BigTreeTech MAX31865 Module for PT100 and PT1000 RTD Sensors

BigTreeTech module based on the MAX31865 converter for connecting platinum PT100 and PT1000 RTD temperature sensors to a controller board through SPI. It supports 2, 3 and 4-wire sensors, provided that the module, wiring and firmware are configured for the same sensor type.

Features

• MAX31865-based RTD-to-digital converter.
• Compatible with PT100 and PT1000 sensors.
• Supports 2, 3 and 4-wire connections.
• SPI communication.
• Declared dimensions: 20.32 × 15.24 mm.
• Declared supply voltage: 5 V.
• Multiple modules may share the SPI bus with a different CS pin assigned to each one, when supported by the board and firmware.

Related sensors

• Trianglelab 4-Wire PT100 Temperature Sensor for High-Temperature Applications.
• Trianglelab 3 × 15 mm PT1000 Temperature Sensor Rated up to 450 °C.

Controller-board compatibility

Installation depends on the specific module revision and controller board. Suitable SPI signals, a chip-select pin and a compatible supply voltage must be available. A physically matching socket does not guarantee that the required signals are assigned to its pins.

The revision is not explicitly identified in the original catalogue information. Check the PCB markings before installation and use the manual for that revision. The DIP-switch settings and installation instructions for V2.0 must not be applied automatically.

If the plug-in stepper-driver format is specifically required, see the BigTreeTech MAX31865 V2.0 Module for PT100 and PT1000 RTD Sensors, after checking controller-board compatibility.

Firmware configuration

• Marlin 2.1.x: select TEMP_SENSOR_0 -5 and configure the nominal sensor resistance, module reference resistance, number of wires, CS pin and SPI bus. Marlin must be compiled and installed after these changes.
• Klipper: use sensor_type: MAX31865 and configure sensor_pin, the SPI bus, rtd_nominal_r, rtd_reference_r and rtd_num_of_wires. A 50 Hz mains filter may be used in European installations.
• RepRapFirmware 3: define the sensor with M308 using the rtd-max31865 type and the chip-select pin assigned to the board or interface.

A PT100 requires a nominal resistance setting of 100 Ω, while a PT1000 requires 1000 Ω. Do not copy the reference resistance from another installation: it must match the value fitted or selected on this module.

Safe installation

Carry out all wiring, jumper and configuration changes with the machine switched off and disconnected. Before enabling the heater, check that the ambient reading is stable and reasonable. Heat progressively and compare the measurement with an independent reference.