ADC signal outlier

RE: ADC signal outlier

djqtsg — Wed, 29 Mar 2017 07:20:13 GMT

We suspect the error is from the sensor; now looking for some signal simulator to generate known signal to test. Thx for your advice.

RE: ADC signal outlier

Jørgen Holmefjord — Wed, 29 Mar 2017 06:59:23 GMT

I mean, if the error originates from the sensor or if it is some error on the MCU/code that outputs wrong data. This is hard to check, which is the reason why I want you to check if you can check if the data originates from the sensor.

RE: ADC signal outlier

djqtsg — Wed, 29 Mar 2017 01:16:04 GMT

The ADC chip is MCP3912 from Microchip, and the PPG is MAX30102 from Maxim.

What do you mean by "outlier data is present on the bus"? Do you mean SPI or I2C has some error? I think unlikely because for one SPI or I2C read, I read several data points; not all of them are outlier, only 1 or 2.

How can I check "if there is problem with reading the data on the MCU"?

RE: ADC signal outlier

Jørgen Holmefjord — Mon, 27 Mar 2017 13:31:41 GMT

It is normal with some noice in sensor readings, but values should typically not get outlier data. Which model of ADC and sensor do you use? Have you checked with a logic analyzer if the outlier data is present on the bus as well, or if there is a problem with reading the data on the MCU?