MAX31865 PT100-PT1000 RTD Platinum Resistance Temperature Detector Module Sensor Amplifier

Specification:

• Product: Temperature Detector Module
• Model: MAX31865
• Interface: SPI
• Compaitable RTD: PT100-PT1000
• Compatible RTD configurations: 2, 3, 4 wire
• Supply Voltage: 3 - 5V
• Supply Current: 10mA
• Size(L*W): 25mm*28mm

Applications

• Automated Brewing & Distilling: Monitor mash and boiler temperatures with pinpoint precision.
• Custom Reflow Ovens: Achieve exact soldering profiles by accurately tracking rapid temperature changes.
• Industrial Process Control: Monitor fluid lines, HVAC systems, and manufacturing equipment.
• Scientific Instruments: Build high-accuracy environmental logging chambers.
• High-End 3D Printers: Upgrade hot-end thermistors to PT100 sensors for printing advanced engineering filaments like PEEK or Nylon.

Features:

• Support 100Ω to 1kΩ(0°C) platinum resistance RTD(PT100 to PT1000)
• Conversion time is 21ms (maximum value)
• SPI compatible interface
• 15-bit ADC resolution with a nominal temperature resolution of 0.03125°C (variable with RTD nonlinearity)
• Total accuracy maintained at 0.5°C (0.05% full range) under the entire working conditions
• Compatible with 2-wire, 3-wire and 4-wire sensor connections
• ±45V Input Protection

Package Includes:

• 1x RTD Temperature Sensor PT100 Amplifier MAX31865
• 1x Male Pin Headers
• 2x Screw Terminals

Frequently Asked Questions (FAQ)

• Does this module work with both PT100 and PT1000 sensors?
  Yes, but you must select the correct reference resistor value in your software library (typically 430Ω for PT100 and 4300Ω for PT1000) that matches the physical resistor soldered on your specific board.
• How do I configure it for a 3-wire PT100 sensor?
  You must cut the tiny trace between the "2" and "4" pads on the back of the board, and flow solder across the "3" pads to bridge them.
• What is the difference between 2, 3, and 4-wire RTDs?
  4-wire is the most accurate as it completely cancels out lead wire resistance. 3-wire compensates for most of it and is the industrial standard. 2-wire is the least accurate over long distances.
• Can I connect this directly to a 5V Arduino Uno?
  Yes, the module has an onboard voltage regulator and level shifting logic, making it safe for 5V systems.
• Can I connect it to a 3.3V ESP32 or Raspberry Pi?
  Yes, it works perfectly with 3.3V logic. Provide 3.3V to the VIN pin.
• Why is my temperature reading completely wrong?
  Check your reference resistor value in your code. Also, ensure your 3-wire jumpers are correctly soldered if using a 3-wire sensor.
• Why does my code return a "Fault" error?
  The MAX31865 has built-in fault detection. This usually means the sensor is not connected properly, there is a short circuit, or the wiring configuration (jumpers) doesn't match the physical sensor.
• How many of these can I use on one microcontroller?
  Since it uses SPI, you can connect multiple modules to the same MOSI, MISO, and SCK pins. You just need a unique CS (Chip Select) digital pin for each module.
• What is the maximum temperature this can measure?
  The module itself only processes the electrical signal. The maximum temperature depends entirely on the specific PT100/PT1000 probe you purchase (often up to 400°C or 500°C).
• Can it read standard NTC thermistors?
  No, this IC is specifically designed for the linear resistance curve of Platinum RTDs.
• Can I use I2C instead of SPI?
  No, the MAX31865 communicates exclusively via the SPI protocol.