Most CNC controls with an Ethernet port speak FTP. It is old, simple and nearly universal — which is exactly why it still matters on a shop floor.
FTP for part programs
The everyday use is moving programs: CAM posts a file on a PC, and an FTP client sends it to the control’s memory or storage. The same connection backs programs up the other way. Compared with a USB stick, nobody walks to the machine, and the latest program version lives in one known place.
FTP for machine data
Some controls go further and publish their own live data as files that can be read over FTP:
Execution state and alarms
- Typical use
- Is the machine running, idle or in alarm?
Part counters
- Typical use
- Parts made, and cycle time between parts
Production and operation logs
- Typical use
- What ran, and when
Tool and maintenance counters
- Typical use
- Tool life, maintenance due
| File content (varies by control) | Typical use |
|---|---|
| Execution state and alarms | Is the machine running, idle or in alarm? |
| Part counters | Parts made, and cycle time between parts |
| Production and operation logs | What ran, and when |
| Tool and maintenance counters | Tool life, maintenance due |
On those controls, ThingConnect reads these files on a schedule — fast-changing ones every few seconds, slow ones every few minutes — and only ever downloads. It never writes or uploads anything to the machine, so data collection cannot change a program.
Limits and network setup
- Polling, not live: files are read on a schedule, so data is a few seconds old rather than instant. Where a control offers OPC UA, that is usually preferred for state.
- Unencrypted: plain FTP should stay on an isolated machine network.
- Not every control: which files exist, and whether FTP is enabled at all, depends on the control and its options.