What are Human Machine Interfaces and Why Are They Becoming More Important?

As the Internet of Things grows, the way we interact with devices will change—causing a modernization of the interfaces that control them.

Carlos Gonzalez | Sep 16, 2015

Engineering technology is living in the world of interconnectivity. The Internet of Things (IoT) is a dominating trend with industrial and consumer products being connected via the internet. To operate these devices, Human Machine Interfaces (HMIs) are becoming more sophisticated. We spoke to four experts in the world of HMI to help us explain the basics.

• Chirayu Shah, Rockwell Automation, commercial program leader for HMI Software
• Lisa Bettes, Rockwell Automation, product manager for electronic operator interface
• Reid Beilke, Beckhoff Automation, industrial PC product specialist
• Alan Cone, Siemens, SIMATIC WinCC marketing manager

1. Siemens provides a variety of HMI options that include high resolution (800 × 480 pixels), operational safety (metal housing and continuous glass front), and long service life (MTBF of backlighting up to 80,000 hours).

What defines Human Machine Interface (HMI) technology?

Beilke: HMI, in its simplest terms, includes any device or software that allows you to interact with a machine. This can be as simple and ubiquitous as the traditional single-touch display mounted on a machine or as technologically advanced as a multi-touch-enabled control panel or even connected mobile technology such as smartphones and smartwatches.

Shah: HMI is considered an interface that allows humans to interact with the machine. Examples of HMI physical aspects could be a machine with touch display, a push button, a mobile device, or a computer with a keypad.

How does HMI improve current systems?

Beilke: From an industrial perspective, the most valuable aspect of HMI technology is the ability to closely monitor production and respond to changing production demands, which improves efficiency and decreases downtime. These benefits are a result of improved diagnostics and monitoring.

Bettes: A properly designed HMI solution not only enhances productivity for the operator, but also provides line of sight into the system to control or maintain the machine. Alarming is a great example of an HMI function that provides visual indicators of a machine’s issue and its severity.

2. Rockwell’s FactoryTalk View SE provides easy-to-understand display screens that help the operator quickly analyze the current automation operation and interact with any current task or alarm condition.

How does HMI relate to Internet of Things (IoT) technology?
Shah: Traditional HMI solutions were stand-alone, isolated terminals that were deployed by an OEM as part of a machine. New HMI solutions are either pre-configured to send data to the cloud or an on-premise solution. The IoT is changing manufacturing plants. More customers are expecting industrial HMIs to work like their cell phones in the way they interact with them. This is driving a big change in the perception of an industrial HMI and how it is expected to operate.

Beilke: IoT represents a dramatic increase in the number of data points in a machine and factory with vertical connectivity reaching into all number of field devices. With technologies such as Open Platform Communications Unified Architecture integrated into PC-based machine controls, it is possible to safely transmit encrypted data from the machine to the cloud and to enterprise level systems. The ability to push data to the cloud also enables engineers to integrate devices as smartphones or tablets, for example, to monitor machine and manufacturing data remotely, or simply take the HMI anywhere.

Cone: As IoT permeates the plant floor, HMI technology plays an important role in connecting people and devices. For that reason, it is imperative that HMIs offer intuitive visualization options and are easily networked with other components on the plant floor. HMIs should be mobile and offer visibility into operations in difficult-to-access areas. Innovative commissioning and service concepts—including system diagnostics—must be built in.

What are the system requirements for HMI?
Bettes: HMI solutions can be a stand-alone terminal base or fairly distributed for larger applications. The latter can involve server-grade hardware, a Microsoft server OS, and multiple nodes to load balance the application requirements.

Beilke: Requirements for this type of system vary depending on the application, but the display usually implements some sort of touch functionality, as this makes the HMI much more user-friendly; touch-type functions are generally very familiar to users. Think about how many times you utilize two-finger operations on your smartphone or tablet. This kind of functionality is increasingly expected on the machine interface; consumer electronics experiences ultimately temper industrial electronics expectations.

3. Beckhoff’s HMI platform utilizes multi-touch technology, allowing for more than two-finger operations. For example, many of the Beckhoff systems enable up to five concurrent touches at one time for numerous gestures such as dynamic scrolling, zooming, and pinching, among others.

What is the learning curve for using HMI?
Beilke: Because of the mainstream acceptance of smart devices such as your smartphone, tablet, or smartwatch, the learning curve is very low for users. Multi-touch functionality is second nature to most people today.

Where can you implement HMI?
Beilke: HMI is implemented in any industry where human intervention with a machine or automated device is necessary. This could be in a machine, plant, building, or even a vehicle. The level of integration and sophistication may vary, but HMI can be added to just about any application type.

Bettes: HMI is widely used in manufacturing—from the automotive industry to the highly regulated pharmaceutical and food industries. Process industries heavily use HMIs, such as in oil and gas, and mining operations in which many processes are managed remotely from a control room.

Beilke: The rise of Industry 4.0 and the Industrial Internet of Things has made this even easier, as we can turn our smartphones into a form of mobile HMI, and technology such as smartwatches has made HMI wearable, increasing accessibility and ease of use.