How to Integrate the Eletechsup NT18B07 RS485 Temperature Acquisition Module with Home Assistant

Introduction

For smart home developers, industrial automation engineers, and DIY electronics enthusiasts, integrating temperature sensors into a centralized monitoring platform is an important step toward building intelligent environmental control systems.

The Eletechsup NT18B07 7-channel RS485 NTC temperature acquisition module provides a practical way to collect temperature measurements from multiple NTC sensors and make the data available to systems that support Modbus RTU communication.

One example of this type of integration can be found in the Home Assistant Community, where developers discussed connecting the NT18B07 to Home Assistant using RS485 and Modbus.

Community reference: Modbus and NT18B07 7CH RS485 NTC Temperature Acquisition Module

1. Connecting NT18B07 to Home Assistant

Home Assistant is a popular open-source home automation platform. With compatible communication hardware and software configuration, Modbus RTU devices can supply sensor data to a centralized automation system.

A typical integration consists of:

• Eletechsup NT18B07 temperature acquisition module

• NTC temperature sensors

• An RS485-to-USB adapter or a compatible RS485 interface

• A computer or controller running Home Assistant

• Modbus RTU configuration and temperature sensor entities

The basic communication architecture is:

NTC Temperature Sensors → NT18B07 → RS485 / Modbus RTU → Home Assistant → Monitoring and Automation

This architecture allows temperature information from multiple measurement points to be incorporated into a home automation dashboard.

2. A Real Home Assistant Community Discussion

The Home Assistant Community thread began in March 2023 and continued with additional troubleshooting and configuration examples in 2024.

On August 7, 2024, a community member reported getting the integration working with an ESPHome-style UART and Modbus controller configuration.

The example included:

• UART communication at 9600 baud

• A Modbus controller configured with a device address of 0x01

• A temperature sensor reading register 0x0000

• A polling interval of five seconds

• A conversion filter that divides the raw register value by 10 and handles signed temperature values

The example illustrates how a Modbus temperature acquisition module can be incorporated into a Home Assistant-based monitoring system.

Please note that the register type, device address, serial parameters, and conversion formula must match the actual module configuration and its documentation. The community example should be treated as a reference rather than a universal configuration for every NT18B07 installation.

3. Potential Applications

Smart Home Temperature Monitoring

Connect NTC probes to different measurement points and display their temperatures in Home Assistant. Depending on the installed sensors and system design, users can monitor indoor rooms, equipment cabinets, or other environments.

Server Rack and Equipment Cabinet Monitoring

Temperature sensors can be placed at several locations inside or around a server cabinet. Home Assistant can display the measurements and trigger notifications or automation actions when configured temperature thresholds are exceeded.

For critical IT equipment, this type of monitoring should complement rather than replace dedicated protection and alarm systems.

Greenhouse and Environmental Monitoring

Temperature acquisition at multiple points can help monitor growing environments, storage areas, and other temperature-sensitive spaces. Home Assistant automations can use the collected readings to initiate configured ventilation or notification routines.

DIY Smart Home and IoT Projects

For makers already using ESPHome, Modbus RTU, or RS485-based equipment, the NT18B07 offers a potential way to add multiple NTC temperature measurement channels without building an entirely separate acquisition circuit.

4. Why Use RS485 for Temperature Acquisition?

RS485 is widely used in industrial and building automation because it supports differential serial communication and is suitable for installations where devices are distributed over longer cable runs.

Combined with Modbus RTU, it provides a structured way for compatible controllers to request measurement data from field devices.

For projects that need centralized temperature monitoring, this approach can reduce the need for separate direct sensor connections to the main controller. The actual cable length, device count, update rate, and noise immunity depend on the complete system design.

5. Integration Checklist

Before integrating the NT18B07 with Home Assistant, verify the following:

1. Confirm the NT18B07 communication protocol and supported Modbus registers.

2. Set the correct Modbus slave address.

3. Match the baud rate, parity, data bits, and stop bits.

4. Select the correct register address and register type.

5. Apply the correct scaling and signed-value conversion for temperature readings.

6. Verify the readings against a known temperature reference.

7. Configure an appropriate polling interval for the application.

These checks can help avoid common problems such as communication timeouts, incorrect register readings, and temperature values with the wrong scale.

Conclusion

The Eletechsup NT18B07 is worth considering for temperature acquisition projects that need to connect multiple NTC sensors to an RS485-based monitoring system.

The Home Assistant Community discussion provides a useful developer reference for exploring Modbus RTU integration and temperature sensor configuration.

For smart home builders, IoT developers, and industrial automation engineers, combining NT18B07 with compatible RS485 hardware and Home Assistant can provide a flexible foundation for centralized temperature monitoring and automation.

Learn more: Visit Eletechsup for product information and technical support.