Modern manufacturing environments grow more sophisticated by the day thanks to ubiquitous Internet connections, networked sensors, and smart machines and instruments. These networks, collectively known as the Industrial Internet of Things (IIoT), provide the means to control industrial equipment from a distance and gather useful data on their condition and operation. HMIs — human-machine interfaces — are the critical link between the machines doing the work, the programmable logic controllers providing instructions, and the people overseeing them. Here’s a crash course in unlocking manufacturing data and the potential of the IIoT using HMIs.
What are HMIs?
Manufacturers already generate reams of data on a daily basis. They just might not be gathering or exploiting it. Raw data is available from many sources, including:
- Machine condition data from sensors to evaluate the efficiency of the machine and whether repair may soon be necessary
- Data from material handling equipment concerning the pace of operations, levels of raw materials, and any other observable bottlenecks
- Product inspection data to track defect rates and pinpoint where errors are occurring on the factory floor
- Data from vehicles and satellite facilities to help optimize deliveries or sync operations with vendors and business partners
HMIs — human-machine interfaces — are the critical link between the machines doing the work, the programmable logic controllers providing instructions, and the people overseeing them. (Image: via mitsubishielectric.com)
Smart sensors and equipment “report to” and receive instructions from programmable logic controllers (PLCs). PLCs instruct networked industrial equipment to carry out condition monitoring, counting, and timing functions, deliver notifications, and perform other simple tasks. They’re a rich source of data throughout a connected manufacturing facility.
However, this data isn’t useful if it doesn’t go anywhere. Human-machine interfaces provide a way to send this data to the parties who will find it most useful. These specialists can then view and act on that data using a visual interface.
Smart industrial equipment requires two things. First, they need a set of instructions and monitoring capabilities. PLCs and sensors provide this. The second thing they need is a user-friendly way for handlers to access information and intervene or make changes. That’s where HMIs come in.
What are the types of HMIs?
Industrial environments have historically used HMIs in the form of Windows-based PCs situated throughout the facility. However, more modern solutions include smaller and lighter “embedded” HMIs. These are oftentimes little more than a single logic board equipped with a touch screen or even just LED indicators.
Manufacturers typically use one or more of the following types of human-machine interfaces:
- Overseer: Complex manufacturing environments require complex connectivity. Overseer HMIs provide multiple Ethernet connections and typically run on Windows. Overseer HMIs are the right choice for facilities that use MES (Manufacturing Execution Systems) or SCADA (Supervisory Control And Data Acquisition).
- Data handlers: If a manufacturer requires real-time data acquisition to facilitate instant feedback and decision-making, data handlers are the right choice. Data handlers reveal data trends and information on equipment alarms. As a result, they typically feature color LEDs with plenty of real estate to dive into graphs and other visual representations.
- Push-button replacer: Some manufacturers think these “analog” solutions are on their way out the door. For some applications, that’s true. For other manufacturing environments that don’t need the functionality of a touch screen, push-button replacers provide convenient, simple, “no-look” interactions for responding to equipment alerts.
Manufacturers may use any one of a number of different communication protocols for networking their IIoT devices, PLCs and HMIs. These include IP/Ethernet, DeviceNet, Profibus, Modus, and others.
More modern solutions include smaller and lighter ’embedded’ HMIs. (Image: via emcourse.com)
How can manufacturers unlock their data using HMIs?
Smart diagnostic instruments, analog instruments (measuring pressure, temperature, flow, and more), embedded sensors, and servo motors are all examples of manufacturing floor assets that benefit from connections to PLCs and HMIs.
HMIs unlock the potential of the data they gather. HMIs store and present data as an easy-to-understand interactive visual, but they also serve as access control devices. Only authorized personnel can read and act upon the data provided by field devices.
Depending on the application, the HMI may store only “exception” data. That means it may only begin logging information when it detects a problem.
As data is collected and organized, the HMI may keep it local or it may send the data to the cloud. Once it’s streamed off the factory floor, this data is useful in enterprise resource planning platforms and may be further analyzed using machine learning.
Here are some of the applications and advantages of using HMIs in a manufacturing setting:
- Deliver advanced warnings for preventive maintenance: HMIs can gather every data point or only those concerning process exceptions. In both cases, HMIs provide real-time preventive alarms for machine conditions. This way, operators are made aware of malfunctions or other problems that could halt production, before it actually does so.
- Provide data on machine failure: If a piece of equipment does fail unexpectedly, HMIs provide access to data that helps pinpoint where something went wrong. This could be data on circuit breaker trips, activated emergency stops, isolated power losses in equipment, or open gates and apertures. The machine won’t start again until the operator addresses the failure.
- Messaging for inventory levels: Manufacturing environments require steady access to inventory items, disposable supplies, and raw materials. HMIs can alert operators about things like low fuel levels or dwindling supplies of raw materials before they run out completely. This helps keep operations running smoothly.
- Safe and central control of various plant functions: Safety is one of the best benefits of using IIoT devices and HMIs. Well-placed HMIs with full-featured touch screens allow operators to see a holistic view of the manufacturing plant. This means they don’t have to enter production areas or subject themselves to unsafe conditions to make changes or gather information.
HMIs unlock the potential of the data they gather. (Image: via epectec.com)
Understanding the potential here requires an example.
Think of the process of manufacturing bricks. It requires a constant flow of materials, machines to move, refine, and process those materials — including mixing and batching — as well as additional equipment to shape and handle works-in-progress and finished products. The final step is quality control. Each brick must meet known parameters for appearance and material density.
This type of large-batch manufacturing requires immediate attention to defects and compromised machinery. Monteiro Tijolos, a Brazilian brickmaker, needed a scalable IIoT solution to oversee each of these processes, and they needed a way for operators to intervene quickly any time exceptions were discovered. After implementing HMIs to deliver charts, visuals, and machine intelligence, they saw their overall production rise by 50 percent.
Getting the most out of HMIs in manufacturing
Ultimately, HMIs are most useful when they’re doing the “thinking” for us. Machine learning — and what some call “explainable AI” — is an important component here. The best HMIs for manufacturing don’t just display raw data. They must also provide interpretations of that data.
In other words, connected manufacturing assets today and into the future won’t just “talk” about their condition or performance using HMIs — they’ll also be able to explain it. It’s not a stretch to say that the combination of machine learning and human-machine interfaces is the future of the manufacturing industry.
Some factories already realize this vision with entirely automated factories. In cases like these, human-machine interfaces deliver data over a distance, rather than requiring immediate physical input on the factory floor.
Choosing the right HMI solution from among a growing lineup of vendors requires manufacturers to honestly evaluate the types and amounts of data they need to gather and the level of intelligence they require. The end result is a smarter, faster, and more competitive manufacturing business.
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