Brownfield SCADA/DCS Migration Risk Plan

Brownfield migrations require risk segmentation more than big-bang replacement. Practical migration planning isolates critical dependencies and proves each cutover step before production exposure.

Common Failure Points

• Legacy integrations are undocumented and discovered late.
• Cutover windows bundle too many technical changes at once.
• Rollback plans are vague or untested.

Control Strategy

• Use dependency mapping to segment migration waves.
• Separate platform, interface, and HMI changes into controlled phases.
• Define objective go/no-go criteria for every cutover.

Implementation Steps

• Build interface test harnesses for legacy protocol validation.
• Run pilot migration on one low-risk area first.
• Rehearse rollback with timed drills before major cutovers.

KPIs to Track

• Cutover defect density
• Rollback execution time
• Unplanned downtime minutes
• Post-cutover support tickets

30-60-90 Day Plan

• Day 1-30: map dependencies and define migration waves.
• Day 31-60: run pilot and validate rollback runbook.
• Day 61-90: execute first production wave with live metrics.