Human machine interfaces (HMIs) have come a long way since the days of buttons and flashing lights. Today's versions offer full-color, high-resolution displays with multi-touch gesture functions. It's not just the outward appearance that has changed. Devices provide advanced functionalities like data logging, data transfer, and backup and restore capabilities. They assist in troubleshooting and repair, and even support remote connectivity. In an industrial marketplace that demands flexible solutions, modern HMIs offer OEMs and end-users and increasing number of options to streamline operations and control costs.
In manufacturing, it comes down to simple mathematics: If you're not making a product, you're losing money. This is the driving force behind factory visibility. Companies want to mine data from smart components and networked machines to gain real-time insight into their operations. If there’s a problem with the equipment, they want to diagnose and repair it quickly. Better yet, they want to identify problems early enough to address the issues in a strategic fashion, before components fail and impact throughput.
This has led to an increasing focus on intelligent, multifunction, networked components. Modern HMIs are a part of this evolution. They have processors and onboard memory that enable them to do much more than just display current system values. They present data in context, enabling the viewer to understand meaning and trends in order to predict what is likely to happen next (see figure 1). As part of a factory visibility architecture like e-F@ctory, intelligent HMIs significantly increase overall equipment effectiveness (OEE).
Making maintenance easier
Real-time feedback equips organizations to shift from preventative maintenance to predictive maintenance. Instead of running components to failure or swapping them out early, organizations can monitor performance for indicators of problems. If the torque requirement of an axis changes, for example, it could indicate the start of lubricant breakdown. Repeated positioning errors can mean that the motor or load have gone out of alignment. A quick response can prevent downtime. The question is how to get the information in the hands of staff who are in a position to act on it.
A common scenario today is for smart, networked components to send alerts to the maintenance department. All too often, however, maintenance teams are spread thin, with a handful of people struggling to keep up with the demands of facilities several hundred thousand square feet in size. Multifunction HMIs can notify the operator of anomalous behavior the moment it occurs, along with detailed instructions on how to respond.
Fast fault recovery
There’s a world of difference between conditions that need treatment at leisure and failures that demand an immediate response. One of the core benefits of an intelligent HMI is its ability to display alarms based on real-time feedback. Consider a line that shuts down as a result of a door ajar somewhere on the machine. There was a time the HMI would have just shown an error code and the rest would have been left to detective work. Circling equipment to check all of the doors doesn’t present much of a problem for a tabletop blister-packing machine encapsulating antibiotics but for a two-story, 100-foot-long printing line, downtime can stretch out for a long, expensive time while operators check door after door to find the one that triggered the alarm.
With today’s intelligent, connected machines, a sensor on the open door sends a signal to the PLC, which relays it to the HMI. The HMI, in turn, shows an alarm, along with a 3-D rendering of the machine highlighting the problem door, courtesy of the full-color, high-resolution display.
In the case of a more challenging error, operators can once again access a PDF from the HMI. If there’s a problem with a servo motor, for example, the operator can follow the instructions on the screen to adjust or even replace the device. They don’t have to wait for maintenance or look around for operating manuals. HMI displays real-time feedback, diagnoses the fault and guides the operator through the repair to get the equipment back up and running.
The combination of storage and connectivity enables smart HMIs to support backup and restoration functions to simplify swapping out components. The PLC, for example, can be figured to back up to the HMI memory on a set schedule. When the controller fails, staff replaces the device, then loads the code directly from the HMI to get the system up and running very quickly. There is no need to back up changes to a computer hard drive and manually upload it at installation. Once again, it comes down to speed and efficiency. Less downtime means more time spent manufacturing product.
Of course, not every error is something that can be resolved by the operator. Inevitably, circumstances will arise requiring intervention by maintenance or the machine builder. Here too, real-time feedback served up by the HMI can speed return to service. Fitted with SD cards, the units can serve as data loggers, capturing activities and events that take place over the course of a shift. That can provide immediate feedback to the operator in the event of a fault, but maintenance can also take advantage of it to view machine response during troubleshooting and repair. Data can be even more valuable after the fact. If downtime occurs on the night shift, for example, the data log can be used in forensic analysis to identify root causes. If one shift consistently outperforms the others, management can view and analyze activities to understand how to duplicate the results with the rest of the organization.
Enhanced access
Modern HMIs go beyond mere control interfaces to act as engineering access points to the rest of the machine. There was a time connecting to a PLC or drive, for example, meant bringing a laptop and cables down to the floor and opening up the cabinet or climbing around on the machine to get to the device. HMIs with USB ports provide an easier option. Technicians can plug in with a basic cable and update the programming on the PLC or tune the drive without ever opening the cabinet door.
Devices with higher levels of functionality take it one step further. Instead of just simplifying connectivity, some HMIs allow staff to access the PLC logic directly through the HMI itself. They can tune drives, review encoder output, and accomplish a variety of other tasks. The days of running back to the office for a laptop are gone; maintenance can monitor the software to identify the cause of the fault or even make changes without any need for a computer.
In these days of 24/7 operation, crises can happen at any moment. Mobile applications via Web servers can enable end users, OEMs, and integrators to view the HMI from across town – or across the globe. The ability to monitor and control the machine as though they were right in front of it provides a powerful tool for handling faults and out-of-spec conditions.
Real-time feedback can enhance productivity and reduce the cost of operations, but only if organizations are able to leverage it effectively. Intelligent HMIs provide a number of tools and capabilities to put data in the hands of those best equipped to take advantage of it. Find out what the latest generation of HMIs can do for you and start saving today.
Meet the tools: GOT2000
The GOT2000 family of graphic operation terminals provides tools to leverage real-time feedback as part of a factory-visibility architecture like Mitsubishi Electric’s e-F@ctory. Although the product line includes modest versions for more basic applications, the top-of-the-line GT27 features a full-color display with XGA (1024x768) resolution and multi-touch gesture functions. A variety of standard interfaces and communications protocols make it easy to interface with both machine and enterprise networks. It includes GOT Mobile, which enables it to be accessed remotely by mobile devices. With data logging capabilities, as well as image recording, image playback, video image input, and RGB output capabilities, the controller has the functionality to support on-the-spot troubleshooting diagnostics and repair. Find out more here.
Further Reading
e-F@ctory
GOT2000 Catalog
