VF Output

hpiz

Hello,

I am a very happy owner of a Duet2 for 5 years and a new Duet3 6XD owner.

I kind of have a feeling this is not gonna be possible but I have a request.

I bought a VFD for my 3.5Kw ATC spindle for a new build, it has a high frequency spindle speed reference input that I had wrongfully assumed was PWM based.

Instead the VFD accepts a variable frequency between two configured frequency values (eg 0-50khz, 100hz-1000hz) to reference the desired speed.

It obviously has the normal 0-10V analog input, but I've always been displeased with the non-linearity of the the signal received from the available PWM->0-10V converters.

A truly digital speed signal would be ideal.

Changing the PWM frequency for the spindle does work, but obviously does not change during runtime.

And so comes where I think this may be impossible. Is changing the PWM frequency similar to PIN assignments in that it needs a proc reboot?

I would love if I could have, say....

M950 R0 C"!io7.out.iso+out5" L24000 S1 ; Create spindle index 0, with PWM pin on heater 3 and 12000 RPM achieved at full PWM, S1 state to indicate a variable freq instead of variable PW

I would be more than happy to beta test if this is possible.

Thank you for all the work and dedication to the Duet hardware, firmware, and community.

oliof

@hpiz both duet3 6HC and duet 3 mini 5+ have a VFD header. 6HC next to the erase header , mini close to the middle of the board.

See the wiring diagrams at https://docs.duet3d.com/en/How_to_guides/Wiring_your_Duet_3

and https://docs.duet3d.com/en/User_manual/Machine_configuration/Configuration_CNC#connecting-a-spindle

for more details.