The recommended PCB layout for the MAX31865EUT-T involves keeping the thermocouple traces as short as possible, using a dedicated ground plane, and avoiding running digital signals near the thermocouple inputs. A 4-layer PCB with a dedicated analog ground plane is recommended.
Cold junction compensation can be handled using an external thermistor or thermocouple connected to the CJIN pin. The MAX31865EUT-T has an internal cold junction compensation algorithm that can be enabled by setting the CJEN bit in the configuration register.
The maximum cable length for the thermocouple inputs depends on the type of thermocouple and the noise environment. As a general rule, keep the cable length as short as possible (less than 10 feet) to minimize noise pickup and ensure accurate readings.
Calibration involves setting the gain and offset registers to compensate for any errors in the thermocouple or the MAX31865EUT-T itself. A calibration procedure can be implemented using a known temperature reference point and adjusting the gain and offset registers accordingly.
Noise can affect the accuracy of the temperature readings. The MAX31865EUT-T has built-in noise filtering, but it's still important to minimize noise pickup by using twisted pair cables, shielding, and keeping the thermocouple inputs away from digital signals.
MAX3189EUT-T datasheet
by Maxim Integrated Products
