Generic question about platform / how to start

I would like to know what is the „best“ way (or how would you do this) for the project described below:

I have a „Controller“(the controller is an PLC from Siemens) somewhere in my local network. The controller is used to handle all the logic inside a huge machine.

Then I have about 20 „User GUIs“ with Windows 10 OS also in my local network. They all needs to interact with the controller.

This means: The controller have some data for GUI 1 and some for GUI 2 an so one.

But I dont want that each „User GUI“ is talking directly to the Controller. I need something between.

Right now I do it this way: I wrote an asp.net mvc application. In a timer loop (about 500ms) I put/get data to/from the controller.

And then I am using signal R to publish the data(if data changed) to each single User GUI. Each of then is having a unique connection id.

The website is hostet on a IIS in our local web. As soon as the website starts on the IIS it collects the data from the controller.

After you open the (single) web page on one of the User GUIs - the GUI opens a hub connection and the data will be send via Signal R to the User GUI.

What could be another way to achieve this? Maybe a WPF app on each User GUI and a service or api to handle the data access between controller and User GUIs?