Driving a Chinese spindle VFD from mach3

[jcb121]

Does anyone do this and can tell me how to?

some posts suggest using a pwm to 10v converter and doing something or another with it

other post suggest getting a usb to RS845 connection to the VFD with varying results of success. This is using the plugin and .Dll.

can anyone give me a quick point in the best direction?

I want to try this with my 1.5kw spindle but I Will be doing this with my 3kw spindle.

Thanks.

[JAZZCNC]

I've used several of these spindle boards from Roy at DIYCNC with no problems, simple and easy. http://www.diycnc.co.uk/html/spindle_boards.html

You only really need this if you want to control the speed.
If you just want to turn on/off then usually your BOB will have relay outputs so just use these to control Run signals on VFD.

[John S]

If you are using that board of Roys then use a completely separate 12v supply for it in no way connected to anything else on the panel.

Do not rely on the onboard 12v to 12v DC supply especially if you have long cable runs.

[JAZZCNC]

If you are using that board of Roys then use a completely separate 12v supply for it in no way connected to anything else on the panel.

Do not rely on the onboard 12v to 12v DC supply especially if you have long cable runs.

Yes I never do John, same with USB powered BOB's etc I always run them from there own supply.

[jcb121]

I've used several of these spindle boards from Roy at DIYCNC with no problems, simple and easy. Spindle boards

You only really need this if you want to control the speed.
If you just want to turn on/off then usually your BOB will have relay outputs so just use these to control Run signals on VFD.

i have a DIYCNC BOB and it's pretty basic. or at least I think it is, I don't even use the charge pump feature :l

So I'd run a wire from my BOB to a relay then to one of the terminals on the VFD and I'm guessing I have to connect the grounds of the VFD to the BOB?

ninja edit: i may have to buy one of These

and in mach3.... I've not a clue! all I know how to do is Jog, load g-gcode and zero it! I'm truly a mach beginner.

I might just buy a usb to RS845 and run it like this
at least there's a bit of documentation.

[JAZZCNC]

So I'd run a wire from my BOB to a relay then to one of the terminals on the VFD and I'm guessing I have to connect the grounds of the VFD to the BOB?

No on the VFD there's Signal terminals for Run/stop and direction. You take a wire from the DCM terminal on VFD and pass it thru the contact of the Relay on the BOB then back to the Run terminal on VFD.
Then when the G-code fires M3 command the output on the BOB turns it's on board relay on and the contacts close making the Run signal active. When the G-code fires M5 the output goes OFF and relay closes it's contacts.

EDIT: If your BOB doesn't have Relay then you can use a separate Relay and control thru the output of the BOB but the relay coil must be able to work with the low current that will probably come from BOB output.

You can do the same for Direction but don't recommend you do that has you'll rarely if ever have need and it's easy to miss type 4 (M4) instead of 3 and spindle start in reverse.!!!!

For speed control you have to have some way of Digitally controlling VFD IE: RS485 or using Analogue signals and sending the VFD 0-10v signal to it's analogue terminals which control speed.
Problem with Analogue is you have to have some way to convert Digital signals coming from the PC back to analogue and at the correct voltage 0-10v. Zero being Off Ten being full speed and all voltages in between being relative to the speeds setup in control software.

To be honest I rarely use Speed control thru G-code and just control thru VFD but do have G-code start and stop spindle then i can walk away knowing it will stop when done or if E-stop occurs when I'm not around.