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AD7124-4 RTD Configuration

Question asked by Balt on Jul 5, 2018
Latest reply on Jul 17, 2018 by JellenieR

Hi,

 

I'm trying to configure AD7124-4 to read from a RTD.

 

I've set my registers as follow:

 

ADC_CONTROL(0x01) = 0x1080

IO_CONTROL_1(0x03) = 0x0024BA

CHANNEL_0(0x09) = 0x8043

CONFIG_0(0x19) = 0x9EC

 

If i set a 100 ohm resistance i read from the data register the value "8A0C2A"

If i convert the value in ohm using the formula described in the document "Completely Integrated 3-Wire RTD Measurement System Using a Low Power,Precision, 24-Bit Sigma-Delta ADC" i obtain a value of 25 ohm.

 

If i set a 200 ohm value i obtain a value of 50 ohm, every time 1/4 of the set resistance.

 

I have forgot to set some configuration in the register?

 

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