Turn Industrial Analog Signals into Home Assistant Sensors

Many industrial sensors use standard analog outputs such as 4–20 mA, 0–5 V, or 0–10 V. These signals are common in pressure transmitters, level sensors, process instrumentation, and industrial measurement equipment.

However, connecting these sensors to a smart home or building automation platform is not always straightforward. Home Assistant is designed to work with digital integrations, while many industrial sensors still rely on analog voltage or current signals.

The Eletechsup N4AIA04 4-Channel Analog Input Acquisition Module provides a bridge between these two worlds. It acquires voltage and current signals and makes the measurement data available through RS485 using Modbus RTU.

An interesting development is that the N4AIA04 is already listed in a community-developed Home Assistant integration project on GitHub.

GitHub project: https://github.com/arturmietek/ha-modbus-manager

This project, called ha-modbus-manager, provides a Modbus RTU/TCP device-management integration for Home Assistant. Its documented built-in device definitions include eletechsup_n4aia04.yaml, specifically identifying the Eletechsup N4AIA04 four-channel analog input module.

This gives developers a practical starting point for exploring Home Assistant integration rather than building every part of the device definition from scratch.

1. What Is the Eletechsup N4AIA04?

The N4AIA04 is a compact four-channel analog acquisition module designed to collect different types of voltage and current signals.

According to the official Eletechsup product page, its input channels are configured as follows:

Channel	Input type	Measurement range
CH1 / V1	Voltage	0–5 V
CH2 / V2	Voltage	0–10 V
CH3 / C1	Current	0–20 mA / 4–20 mA
CH4 / C2	Current	0–20 mA / 4–20 mA

Other key specifications include:

• Communication interface: RS485

• Protocol: Modbus RTU

• Power supply: DC 8–25 V

• Voltage resolution: 0.01 V

• Current resolution: 0.1 mA

• Stated measurement accuracy: 1%

• Supported Modbus function codes: 03 and 06

• Configurable Modbus device addresses for multi-device installations

The combination of voltage and current inputs makes the N4AIA04 useful for projects that combine different sensor output types.

Official product page: https://eletechsup.com/products/n4aia04-dc-12v-4-20ma-0-5v-0-10v-voltage-signal-acquisition-rs485-modbus-rtu-module

2. GitHub Integration: N4AIA04 Meets Home Assistant

Home Assistant is widely used for home automation, energy monitoring, environmental monitoring, and custom dashboards.

The GitHub project ha-modbus-manager provides a way to integrate Modbus RTU or Modbus TCP devices into Home Assistant.

Its README lists the following N4AIA04 device definition:

eletechsup_n4aia04.yaml

The project documentation describes a workflow that includes:

1. Installing the Modbus Manager integration.

2. Configuring an RTU serial bus or TCP gateway.

3. Adding a Modbus slave device.

4. Selecting a built-in device definition or supplying a custom YAML definition.

5. Monitoring and decoding register values using the project's CLI tool.

The repository also documents a command-line monitor that can display raw hexadecimal register values alongside decoded and scaled measurements.

This is useful during commissioning because engineers can compare the raw Modbus response with the values shown in their Home Assistant entities.

Important distinction: The public repository confirms that an N4AIA04 device definition is included in the software project. Its presence alone does not prove that every configuration has been tested successfully with every N4AIA04 hardware revision. Verify the register mapping and scaling against the device documentation and your own hardware.

GitHub repository: https://github.com/arturmietek/ha-modbus-manager

3. Application Example: Monitoring a 4–20 mA Pressure Transmitter

One common industrial application is reading a pressure transmitter with a 4–20 mA output.

Eletechsup's public N4AIA04 FAQ discusses a user question involving a pressure sensor with a 0–50 mbar range and a 4–20 mA output. The manufacturer's response explains that the C1/C2 inputs can directly read current values from 0 to 22 mA, with a reported unit of 0.1 mA.

For a linear 0–50 mbar pressure transmitter:

Pressure (mbar) = (Measured Current − 4 mA) / 16 mA × 50 mbar

For example:

Measured current	Calculated pressure
4 mA	0 mbar
8 mA	12.5 mbar
12 mA	25 mbar
16 mA	37.5 mbar
20 mA	50 mbar

The N4AIA04 acquires the electrical current measurement. The engineering-unit conversion can then be implemented in the Home Assistant configuration, a template sensor, or another layer of the monitoring system.

This makes it possible to display pressure values rather than raw milliamp readings.

For any real installation, confirm the transmitter's range, scaling, wiring, and register format before relying on the calculated pressure.

4. Other Potential Home Assistant Applications

Water Tank Level Monitoring

A compatible 4–20 mA level transmitter can provide an analog signal to the N4AIA04. The measurement can then be converted into a percentage or a physical liquid level in Home Assistant.

Potential dashboard features include:

• Current tank level

• Low-level notifications

• Historical level graphs

• High-level warnings

The actual scaling depends on the transmitter's configured measurement range.

HVAC and Building Monitoring

The voltage inputs can be used with compatible 0–5 V or 0–10 V transmitters.

Possible applications include monitoring selected building or equipment signals, collecting readings from analog-output sensors, and displaying measurements on a Home Assistant dashboard.

The sensor output must match the selected N4AIA04 input range.

Industrial Equipment Monitoring

A compatible pressure or other analog-output transmitter can provide measurements for remote monitoring and historical trend analysis.

Home Assistant can act as a visualization layer, while the original industrial controller remains responsible for time-critical control and safety functions where required.

DIY Automation and Test Equipment

Developers can combine the N4AIA04 with a USB-to-RS485 adapter or a compatible Modbus gateway to experiment with analog signal acquisition.

The same acquired values can potentially be used by Home Assistant, Python applications, or other Modbus-compatible monitoring tools.

5. How to Connect the N4AIA04 to Home Assistant

A typical installation consists of four parts:

Analog sensor → N4AIA04 → RS485 interface → Home Assistant

Step 1: Connect the analog sensor

Choose the correct channel for the sensor output.

For example, connect a compatible 4–20 mA transmitter to C1 or C2. Check the manufacturer's wiring diagram before powering the circuit.

Step 2: Power the N4AIA04

Supply the module with DC power within its specified 8–25 V range.

Check the power-supply polarity and ensure that the sensor wiring is appropriate for the module's input circuit.

Step 3: Establish the Modbus connection

Connect the module's RS485 interface to a compatible USB-to-RS485 adapter or a supported RS485 gateway.

Configure the serial port, baud rate, parity, stop bits, and slave address according to the module's documentation.

Step 4: Install the Home Assistant integration

Follow the installation instructions in the GitHub repository:

https://github.com/arturmietek/ha-modbus-manager

The project documents installation through HACS or manual installation. After installation, restart Home Assistant and configure the Modbus bus.

Step 5: Add the N4AIA04 device definition

Select the built-in N4AIA04 definition if it is available in the installed version of the integration.

If a custom configuration is required, review the YAML definition and compare its register addresses, data types, and scaling with the official N4AIA04 documentation.

Step 6: Verify the readings

Use the integration's monitoring tools or another Modbus RTU client to inspect the raw register values.

Compare the readings with a known input signal or reference instrument before creating automations.

Step 7: Create Home Assistant sensors

Once the readings are verified, configure suitable entities for the measured quantities.

For example, a pressure transmitter could be displayed as a pressure sensor after the current reading has been converted into mbar.

Threshold notifications, dashboards, and historical graphs can then be added according to the project's requirements.

6. Why This Combination Is Interesting for Developers

The N4AIA04 and Home Assistant integration project address different parts of the same problem.

The N4AIA04 handles analog signal acquisition and Modbus communication.

The ha-modbus-manager project provides a software framework for defining Modbus devices and exposing their readings in Home Assistant.

Together, they offer a potential path for bringing industrial analog measurements into a familiar automation dashboard.

Key benefits include:

• Four analog input channels: Support compatible voltage and current sensors.

• Standard Modbus RTU communication: Use a widely adopted industrial serial protocol.

• Home Assistant integration framework: Start with a community project that includes an N4AIA04 device definition.

• Flexible data presentation: Convert raw electrical readings into engineering units.

• Remote visualization: Use Home Assistant dashboards and historical graphs once the integration is configured.

• Developer-friendly troubleshooting: Inspect raw and decoded register values during commissioning.

The open-source integration is independently developed. It should not be represented as an official Eletechsup software product unless an official partnership is confirmed.

7. Useful Technical Resources

Eletechsup N4AIA04 official product page

Specifications, input ranges, power requirements, and product details:

https://eletechsup.com/products/n4aia04-dc-12v-4-20ma-0-5v-0-10v-voltage-signal-acquisition-rs485-modbus-rtu-module

GitHub: ha-modbus-manager

Home Assistant integration, YAML device definitions, setup instructions, and CLI monitoring:

https://github.com/arturmietek/ha-modbus-manager

Eletechsup N4AIA04 FAQ: Current input

An example involving a 4–20 mA pressure transmitter:

https://eletechsup.com/blogs/news/n4aia04-faq

Conclusion

The Eletechsup N4AIA04 is a compact four-channel analog acquisition module for voltage and current signals, including 4–20 mA industrial transmitters.

Its RS485 Modbus RTU interface makes it suitable for integration with compatible PLCs, industrial computers, and custom monitoring applications. The public ha-modbus-manager GitHub repository provides an additional starting point for developers who want to explore N4AIA04 integration with Home Assistant.

For engineers working on Home Assistant analog sensors, 4–20 mA pressure monitoring, Modbus RTU integration, or industrial sensor dashboards, this combination is worth investigating.

Explore the N4AIA04:
https://eletechsup.com/products/n4aia04-dc-12v-4-20ma-0-5v-0-10v-voltage-signal-acquisition-rs485-modbus-rtu-module

Explore the GitHub project:
https://github.com/arturmietek/ha-modbus-manager

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