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Write an NFC tag

Encode a task point's identifier onto a blank NFC tag and place the tag on the physical asset.

Required role

Mapper.

Overview

NFC tags are physical, stick-on (or bolt-on) labels with a small chip inside. A mapper writes the task point's ID onto the tag, then physically attaches the tag to the equipment. Thereafter, any technician holding a phone near the tag can jump straight to the task — see Scanning NFC tags.

Writing is a mobile-app-only feature. The web portal has no way to write a physical tag.

The app writes tags in the format:

NFC_<TYPE>_<id>

For example, NFC_TASKPOINT_4827. The encoding is a single NDEF text record — standard, readable by any NFC-capable device.

Prerequisites

  • You have the Mapper role.
  • The task point already exists in the hierarchy. (You can create the task point and write its tag in one session — see Creating hierarchy.)
  • You have blank, writable NFC tags on hand.
  • Your device has NFC hardware and NFC is enabled.

Choosing tags

Not all NFC tags are equal. For industrial environments:

Tag attribute Recommendation
Chip type NTAG213 (minimum) or NTAG215 (more storage, longer URL support if needed later).
Enclosure Durable, enclosed tags — plastic encapsulated or in an epoxy dome. Plain paper stickers don't survive grease, steam, wash-down, or temperature cycling.
On-metal compatibility If the tag mounts on a ferrous surface, buy "NFC on-metal" variants. Plain tags detune severely on metal and may not scan reliably.
Temperature rating Match to the environment. Hot / cold rooms need rated tags.
Size Larger tags give more reliable reads but need more real estate. 30 mm diameter is a common industrial default.

A good starting kit: a pack of 100 NTAG213 on-metal tags, plastic enclosed, ~30 mm diameter. Cheap per-tag; replacements are easy.

Steps

1. Open the task point

Three ways in:

Menu → Hierarchy → drill to the task point → open.

Right after you create a task point, the detail screen offers Write NFC tag as a next-step action.

Some installations surface Write tag from a task's context menu.

2. Tap "Write NFC tag"

A prompt appears: "Hold the NFC tag against the back of your device."

3. Hold the tag against the antenna

Same antenna position rules as scanning:

  • Most Android phones: upper back.
  • iPhones: top edge near the notch.

Hold still for 1–2 seconds. The phone writes, verifies, and the app confirms: Tag written.

4. Physically apply the tag

Do this before you leave the asset:

  • Clean the surface (a wipe is usually enough).
  • Peel the backing off if the tag is adhesive-backed; use a bracket / bolt-on for industrial-mount tags.
  • Place in a visible, reachable spot — where a technician with a phone can comfortably press up against it.
  • Avoid placing over labels, moving parts, or areas that see heavy wash-down if your tags aren't rated for it.

5. Test-scan

Walk away, come back, scan the tag with the same phone (or a different one). The task point should open. See Scanning NFC tags.

If the scan fails, re-check the placement and antenna positioning, then retry.

Most NTAG chips support a permanent write lock — once locked, the tag content can't be overwritten. This protects against accidental or malicious rewriting.

After you're sure the tag works:

  1. Re-tap Write NFC tag on the task point.
  2. Choose Lock tag after write (if available on your installation).

Locking is permanent

A locked tag can't be re-programmed. If the task point's ID changes for some reason (unlikely, but possible), the tag becomes useless and has to be replaced. For most installations the tradeoff favours locking; for volatile installations it may not.

Writing on metal

Even with on-metal tags, placement matters:

  • Keep ~2 mm of plastic / paint between tag and bare metal if possible.
  • Avoid placing directly over welds (they distort the RF field).
  • Test-scan more carefully — on-metal tags can be finicky with some phone models.

If you're consistently having trouble on a particular asset class, switch to larger on-metal tags or use a plastic spacer between tag and metal.

Replacing a damaged tag

If a tag gets damaged (hit, washed off, painted over):

  1. Remove the old tag.
  2. Take a new blank tag.
  3. Open the same task point.
  4. Write NFC tag — writes the same ID onto the new tag.
  5. Apply the new tag.

The task point's scan history carries forward; the physical tag is the only thing that changes.

Batch writing

If you have a hundred task points to tag in one session:

  • Pre-stage tags in labelled bags (one per task point) so you don't mix them up.
  • Use the Next task point button (if present) to step through task points on the same asset without going back to the hierarchy every time.
  • Two-person workflow: one person with the phone, the other applying tags. About 20 seconds per tag in a rhythm.

Things to watch for

Don't write the same tag twice

Every NFC tag should map to exactly one task point. If you accidentally write the same physical tag with two different IDs, the last write wins — and you've stranded a task point without a tag until you notice.

Keep a few blank spares in your pocket

Once you start tagging regularly, you'll find broken / damaged tags to replace. Having a handful of blanks on hand turns a "come back later" into "fix now".

Tags have scan counters (sometimes)

Some chips log a scan count. Mappers can review scan counts via the NFC tags page to spot heavily-used vs unused tags — useful data for plant optimisation.

Troubleshooting

Problem Fix
"Write failed" Hold longer; reposition phone; try a fresh tag (the first one may be DOA)
Tag verifies but doesn't scan later Placement issue — too close to metal, or antenna can't reach it in-situ
Can't find "Write NFC tag" in the app Your role may not have mobile.nfc.write — check your role with your Admin
Tag reads the wrong task point Rewrite it — open the intended task point first
Tag scans once, then stops working Physical damage, moisture ingress, or a locking step went wrong — replace