Aging control systems often suffer from lost documentation, lack of support, limited availability of parts, poor performance, and a general loss of efficiency. For every organization struggling with their outdated control systems, there comes a point when you can no longer avoid the discussion around maintaining versus upgrading.
While the process of upgrading your control system can seem daunting, it doesn’t have to be. Diligent planning can make this process manageable and mitigate the risk associated with upgrading a control system. Here are three steps to planning your upgrade:
- Determine your upgrade approach
- Prioritize your upgrades
- Assemble an upgrade plan
Let’s take a brief look at each of these steps.
Determine Your Upgrade Approach
At a high-level, control system upgrades can be classified as two types—hardware-only and hardware/software obsolescence migration. Hardware-only obsolescence migration is the lower cost option, which may be inherently appealing. However, because this method forces the new hardware to continue using the previous hardware’s software, you may not see the boost in efficiency or functionality you are looking for. This option should only be used if the system will not gain additional value with software upgrades or if the system is scheduled to be decommissioned in the next few years.
The preferred upgrade method is to perform a more complete hardware/software obsolescence migration. Not only is the hardware upgraded, but the programmable logic controller (PLC) program is rewritten, incorporating modern software practices.
The hardware/software approach is usually a more extensive, higher-cost, and higher-risk approach; however, the benefits should far exceed those of a hardware-only migration for systems that will be in use for three or more years after the upgrade.
Software used in the 1990s compared to typical high-performance human-machine interface (HMI) used today.
Prioritize Your Plant’s Upgrades
To make the process of a control system upgrade more manageable, it’s best to think about your control system as a number of smaller subsystems that make up one cohesive unit. This makes it easier to identify and prioritize the systems that need upgrading rather than thinking about a full system revamp. For example, can you replace a few PLCs without replacing the entire supervisory control and data acquisition (SCADA) system, or vice versa?
Additionally, as the Industrial Internet of Things (IIOT) continues to expand, and plant floors are becoming increasingly interconnected, using modern data connectivity methods is increasingly important. Therefore, at this point, you should also determine if your existing system is using outdated forms of technology that could be putting you at a competitive disadvantage.
Assemble an Upgrade Plan
With many stakeholders needing to be involved in a control system upgrade, and each one having different key concerns, putting together an upgrade plan is not always an easy task. Some questions to help get started with a productive interdepartmental discussion should include:
- Does high-level management have long-term plans that will impact the viability of the project
- What capital dollars could be available for an upgrade?
- Does the operations team have direction that the upgrade is a priority, and the impact to production can be anticipated and expected?
- Does the maintenance team fully understand the long-term goal of the business needs?
- Does the IT group have policy and technology in place that could be an asset to the project or a hurdle?
With prior proper planning, the process of performing a control system upgrade can be greatly simplified.
Learn more about how to properly plan for your control system upgrade as well as key risk mitigation strategies to employ during your upgrade in the white paper, Five Risk Mitigation Techniques for Control System Upgrades.