How Zora names a device on the bus

Every device on an NMEA 2000 backbone has two names: a bus address and a CAN NAME. Zora keeps track of devices by the CAN NAME. This page explains why, and what it means for your settings. To set up the port, see NMEA 2000 / CAN Bus.

The bus address moves

A device claims a bus address, a small number, when it joins the backbone. If two devices want the same address, the one with the lower CAN NAME keeps it and the other picks a free one. So adding a device, removing one, or powering them up in a different order can move a device to another address.

A setting stored against an address would then point at whatever device holds that number now.

The CAN NAME stays

The CAN NAME is the device's own 64-bit identity. It sends it in its address claim (PGN 60928), and it is built from:

• the unique number
• the manufacturer code
• the device instance
• the device function and device class
• the system instance
• the industry group

Two devices of the same model still have two CAN NAMEs, because each has its own unique number. Two identical GPS receivers stay two sources.

What Zora does with it

Zora identifies every device by its CAN NAME. There is no setting for this. Zora holds it at every start and on every save, so a Setup page left open from before cannot put the address form back.

Source priorities that name a device by its bus address are rewritten to its CAN NAME, in the same order, and then take effect. See Source priorities.

The bus address still shows on the Sources tab of the port, as Device followed by the number. That number can change; the device it belongs to is the same.