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Required extra fields

The station can remember which tag belongs to which spool by storing two values on the spool in Spoolman, in two extra fields. Spoolman 0.27 and later also has its own tag list, which the station uses as well. The station never creates the extra fields for you.

Do you need them?

Your Spoolman Extra fields
Older than 0.27 Required. Create them once, before you write your first tag.
0.27 or later Optional. The station links each tag in Spoolman's own tag list instead. If the fields exist, the station keeps filling them as well, which helps older station firmware and other tools that read them.

Without the fields, the tag's unique ID is kept only on the tag itself and on the station.

The two fields

Key Belongs to (Spoolman calls this the entity) Type What the station stores in it
nfc_uid Spool Text The permanent UID of the tag that is on this spool.
opentag_instance_uuid Spool Text The unique ID the station wrote onto that tag.

Together they identify one physical spool, even when you own several spools of the same filament.

Steps

  1. Open Spoolman in a browser.
  2. Open Spoolman's settings and go to the extra fields for Spool (the station's own message calls the place "Settings > Extra Fields > Spool"). Spoolman keeps separate extra fields for spools, filaments and vendors (it calls these entities). These two must be Spool fields. Fields created for Filament or Vendor are not seen by the station.
  3. Add a field with the key nfc_uid and the type Text. The display name is up to you, for example "NFC tag".
  4. Add a second field with the key opentag_instance_uuid and the type Text. The display name is again up to you, for example "OpenTag ID".
  5. Check the result from the station's web page: Settings → Integrations → Test. No warning under the Spoolman line means both fields were found.

The keys must match exactly: lower case, with underscores. Leave the fields empty on your spools. The station fills them in when it links a tag and empties them when you clear the tag.

What happens when they are missing

On Spoolman 0.27 or later nothing goes wrong: there is no warning, and writing, identifying and clearing use Spoolman's tag list.

On older Spoolman the station refuses to write or link a tag until both fields exist, and tells you which one is missing:

Spoolman is missing the Spool extra field 'nfc_uid'. In Spoolman open Settings > Extra Fields > Spool and add it with type Text.

When both are missing the message names both:

Spoolman is missing the Spool extra fields 'opentag_instance_uuid', 'nfc_uid'. In Spoolman open Settings > Extra Fields > Spool and add them with type Text.

Where you see it:

  • Browser: under the Spoolman line on the Integrations card in Settings, after Test.
  • Touchscreen: on the "Needs attention" page when you try to write or link a tag. The touchscreen does not check the fields before that.

On older Spoolman a clear is different. The station erases the tag first and checks the fields afterwards, so the tag ends up blank but its link stays on the spool in Spoolman, and the station stops at "Unlink not finished". Add the fields, then tap TRY UNLINKING AGAIN (browser: Retry Spoolman cleanup). See Clear and reuse a tag.

The same message appears when a field exists but has a type other than Text, or was created for Filament or Vendor instead of Spool. Delete the wrong field in Spoolman and create it again as described above.

If something goes wrong

What you see What it means What to do
"Spoolman is missing the Spool extra field …" although you created the fields (Spoolman older than 0.27) The field was created for Filament or Vendor, has the wrong type, or the key has a typing error. Compare the keys letter by letter. Check that both are Spool fields of type Text. Then click Test again.
"Multiple NFC UID owners; clean up Spoolman before continuing" Two spools carry the same tag UID in nfc_uid. In Spoolman, empty the field on the spool that does not have the tag.
"Instance UUID belongs to another Spoolman spool" Another spool already carries this tag's ID. In Spoolman, empty opentag_instance_uuid on the spool that does not have the tag.