I have a Pi 3 connected to an ADC Pi plus board. Currently it is sampling the output from a RTD and when measured with a multimeter, the output is stable, but when measured in the 12, 14 or 16 bit sampling modes we see fluctuations of +- 0.2v. If the sampling rate is changed to 18bit, this fluctuation ceases.
We have traced this issue down to the bit rate, and are confident of the output from the RTD. Has anyone has any issues sampling at lower bitrates that may explain our problems?