Human-machine interface (HMI) migrations seem to be a constant churn that never really feels complete. Even if you were to standardize on a single vendor, that vendor would inevitably have several different product lines that come in a variety of sizes with several different button layouts. Once you finally wrap your head around the options, a new generation is out, adding another layer to the obsolescence totem pole.
We’ve worked with clients that manage to implement site standards that dictate the vendor, model and even size of any physical HMI. Some clients even go as far as defining lifecycle terms and the process for migrating to another generation within the product family. The plans are never bulletproof, though. What happens if the aspect ratio changes and the panel cutout size is different? What do you do about OEM equipment that comes in with HMI choices that are all over the place? How do you manage an inventory that has thousands and thousands of dollars of physical HMIs and that looks like something out of an automation museum?
These issues only cover a single aspect of problems surrounding thick clients. Thick clients often have operators, engineers and administrators sharing a single logon for everything. It becomes nearly impossible to control who has access (raise your hand if you have seen or currently have sticky notes on your HMI with the login information), let alone keep a log of who exactly is signing in and what is being done. This ranges from a mild headache to non-compliance in certain regulated industries.
When considering the quickening release schedules, inventory maintenance costs, and lack of robust electronic records, physical HMIs become a prime target for modernization. Separating the application and hardware layer by moving to a server-client architecture is the first step in this journey. Adding thin clients to the mix takes the whole process to the next level. With tools such as ThinManager available, a lot of the difficulty of setting up a thin-client architecture has been eliminated.
Several integrators, Panacea included, have developed a standard service offering to evaluate a physical HMI install base, discuss modernization options, develop a risk mitigation plan, and execute migrations with little to no downtime during the switchover. The evaluation phase is arguably one of the most important phases because it helps internal engineering teams or Integrators develop a plan to merge the islands of automation into a single platform. We often find that there are different standards, libraries and design methodologies used across a plant, so having a solid plan for creating parity across all screens/libraries with minimal impact to the operator is a top consideration.
Modernizing physical HMIs to a server-client architecture brings a whole host of benefits to your operation outside of shiny new metal and plastic. Increased mobility, longer lifecycles, better defined migration paths, increased regulatory compliance and increased security are just a small cross-section of benefits you’ll find by making the leap to thin clients. As our plant architectures continue to age, modernizing your HMI install base is a low-hanging fruit with an immediate return on investment that is worth making a top priority.
William Aja is vice president of customer operations at Panacea Technologies Inc., a certified member of the Control System Integrators Association (CSIA). For more information about Panacea, visit its profile on the Industrial Automation Exchange.
