

  is this right?

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  Tim Beaulieu

  • 20 de maio de 2020 13:27

  We should be able to follow this example:

  

  But I believe we'll set the following:
  Y1 = 0
  Y2 = 100
  X1 = 1/5(65535) = 13107
  X2 = 65535

  a = (100 - 0) / (65535-13107) = 0.001907377
  b = (100 * 13107) - (0 * 65535) / (13107-65535) = -25

  so y = 0.001907377x - 25

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