Would it be beneficial to rewrite the HMI as client-service app? - Feasibility study

Introduction

This study aims to explore if it is feasible to redevelop the company’s existing system in the following manner:

• The system is based on client-service architecture, utilizing the WCF framework
• The model behind the service is described in setting files
• Multiple HMI (as clients) connect to the service, communicating with callbacks/events
• A web-based ASP.NET HMI can be connected to the system as client as well as a WPF application

The prototype

• The developed prototype has the following specifications:
• The service contains hard-coded objects, that consists the model.
• Two types of client connect to the service: An ASP.NET Core website and a WPF application, multiple instances of both can connect to the service.
• The data is shown on both platform and can be modified in a way the changes appear on all client and modify the setting file.

Results The protoype contains a WPF client application (a modified version of an earlier project of redesigning the current HMI). The client includes a proxy class and handles the connection with manually added service reference. The service implements the IHMIcontract interface and hosted by a separate project, serviceHost, through TCP. There is also a second host project; an IIS host for ASP.NET clients. The service contains dummy device objects to pass on to the clients.

Alternatives Socket.io - enables real-time bidirectional event-based communication. Advantages: Shorter learning curve than WCF Modern, widely used Disadvantages: Requires Node.js to implement service Client needs extra framework (eg. SocketIO4Net, SocketIOClientDotNet)