Module 15 · Lesson 3

Change control and safe modifications

Manage scope, risk, backups, review, testing, rollback and as-built documentation for control-system changes.

Learning outcomes

Explain the key principles of change control and safe modifications.
Carry out a structured practical check or configuration task.
Recognise common faults, risks and evidence needed for diagnosis.

Before you begin

Change request, risk assessment and rollback package.

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

Step-by-step learning

Describe the reason, affected assets and expected benefit.
Assess safety, process, cybersecurity and operational risks.
Back up all affected configurations and define rollback criteria.
Implement, test, monitor and update drawings/software records.

Ian's practical tips:

Small “temporary” changes are often the ones that escape documentation.
A rollback plan should be executable under pressure.

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.