Connect N3uron with MQTT and Modbus Support Devices

Introduction

In industrial automation, Modbus stands out as one of the most common protocols. MQTT has emerged as the leading protocol for IoT in industrial automation due to many characteristics. Its lightweight design, efficiency, scalability, and support for asynchronous messaging are notable. In MQTT, devices communicate only when there's a reportable event, contrasting with constant update checks. This event-driven approach, coupled with reporting by exception—sending data only when it deviates from norms or on specific triggers—conserves bandwidth and resources, optimizing data transmission for critical IoT applications.

The potent pairing of reTerminal DM and N3uron Duo facilitates efficient plant management by providing robust connectivity and data manipulation capabilities. This Wiki emphasizes the significance of Modbus TCP in industrial settings, highlighting the seamless integration of MQTT devices to further enhance connectivity.

Prerequisites

Hardware

reTerminal DM
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Software

We highly recommend studying the Getting Started with N3uron guide. It provides essential insights into navigating the N3uron web interface, understanding concepts such as the Web UI and Web Vision module, grasping the concept of tags, and creating basic dashboards. If you haven't explored these fundamentals yet, it's advisable to do so before proceeding further. You can access the guide through the provided link.

Configure Ethernet settings

Since your PLC IP domain is different from your wireless settings, you may have to change the IP configuration manually. For that,

• Step 01: Run the following command:

sudo nano /etc/dhcpcd.conf

• Step 02: Then configure the Ethernet port settings according to your PLC network domain and set priorities using the 'metric' command. The lowest metric has the highest priority.

Modbus Module Create and Configuration

Create a Module Instance Within N3uron’s WebUI Interface

• Step 01: In the Navigation panel, select Config.
• Step 02: In the Explorer panel, select Modules.
• Step 03: Click on the Model menu and select New Module.

• Step 04: The instance can be given any name but for the example, we will use ModbusClient.
• Step 05: Set the Module Type property to ModbusClient. Leave the rest of the properties as their default values and click Save.

Channel Creation and Configuration

• Step 01: Under the created Modbus Client and Model, select New Channel. Give the channel name as Client.

• Step 02: Now, we are going to communicate with the PLC using Modbus TCP. Please provide the IP address for the PLC and the port address.

note

If you are using Modbus RTU, there are various configurations to consider. To do that, you need to provide details such as the COM port, baud rate, etc. For more information on configuring both Modbus RTU and TCP protocols on N3uron, refer to the provided guide.

• Step 03: Add a device: Each channel can have one or more devices. Set a name for the device and proceed with the configuration. In this case, the device name is PLC.

• Step 04: There are a few settings that you can adjust through this interface. You can find more details from this link. However, for this case, we'll keep them as they are.

Tag Configuration

• Step 01: Go to the WebUI, select Config, and then click on Tag. In the Model section, click on the menu and choose New Tag. Name it Q1. Normally Q is used to indicate the output coil.

• Step 02: Then you need to do the following configurations.

  - Source : Enabled/Yes
  - Module Type : ModbusClient 
  - ModuleName: ModbusClient
  - Config: Device: Client/PLC
  - Modbus address: 008931
  - Data type: Boolean 
  and Save it.

note

It is advisable to refer to the PLC or device manufacturer's datasheet regarding Modbus addresses. There, you will find details about input, output, and holding addresses. According to these specifications, adjustments should be made in the Modbus address line in the tag configuration. For instance, if the manufacturer notates the output coil Q1 as 8193, the address should be configured as 008193. Similarly, if the network input is denoted as 1 and it is a coil type, the address should be set as 000001.

• Step 03: Real-time simulation

Once connected to the system, you can view the real-time status of output coils and input coils.

note

Interaction with the PLC via the N3uron interface requires appropriate access permissions, including both read and write capabilities.

Create a MQTT Module Instance Within N3uron’s WebUI Interface

• Step 01: In the Navigation panel, select Config.
• Step 02: In the Explorer panel, select Modules.
• Step 03: Click on the Model menu and select New Module.

• Step 04: The instance can be given any name but for the example, we will use MQTT.
• Step 05: Set the Module Type property to MqttClient. Leave the rest of the properties as their default values and click Save.

Configure N3uron’s MQTT Module

• Step 01: In the Explorer panel, select the MQTT instance you have just created.

• Step 02: Click on the Model menu button and select New Connection.

• Step 03: Give the New connection a name. In this example, it has been named MqttClient:

  - Destination broker : Custom 
  - Authentication mode: Password
  - Username : Your Broker Username
  - Password: Your Broker Password
  - Protocol:MQTT
  - Broker URL:Broker ip

  Save configurations

Subscribe to a Topic Using N3uron’s MQTT Module

• Step 01: In the Model panel, right-click on the AWS Connection, select New Subscriber, and give it a name. In this example, we will simply use Subscriber.

• Step 02: Click on it and add a name in the Topic field. In this example, we have used device/data.

note

For testing and hands-on experience, we have provided you with an Arduino code that can be run on XIAO. Additionally, you will need to input your own credentials into this code before uploading it.

• Step 03: Set the following properties using the values shown below, leaving the rest of them as their default values:

  - Qos: Qos 0.
  - Encoding: UTF8
  - Compression: None
  - Serialization: JSON
  - Data parser/Type: MqttClient JSON

  And Save it.

note

Here, we utilize a data parser configured for MQTTClient JSON format. The XIAO device publishes data to the broker in this format. If your device does not publish data in this specific format, you will need to identify the format it uses and create a custom JavaScript code snippet to handle the devices accordingly. For further guidance, please refer to the provided guidelines.

Create a Tag

• Step 01: Within the Explorer panel, select Tags.
• Step 02: In the Model menu, right-click on the folder icon, select New Tag, and give it a name. In this example, we will use test.

• Step 03: In the Configuration panel, set the following properties using the values shown below, leaving the rest of them as their default values:

  - Type: Number.
  - Source/Enabled: Yes
  - Module Type: MqttClient
  - Module name: MQTT
  - Config/Subscriber: MqttClient/Subscriber

  Click on Save.

• Step 04: Real-time simulation Once connected to the system, you can view the real-time status of output from the MQTT Broker.

Bonus : Lets Publish Status of Factory with AWS

note

We have provided step-by-step instructions on how to connect an AWS cloud to your reTerminal DM device. If you are new to this wiki, please refer to this link.

• Step 01: In the Explorer panel, select the MQTT instance you have just created.
• Step 02: Click on the Model menu button and select New Connection.
• Step 03: Give the New connection a name. In this example, it has been named MqttPublisher.

• Step 04: Configure the connection properties:

  • A: Select Amazon Web Services from the Destination Broker drop down menu. Authentication mode will be Certificate. Also Client Id is N3uron in this example.
  • B: Load the Certificate, Private key and CA certificate you downloaded and saved when you created the Thing in the AWS IoT Console.
  • C: In the AWS IoT console, in the left-hand menu, go to Settings and copy your Device Data Endpoint. Go back to N3uron and paste it in the Broker URL field.
  • D: Leave the rest of the properties as their default values and click on Save.

• Step 05: Within the Model panel, right-click on the MqttPublisher Connection you have just configured, select New Publisher, and give it a name. In this example, we will simply use AWS.

• Step 06: Click on it and add a name in the Topic field. In this example, we have used N3uron.

• Step 07: Click on the Tag Filter button, select New Tag Filter, and change the default name. In this example we have used TagFilter. Leave Mode, Path, and Regex pattern as their default values. With this configuration, every tag configured in N3uron will be published to our AWS Broker.

• Step 08: Go to the AWS IoT console and in the left-hand menu, select MQTT test client.Click on the Subscribe to a topic tab, enter N3uron in the Topic filter to subscribe to everything, and click on Subscribe.

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