Standardizing control room HMIs
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.