Standardizing control room HMIs
The operator interfaces to control manufacturing systems have grown from push buttons and lighted switches to today’s computerized and engineered HMI touchscreens that control virtually every part of the manufacturing facility. Sophisticated graphical interfaces with 3D representations of equipment, HMIs provide a window into the controls and/or manufacturing intelligence system. Unlike controller code that is seen by few, anyone can see the HMI.
As the manufacturing industry moves rapidly into the virtual, paperless era, the standardized working environment for managing manufacturing operations requires tools such as HMI 3D visuals and flat screen monitors in control rooms and at strategic points throughout the facility. Imagine a plant with large flat screens at key locations and standardized HMI screens at every control point for process and production. The entire plant becomes a virtual control room. It is becoming the norm, not the exception.
Today’s manufacturing environment demands a leaner workforce, higher machine and system efficiencies, greater flexibility, and increased productivity and quality targets, which sets the stage for the highest efficiency in standardized HMI performance for operational excellence.
HMI system standardization
Standardization involves graphic standards, naming conventions, and application design concepts—a consistent look and feel to promote greater efficiency on the plant floor. It is the best practice of applying easily recognized visuals to increase the productivity at the point of use. As standards become applied on an enterprise scale, overall benefits multiply.
At the system and machine level, standardization provides consistency to promote user confidence with regard to expectations on how things operate. For example, a button that takes the user back to the main menu should be placed in the same location every time it is used. If the location varies from screen to screen, confusion and inefficiency prevail. In addition, if controls for seldom-accessed devices work the same way as those for frequently accessed devices, then the user will have a basis on how to interact with them.
At the site level, users who move between manufacturing systems understand how controls work regardless of assignment. Consistent controls between manufacturing systems benefit operations by allowing them to efficiently work on multiple systems more seamlessly. In addition, maintenance benefits from consistent troubleshooting capabilities across the systems. For example, a motor fault on Line A is reported and reset exactly the same way as on Line B. Finally, consistent HMI systems reduce training effort for both students and trainers.
The maximum benefit of HMI standardization is realized at the enterprise level. Users who move between sites know how to operate and troubleshoot more efficiently. Training and documentation become even more efficient. And, from a development perspective, operations with the proven best practices can leverage solutions across the enterprise. For example, Plant A may have more experience on the process while Plant B has more experience on packaging. Plant A can leverage process solutions for both sites while Plant B leverages packaging solutions. Standardization allows both plants to share solutions and maximize the capability across multiple sites.
The result is a seamless workflow for the workforce to operate at the highest level of performance. The standardized HMI also facilitates fast and easy training on changes or updates, and new employee training is consistent across the entire workforce.
The three most important benefits of standardized HMI are:
- Increased productivity: The ease of use and functionality of HMI systems will increase overall equipment effectiveness and workforce productivity. The updated control system makes it easier to start, stop, troubleshoot, and make changes in production.
- Easy-to-understand technology: In addition to increased productivity for operators, other tasks improve as well. Training, troubleshooting, and line changes are simplified. A trained line operator can walk up to the HMI at any time and easily understand what is going on in a particular stage of production. Applied programming standards make it easy for users to dig deeper into the controls through the HMI to receive more information about a situation.
- Cost efficiency: The return on investment for HMI standardization is quickly recaptured through the efficiency it brings to operations through reduced downtime for equipment issue resolution and changes, and increased productivity by operators, maintenance, and engineering.
It’s important to focus on an efficient HMI design that functions well and looks good. Flashy animations and software might look impressive in an HMI demonstration, but they don’t contribute to the HMI’s effectiveness. In fact, they slow down the operator’s navigation to devices and information. It is an HMI best practice to turn data into actionable information.
On next page, learn more about programming standards, 3D HMI, and next generation HMI.
The ability to achieve the same look and feel across platforms isn’t a luxury, it’s an operating necessity. Good HMI platforms are often driven by end users to integrate with their currently installed systems.
Standardization translates into sustainable efficiency with regard to development. The platform provider tends to have well-defined and more rigid HMI standards to minimize costs, while some system integrators also have well-defined HMI standards with more flexibility to accommodate the customer’s requirements. It is possible to blend flexibility and standardization with an 80/20 approach: a standard that accommodates 80% of provider standards with 20% for project-specific requirements. Applying standards at the proper level of granularity is vital to this approach. In addition, proven standards can be deployed across different software platforms for maximum flexibility.
Because the HMI and controller devices work closely together, HMI standards advance additional efficiencies through controller programming standards. Consistency on the graphic and logic sides further reduces effort and provides more time for the 20% project-specific requirements. This leads to enhanced code reusability, which significantly reduces application development effort. In the same way that standards help the customer to leverage consistent experience in the enterprise, standards also help developers to not reinvent the wheel and apply industry expertise effectively.
Beyond application development, standards facilitate documentation and training. Standard documentation and training materials can be developed for the 80%, forming a module—complete with graphics, controller code, documentation, and training materials. These modules can form the basis for a comprehensive application development library.
A top-down view of a production line is typical in an HMI. However, when the line contains a spiral or multilevel conveyor, a top-down view will significantly diminish the power of the HMI for appropriate line management. Ideally, an HMI should be capable of viewing the line from the side, and at different angles and levels—with the ability to zoom in at any point. This provides operators and technicians with the ability to clearly see what is happening on the entire line from the perspectives they need to make better decisions and changes. In addition to multiple views, the 3D approach provides an opportunity to use additional graphical techniques to add clarity to complex equipment arrangements:
- Equipment can be hidden for a particular view so the HMI screen can focus on the components that are important.
- Equipment can be rendered transparent to provide common reference points without being distracting.
- Cutaways, elevations, and key views can be generated to add additional clarity as needed.
- Use of a model allows changes to be made one time. Multiple affected views can be regenerated quickly, saving time.
Next generation HMI
The new software and hardware technology available today presents the opportunity for the next generation HMI to provide information, not just data. It has flooded users with data, but the challenge is extracting actionable information at the point of use.
The flexibility of the HMI can bring the information to the operator anywhere on the plant floor, and the large flat panel displays or scoreboards on the plant floor bring information to users where needed. With a glance, users can understand how the line is performing, display faults, warnings, quality issues, and performance to established key performance indicators (KPIs) and production goals. This real-time information allows the operator to make the appropriate decisions and changes to meet or exceed targets.
Other interactive interface devices, such as smartphones and tablets, connect with the same customized and standardized view of actionable information delivered to those who need it, where they need it, anywhere in the enterprise. Smartphones provide a window into KPIs, critical faults, and quality issues, allowing the ability to make higher level decisions for overall operational excellence.
Tablets provide mobile wireless HMI for diagnostics and troubleshooting. Using a tablet as a troubleshooting tool puts the HMI where the technician needs it, typically on the plant floor and always on the move.
Workflow software provides a logical extension to the HMI. The HMI provides a here-is-what-is-happening, here-is-what-is-wrong view. Shared workflow provides the now-what to the equation for information on the location of the root cause of the alarm or quality issue, and the action to take to correct it. The addition of standardized workflow in next generation HMIs raises the level of operational efficiency to the next level.
Workflow can be applied in several different ways:
- Standard operating procedures: Streamline and send a consistent message on how things should be done
- Changeovers and machine setup: Track critical planned downtime events and provide feedback to increase efficiency when not in production
- Online reference and documentation: Provide relevant reference information at the appropriate time and place; supplement training with quick references, single point lessons, and interactive tutorials
- Fault correction: Provide troubleshooting procedures for machine stops, quality issues, and performance deviations.
Data gathered from the workflow provides an electronic record of what happened when to ensure procedures are being followed. This helps close the loop on continuous improvement initiatives.
Supported by a smart HMI, and armed with and actively broadcasting information, operators and technicians can move seamlessly through the facility with confidence to keep production at the highest level. Workflow augments training by providing real-time and pertinent access to standard procedures, troubleshooting guides, and valuable reference material. Automated escalation of critical faults and quality issues ensures that the right people are informed at the right time to take right action.
The next generation HMI creates an environment where operators and technicians are moving with the speed of manufacturing and looking ahead to make decisions to impact the bottom line of the business.
Chris Parkinson is a control systems engineer at Polytron Inc., where he has worked for nearly 20 years. He is a graduate of Georgia Institute of Technology and specializes in HMI and data tracking solutions.