In this guide
Every automation product eventually leaves the catalogue. A plant that runs for decades will meet this repeatedly, and the choice is whether to meet it on your own schedule or at 02:00 with a machine down.
Lifecycle stages
Manufacturers describe lifecycle differently, but the pattern is similar:
| Stage | What it usually means |
|---|---|
| Active | Available to buy, fully supported |
| Phase-out announced | Still available, with a successor named and a date for the end of sales |
| Discontinued | No longer sold new. Spares and repairs may continue for a defined period |
| Obsolete | No manufacturer support. Parts come from stock, the used market or repair |
Look up the exact status and dates on the manufacturer's own site. They change.
Step 1: audit what you have
List every controller, drive, HMI and power supply on critical machines, with full order numbers and versions. Photograph labels if you have to. You cannot plan for parts you have not identified. The spares register template in our resources gives you the columns to fill.
Step 2: rank by consequence
Rank each part by what happens when it fails, and how long a replacement takes. Parts that stop a line and take weeks to source are your first priority.
Step 3: choose a path for each
- Hold spares: right for parts that are reliable and still obtainable, and where an upgrade is not yet justified
- Last-time buy: if a part is about to be discontinued, buy what the remaining life of the equipment needs
- Migrate: move to the current successor while the old part is still available, so that you can test and commission calmly
- Run to failure: only for non-critical parts, with a plan
Step 4: protect the software
Hardware is half the risk. Keep current backups of every program, with the matching engineering software version, licence details and firmware versions. A spare CPU is useless without the program to load.
Step 5: revisit it
Lifecycle status changes. Review the register once or twice a year and after any major change to the plant.
Partial migrations
A full plant upgrade is rarely practical. Many sites replace the controller or the drives first, keep the field wiring, and migrate in stages. An engineer can help you work out a sequence that limits downtime.
Send us your list of part numbers and we will tell you what we can source, what has long lead times, and what looks risky.