MAX6675

MAX6675 Module Description

The MAX6675 module, in combination with a K-type thermocouple, enables temperature measurement of objects and the environment. The thermocouple can measure temperatures in the range of 0 - 1024°C, but due to the thermocouple’s body limitations, the maximum measurable temperature is 600°C. This module is commonly used in soldering stations, boilers, digital thermometers, ovens, and other temperature-controlled devices.

Functional Overview

The module is based on the MAX6675 chip, which converts analog signals from the K-type thermocouple into digital temperature readings. The sensor signal is processed by an operational amplifier, followed by a 12-bit ADC (Analog-to-Digital Converter). The processed data is transmitted to the microcontroller via the SPI (Serial Peripheral Interface).

Notably, the SPI interface lacks an MOSI pin, meaning that data transmission occurs only from the MAX6675 to the microcontroller. A key feature of this chip is the cold junction compensation, achieved through a built-in temperature sensor.

Connections & Power Supply

The module interfaces with the Arduino platform and other microcontrollers using SPI, requiring three pins:

• SCLK – Clock signal
• CS – Chip select
• DO – Data output from the sensor to the microcontroller

The module operates on a 3.0V to 5.5V power supply, which can be provided by an external source, an Arduino Uno, or another microcontroller. The power connections are:

• VCC – +5V supply
• GND – Ground

Thermocouple Connection

The thermocouple connects via a screw terminal, with polarity markings indicated on the PCB.