The MAX31855 is designed for ungrounded thermocouples. However, it is possible to get reliable conversion results if the T- and GND pins of the MAX31855 are connected to the same ground reference as the…
No, each MAX31855 version can only be paired with the corresponding thermocouple type. For example, MAX31855K can only be used with K-type thermocouples, MAX31855J can only be used with J-type thermocouples…
MAX31855 is designed to provide the cold-junction compensated thermocouple temperature through SPI interface. However, greater accuracy may be achieved using some additional math. Thermocouples are inherently…
The MAX31855 SO pin is high-impedance when /CS is inactive so you can have the SCK and SO pins common to as many MAX31855 devices as you want, you will just need to have separate /CS control for each chip…
The MAX31855 uses its own die temperature as the cold junction temperature when compensating for the thermocouple value. The actual cold junction is located where the thermocouple cables contact the circuit…
If there is significant noise on the supply to the MAX31855, you will experience some errors in the temperature conversion results, so implementing a voltage regulator on VCC would be advised. As an example…
The reference junction temperature is provided to support linearization of the thermocouple, per NIST standards. Thermocouples are inherently non-linear. Thus, linearization increases accuracy. Linearizing…
No, the typical conversion time is 70ms, thus the sampling rate would be approximately 14 samples per second. The maximum conversion time is 100ms, thus the sampling rate would be 10 samples per second…
Yes, the data read out as the first 14 bits compensates for cold-junction using the linear correction formula. Allow 200ms after start-up before reading data, you may read every 100ms thereafter. See …
The SO output is a push-pull structure, as indicated in the electrical characteristics table of the datasheet: Output High Voltage - VOH = VCC - 0.4V, @ IOUT = -1.6mA Output Low Voltage - VOL = 0.4 V,…