The Case for and Against Legacy SCADA and HMI systems

Posted: 16 March, 2021

It's not uncommon for SCADA and HMI systems to run to the point of failure, but is that really the best way to ensure future growth and stability? It's long past time for companies to evaluate how much their legacy systems may be costing them in terms of reduced productivity and long-term stability. It's entirely possible to update legacy HMI and SCADA projects to better, more stable software, without undoing all the hard work of designing the system in the first place.

There are some cases in which it makes sense to keep legacy systems operational. Updating the system may not be worth the cost of buying new hardware, or newer and better hardware may not be available in specific niche industries. Legacy analog systems can be made more secure than modern systems that rely on remote accessibility and cloud access. There is also an argument to be made that the time and work invested into legacy systems may outweigh the benefits of new development.

However, few of these arguments hold up in the case of critical infrastructure systems. The longer a system uses obsolete or outdated hardware and software, the greater the chance that it will experience a critical failure that cannot be repaired because parts for the machine are unavailable, or because qualified technicians no longer exist for it.

There are many benefits to updating an older system, even if the development costs are significant. Modern HMI and SCADA systems offer security updates for known exploits that may not have patches in older versions. They support more stable and more powerful operating systems, and are able to offer tools for better graphics and the ability to communicate with both old and new hardware. New features such as better trends, recipe and batch control, alarm management, and web capabilities may also bring far greater efficiency to a process.

Paths to controlled updates

There are ways to mitigate the burdens of retrofitting or updating an obsolete system. For example, AVEVA offers import wizards for applications developed in software like FactoryTalk ME/SE, PanelMate, and PanelBuilder, making it easy to bring a legacy system into a modern software platform in order to add features or make changes.

Another way that older systems can be updated gradually is by taking advantage of the wide range of drivers for both older and newer protocols in SCADA/HMI software like AVEVA Edge. By taking a modular approach to machines and adding new devices and hardware to existing systems, it’s possible to draw much more functionality out of legacy infrastructure and easily integrate new features into existing systems.

AVEVA has always taken steps to ensure that upgrading and retrofitting legacy systems is as painless as possible. That’s why even applications built in legacy software like InduSoft Web Studio 1.0 can still be opened and edited in AVEVA Edge.

To learn more about AVEVA Edge, you can take a look at some of the information we have available, including videos on converting PanelMate, PanelBuilder, and FactoryTalk applications into fully compatible AVEVA Edge applications.