Connects to the Elegoo Centauri Carbon over its network protocol, SDCP: status, temperatures, uploads, start, pause, resume, cancel and camera snapshots. Elegoo printers that run Klipper (Neptune 4) work through the Moonraker connector instead.
For users
On the printer
- On the touchscreen, open Settings, then Network, and connect the printer to your network.
- Note the IP address shown with the connected network. Your router's device list shows it as well.
- If your firmware has a network control setting, turn it on. No account, access code or key is needed.
In SlicerX
- Add a printer and choose Scan. SlicerX sends one broadcast on your network and the printer answers. The scan runs only when you start it.
- If it does not appear, choose Elegoo and enter the IP address. The port is 3030.
Neptune 4 printers run Klipper and use the Moonraker guide.
Print options
Start passes bed leveling (Calibration_switch, default on) and timelapse (Tlp_Switch, default off).
Network and firewall
| Port | Protocol | Used for |
|---|---|---|
| 3030 | TCP | status and commands (WebSocket), file upload (HTTP) |
| 3031 | TCP | camera stream |
| 3000 | UDP | scanning |
Common problems
| Message or symptom | Cause and fix |
|---|---|
| "is unreachable" or a timeout on connect | Wrong IP, printer off, or the printer is already serving other apps. Close the slicer, phone app or other tools that use it. |
| Upload fails | The printer is printing, storage is full, or port 3030 is blocked. |
| A finished print shows as idle | The printer's completed status has no documented code, so it reads as idle. |
| A command is refused | The printer is in a state that does not allow it, for example pausing while idle. |
| No G-code console | SDCP does not have one. |
Untested on hardware
Written from the public protocol and a community write-up, and checked against a simulator, not a printer. Check first: the upload form fields, the status codes and the unit of the time counters (read as seconds).
For integrators
Plugin id elegoo. Capabilities: status, events, upload, start, pause, resume, cancel, camera. No G-code console.
Printer config: host, optional port (3030).
Protocol
WebSocket at ws://host:3030/websocket, JSON envelopes {Id, Data:{Cmd, Data, RequestID, MainboardID, TimeStamp, From}, Topic}. The mainboard id comes from the first status message. Commands: 0 refreshes status, 128 starts (Filename /local/name.gcode), 129 pauses, 130 stops, 131 resumes, 386 enables the MJPEG stream and returns its URL, which must be on the printer's host. Replies carry Ack (0 ok, 2 file not found). A ping goes out every 20 seconds because the printer closes idle sockets after 60. The connection reconnects every two seconds after a drop and the printer reads as offline meanwhile.
Upload is POST /uploadFile/upload, one megabyte per request, form fields Check, S-File-MD5, Offset, Uuid, TotalSize, File.
Status mapping: PrintInfo.Status 13 and 20 printing, 5 and 10 paused, 8 and 9 preparing, otherwise idle.
Scanning broadcasts M99999 to UDP 3000 and parses the JSON replies.
Events and rate
Pushed by the printer. Status events fire when anything other than the timestamp changes.
Testing
elegoo_sdcp_contract in tests/drivers.rs, against a fake with hand written WebSocket framing.
Sources
SDCP V3.0.0: https://github.com/cbd-tech/SDCP-Smart-Device-Control-Protocol-V3.0.0. Centauri Carbon notes: https://github.com/WalkerFrederick/sdcp-centauri-carbon.