Machine stuck on BUSY

The control protocol for the Polargraph goes like:

1. MACHINE SAYS: READY
2. CONTROLLER SAYS: Here's a command C17,100,100,END
3. MACHINE SAYS: Thanks, going to work on this for a bit BUSY
4. CONTROLLER SAYS: Ok, I'll wait.
5. MACHINE SAYS: Ok, I've done my line READY

Etcetera.

If the command never finishes, then the machine stays BUSY forever.

As always, the first step to diagnosis is to open the debug console in the Controller with Ctrl-C, and look at what is really happening.

#But why would the command never finish?!

• It might just a very long-running command. This could be because:

  • you've forgotten to do "set home" before doing your first move
  • you've got the speed set extremely low
  • your machine is set up wrong, so what looks like a small move on the screen is actually a very very large move for the machine

• The machine might have crashed, or become corrupted when it received the command

As always, the first step to diagnosis is to open the debug console in the Controller with Ctrl-C, and look at what is really happening.

See these instances:

• http://www.polargraph.co.uk/forum/polargraphs-group2/troubleshooting-forum5/busy-message-after-initiating-controller-thread476.0/
• https://github.com/euphy/polargraph_server_polarshield/issues/9

I hesitate to suggest this because it doesn't make any sense, but this seems to be a problem for boards with RAMPS, rather than with Polarshield. I can't believe that it is anything to do with the RAMPS hardware, because the Arduino drives blind - that is, it receives no information or guidance from the RAMPS.

It is possible however, that almost all machines with RAMPS were once machines with a previous 3D-printer firmware on, and so the EEPROM on those machines is already loaded with information. Certainly that's what happened in the first link above. HOWEVER... I don't understand why having a pre-stocked EEPROM would make it any less reliable than a fresh one.

I can't replicate this, and I don't support using RAMPS.

In the first case, uncomment the lines

#define DEBUG_STATE #define DEBUG_COMMS

In polargraph_server_polarshield to get a more verbose output from the machine, and then watch the communications carefully.