Module 15 · Lesson 1

Control narratives, I/O lists and functional design

Turn process requirements into testable control narratives, cause-and-effect tables and I/O definitions.

Learning outcomes

Explain the key principles of control narratives, i/o lists and functional design.
Carry out a structured practical check or configuration task.
Recognise common faults, risks and evidence needed for diagnosis.

Before you begin

Process description, P&IDs and stakeholder requirements.

Safety: Use site procedures, approved test equipment and competent supervision. Never bypass a protection or interlock without formal control.

Step-by-step learning

Define normal modes, sequences, permissives, trips, alarms and fallback states.
Build an I/O list with tag, type, range, units and fail state.
Create cause-and-effect tables for critical events.
Review the design with operations, maintenance and safety personnel.

Ian's practical tips:

Ambiguity discovered on paper is cheap; ambiguity discovered during commissioning is expensive.
Write requirements so each statement can be tested.

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.

I completed the lesson activity. I checked the result safely. I can explain the fault-finding approach.