Controls obsolescence rarely announces itself. It accumulates quietly until an unplanned failure forces a decision on the worst possible day. This self-audit helps you put a rough number on that hidden exposure for a specific machine. Score each signal, total it up, and see where the machine lands.
How to score
For each signal below, give the machine the points shown if it is true. Add up the total at the end.
Platform and parts
- PLC or control platform is discontinued by the manufacturer — 3 points
- Replacement processors or modules are difficult to source / back-ordered — 3 points
- You depend on refurbished or secondary-market control components — 2 points
- Programming software requires an obsolete computer or operating system — 2 points
- The OEM has ended support for the control platform — 2 points
Documentation and knowledge
- The PLC/HMI program source is missing — 3 points
- The program exists but is undocumented or not understood — 2 points
- Electrical drawings are missing or badly out of date — 2 points
- Only one person really understands the control system — 2 points
Behavior and dependency
- Recurring faults cluster around the controls (not the mechanics) — 2 points
- A controls failure would stop a critical, hard-to-replace line — 3 points
- Upgrades or data/diagnostics you want are blocked by the aging controls — 1 point
- The machine is mechanically sound and still productive — 1 point (this raises the stakes: the asset is worth protecting)
Total your score
- 0–6 — Low exposure. The controls are not an immediate risk. Keep an eye on parts availability and documentation, and re-audit periodically.
- 7–14 — Moderate exposure. Real obsolescence risk is accumulating. This is the window to evaluate and plan on your schedule — before a failure sets the schedule for you.
- 15+ — High exposure. The control system is a significant unplanned-downtime risk on a machine that may well be worth keeping. A formal evaluation is warranted sooner rather than later.
What a score does and does not tell you
A high score does not automatically mean "modernize." It means the controls carry enough obsolescence risk that the machine deserves a real evaluation — which might still conclude keep-and-monitor, or (if the machine itself is near end of life) replace. The audit measures exposure, not the answer. The four outcomes — keep, modernize, sell, replace — come from evaluating the actual asset.
Why exposure is worth acting on early
The theme running through every high-scoring signal is the same: unplanned failure. Obsolete controls do not fail on a convenient schedule, and the cost of a forced, unplanned outage on a critical line dwarfs the cost of a planned evaluation. Scoring the risk is how you get ahead of it.
Before you replace the machine, understand your options
If this self-audit put your machine in the moderate or high range, the next step is to turn a rough score into a real picture. A Modernization Assessment evaluates the actual controls and the whole asset — so you can act on evidence while the decision is still yours to plan.