Centroid Community CNC Support Forum

So here's how things are setup.

PM940V conversion running Acorn into a Delta VFD-E. The base specs on this motor are 0-1390 RPM and I have Acorn currently configured to this.
The spindle itself is driven by a belt from the motor with two possible pulley arrangements. The low gear arrangement is approximately 1:1 However, the high gear drive is 1:3.75.

So, if I tell my VFD to run at 1000 RPM, it drives the motor to 1000, and in high gear, this drives the spindle to 3750. Furthermore, the spindle has a 24V hall effect sensor which reads the spindle RPM and sends it to Acorn. However, this particular spindle reads FOUR pulses per rev instead of one.

Is there a way to account for both of these in CNC Mill 12 so that I can put actual spindle RPM in my Fusion toolpaths and Gcode instead of having to manually calculate for the speed multiplier?

Basically, I want the Mill software to be able to read 3750 RPM in the Gcode and send a 1000 RPM frequency signal to the VFD, as well as show me 3750 on the RPM readout instead of 15000.

Hardware: PM940V with Acorn Rev4, spindle motor 0-1390 RPM. 1:3.75 pulley ratio to spindle with 4 pulse/per rev hall effect sensor
Software: CNC Mill 12 Pro, Fusion 360 CAD/CAM.

Have attached a photo of the belt drive and motor assembly for reference. Also attached is current Report

Basically, I want the Mill software to be able to read 3750 RPM in the Gcode and send a 1000 RPM frequency signal to the VFD,

The only way to make that happen is to tell the PLC which position the belt is in. That is typically done either with:
1) A switch or sensor on a PLC input (easier to implement on a back gear lever than a belt)
2) A VCP button to indicate high range vs. low range
3) M functions (e.g. M41 / M44) you have to execute at MDI or in your program

Once the PLC knows what position the belt is in, it can set SpindleRange_W to either 1 or 4, which will then trigger code that uses Parameter 65 to compensate speed commands and, if necessary, direction.

https://centroidcncforum.com/viewtopic.php?f=63&t=1650 tells how to calibrate your VFD.

Parameters 65-67 control the spindle gear ratio settings. I believe there is also a setting in the Wizard for this.

tblough wrote: ↑Mon Jan 03, 2022 3:19 pm https://centroidcncforum.com/viewtopic.php?f=63&t=1650 tells how to calibrate your VFD.

Parameters 65-67 control the spindle gear ratio settings. I believe there is also a setting in the Wizard for this.

That describes how to get your VFD to spin your motor at the commanded speed. The motor IS spinning at that speed, but it's driving the spindle through a belt which has a multiplication factor.

You don't tune the VFD for the motor speed, reading carefully, the document tells you how to get the SPINDLE to spin at the commanded speed. You tune if for the spindle speed when in high range. You then use the gear ratio parameters for the other ranges.

If you only have one speed and no others, then it's just a matter of tuning the VFD for the correct spindle speed.