Since I need 8 thermocouples measurments, I stacked 2 CN0391 shields on a Arduino Mega 2560 card.
In order to test the cards separately, I keeped the cards stacked and only changed the jumper position of the second card to position 3-4 accordingly to the user guide.
I also changed the #define CS_PIN to 9 in the communication.h in order to be consistent with the hardware configuration.
In that case, the measured temperatures are about 210°C on the channels instead of about 21°C. When testing with a single board and same jumper configuration (pin 9, J1 on 3-4) everything works fine...
I think I have missed something on the SPI configuration but have no idea on where is the problem. Do you have any idea ?
Thanks in advance