How To Articles > How to Access Sparkplug B Data from a C# or VB .NET Application

How to Access Sparkplug B Data from a C# or VB .NET Application

How to Access Sparkplug B Data from a C# or VB .NET Application

Open Automation Software allows you to establish direct connections to data from MQTT brokers at Sparkplug B Edge of Network Nodes. The OASData component enables you to access real-time and historical data from a local or remote OAS instance with various versions of .NET, including .NET 5, .NET 6, .NET 7, .NET Core 2.0 or later, .NET Framework 4.61 or later, Xamarin.iOS 10.14, Xamarin.Android 8.0, and UWP This tutorial guides you through the process of downloading and installing OAS, configuring a Sparkplug B driver, defining tags, and reading and writing data to them using the .Net Data Connector. You can find code examples in C# and Visual Basic on this page.

Step 1. Download and Install the Open Automation Software and Start the OAS Service

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 one or more of the Open Automation Software features. Select the default Typical installation if you are not sure what features to use or the Custom installation if you want to save disk space on the target system.  When prompted agree to the End User License Agreement to continue the installation.

For more detailed instructions and video tutorials, visit the installation guide for your system:
Windows Installation | Linux Installation | Raspberry Pi Installation | Dockers Installation

When the installation is finished the OAS Service Control application will appear.  Use this application to start the 4 Services. If this is the first time installing the software it will automatically enter Runtime with an example Tag Configuration.

Step 2. Set Up Sparkplug B Host App to Access EoN Node Data.

Select Configure-Drivers.

Configure Drivers

Enter a meaningful Driver Interface Name that you will refer to this connection and define the properties.

Set the driver to Sparkplug B.

Enter the Host property to the IP Address of the of the host broker or just use localhost for a local broker. 

Set the Port property of the host broker to connect to.  The default port is 1883 or 8883 for SSL.

Note: The OAS MQTT Broker can be used to host data locally.  To use another broker on the default ports on the same computer change the OAS MQTT Broker Port under Configure-Options-MQTT Broker.

Enter the User Name and Password if required.

Set the MQTT Protocol Version to V311 or V500.

Set the Client ID to a unique value, each driver interface must have a specific value different than all other clients connecting to the host.

Set the Mode to Host App for OAS to control the online state of each Edge of Node defined to the shared Host Application ID. Or set to Client App to access EoN Node data without controlling their state.

Set the Host ID to the specific value that the Edge of Nodes will be using as the Host Application ID.

Set the Sparkplug B Version to 2.2 or 3.0.

To automatically add tags for each Metric from the matching Group, Edge of Nodes, and Devices enable the property Add Client Tags Automatically.

When enabled optionally set the Filter Groups, Edge Nodes, and Devices that tags should be added from for each of their Metrics.  Leave the Filter fields blank to include all Edge of Nodes publishing data to the broker.

Select the Add Driver button in the left part of the form to add the Driver Interface as an available selection when defining Tags in the next step.

Add Driver

You are now ready to add tags for specific Sparkplug B EoN Node Metric values.

Note: If the Driver Interface property Add Client Tags Automatically was enabled tags will be created for you, you can skip this step to add tags manually.

Select Configure-Tags.

Menu Configure Tags

Note: You can add organizational Groups as many levels deep as you prefer and add tags to groups.  To do this first add a Group to Tags Group at the root level, then right click on the Group in the right window to add additional Groups or Tags.

Select Add Tag.

Add Tag

Change the Data Source Tag property to Sparkplug B.

Select the correct Driver Interface from the Driver Interface pull down list.

Specify the Client Group IDClient Edge Node IDClient Device ID, and Client Metric Name for the Edge of Node Metric value to read and write.

Select the Data Type of the Tag to match the data type of the Metric.

Select Apply Changes and the current value for the Metric should appear with Good Quality.

Select the Save button from the toolbar to save your configuration.

Save Button

You can view the Getting Started with Sparkplug B Video to familiarize yourself with the above steps to setup OAS as a Sparkplug B Edge of Network Node and a Host Application

  • 00:00 – Introduction
  • 01:10 – Download OAS
  • 01:46 – Quick Start
  • 02:08 – Edge of Network Node
  • 05:52 – EoN Tags
  • 07:04 – Host Application
  • 09:20 – SpB Client Tags
  • 10:22 – Programatic Interface
  • 10:59 – CSV Export / Import
  • 12:27 – Multiple Metric Tags
  • 13:46 – Modbus
  • 16:10 – DCMD Metric Write
  • 17:00 – Data Route
  • 17:58 – Networking
  • 18:17 – Save Configuration
  • 18:56 – OAS Platform

Step 3. Configure Your Tags

OAS provides multiple ways to add and define tags:

To add a Tag manually:

  1. In the OAS Configure Application, select Configure >> Tags from the top menu.

  2. Select localhost or the remote service you wish to modify with the Select button to the right of the Network Node list.

  3. Click on the Add Tag button located at the top of the Tag browser on the left portion of the screen.

  4. A dialog box will appear. Enter a name for your new tag and click ok.

  5. A configuration screen will appear for your new tag. Select your data source type in in the Data Source dropdown box.

  6. Specify the correct data type in the Data Type dropdown box.

  7. Click Apply Changes at the bottom right of the window.

For more detailed instructions on configuring your tags, click here to see our Getting Started Tags tutorial.

Step 4. Access Your Data from a C# or VB .NET Application

The .NET Standard 2.0 OASData assembly is used to provide read and write access to OAS tag variables and can target .NET 5, .NET 6, .NET 7, .NET Core 2.o or greater, .NET Framework 4.61 or greater, Xamarin.iOS 10.14, Xamarin.Android 8.0, and UWP

Start a new Visual Studio Project or Open Your Existing One

Microsoft Visual Studio 2015+ is recommended. For developing cross-platform .NET Standard or .NET Core solutions, Visual Studio 2019+ is recommended. For developing Android and/or iOS solutions, be sure to include Xamarin extensions to Visual Studio. After creating a new Visual Studio project, add a reference to the OASData assembly and all its dependencies, found in the OAS installation directory. This is typically:

C:\Program Files\Open Automation Software\OAS\Controls\NetStanard\OASData\OASData.dll

Create an instance of the OASData.Data class

static OASData.Data oasd = new OASData.Data();

Your application typically does not need more than one instance of the OASData.Data class. So, this can be created when your application starts.

Read Tags Asynchronously

oasd.ValuesChangedAll += OASDValuesChangedAll; 
private void OASDValuesChangedAll(string[] Tags, object[] Values, bool[] Qualities, DateTime[] TimeStamps);

oasd.AddTags(new string[] {

Values are returned in the ValuesChangedAll event anytime values change in a tag variable. AddTags adds tags for subscription.

Read Tags Synchronously

Values = oasd.SyncReadTags(Tags, ref Errors, 10000);
  • This call returns an object array with the values for each tag variable.
  • Tags is a string array of tag names and variables to read.
  • Errors is an integer array returning: 0 if the tag variable quality is good 1 if the quality is bad 2 if the value could not be returned within the timeout specified.
  • Timeout is specified in milliseconds to wait for the call to return.

Write Tags Asynchronously

oasd.WriteTags(OASTags, OASValues);

With this call, if the tags data source is defined to a device, for example: Modbus; Siemens; Allen Bradley MQTT; OPC UA, or application writes to .Value will be written to the source defined.

Examples: Modbus, Siemens, AB, OPC UA, MQTT

  • Tags is a string array of tag names and variables.
  • Values is an object array containing the values to write to each tag.
  • TimeStamps array can optionally be provided to set the time of the value if the Data Source of the Tag is Value.

Write Tags Synchronously

Errors = oasd.SyncWriteTags(Tags, Values);
  • Tags is a string array of tag names and variables.
  • Values is an object array containing the values to write to each tag.
  • Errors is an Integer array that returns: 0 when successful; 1 when OAS Engine is not reachable; 2 when the Tags array size is not equal to the Values array.


Tag names can include an IP Address, network node name, or registered domain name if the application is deployed remote from the OAS Engine.

Basic Networking Example:


Live Data Cloud Networking Example:


For more information, see Getting Started with OASData and IIoT Example Service Code or watch the video below: