Waveshare Modbus RTU Analog Input 8CH

Waveshare Industrial Modbus RTU Analog Input 8CH Module

Manual d'instruccions

Model: Modbus RTU Analog Input 8CH

1. Introducció

The Waveshare Industrial Modbus RTU Analog Input 8CH module is a high-precision industrial-grade data acquisition device designed for robust and reliable performance in various industrial environments. It supports 8 channels of simultaneous analog input, capable of acquiring both voltage and current signals with 12-bit resolution. Utilizing the standard Modbus RTU protocol over an RS485 interface, this module offers wide compatibility with industrial control systems such as PLCs and host computers.

Key features include a wide DC 7~36V power supply range, multiple isolation protections (power, magnetic, resettable fuse, TVS), and configurable input ranges, making it a versatile solution for precise analog data monitoring.

Waveshare Modbus RTU Analog Input 8CH Module with highlighted features
Figure 1: Waveshare Industrial Modbus RTU Analog Input 8CH Module highlighting 12-bit high-precision, voltage/current acquisition, wide voltage, Modbus RTU, and multiple isolation protection.

2. Features At A Glance

  • High-Precision Acquisition: 12-bit resolution with an accuracy of ≤3% for precise data.
  • Multi-Channel Input: 8-channel simultaneous analog acquisition.
  • Flexible Input Modes: Supports single-ended/differential input and simultaneous voltage i adquisició actual.
  • Configurable Ranges: Vol múltipletage and current ranges configurable via software (e.g., 0-5V, 1-5V, 0-10V, 2-10V, 0-20mA, 4-20mA).
  • Modbus RTU Protocol: Standard protocol for wide compatibility with industrial systems.
  • Interfície RS485: Allows cascading of multiple devices with configurable addresses (1~255).
  • Vol. Amplitage Font d'alimentació: Operates on DC 7~36V.
  • Industrial-Grade Isolation: Onboard unibody power supply isolation and magnetic isolation for signal integrity and strong anti-interference.
  • Protecció robusta: Features resettable fuse, TVS (Transient Voltage Suppressor) for surge, over-current/over-voltage, lightningproof, and ESD protection.
  • Funcionament estable: Built-in oversampling digital filtering algorithm and watchdog for stable output without crashing.
  • Fàcil instal·lació: Rail-mount case design (35mm standard guide rail) and support for stacking combination.
  • Indicadors d'estat: Three LEDs (RXD, TXD, STATUS) for monitoring MCU and communication status.

3. Especificacions

Paràmetre Modbus RTU Analog Input 8CH Modbus RTU Analog Input 8CH (B)
Interfície de comunicació RS485
Velocitat de transmissió 4800, 9600, 19200, 38400, 57600, 115200, 128000, 256000
Default Communication Format 9600, N, 8, 1
Protocol Modbus Standard Modbus RTU protocol
Font d'alimentació DC 7~36V
Sampling Precisió 12-bit resolution, accuracy ≤3%
Taxa d'actualització de dades 25 Hz
Mode d'entrada Supports single-ended/differential input, supports voltage and current simultaneous acquisition
default Mode 8-ch current mode, 0~20mA 8-ch voltage mode, 0~10V
Interval 0~5V/1~5V
0~20mA/4~20mA
0~10V/2~10V
0~20mA/4~20mA
Actual Sampling Resistor 249Ω 499Ω
Dimensions of the Modbus RTU Analog Input 8CH module in millimeters
Figure 2: Module Dimensions (Unit: mm)

4. Contingut del paquet

The package contents vary slightly depending on the version purchased:

Modbus RTU Analog Input 8CH (Standard Version)

  • Modbus RTU Analog Input 8CH x1
  • Power supply terminal adapter x1
Package content for Modbus RTU Analog Input 8CH standard version
Figure 3: Package contents for the standard 8CH module.

Modbus RTU Analog Input 8CH (B) (B Version)

  • Modbus RTU Analog Input 8CH (B) x1
  • Power supply terminal adapter x1
  • Jumper cap 10PCS x1
Package content for Modbus RTU Analog Input 8CH (B) version
Figure 4: Package contents for the 8CH (B) module.

Nota: The power supply for this product is not included. A 12V power supply is recommended if needed.

5. Configuració i instal·lació

5.1 S'ha acabat la interfícieview

Familiarize yourself with the module's interfaces:

Interface diagram of the Modbus RTU Analog Input 8CH module showing power, RS485, analog inputs, and LED indicators
Figure 5: Module Interface Introduction. Labels include 7-36V DC Power supply, GND, AI1-AI8 inputs, A+, B- for RS485, and RXD, TXD, STATUS LED indicators.

5.2 Connexió a la font d'alimentació

Connect a DC 7~36V power supply to the 7-36V i GND terminals. Ensure correct polarity. The module features anti-reverse protection, ESD protection, and power supply/signal dual isolation for enhanced safety and reliability.

Wiring diagram for DC power supply and isolated RS485 interface with protection features
Figure 6: Wide Voltage Power Supply and Isolated RS485 Interface Connection. Illustrates DC 7-36V power input and isolated RS485 connection, along with anti-reverse, ESD, and dual isolation protection.

5.3 Connexió de comunicació RS485

Connect the RS485 A+ and B- terminals to your host device (PC or PLC). Multiple modules can be cascaded on the RS485 bus by setting unique device addresses (1~255) for each module.

Connection diagram showing multi-device cascading via RS485 and simultaneous voltage/current acquisition
Figure 7: Connection Diagram. Shows how the module connects to a host via RS485 and supports multi-device cascading, as well as simultaneous voltage i adquisició actual.

5.4 Analog Input Configuration

The module supports both voltage and current acquisition. The input mode (voltage or current) is switchable via jumpers. Specific ranges are configurable via software.

  • Modbus RTU Analog Input 8CH (Standard): Supports 0~5V/1~5V and 0~20mA (default)/4~20mA.
  • Modbus RTU Analog Input 8CH (B): Supports 0~10V (default)/2~10V and 0~20mA/4~20mA.

Refer to the detailed wiring and jumper settings in the diagram below for configuring voltage or current acquisition and selecting the appropriate range.

Diagram illustrating jumper settings for voltage and current acquisition and configurable ranges for both module versions
Figura 8: Voltage/Current Acquisition and Configurable Ranges. Shows jumper positions for voltage (OFF) and current (ON) acquisition, and the available ranges for both 8CH and 8CH (B) versions.

5.5 Physical Installation (Rail-Mount)

The module is designed for 35mm standard guide rail mounting. It comes with a rail-mount buckle for easy installation. For stacking multiple modules, remove the rail-mount buckle from the outer module, then assemble the modules together using screws.

Module mounted on a 35mm standard guide rail
Figure 9: Rail-Mount Support. The module is shown securely mounted on a 35mm standard guide rail.
Diagram showing how to stack multiple modules together
Figure 10: Stacking Installation. Instructions for combining multiple modules via screws after removing the rail-mount buckle.

6. Instruccions de funcionament

6.1 Primary Function

The module's primary function is to acquire analog data from 0~20mA or 0~10V sensors and transmit it to a host device (PC or PLC) using Modbus RTU protocol commands via the RS485 interface.

Diagram showing the data flow from sensor to host via the acquisition module
Figure 11: Primary Function. Data acquisition flow from a 0-20mA/0-10V sensor through the acquisition module to a host system via RS485.

6.2 Modbus RTU Communication

The module operates as a Modbus RTU slave device. Your host system (master) will send Modbus commands to read the analog input registers. The default communication format is 9600, N, 8, 1 (Baud Rate, Parity, Data Bits, Stop Bits). The device address is configurable from 1 to 255.

For detailed Modbus register maps and command structures, please refer to the product's Wiki page mentioned in the 'Warranty & Support' section.

6.3 Indicadors LED

  • RXD LED: Indicates data reception activity on the RS485 interface.
  • TXD LED: Indicates data transmission activity on the RS485 interface.
  • LED ESTAT: Indicates the MCU's working status. Refer to the Wiki for specific status codes or patterns.

7. Manteniment

  • Neteja: Keep the module clean and free from dust and debris. Use a soft, dry cloth for cleaning. Avoid using liquids or abrasive cleaners.
  • Condicions ambientals: Ensure the module operates within its specified temperature and humidity ranges to prevent damage.
  • Actualitzacions de firmware: Check the Waveshare Wiki periodically for any available firmware updates that may improve performance or add features. Follow the instructions provided for safe updating.
  • Integritat de la connexió: Regularly inspect all wiring connections (power, RS485, analog inputs) to ensure they are secure and free from corrosion or damage.

8. Solució De Problemes

  • Sense alimentació/El mòdul no respon:
    • Verify the DC 7~36V power supply is correctly connected and providing the specified voltage.
    • Check the power supply terminal adapter for proper connection.
    • Ensure the power supply itself is functional.
  • No Communication via RS485:
    • Confirm RS485 A+ and B- connections are correct.
    • Check the baud rate, parity, data bits, and stop bits settings on both the module (default 9600, N, 8, 1) and the host device.
    • Verify the module's device address is unique and matches the address used by the host.
    • Ensure the RS485 bus is properly terminated if necessary (refer to RS485 best practices).
    • Check the RXD/TXD LEDs for activity. If no activity, check wiring and host communication settings.
  • Inaccurate Analog Readings:
    • Confirm the correct input mode (voltage/current) is selected via jumpers.
    • Verify the software-configured range matches the sensor's output range.
    • Ensure the sensor is correctly wired to the AIx+ and AIx- terminals.
    • Check for external electrical noise or interference in the environment.
    • Assegureu-vos que el sensor en si estigui calibrat i funcioni correctament.
  • Module Crashing/Unstable:
    • While the module has a built-in watchdog, ensure the power supply is stable and within the specified voltage gamma.
    • Check for excessive heat if operating in a confined space.

9. Consells d'usuari

  • Configuració del programari: Always refer to the official Waveshare Wiki for the latest software tools and detailed instructions on configuring input ranges and device addresses.
  • Wiring Best Practices: For industrial environments, use shielded cables for analog inputs and RS485 communication to minimize interference. Ensure proper grounding.
  • Prova: Before deploying in a critical application, thoroughly test the module with known voltage/current sources across all desired ranges to verify accuracy and stability.
  • Documentació: Keep a record of your module's configuration (device address, baud rate, input ranges) for easier troubleshooting and maintenance.

10. Garantia i assistència

For detailed technical documentation, programming guides, software tools, and further support, please visit the official Waveshare Wiki:

www.waveshare.com/wiki/Modbus_RTU_Analog_Input_8CH

Logotip de recursos i serveis de Waveshare
Figura 12: Recursos i serveis de Waveshare.

Waveshare provides comprehensive resources to assist users with their products. Please refer to the Wiki for the most up-to-date information and troubleshooting guides.

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