View Full Version : G-Rex & Spindle Control???

03-05-2009, 06:51 AM
I'm contemplating dumping my noisy wood router and getting a spindle
and VFD for my cnc, but I thought that I heard that the G100 doesn't
allow for spindle control with Mach3? Is this the case, or am I

Are there any other limitations with the G100 that I should be aware
of for the future as well? I know there's some question about 3D
stuff also?

System: G100, G203v's, Mach 3.



Don Williams
D.E.Williams Guitars

03-05-2009, 06:24 PM
Hi Don,

The G100 does cater for spindle control. It produces a 0-5V analog voltage from the speed setting in Mach3. The voltage that is output is a proportion to the maximum spindle speed. As an example.

Max spindle speed is 2000rpm.
Mach3 commanded speed 500rpm

G100 voltage output = 500rpm/2000rpm *5V = 1.25V

The G100 generated analog voltage outputs are NOT isolated. So you need to be careful as to how you use it with a VFD or motor controller. Some of these have the 0V reference for the 0-10V control input at around 10V below the mains voltage.

If this is the case, it will cause a lot of excitement and damage if you connect the G100 to it.

I produced a DigiSpeed, the DC-03 that was designed to interface the G100 to VFDs and DC motor controllers.

The DC-03 will take a 0-5Vdc analog voltage and produce an ISOLATED 0-10Vdc control voltage suitable for VFDs and DC motor controllers.

It also has an optional DC/DC converter that is useful as some DC motor controllers can only supply 1-2 mA for the control voltage supply. VFDs can usually supply 10-20mA for ther control voltage supply.

I hope this helps,



03-16-2009, 04:41 PM
Thanks much...