# MCP3428 4-Channel 4-20mA 16-Bit Converter

I’m using CH1 and CH2 to measure two 4-20mA sensors, each sensor is power with 24V.
For the sample I’m using 16bit with Gain 2x.
I’m using the following code:

E.g. for CH1 I’m using a pressure sensor (0-25bar 4-20mA).
How do I convert the raw value into the sensor’s value?
Is there a way to calculate the raw value ranges for 4mA and 20mA?

Thank you for support in advance.

Hi,

if you can share couple of things i can write the formula for you which will convert raw values to pressure values

1. raw value when pressure is 0 bar ( it should be around 2900)
2. raw value when pressure is 25 bar ( it should be around 14490)
Thanks

Thank you for the reply.
But what I need are the ADC raw values for 4mA and 20mA.

The range of 14490 and 2900 seems not to be right.
For e.g.11.0bar I’ve measured 10.84mA => 15451 (ADC raw value)
With the range above I’ve would get 27.1 bar.

What couple of things do you need for the formula you’ve mentioned?

my bad… i didnt see that your gain is set to two

1. at 4mA the raw ADC value will be around 5813
2. at 20mA the raw ADC value will be around 29390.

Thank you for the reply.
How did you get the values for these ranges?

Is there a forumula for the ADC, e.g. if you put mathematically 4mA in the channel that you get the raw value?

You can use this formula
mA = 0.000688 * raw_adc