The Connect button doesn't work, or there's no port to choose

• Use Google Chrome or Microsoft Edge on a desktop or laptop computer. Other browsers, phones and tablets can't connect over USB.
• The Device Library connects over USB only. It can't use Bluetooth.
• Try a different USB cable. Some cables only carry power.

“Axiom did not answer over USB”

Another page or program is probably using Axiom's USB connection.

1. Close other tabs using Axiom, such as the Axiom app or the web updater, and any serial monitor programs.
2. Unplug Axiom, plug it back in, and click Connect Axiom via USB again.

“This Axiom's firmware does not support the device library”

Axiom needs Device Library firmware. Install it from the web updater (see Getting started), then connect again.

USB stopped responding after a restart

Restarting Axiom can occasionally leave the USB connection unresponsive. Unplug Axiom, plug it back in, click Connect Axiom via USB, then Refresh device. Never assume an interrupted action worked: refresh and check Axiom's state first.

My sensor doesn't appear when I scan the bus

If there's no row at the sensor's address in Test & tune → Scan bus, Axiom can't see the device at all. No profile will fix that.

• Switch Axiom off, check the wiring and connections, then switch it on and scan again.
• Check the sensor's I²C address in its datasheet. Some boards have jumpers or pads that change it.
• Check the sensor is getting power.

My sensor appears but is “unclaimed”

Axiom can see something at that address, but no profile recognises it. Click Find catalogue candidates, or add or write a profile. See Adding a new sensor.

My sensor is claimed by the wrong type

Different chips can share an address.

• If a built-in profile claimed it, add your own profile for the device. Yours is tried first. Give it a detectionValues check that tells the two apart.
• If your profile claimed something it shouldn't have, its detectionValues is probably empty or too loose. Empty means “anything at this address”. See Writing device profiles.
• If you don't use a built-in type at all, you can disable it. See Customising and disabling.

I installed a profile but nothing changed

• Did you restart? The status strip shows Written — restart to apply until you click Restart Axiom.
• Give it a minute. Straight after a restart, Axiom may still be finding its devices. Wait a little, then Scan bus again.
• Check Install → What Axiom did with the file it has. If rejected isn't 0, the page shows the first error.
• For a customised built-in profile, the built-in version is still tried if yours doesn't identify the device. Check Origin on the Test & tune tab: it should say yours.

The readings look wrong

A claimed device means a profile matched it, not that the decoding is right. Check resp.b and the attribute keys (t, at, m, s, d, a) against the datasheet. See Writing device profiles.

“Your Axiom refused 1 entry: …”

Axiom rejected at least one profile when it started. Other profiles in the same file may still have been accepted. Fix the entry named in the error in Advanced JSON, then write and restart again. Common causes:

• the profile uses an address reserved for Axiom's own hardware, such as 0x36
• deviceType doesn't match the entry's name
• the library has more profiles, or more bytes, than Axiom allows (the Install tab shows both limits)

The Check messages say something is wrong

Check messages in the editor are advice. They don't stop you writing, and Axiom may accept something the checks warn about, or the other way round. What Axiom reports after restarting is the final word.

Another app stopped getting data

If you left live readings running in the Device Library, click Stop readings and Disconnect before using another app with Axiom.