Hi Brian,

My memory grows dim but I seem to recall there is an issue with this device self heating. I had a similar problem some time ago using Pt100 RTD's even though excitation was only 1mA - but being continually powered made the difference.

It may not be your code at all - can you power it down, let rest/cool down/acquire ambient temperature then power up, sample and power down again? This would prove any chip self heating.

This being the case some tests could establish if the self heat value is a constant, maybe then a calibration factor or offset could be included? Worse case a lookup table.

I hope this helps.

Kind regards,
Bill