Current measurement offsets between channels of MCP3428

Hardware
1

I’m using MCP3428 (PR33-28) to measure 4-20 mA process loops. I’m surprised to find that I see a few hundred microamps difference when measuring the same current source on different channels. Using a test current source I see that this is reproducible and it appears to be a static offset over the dynamic range of the ADC.

Any advice? I’m surprised to see such a dramatic systematic error.

2

Hi,
the on board parts have around 2% tolerance .

For best results i will recommend calibrating each channel individually.

Thanks

3

Thanks for your reply Bhaskar. I’ll solve this problem in software.