Learning outcomes
- Explain the key principles of functions, data structures and reusable code.
- Carry out a structured practical check or configuration task.
- Recognise common faults, risks and evidence needed for diagnosis.
Module 7 · Lesson 3
Functions, data structures and reusable code
Use functions, function blocks, arrays, structures and libraries for maintainable projects.
Before you begin
Programming standard and sample project.
Safety: Use site procedures, approved test equipment and competent supervision. Never bypass a protection or interlock without formal control.
Step-by-step learning
- Create a reusable motor or valve object with command, feedback, alarms and status.
- Use structured data to group related signals.
- Version and document library blocks.
- Test block behaviour independently before deploying widely.
Ian's practical tips:
- Reusable code saves time only when interfaces and version control are disciplined.
- Avoid hidden global dependencies inside supposedly reusable blocks.
Fault-finding questions
- What should be happening, and what evidence proves it?
- Where is the last known correct signal, voltage, state or process condition?
- What changed immediately before the fault?
- Can the system be divided into smaller testable sections?
Practical activity
Create a one-page test record for this lesson. Include expected values, measured results, equipment used, risks controlled, defects found and the final proven condition.