Generating an ENI file

An ENI (EtherCAT Network Information) file describes your bus topology and drives network bring-up. You generate one from the live bus once, commit it to your project, and then reuse it every time you start the network. The eni command both creates and verifies these files.

Step 1 — Gather your ESI files

Generation matches the devices on your bus against their ESI (EtherCAT Slave Information) description files. Put the ESI XML files for your devices in a single directory, for example /usr/share/lxmaster/esi.

Step 2 — Generate the ENI

sudo lxmaster eni gen \
    --esi-dir /usr/share/lxmaster/esi \
    --out network.eni.xml

This scans the live bus, matches each device to its ESI, and writes a standards -compliant ENI. If you do not pass --cycle-ns, eni gen defaults to a 1 ms cyclic period (1000000 ns), a common starting point. To use a different period, set it explicitly, for example --cycle-ns 500000 for 500 µs.

What you'll see: progress as each device is matched, followed by confirmation that network.eni.xml was written. This file is now the description of your network.

Step 3 — Verify the ENI matches the bus

Whenever you want to confirm the physical bus still matches your saved ENI:

sudo lxmaster eni verify --eni network.eni.xml

What you'll see: it compares the device count, vendor ID, product code, and revision against the ENI and prints PASS or FAIL. It exits 0 on a match and 1 on a mismatch, which makes it handy at machine startup or in CI.

tip

Commit network.eni.xml to your project. The library reads it at bring-up, and the cyclic period comes directly from the ENI you generated here.