Ethernet

Every FluidBoard comes with a built-in 10/100 Mbps Ethernet port. Plug in a cable and you're connected — no drivers, no configuration, no fiddling with WiFi passwords.

Why Ethernet?

WiFi works fine on the workbench, but the moment you put your controller inside a shielded enclosure — which is best practice for EMI — WiFi signal drops. Ethernet doesn't care about shielding. It's rock solid, low latency, and just works.

If you're running a VFD, plasma cutter, or any other high-EMI equipment, Ethernet is the way to go. Many professional CNC setups use shielded enclosures as standard practice, and Ethernet is the way to stay on the network without relying on wireless.

A few more reasons WiFi tends to struggle in a workshop:

Interference. VFDs and plasma cutters radiate a lot of electrical noise. A dropped WiFi connection in the middle of a job is annoying at best.
Metal everywhere. Steel frames, enclosures, tool cabinets and the machine itself block and reflect the signal.
A crowded band. The board's WiFi runs on 2.4 GHz, which it shares with every neighbour's router, Bluetooth devices and microwave ovens.
Distance. Workshops and garages are often at the edge of the house network.

None of this affects a cable.

Features

10/100 Mbps auto-sensing — just plug in any Ethernet cable
DHCP by default — gets an IP address automatically from your router
Static IP supported if you prefer a fixed address
mDNS discovery — find your board at http://fluidnc.local without knowing the IP
All services — WebUI, Telnet, FluidWeb, and camera streaming all work over Ethernet
WiFi and Ethernet can run at the same time — you don't have to choose

The Ethernet controller talks to the ESP32 over SPI, so the real throughput is lower than the 100 Mbps link speed. For G-code, the web interfaces and the camera stream that's plenty.

Cabling

Use a decent shielded patch cable (marked STP, FTP or S/FTP). Cat5e is enough; Cat6 doesn't hurt.
Keep the network cable away from motor, spindle and VFD cables. Don't bundle them together in the same cable chain or duct. Where they have to cross, cross at a right angle.
If the board sits in an enclosure, an RJ45 feed-through in the enclosure wall is neater than a cable through a gland, and easier to unplug.
Connect the board to a switch or router, not directly to a PC, unless you've given both sides a static IP.

Configuration

Ethernet works out of the box with DHCP. No configuration needed for most setups.

If you need a static IP:

ethernet:
  cs_pin: gpio.10
  int_pin: gpio.4
  dhcp: false
  ip: 192.168.1.100
  gateway: 192.168.1.1
  netmask: 255.255.255.0
  spi_freq_mhz: 20

What the settings mean:

cs_pin, int_pin — how the Ethernet chip is wired on the board. Leave these as shown.
dhcp — true to get an address from your router, false to use the fixed address below
ip — the fixed address of the board. It must be in the same range as the rest of your network.
gateway — usually the address of your router
netmask — 255.255.255.0 for almost every home and small-office network
spi_freq_mhz — the speed of the connection between the ESP32 and the Ethernet chip

Static IP or DHCP reservation?

You want the board to have the same address every time, so bookmarks and senders keep working. There are two ways to get there:

DHCP reservation (our preference). Leave dhcp on and tell your router to always give the board the same address. Everything is managed in one place, and if you ever change routers the board simply gets a new address instead of becoming unreachable.
Static IP. Set the address on the board itself. Pick an address outside the range your router hands out, otherwise two devices may end up with the same address. Your router's settings page shows that range.

Troubleshooting

Symptom	Likely cause	What to do
No link lights on the switch or router port	Cable or port problem	Try another cable and another port
Link, but `fluidnc.local` doesn't open	mDNS not supported by the device you're using	Use the IP address instead; your router's list of connected devices shows it
Unreachable after setting a static IP	Wrong range, gateway or netmask	Check that the first three numbers of `ip` match your network, and that `gateway` is your router
Connection works, then drops at random	Two devices using the same IP	Move the static IP outside the DHCP range, or use a DHCP reservation
Drops when the spindle or plasma starts	Electrical noise	Re-route the cable away from power wiring, use a shielded cable, check grounding

A quick test from a PC on the same network: open a command prompt and run ping 192.168.1.100 (with your board's address). To check stability over time, run ping -t 192.168.1.100 on Windows (on Mac or Linux, plain ping keeps running) while you start the spindle. Lost replies tell you the problem is in the network, not in your sender.

We do not support EtherCAT for servo motors.

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