Achieving traceability in PLC software

To reduce the risk of latent errors software development must be carried out using quality assurance procedures and applying the concept of traceability. It should be possible to show how the needs of the user have been satisfied, that the software is free of unwanted functions, and the design is complete. The history of modifications or errors should be recorded to show where changes have affected the design. The programmable controller manufacturers are supplying PC based computer aided software engineering tools working with Windows. This provides the framework for drawing up a quality plan and establishing traceability links