N4DSC08: 8-Channel RS485 DS18B20 Temperature Acquisition Module for Industrial Monitoring

N4DSC08 is an 8-channel digital temperature acquisition module designed for industrial monitoring, remote data collection, and automation applications. It supports up to eight DS18B20 temperature sensors and communicates with a host controller through an RS485 interface.

By combining multi-channel temperature measurement with Modbus RTU communication, the N4DSC08 allows users to collect temperature data from multiple locations through a single compact module. It is suitable for integration with PLCs, industrial computers, embedded controllers, SCADA systems, and other Modbus-compatible devices.

For developers and system integrators, the N4DSC08 provides a practical way to add multi-point temperature monitoring to an existing industrial control system without designing a dedicated temperature acquisition circuit from scratch.

2. Key Features of the N4DSC08

Eight Independent Temperature Channels

The N4DSC08 supports eight DS18B20 digital temperature sensors. Each sensor is connected to its corresponding channel, allowing temperatures at different locations to be monitored independently.

This multi-channel architecture is useful for applications that require several measurement points, such as equipment cabinets, production lines, greenhouses, storage rooms, and building automation systems.

Standard RS485 Communication

The module uses RS485 for communication with a host controller. RS485 is widely used in industrial environments because it supports differential signaling and allows compatible devices to communicate over a shared bus.

Multiple compatible Modbus devices can be connected to the same RS485 network, subject to proper addressing, wiring, termination, and network design.

Modbus RTU Protocol

The N4DSC08 supports Modbus RTU, allowing a compatible Modbus master to read temperature values from the module's registers.

This makes integration straightforward for developers working with PLCs, industrial PCs, Python applications, embedded controllers, and monitoring software.

Flexible Power Supply

According to the published technical documentation, the N4DSC08 operates from a DC power supply in the 7–30V range. Its documented maximum working current is approximately 18mA.

The module also provides reverse-polarity protection, helping protect the hardware against an incorrectly connected supply.

Compact Installation

The bare circuit board measures approximately 75 × 50 × 14mm, while the version with a DIN-rail housing measures approximately 80 × 54 × 26mm.

The compact design makes the module suitable for installation inside electrical control cabinets, equipment enclosures, and industrial monitoring panels.

3. Technical Specifications

Parameter	Specification
Manufacturer	Eletechsup
Model	N4DSC08
Function	8-channel temperature acquisition
Supported sensor	DS18B20
Number of channels	8
Communication interface	RS485
Communication protocol	Modbus RTU
Power supply	DC 7–30V
Maximum working current	Approximately 18mA
Default serial settings	9600 baud, N, 8, 1
Communication address	Configurable through Modbus commands
Board dimensions	75 × 50 × 14mm
Dimensions with DIN housing	80 × 54 × 26mm
Board weight	Approximately 36g
Weight with DIN housing	Approximately 66g

Specifications are based on the published product information and the third-party GitHub documentation. Please consult the current product manual for the latest configuration details.

4. Understanding the N4DSC08 Modbus Registers

One useful resource for developers is the public GitHub repository maintained by Cyb3rn0id, which documents the N4DSC08 hardware and its Modbus register map.

The documentation identifies the onboard microcontroller as a Puya PY32F002A, the RS485 transceiver as a CS48520S, and the voltage regulator as a 78M05.

It also describes the temperature registers, communication settings, and hardware dimensions.

Temperature Input Registers

The documented input registers use Modbus function code 04 (Read Input Registers).

Input Register Address	Sensor Channel
0	D1
1	D2
2	D3
3	D4
4	D5
5	D6
6	D7
7	D8

Each temperature value is represented as a signed 16-bit integer (INT16), with the temperature expressed in tenths of a degree Celsius.

For example:

• A register value of 253 represents 25.3°C.

• A register value of 187 represents 18.7°C.

• A register value of -45 represents -4.5°C.

The documented value -32768 (0x8000) indicates that a sensor is disconnected, faulty, or otherwise not communicating correctly.

This error indication is particularly useful in automated monitoring systems because the host controller can distinguish an invalid sensor reading from a normal temperature measurement.

Alternative Holding Register Access

The GitHub documentation also describes temperature values duplicated in holding registers starting at decimal address 160 (hexadecimal 0x00A0).

These registers are documented as read-only and can be accessed using Modbus function code 03 (Read Holding Registers).

Developers should verify register addressing conventions in their chosen Modbus library, since some software uses zero-based offsets while other software uses one-based reference notation.

Communication Configuration

The documented default serial settings are:

• Baud rate: 9600bps

• Data bits: 8

• Parity: None

• Stop bits: 1

The Modbus device address can be changed through Modbus commands. The GitHub documentation identifies the default address as 1.

The register documentation also describes configuration options related to baud rate and long sensor wires. Because some settings are based on reverse engineering and are not fully verified by the author, users should confirm them on their own hardware before deploying them in production.

5. Example: Reading Eight Temperature Channels with Python

A compatible Modbus RTU master, such as a USB-to-RS485 adapter connected to a computer, can be used to read the temperature registers.

The following example uses the Python pymodbus library to read eight input registers and convert the returned values into degrees Celsius.

from pymodbus.client import ModbusSerialClient

client = ModbusSerialClient(
    port="COM3",       # Change to your serial port
    baudrate=9600,
    bytesize=8,
    parity="N",
    stopbits=1,
    timeout=2
)

if client.connect():
    try:
        response = client.read_input_registers(
            address=0,
            count=8,
            device_id=1
        )

        if not response.isError():
            for channel, raw_value in enumerate(
                response.registers, start=1
            ):
                # Convert the unsigned Modbus word
                # to a signed 16-bit integer.
                if raw_value >= 0x8000:
                    raw_value -= 0x10000

                if raw_value == -32768:
                    print(f"Channel {channel}: Sensor error")
                else:
                    temperature = raw_value / 10.0
                    print(
                        f"Channel {channel}: "
                        f"{temperature:.1f} °C"
                    )
        else:
            print("Modbus communication error")

    finally:
        client.close()
else:
    print("Unable to connect to the serial port")

Compatibility note: This example uses the device_id argument found in recent PyModbus versions. Older versions may use a different argument name. Install a compatible version and check the current PyModbus documentation before running the example.

Before testing, confirm the RS485 A/B wiring, serial port, slave address, and power supply. The example assumes that the module uses the documented default address of 1 and default serial settings.

6. Typical Applications

Industrial Equipment Monitoring

Monitor temperatures at multiple points inside machinery, electrical cabinets, and production equipment. The collected data can help operators identify abnormal temperature changes and support preventive maintenance.

Greenhouse and Agricultural Automation

Install temperature sensors in different zones of a greenhouse to collect environmental data. A PLC or automation controller can use the readings to manage ventilation, fans, or other equipment.

HVAC and Building Management

Use the N4DSC08 to monitor temperatures in equipment rooms, utility spaces, and other building areas where DS18B20 sensors are appropriate.

Warehouse and Storage Monitoring

Collect temperature readings from multiple locations within warehouses and general storage environments. For applications requiring regulatory compliance, calibration, or certified temperature records, the complete monitoring system must be validated separately.

PLC and SCADA Integration

Connect the N4DSC08 to a compatible Modbus master and integrate its temperature readings into an existing PLC, SCADA, or industrial computer system.

Remote Data Acquisition

Combine the module with an industrial gateway or computer to log temperature data, generate alarms, and display trends through a local or remote monitoring platform.

7. Practical Installation Considerations

For reliable operation, several points should be considered during system design.

Sensor wiring: Use suitable wiring and follow the DS18B20 connection requirements. Long sensor wires may require additional configuration or improved wiring practices. The GitHub documentation describes a setting for sensor wires longer than five metres, but its behavior should be verified on the actual module.

RS485 network design: Use appropriate twisted-pair cabling, termination, and biasing where required. Keep the bus topology and cable length within the capabilities of the complete communication network.

Electrical protection: Although the module includes reverse-polarity protection, the installation should still use a suitable power supply and appropriate electrical protection.

Temperature accuracy: Measurement performance depends on the DS18B20 sensor, installation conditions, wiring, and the overall system. Verify the sensor's specifications and any calibration requirements for the intended application.

Industrial deployment: Test communication reliability, sensor disconnection handling, and recovery behavior before using the module in a critical monitoring system.

8. Why Choose Eletechsup N4DSC08?

The N4DSC08 combines eight digital temperature inputs, an RS485 interface, and Modbus RTU communication in a compact module.

For equipment manufacturers, automation integrators, and developers, this can reduce the work required to design and integrate a multi-channel temperature acquisition solution.

Its standard communication protocol and documented register map also make it suitable for projects that need to exchange temperature data with existing industrial hardware and software.

Conclusion

The Eletechsup N4DSC08 8-Channel RS485 DS18B20 Temperature Acquisition Module provides a practical solution for collecting temperature data from up to eight locations through a single Modbus RTU interface.

The combination of multi-channel sensing, compact hardware, flexible DC power input, and standard industrial communication makes it a useful option for temperature monitoring and data acquisition projects.

Developers can also refer to the publicly available GitHub documentation for additional information about the hardware, Modbus registers, and communication configuration.

Product information: Eletechsup N4DSC08 Official Product Page

Technical reference: N4DSC08 Documentation on GitHub

Eletechsup — Practical Electronic Modules for Industrial Control, Monitoring, and Automation.