HMI best practices in technology

Advances in connectivity, PC-based control and multi-touch functionality boost value of human machine interfaces (HMIs).

By Reid Beilke June 13, 2014

The best human-machine interfaces (HMIs) are designed for easy use by all operators on the plant floor. This optimization leverages modern technology advances and can affect every aspect of the HMI – from the way it looks, to the way it behaves, to the way it can connect the user to live data from the plant and to live support from the machine builder or equipment vendor. Open, "vendor-neutral" connectivity solutions such as the OPC UA (Unified Architecture) communications model are increasingly important to establish this connectivity. 

Connectivity for better, enterprise-wide access to data

The modern HMI and OPC UA can help serve as a conduit that connects the user to the machine, the plant floor, to the MES layer and other higher level enterprise systems and back again. This enables the implementation of more intelligent and connected systems. OPC UA client and server functionality can be available in a PC-based controller without a hardware add-on. The PC-based hardware can even be in the form of a panel PC which can serve as the all-in-one HMI and controls hardware. Pushing data to the cloud via OPC UA can be easily accomplished with two or three simple function blocks used within the controller which can facilitate a completely secured connection from the controller to the cloud. 

Look first to the HMI for troubleshooting and support

HMI can also be the key enabling technology in the area of troubleshooting and support. Hands-on troubleshooting requirements can be decreased to a minimum by integrating rich diagnostic capabilities into the HMI. Today, there is no need for problems to be resolved the old fashioned way by opening up the electrical cabinet and logging into a hardware PLC and struggling through Ladder logic to get production up and running again.

With a PC-based automation system that uses programming software that works for controllers, networking, motion, and HMIs, the HMI can visually show a wealth of diagnostics information such as production data and measurements relating to the health of equipment such as temperature, vibration, energy use, etc.

Built-in diagnostics capabilities of EtherCAT can also quickly localize the source of problems for faster corrective measures. Possible troubleshooting techniques can be displayed as on-screen options on the HMI along with multimedia materials for tutorials and documentation. The machine builder can decide how much direct operating system (OS) access to give the end users on the PC-based controller. It is easily possible today for machine builders to embedding media players within the HMI software to play tutorial/troubleshooting multimedia.

A range of standard tools can also facilitate remote connectivity to off-site support from the machine builder or equipment vendor which is also more often the case today. This takes the burden off of the end-users so they can put more of their time and efforts behind production-related concerns. This is especially important for operations that simply don’t have the budget to employ as many controls or software specialists on-site.

Don’t forget the screen itself: Multi-touch HMIs change the game

A major new development that enables enhanced user-friendliness to HMI hardware is the advent of multi-touch technology in industrial applications. Well beyond a simple "cool factor," multi-touch can enable easier and more intuitive access to more detailed plant information, such as scrolling through detailed machine views with pop-ups that can indicate important updates or problem areas. Users can pinch and zoom into specific machine modules for more information on a targeted area. This can be a much more user-friendly experience than a traditional single-touch interface which may require far more time spent clicking through different machine views and menu options.

Multi-touch-enabled control panels and panel PCs have up to five simultaneous points of touch on the screen at any time.

These are designed for industrial use so they feature robust, stable construction and protection ratings up to IP 65. The multi-touch panels with projective capacitive touchscreen (PCT) technology feature a high touch-point density, which enables accurate, safe and jerk-free operation even in minute steps. These are available in multiple formats such as 16:9, 5:4, 4:3, as well as versions in landscape or portrait orientation. In addition, screen sizes and resolutions from 7-in., 800 x 400 pixel resolution up to 24-in., 1920 x 1080 pixels are available with numerous variants in between for maximum flexibility for the application. While multi-touch functionality isn’t yet a "must have" for most industrial applications, HMI users are increasingly influenced by consumer electronics technology with multi-touch so the demand for industrial equivalents will continue to grow. 

HMI leverage

Machine builders that are able to leverage the connectivity, troubleshooting and multi-touch technologies now will establish better practices for end users and will have at least a temporary competitive advantage over much of the competition in the areas discussed previously. Over time, the benefits and savings will become better known by end users and ultimately, the preferences of today will become the requirements of tomorrow.

– Reid Beilke is industrial PC product specialist, Beckhoff Automation. Edited by Mark T. Hoske, content manager, CFE Media, Control Engineering,


Key concepts

  • Human machine interface hardware and software involves look, function, and connectivity.
  • Open, "vendor-neutral" connectivity solutions such as the OPC UA (Unified Architecture) communications model help.
  • The modern HMI and OPC UA can help serve as a conduit that connects the user to the machine, the plant floor, to the MES layer and other higher level enterprise systems and back again.

Consider this

Are older HMIs that still work costing you missed opportunities?

For more information: 

ONLINE extra

See related HMI articles below.