What is control logic?
Control logic is the software that determines how an industrial machine or process behaves. It reads operating conditions, evaluates modes and permissives, coordinates sequences, regulates process values, issues commands, and decides how the system responds to a fault. The program may run in a PLC, PAC, DCS, DDC controller, SoftPLC, industrial computer, or purpose-built controller.
When does control logic need maintenance?
Control logic requires maintenance when its behavior does not align with requirements, or when its operating context changes. For example, an operator might notice unexpected behaviors or sequences that occur seemingly at random. A sensor might need replacement, but the original model is no longer manufactured. New management policies and production standards can invalidate assumptions embedded in the controls of your older machines.
Production changes can also require updates to control logic. Increasing line speed or throughput may require adjustments to existing timing and permissives. Introducing a new product or packaging format might require additional recipe parameters and changeover logic. New operating modes, such as clean-in-place cycles or automated idle states, may also need to be implemented.
How can we help?
Working with existing control logic can be difficult when documentation is missing, original developers are unavailable, or programming tools are obsolete. Even with access to the source code, incomplete documentation and interactions between connected systems can make it difficult to understand the consequences of a change.
Working in these low-information environments is our specialty. We help you analyze, troubleshoot, modify, and modernize control systems without relying on continued OEM support. We document the changed logic and test it away from production where possible. We also establish acceptance and rollback criteria for the production transition. Your organization can then understand and continue to maintain the control logic.