GRBL Error and Alarm Codes
Below is a list of possible Errors and Alarms which you may encounter while running your GRBL based CNC machine, whether it's one of our Nighthawk family of controllers, or a 3rd-party GRBL controller on something like a laser engraver, pen plotter, or router. In our Commander software you will see the status indicator flash red with ALARM or ERROR when any of the following occur, and you can click on the box for an explanation.
Errors
1. GCODE Command letter was not found
2. GCODE Command value invalid or missing
3. GRBL '$' not recognised or supported
4. Negative value for an expected positive value
5. Homing fail. Homing not enabled in settings
6. Min step pulse must be greater than 3 usec
7. EEPROM read failed. Default values used
8. GRBL '$' Command only valid when Idle
9. GCODE commands invalid in Alarm or Jog state
10. Soft Limits require homing to be enabled
11. Max characters per line exceeded. Ignored.
12. Grbl '$' setting exceeds the maximum step rate.
13. Safety door opened and door state initiated.
14. Build info or start-up line > EEPROM line length
15. Jog target exceeds machine travel, ignored.
16. Jog Cmd missing '=' or has prohibited GCode.
17. Laser mode requires PWM output
20. Unsupported or invalid GCode command.
21. > 1 GCode command in a modal group in block.
22. Feed rate has not yet been set or is undefined.
23. GCode command requires an integer value.
24. > 1 GCode command using axis words found.
25. Repeated GCode word found in block.
26. No axis words found in command block.
27. Line number value is invalid.
28. GCode Cmd missing a required value word.
29. G59.x WCS are not supported.
30. G53 only valid with G0 and G1 motion modes.
31. Unneeded Axis words found in block.
32. G2/G3 arcs need >= 1 in-plane axis word.
33. Motion command target is invalid.
34. Arc radius value is invalid.
35. G2/G3 arcs need >= 1 in-plane offset word.
36. Unused value words found in block.
37. G43.1 offset not assigned to tool length axis.
38. Tool number greater than max value.
Alarms
1. Hard limit triggered. Position Lost.
2. Soft limit alarm, position kept. Unlock is Safe.
3. Reset while in motion. Position lost.
4. Probe fail. Probe not in expected initial state.
5. Probe fail. Probe did not contact the work.
6. Homing fail. The active homing cycle was reset.
7. Homing fail. Door opened during homing cycle.
8. Homing fail. Pull off failed to clear limit switch.
9. Homing fail. Could not find limit switch.
Arming yourself with the knowledge of what the Error or Alarm is you are encountering can help you determine the reason behind it, and the best course of action to resolve it.