MLX90614 Producing Incorrect Surface Temperature Readings

I recently tried to verify surface temperature readings of an MLX9014 infrared sensor comparing against a Campbell Scientific SI111SS infrared sensor and found that the MLX sensor consistently read 4-5C hotter than the actual temperature of the surface. The surface I was using is a black aluminum plate with thermo-electric heaters on three sides. The sensors were positioned in such a way that they could only see the plate and the plate was left at ambient temperature to provide a common sense type test. I’m using an Arduino mini pro 3V 8MHz board and the Sparkfun MLX90614 library. Both sensors assume a surface emissivity of 1. Any help is appreciated!

Hi Rich_D,

While I would expect the Campbell Scientific IR Sensor to be much more accurate than the MLX90614, 4-5 degrees of is a bit high but not entirely unexpected. How are you using the MLX90614? Can you please take a few photos of your circuit and attach them to your reply? Is the temperature 4-5 degrees off consistently regardless of the object you are measuring? Also, how far away are you measuring with the MLX90614?