How to Transfer Data from Sparkplug B to Modbus

Open Automation Software can be used to transfer data from Sparkplug B Edge of Network devices to a Modbus device using Modbus TCP, Modbus RTU, and Modbus ASCII locally or over a network. This guide walks you through downloading and installing OAS, configuring a simulated Edge of Network node, a Host App connector, a Modbus connector and a tag to write to the Modbus device.

Typically you will also have an Edge of Network (EoN) node configured. For the purposes of this guide, you will create an EoN node and a Tag to simulate data changes. You can also use your own EoN node if you already have one.

This guide uses the Data Route feature of OAS to transfer a Tag's value to another Tag's value using the Tag-to-Tag method.

For this guide on how to transfer data between Sparkplug B and a Modbus device you will need:

• A Modbus device or simulator connected to your workstation

1 - Download and Install OAS

If you have not already done so, you will need to download and install the OAS platform.

Fully functional trial versions of the software are available for Windows, Windows IoT Core, Linux, Raspberry Pi and Docker on our downloads page.

On Windows, run the downloaded setup.exe file to install the Open Automation Software platform. For a default installation, Agree to the End User License Agreement and then click the Next button on each of the installation steps until it has completed.

If you'd like to customize your installation or learn more, use the following instructions:

• Windows Installation
• Linux Installation
• Raspberry Pi Installation
• Docker Installation

The OAS Service Control application will appear when the installation finishes on Windows.

Click on each START SERVICE button to start each of the three OAS services.

2 - Configure OAS

Web Configuration Application

Configuration of the OAS server is performed from the built-in Web Configuration Application. This is the main application for accessing any settings within the OAS server and is completely self-contained within the server.

You can reach this by opening your browser to:

http://<your server>:58725/app/config

If you are browsing from the OAS machine itself, you can use localhost, otherwise use the IP address of the machine. You will also need to ensure port 58725 is open on both the client and the server or you may not be able to reach the application.

On a new installation the OAS engine has no accounts yet, so the first screen you see is Create Admin Account. Once the administrator account exists that screen is not shown again, and browsing to the application displays the sign in screen instead.

1. Enter a name for the administrator in the Admin user name field. Typically you would use admin, but you can use whatever name you choose.

2. Enter a password in the Password field, then enter the same password again in the Confirm password field.

3. Click on the Create admin & sign in button. The account is created and you are signed in to the engine.

To sign in from then on, enter the Network node of the OAS engine, then the Username and Password of your account, and click on the Sign in button.

Legacy Configuration Application

1. From your operating system start menu, open the Configure OAS application.

2. Select the Configure > Tags screen.

   Important

   If this is the first time you have installed OAS, the AdminCreate utility will run when you select a screen in the Configure menu. This will ask you to create a username and password for the admin user. This user will have full permissions in the OAS platform.

   For further information see Getting Started - Security.

3. If this is the first time you are logging in, you will see the AdminCreate utility. Follow the prompts to set up your admin account. Otherwise, select the Log In menu button and provide the Network Node, username and password.

   

   

3 - Check that the MQTT Broker is enabled

If you are using the OAS MQTT Broker, you can follow the steps below to ensure it is enabled, otherwise you can skip this step.

1. Select Options in the sidebar.

2. Expand the MQTT Broker section.

3. Check that the OAS MQTT Broker Enable toggle is turned on and the OAS MQTT Broker Port is configured as 1883.

   

4 - Create Security Group and User

When using Sparkplug B over the OAS MQTT Broker, you need to configure a security group and a user to provide Tag read/write access. You'll need these credentials when creating the Sparkplug B connector instances later.

ℹ️ You can skip this step if you already have your own MQTT Broker.

1. Select Security in the sidebar.

2. Click + Add, enter a Name such as SparkplugAccess and click Create. Once created, the security group name should appear in the list of security groups.

   

3. In the Read Tags section, ensure Disable All Tags From Reading is turned off.

   

4. In the Write Tags section, ensure Disable All Tags From Writing is turned off.

   

5. Select Users in the sidebar.

6. Click + Add, enter a User name such as sparkpluguser, set a Password, set the Security group to SparkplugAccess and click Create. Once created, the user name should appear in the list of users.

   

5 - Set up Sparkplug B Host App

In this section you will create a Sparkplug B driver configured using Host App mode. When you link EoN nodes to this host using the Host ID OAS will automatically create the Tags provided by the EoN node.

1. Select Drivers in the sidebar.

2. Click + Add, enter a name such as SpB Host App in the Driver Interface Name to give this driver interface a unique name, and click Create. Once created, the driver interface name should appear in the list of drivers.

3. Ensure the following parameters are configured:

   • Driver: Sparkplug B
   • Host: localhost
   • Port: 1883
   • User Name: sparkpluguser
   • Password: the password you configured in the previous step
   • Protocol Version: V500
   • Client ID: OAS_Client_Host
   • Mode: Host App
   • Host ID: OAS_Host (you will need to use this in your EoN node configuration)

   

   ℹ️ If you are using your own MQTT Broker, ensure that you configure the Host, Port, User Name, Password and Protocol Version accordingly.

4. Turn on Enable and click on the Apply changes button. The driver interface is not active until it is enabled and the changes are applied.

   

6 - Create Source Sparkplug B EoN node

In order to simulate the Edge of Network (EoN) node acting as a data source, we can use the features available in OAS to create an EoN using a Sparkplug B connector instance and leverage the built-in MQTT broker.

ℹ️ You can skip this section if you want to use your own existing EoN node. You'll have to ensure that your EoN node is configured with the details in step 3 below so that it can talk to the OAS Host App.

1. Select Drivers in the sidebar.

2. Click + Add, enter a name such as EoN Source Node in the Driver Interface Name to give this driver interface a unique name, and click Create. Once created, the driver interface name should appear in the list of drivers.

3. Ensure the following parameters are configured:

   • Driver: Sparkplug B
   • Host: localhost
   • Port: 1883
   • User Name: sparkpluguser
   • Password: the password you configured in the previous step
   • Protocol Version: V500
   • Client ID: OAS_Source_Node
   • Mode: Edge Node
   • Group ID: SourceGroup
   • Edge Node ID: SourceNode

   

4. Turn on Enable and click on the Apply changes button. The driver interface is not active until it is enabled and the changes are applied.

   

7 - Create a Tag attached to EoN for data source simulation

Now that the EoN node has been created we want to be able to publish data from it so we can simulate data being generated by the EoN node.

ℹ️ If you skipped creating an EoN node in OAS and you already have your own EoN node configured, you can skip this section as well and instead generate some data in your own EoN node.

1. Select Tags in the sidebar.

2. If you want to add a Tag to the root Tags group make sure another tag at the root is selected. Click the [+] button and select Add Tag.

   

   If you want to add a Tag to a Tag Group, select the Tag Group first and then click on the [+] button. Alternatively, you can right click on a Tag Group and select Add Tag.

   You can also add Tag Groups by clicking the [+] and selecting Add Group.

3. Provide a Tag Name such as TemperatureSensor and click the Create button.

   

4. To assign this Tag to a Sparkplug B node configure the Host properties to match your EoN node Group ID and Edge Node ID properties.

   • Host Group ID: SourceGroup
   • Host Edge Node ID: SourceNode
   • Host Device ID: EoN Data Source
   • Host Metric Name: Temperature

   

5. Click on the Apply changes button to apply the changes.

8 - Verify Host App Tag Generation for Data Source

You will now check to make sure the Tag Group folder structure and Tag for the Temperature metric was automatically generated and that any updates to the TemperatureSensor tag will flow through from the EoN node to the generated Tag.

1. Select Tags in the sidebar.

   Tips

   If you were already on the Tags screen, you may need to click on the ↻ refresh button next to the Node field to refresh the tag list.

2. You will see a Tag Group structure starting with a parent folder called SpB Host App and then a sub-folder for SourceGroup, another sub-folder for SourceNode and finally a sub-folder for the EoN node called EoN Data Source. The Temperature tag representing the Temperature metric is inside this final sub-folder.

   As you can see the Sparkplug B host app driver has automatically generated the folder structure and Tags.

   

3. Select the Temperature tag in the EoN Data Source sub-folder. You should see a value of zero (0) and the Client parameters configured according to the EoN node Host properties. These properties were automatically configured by OAS.

   

4. Now you will test the data flow.

   ℹ️ If you have your own EoN node configured and you skipped creating an EoN node in OAS then you can trigger a data change in your EoN node to test the configuration.

   If you created an EoN node in OAS you can select the TemperatureSensor tag in the root Tags folder. Type in a value of 24.9 in the Enter Value field and click on the Apply changes button. If everything is working correctly, this change should trigger the EoN node to publish a new value via the OAS MQTT Broker.

   

5. Select the Temperature tag again in the EoN Data Source sub-folder. You should now see a value of 24.9.

   

9 - Configure Modbus Data Destination

In the following steps you will create and configure a Modbus Connector to act as a data destination. This will use a Master connection type and an Ethernet TCP connection. It assumes that your device is using the default port 502.

1. Select Drivers in the sidebar.

2. Click + Add, enter a meaningful Driver Interface Name to give this driver interface instance a unique name, and click Create. Once created, the driver interface name should appear in the list of drivers.

3. Ensure the following parameters are configured:

   • Driver: Modbus
   • Type: Master
   • Connection: Ethernet
   • Ethernet Type: TCP
   • Port Number: 502

4. Specify the device IP in the IP Address field.

   

5. Turn on Enable and click on the Apply changes button. The driver interface is not active until it is enabled and the changes are applied.

   

10 - Add Data Destination Tag

In this section you will create a Tag to represent a data point that you want to write to.

1. Select Tags in the sidebar.

2. If you want to add a Tag at the root of the tag list, make sure no Tag Group is selected and click on the + button, then choose Add tag.

   

   If you want to add a Tag to a Tag Group, select the Tag Group first and then click on the + button and choose Add tag here.

   You can also add Tag Groups by choosing Add group.

3. Provide a Tag Name such as TemperatureOutput and click the Create button.

   

11 - Assign Modbus as Tag Data Destination

You will now set the Tag's data source to the Modbus driver interface that you created previously to act as a data destination.

1. Select the Tag that will be associated with the Modbus destination.

   

2. Set the Data Source to Modbus.

3. Set the Select Driver Interface drop-down to the ModbusDestination interface created previously.

4. Configure the Modbus parameters accordingly based on your device requirements.

   • Device Address: The Modbus station number [default: 1]
   • Memory Type: The Modbus data model table type [Coil Status, Input Status, Input Register, Holding Register]
   • Address: The register to read/write based on the address offset
   • Modbus Data Type: The Input and Holding Register data type
   • Zero Based Address: Whether the Address starts at 0 or 1 [default: true]
   • Word Swap & Byte Swap: Adjust as required for your controller type [default: false]

5. Set the polling rate in seconds by setting the Polling Rate property [default: 1 second].

   

6. Click on the Apply changes button to apply the changes.

7. Check that the quality status is Good and the Tag value is as expected. If the PLC does not hold any value in the given register then the value will remain zero.

12 - Configure Tag-To-Tag Data Route

In this section you will configure the Target of the source Tag to be the destination Tag value. This means whenever the source Tag value is updated, the destination Tag value will also be updated. This will cause a write operation on any associated driver if it is supported.

1. Select the source data Tag.

   

2. Scroll down to the Target section.

   

3. Enable the Enable Write to Target option.

   

4. Click on the Browse… button, select the destination Tag and click on the Use this tag button.

   

5. Optionally, configure the Deadband property or enable Write Continuously to configure a continuous writing frequency.

   

6. Click on the Apply changes button to apply the configuration.

7. To verify that your data transfer is working correctly, select the destination Tag and check that the Tag value matches the Tag value of the source Tag.

   

   You should also verify that the Tag value has been written to your destination device. Depending on your configuration in step 5 above, this destination value should be updated whenever the source value changes or at the given frequency.

13 - Modbus Troubleshooting

• Check your device address and register address and if the device is using Zero Based Addressing.
• Ensure the data types for the Tag and the Modbus Data Type match and if they are boolean or numeric values.
• Check your IP addresses and ports and any firewalls that might be enabled in the operating system.
• Enable Log Modbus Communications in the System Logging section of the Options screen in the Web Configuration Application and check the log files for any errors.
• Use tools such as Wire Shark to troubleshoot deeper connection and protocol issues.

14 - Save Changes

Once you have successfully configured your OAS instances, make sure you save your configuration.

On each configuration page that has a Save button, click on it.

If this is the first time you are saving the configuration, or if you are changing the name of the configuration file, OAS will ask you if you want to change the default configuration file.

If you select Yes then OAS will make this configuration file the default and if the OAS service is restarted then this file will be loaded on start-up.

If you select No then OAS will still save your configuration file, but it will not be the default file that is loaded on start-up.