Print Job State Machine - CooperGerman/Happy-Hare GitHub Wiki

Happy Hare keeps track of the current print state in a similar way to the klipper print_stats module. It is subtly difference and can even work when streaming a job for Octoprint (altough some special precautions must be taken). The current state is available via the printer variable printer.mmu.print_job_state. This can be useful in your own custom gcode macros but also ensures that Happy Hare restores things like temperatures, stepper motor current and idle_timeout at the right time.

It is a good idea to familiarize yourself with this to aid debugging and state recovery even if you are not using in your own macros.

#f03c15 #c5f015 #1589F0 Job State Transitions

[!IMPORTANT] Users printing from the "virtual SD-card" via Mainsail or Fluuid don't have any extras steps to take but if streaming a job (e.g. from Octoprint) the user is responsible to add _MMU_PRINT_START to their print_start macro or sequence and _MMU_PRINT_END to their end_print macro or sequence. The addition of those commands on "virtual sd-card print" will not cause harm but they are but are unecessary and will be ignored (hence the underscore naming). Also note that the print_start_detection setting can be used to disable the automatic behavior and act like a job streamed from Octoprint.

stateDiagram-v2
    initialized --> started: (print_start)
    note left of initialized: reset
    standby --> started: (print_start)
    note left of standby: idle_timeout
    ready --> started: (print_start)
    started --> printing
    printing --> complete: (print_complete))
    printing --> error: (print_error)
    printing --> cancelled: CANCEL_PRINT
    printing --> PAUSE: mmu error or MMU_PAUSE
    state PAUSE {
        direction LR
        pause_locked --> paused: (MMU_UNLOCK)
    }
    PAUSE --> printing: RESUME

State machine transitions in detail...

MMU starts in initialized state. On printing it will briefly enter started (until _MMU_PRINT_START is complete) then transition to printing. On job completion (at end of _MMU_PRINT_END) or job error the state will transition to complete or error respectively. If the print is explicitly cancelled the CANCEL_PRINT interception transitions to cancelled. If idle_timeout is experience the state will transition back to standby. ready is a resting state similar to standby an just means that the printer is not yet idle.

While printing, if an mmu error occurs (or the user explicitly calls MMU_PAUSE) the state will transition to pause_locked. If the user is quick to respond (before extruder temp drops) the print can be resumed with RESUME command. The MMU_UNLOCK is optional and will restore temperatures allowing for direct MMU interaction and thus can be considered a half-step towards resuming (must still run RESUME to continue printing).

[!NOTE]

  • MMU_PAUSE outside of a print will have no effect unless MMU_PAUSE FORCE_IN_PRINT=1 is specified to mimick the behavior (like z-hop move and running PAUSE macro, etc).
  • Directly calling PAUSE will stop the job but will have no effect on the MMU (i.e. it does not put the MMU into the pause_locked state, only MMU_PAUSE does that.
  • When entering pause_locked Happy Hare will always remember the toolhead position and, if configured, perform a z-hop, but will also run the user PAUSE macro
  • When RESUME is called the user RESUME macro will be called, finally followed by Happy Hare restoring the original toolhead position.
  • Outside of a print the toolhead is never moved by Happy Hare (only user's PAUSE/RESUME macros).
  • MMU_PRINT_END STATE=xxx if called directly can accept states complete|error|cancelled|standby|ready although typically would only be called with complete|error