Case Studies

Red Lion HMI Web Server

Red Lion HMI Web Server to Read/Write PLC Tags

Posted in HMI and SCADA, Manufacturing Automation and Intelligence, PLC Programming, Specialty Machinery


DMC retrofitted a client’s existing PLC production system with a modern HMI. The Red Lion HMI provides a better user interface (UI) and is connected to the client mainframe, allowing recipe and job data to be easily loaded into the PLC from the server network. In streamlining their work-order process, DMC was able to increase the efficiency and competency of the client’s system.


DMC used a Red Lion HMI interface for the Mitsubishi PLC running on the customer's machine. Our engineers then connected the HMI to a middleware PC running a java application so that the mainframe and Red Lion HMI could communicate. Configuring Red Lion as a web server, the HMI not only downloaded job data from the middleware to the PLC, but it fetched live tags from the PLC as well. Downloading job data was completed using HTTP POST method, while fetching tags utilized GET method.

DMC also provided a simulation mode on the Red Lion HMI. This mode simulated the live PLC so that testing could be done offline resulting in minimal PLC downtime. An additional web page simulated the middleware posting of job data to the Red Lion HMI.

Learn more about DMC's HMI programming services.

Customer Benefits

  • Reduced operator error by replacing manual recipe entry with automatic transfer over network
  • Increased throughput with clearer UI ease of use
  • Allows faster process improvements with access to immediate production and quality data