I'm wondering how to go about controlling MY VFD

Handymanpa54

I'd like to use Duet 2 Ethernet. My VFD has FWD or REV and variable speed by 0 to 10 volt input. I saw where I can get a pwm to Voltage converter. I'm wondering which out put of the duet can do this? Maybe I would need to use 2 outputs? I think I can get PWM from heater or fan, but thats only enough to control speed.
I'm sure you guys have a better general knowlege of the Duet2 than I do. Steer me in the right direction!

Mark

fcwilt

@handymanpa54

How accurate does the speed control need to be?

Is the direction control one or two inputs.

If there are two inputs what happens if they both are the same?

Frederick

jay_s_uk

@handymanpa54 I use heater outputs but fan outputs will do as well.
I use a pwm to analogue converter

cjm

@handymanpa54 There are a couple of guides on this forum about controlling a VFD using a PWM to analogue converter that might be helpful to you:

This link explains how to connect an off-the-shelf PWM to Voltage converter and configure the Duet:
https://forum.duet3d.com/topic/19938/huanyang-vfd-2-2kw-water-cooled-spindle-to-d3mb6hcv1-mainboard

This link explains how to make your own PWM to 10V analogue converter and also describes a safe way of connecting the Duet to the VFD's FWD/Run and REV/Direction inputs using opto-isolators to match the different signal levels.
https://forum.duet3d.com/topic/19968/duet-integration-with-an-askpower-a131-vfd?_=1626895012655

The following is an example of what you'd add to your config.g for the Duet 2 to setup the VFD and FWD/REV controls (NB for RRF firmware version 3.3RC1 and up):

M950 R0 C"exp.13+exp.8+exp.14" Q2000 L0:20000   ; Create spindle index 0, PWM frequency 2KHz, 
                                                  ; Lmin:max rpm ranges from 0rpm at PWM=0% to 20000rpm at 100% PWM
                                                  ; spindle speed PWM pin	: exp.13 
                                                  ; spindle run pin 		: exp.8
                                                  ; spindle direction pin 	: exp.14
M563 P0 R0 S"Spindle"                             ; Create Tool 0 with Spindle 0 and call it Spindle 
G10  P0 X0 Y0 Z0                                  ; Set Tool 0 axis offsets
M568 P0 F0					  ; Set Tool 0 to default RPM of 0
T0						  ; Select Tool 0 (or make sure generated by CAM)
 
; CNC Mode (Firmware 3.3RC1+)
M453

You can then use M3 S8000 to set the spindle to 8000 RPM clockwise, or M4 for counter-clockwise rotation and M5 to stop the spindle .

Handymanpa54

@fcwilt Hi, Speed control does'nt need to be very precise. I just need to get it in the ball park so cuts will be fast enough. There are 2 inputs for reverse and forward. x1 on and x2 off is forward, x1 off and x2 on is reverse.

Mark

fcwilt

@handymanpa54

If both are off is that "neutral"?

If both are on is that "burn out the windings"?

Thanks.

Frederick

Handymanpa54

@fcwilt Both off nothing going and both doesent sound good. I don't know what would happen.