How often a spectrophotometer should be certified
At the start of each shift, check the instrument on its own tile. If that fails, do not use this instrument’s numbers. Send it back to the maker or follow the maker’s interval for calibration; twelve months is common. If the contract wrote shorter, follow the contract. A passing tile check does not skip the yearly calibration.
At the start of each shift, check the instrument on its own tile. If that fails, do not use this instrument’s numbers. Send it back to the maker or follow the maker’s interval for calibration; twelve months is common. If the contract wrote shorter, follow the contract. A passing tile check does not skip the yearly calibration.
Two kinds of check
The tile is the instrument’s own white or a small set of patches, used to see whether this day has drifted. It takes minutes, so it sits at start-up. It will not catch an expired certificate or a geometry change that needs a lab comparison. Yearly calibration, or the interval in the contract, is what yields a certificate you can show a customer.
Two instruments can both “pass the tile today” and still sit apart. Tile pass only says this unit is steady against its own tile.
When you must not measure production
| Situation | Can you accept with it | Action |
|---|---|---|
| This shift’s tile not done | No | Do it first |
| Tile failed | No | Take it out of service; swap or send for repair |
| Tile passed, certificate expired | Process may look; acceptance follows the contract | Calibrate first |
| Certificate in date and tile passed | Yes | Write both |
When you record, write
- Tile result and date on the first report of the day.
- Certificate expiry next to the instrument.
- Do not delete a fail. Write which instrument you switched to.
