You could set PD001 to 1 so that it accepts external terminal command and PD002 to control speed. Maybe then Mach can be set to directly control Run, Stop and EStop commands and speed by plugin.
But I don't think that you can drive VFD directly with LPT since it is TTL level (5V) and VFD operates on 24V. You probably would fry the port.
Simple interface card with relays, buffer chip, optocouplers can help. I you are able to DIY:



If you have any question about circuit, shoot

Hello Kare and All,
If people are using opto coupled Breakout boards or any open collector output with external pullup resistor then all you need to do is remove Pullup resistor tying the output to 5Volts from the output you require and this will happily switch these inputs and if you have a multimeter you can isolate the resistor and remove it or as I have done just lift one side so I can put it back if required you can be up and running in 20mins.
I am using this setup at the moment using PD001 as 1 and PD002 as 0 as I posted earlier this allows me to switch run ON and will run at the frequency set in PD003 this allows you to increase or decrease speed from the VFD's keyboard.
Also just as a safety measure make sure PD024 is set to ! this allows stop button on VFD to switch spindle Off under controlled deceleration, this is useful if you are using these inputs or RS485 if Mach3 or your system locks up.
If you have any questions please let me know.
All the best,
BK.

Hello Kare,
Hope you don't mind me asking, but what software are you using to generate that schematic?
Really nice diagram.
Thanks,
BK.

Thanks BK,
 it's made with Altium Designer (former Protel DXP).

Hi all,
Got my self a vdf witout the com chip.
Any luck with solderin on a new chip Kare? anyone?
Just wondering so I don't waste money bying a chip thats useless.

Regards Ullteppet

Hi Ullteppet,
still waiting for chip to come. Will post results when it arrives.

Cheers

Hi,
After spending a considerable period of time reading through this thread, it was with some trepidation that I installed my usb to RS485 converter, that I had sitting on the shelf and connected it to the Huanyang VFD. I installed the plugin, set my com port and VFD as per the PDF included in the plugin, configured Mach3 as described, input 500rpm for the spindle and clicked start.

I nearly collapsed when it just worked!

The converter is the same as the photo that was previously posted.

A big thank you to the developer/s of this plugin.


Cheers
Dave

My VFD also had no chip. I got 5 MAX485CSA from ebay http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=290463383670 shop icmarket2009 £1 each. Not too hard to solder it in place, very small and my eyes aren't what they were for close up work  tinned the pads used tweezers to place and get it sat on all the pads and held down with the tweezers and just dabbed the legs on the pads.

Plugged the sucker in, installed the plugin in Mach, enabled it, programmed the VFD with

PD001   2   commands
PD002   2   frequency
PD163   1   VFD address
PD164   1   Baud Rate 9600
PD165   3   8N1 RTU

as per instructions

and tadaaaa.. nothing..
in the plugin config it just showed 99 in the PD001 and PD002 lines. ahhh

swapped my cables, tried again, 99. re-programmed FVD PD163 with 2 and changed plugin config VFD address to 2

nothing.. 99

swapped my cables back.... got a 2 in PD001 and PD002

hit the spindle start and got.. nothing, went into spindle calibration and still nothing.

loaded up some g-code set some safe zero's and hit start. IT'S ALIVE!!! 2460rpm shown on VFD for 2950 on Mach.

reset max revs on VFD P0144 to 3000 now getting 2949 rpm on VFD.

not haing used Mach controlled spindle before it was just set for zero rpm that had been the problem since I got the 2's showing in the plugin config.

yehaa.. so solder away, all should be shiny 

Good news and good work!!

Nice work!
I'm ordering the chip now :-D