Configure Masso to Check if VFD is on

Is there a way to configure the masso to check if the VFD is on/active and not to run the program if inactive/off?

I can get a logic high from the VFD if it is on without a fault. Can I send this signal to the Masso and have it pause the job until it is on?

I use ‘m66_wait_for_input’ command to achive that. It check for 30 sec if ‘auxiliary 4’ detect that the vfd is running. If so, it continu. if not it display a message and wait for cycle start to be press.

I first connected the multi-output (FA and DCM) of my vfd and G3 TTL input 17 configure as ‘Auxiliary 4’.

  • vfd FA connected to G3 TTL input 17
  • vfd DCM connected to G3 GND

Then I added these lines at the beginning of my GCODE just after the first Sxxxx M3.

MSG Waiting for spindle to start (30 sec max)
M66 P4 L3 Q30000 S2
MSG Please start VFD (Press cycle-start to resume)

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What level of safety, or what functionality, would you like to see?

Initial thoughts are having the VFD signal control a relay that is part of E Stop circuit, or alternatively have it as a configurable input on Masso - one that may not stop everything, and would allow it to be cleared (with or without rehoming would need to be decided/determined depending on your choice).

If you want those lines to be added by the post processor automatically, just add the yellow line to your fusion 360 post processor file.


forceSpindleSpeed = false;
writeBlock(sOutput.format(spindleSpeed), mFormat.format(tool.clockwise ? 3 : 4));
writeBlock(“MSG Waiting for spindle to start (30 sec max)”);
writeBlock(“M66 P4 L3 Q30000 S2”);
writeBlock(“MSG Please start VFD (Press cycle-start to resume)”);

Thank you.

A bit of homework for me and my Masso, Optidrive (vfd) and post processors.

I’ll tell if i get it to work.

Desired Outcome:

  • Spindle and bit dont plunge into work piece if the vfd is not operational. Pause to allow me to switch the vfd on.

I dont want it to respond to "is spindle spinning " as some operations dont hve a spinning spindle, such as drag knife, diamond engraver and pen plotter.


Just to let you know that I published a new post processor as part of ‘onefinity-community-post-processors’ GitHub Package.


You,ll notice that (in response to your outcome) that you can enable/disable each spindle check operation individually for each NC Program. Another precision, each spindle check operation is configurable and do not need any intervention if condition is met before the defined timeout value is reach. But if the timeout value is reach before condition is met then you’ll have to press 'Cycle Start to continue).