I would not recommend that anyone hook up their g540 like I did. There seems to be something really wrong with my setup. I went to test it after re-verifying my connections and found that when I turned on the mill with the g540 hooked up, but with Mach3 in reset and connected to the g540 the spindle turned on by itself. I measured about 12v across P1-P3 and 9.9v on P1-P2. I did not write down the steps I took after that (such as hitting the e-stop for the G540 but I think that I did and that may have stopped it. I then disconnected the vfd from the g540 - though with it still connected to the X3 controller and restarted the mill - same thing, it started up on it's own as soon as the fwd switch was thrown - and this is without the pot connected, that was pretty weird to say the least. I measured the same 9.9v from P1-P2 at that point. I never saw a fault light thoughout on the mill.
I then re-connected the pot without the g540 connected and it ran OK. Finally I reconnected the g540, restarted mach3, checked my configs, changed the spindle setup from 3000 to 2000 steps, rechecked everything and tried again. This time the spindle did respond to Mach3, however it did not seem to be running at the requested speed and I got some funny readings when I checked it:
requested speed P1-P2 P1-P3
200 1.9v 4.9v
600 3.3v 5.2v
800 3.4v 5.2v
1000 3.3v 5.2v
100 0.7v 5.8v
I also checked it with the power on, spindle = 0 and measured 0.1v across P1-P2 and P1-P3 with the G540 connected. I also noticed that my G540 was very warm - too warm to keep a finger on it so I added a block of aluminum to it to help with heatsinking temporarily. So now I am pretty stumped and am going to call it a day and probably will start from scratch next week with this and re-test the gecko again. I am also going to bypass a switch I installed that toggles P2 between the pot and the VFD out from the G540 - in today's testing I removed the pot from P1 and P3 when testing the VFD, the switch was set to select the VFD for the P2 terminal.
A couple things (out of many) that bother me about the readings are - how was there 12v across P1-P3? The highest I had seen it previously was around 6.8v.