Universal Thermocouple Amplifier MAX31856 Breakout Board.
Thermocouples are very sensitive, requiring a good amplifier with a cold-compensation reference, as well as calculations to handle any non-linearities. For a long time, we've suggested our MAX31855K breakout, which works great but is only for K-type thermocouples. Now we're happy to offer a great new thermocouple amplifier/converter that can handle just about any type of thermocouple, and even the ability to give you notification when the temperature goes out of range, or a fault occurs. Very fancy!
This converter communicates over 4-wire SPI and can interface with any K, J, N, R, S, T, E, or B type thermocouple.
This breakout does everything for you, and can be easily interfaced with any microcontroller, even one without an analog input. This breakout board has the chip itself, a 3.3V regulator and level shifting circuitry, all assembled and tested. Comes with a 2-pin terminal block (for connecting to the thermocouple) and pin header (to plug into any breadboard or perfboard). We even added inline resistors and a filter capacitor on-board for better stability, as recommended by Maxim. Goes great with our 270-ADA 1m K-type thermocouple or any other thermocouple, really!
- Works with any K, J, N, R, S, T, E, or B type thermocouple
- -210°C to +1800°C output in 0.0078125° resolution - note that many thermocouples have about ±2°C to ±6°C accuracy or worse depending on the temperature and type, so the resolution will be a lot better than the accuracy!
- Internal temperature reading
- 3.3 to 5v power supply and logic level compliant!
- SPI data requires any 4 digital I/O pins.
Please note this product does not include a thermocouple! Also, the terminal blocks included with your product may vary in color.
Pinouts
Power Pins:
- Vin - this is the power pin. Since the sensor chip uses 3 VDC, we have included a voltage regulator on board that will take 3-5VDC and safely convert it down. To power the board, give it the same power as the logic level of your microcontroller - e.g. for a 5V micro like Arduino, use 5V.
- 3Vo - this is the 3.3V output from the voltage regulator, you can grab up to 100mA from this if you like.
- GND - common ground for power and logic
SPI Logic pins:
All pins going into the breakout have level shifting circuitry to make them 3-5V logic level safe. Use whatever logic level is on Vin!
- SCK - This is the SPI Clock pin; it is an input to the chip.
- SDO - this is the Serial Data Out / Microcontroller In Sensor Out pin, for data sent from the MAX31856 to your processor.
- SDI - this is the Serial DatMAX31856controller Out Sensor In pin, for data sent from your processor to the MAX31856.
- CS - this is the Chip Select pin, drop it low to start an SPI transaction. It is an input to the chip.
If you want to connect multiple MAX31856's to one microcontroller, have them share the SDI, SDO and SCK pins. Then assign each one a unique CS pin.
Additional Pins
There are two more pins that are available for advanced usage.
- FLT - This is the Fault output. If you use the threshold-notification capabilities of the MAX31856 you can monitor this pin and when it goes low there's a fault!
- DRDY - This pin is used for advanced uses where you tell the sensor to begin a reading and then wait for this pin to go low. We don't use it in our library code because we keep it simple with a delay/wait, but it is available in case you need it!
max31856-thermocouple-amplifier EagleCAD PCB files, datasheets, Fritzing object
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