Manual & Safety

LinkGear EMESS-PT 100/1000 Sensor Board for ESPHome

Model EMEPT1

Thank you for choosing the LinkGear EMESS-PT Sensor Board for ESPHome.

Package Contents

1 x LinkGear EMESS-PT 100/1000
Sensor Board

WARNINGS & Safety Information

Before using the device, carefully read this manual.
Keep this manual downloaded or printed in a safe place for later use.
Never connect the device to 230/110 V mains voltage.
Avoid placing objects on the PCB that could short any exposed connections.
Securely connect all probe and power cables before operation.
Only use a suitable 5 V USB-C power supply.
The device should not be opened or repaired by unauthorized personnel.
The device must not be used in wet or humid environments.
Disconnect power before changing wiring or DIP switch settings.
This device is not for medical applications or any safety-critical use.
Only use the left-side USB to power the device and only use the right-side USB to power-passthrough.

Technical Specification

Input voltage/current	5 V via USB-C
Microcontroller	ESP32-WROOM-32E (8 MB), pre-flashed with ESPHome
RTD interfaces	2 x MAX31865 channels for PT100/PT1000 probes
Supported probe modes	2 x 2-wire, or 1 x 2-wire together with 1 x 3-wire or 4-wire
Configuration	DIP switch selectable PT100/PT1000 and 2-wire/3-wire/4-wire operation without soldering
LEDs	6 individually addressable SK6812 LEDs
Buzzer	Passive buzzer for configurable alarm output
Terminals	Screwless spring clamp terminals
Power passthrough	USB-C power passthrough (1A e-fused)
USB to Serial Chipset	Silicon Labs CP2102N
Safety Standard Compliance	CE, RoHS compliant

Compliance

Additional compliance labels for your region may be found on the packaging or the device itself.

Installation

The LinkGear EMESS-PT comes pre-flashed with ESPHome. To connect the device to your network and modify the configuration, adopt it in ESPHome Builder or use the LinkGear Web Flasher.

Connecting to WiFi

The recommended method is using Improv over serial or Bluetooth. Alternatively, you can use the onboard access point and open 192.168.4.1 in your browser.

Connecting via Serial

If the serial port does not open on your computer, install the CP2102N driver from Silicon Labs.

Operation

The board is designed for continuous operation from a stable 5 V USB-C power supply. It powers on as soon as external power is connected.

Default Configuration

The default firmware ships with the right side as channel 1 on GPIO5 configured for a 3-wire PT100 probe, and the left side as channel 2 on GPIO4 configured for a 2-wire PT1000 probe.

Channel	CS Pin	Default Probe Type	Default Wiring
Right / Channel 1	GPIO5	PT100	3-wire
Left / Channel 2	GPIO4	PT1000	2-wire

DIP-Switch Settings (Channel 2)

Please make sure the dip-switches are set according to your sensor to avoid damage to the sensor or the board.

Sensor Type	DIP 1	DIP 2	DIP 3	DIP 4
2-Wire	ON	OFF	OFF	ON
3-Wire	ON	OFF	ON	OFF
4-Wire	OFF	ON	OFF	OFF

Changing PT Type or Wiring

After adopting the device in ESPHome Builder, update the max31865 settings to match the DIP switch positions and connected probe type.

sensor:
  - platform: max31865
    name: "Right RTD Temperature"
    cs_pin: GPIO5
    rtd_nominal_resistance: 100.0
    reference_resistance: 400.0
    rtd_wires: 3

  - platform: max31865
    name: "Left RTD Temperature"
    cs_pin: GPIO4
    rtd_nominal_resistance: 1000.0
    reference_resistance: 4000.0
    rtd_wires: 2

For PT100 use rtd_nominal_resistance: 100.0 and reference_resistance: 400.0.
For PT1000 use rtd_nominal_resistance: 1000.0 and reference_resistance: 4000.0.
For 2-wire use rtd_wires: 2.
Use rtd_wires: 3 or rtd_wires: 4 for 3-wire or 4-wire probes.

Pinout

uC Pin	Function
GPIO22	I2C SCL
GPIO21	I2C SDA
GPIO23	SPI MOSI
GPIO19	SPI MISO
GPIO18	SPI SCK
GPIO5	MAX31865 right side CS
GPIO4	MAX31865 left side CS
GPIO17	SK6812 LED data
GPIO25	Buzzer

Flashing Firmware

This device can be flashed over serial. The simplest option is the LinkGear Web Flasher.

Maintenance

Keep the device clean using a dry, lint-free cloth. Do not use harsh chemicals or abrasive materials. Never clean connected probes or the PCB with pressurized air or liquids while powered.