Sending Historical Data via REST API: Integration with Historian in vNode

In this exercise, we start with a pre-configured data source. For this example, we will use simulated data from Matrikon OPC Simulation, which communicates with vNode through the OPC DA Client module. If you need assistance setting up this connection, you can refer to our other articles. Additionally, we assume that the REST client is on the same PC.

Once the tags are properly mapped, you will need to create a Historian module to store the information historically. First, add the Historian module and associate the relevant tags, configuring them to send their information to this module.

Next, configure the REST Server module to expose historical data. Navigate to the Access option within the module, create a new role with administrator permissions, and enable the GET and POST methods for tag access.

Then, create a Tag Access pointing to the simulated data located in the vNode data root. This will set up a system capable of sending historical data via REST API, efficiently integrating Historian and REST Server in vNode. The REST Server configuration is left at its default; simply click the Save button.

Note: If the REST client is on a different PC, remember to change the connection interface to allow proper communication.

Now, using a REST client, in this case Postman, which you can download from the following link: Download Postman, we will create a connection to query historical data using the following command:

http://127.0.0.1:3003/tags?cmd=history&path=/SimulationServer/Int1/*&start=2025-02-04T14:00Z&end=2025-02-04T15:00Z

When executing this request, you will be prompted for credentials to connect to vNode. Go to the Authorization tab in Postman and select Basic Auth. Enter the following vNode administrator credentials:

• Username: admin
• Password: vnode

Finally, click the Send button to view the response from the vNode REST server.

Created by JF