Question about Digital Ground XGND vs. GND - connecting a VFD to my breakout board

[FranKrause]

Hi Everybody. I'm upgrading my system from a 1.5KW to a 2.2KW spindle, mostly so I'll have a ER20 collet rather than an ER11.

I had my system running fine with the old spindle and VFD, then I switched out the spindle and ran it a bit to test it. Again, everything working fine.

I'm trying to add the 2.2KW VFD - it's the same one as in this listing - https://www.amazon.com/dp/B071P9STVQ it's 110V like my previous VFD, so the power and spindle work fine. When I ran it in manual mode from the control panel on the VFD, everything worked fine. However, when I wired it to my breakout board and tried to run it with Mach3, the frequency change would register on the VFD's screen but the spindle wouldn't turn on. After some troubleshooting I realized that the VFD wasn't switching the "FWD" switch on by connecting it to "XGND." If I cheat and hotwire these two pins together, my spindle turns on. However, I don't know if there's a way to do this with my current breakout board, or if I'll need to get a new one. Is there a specific type of board that will have the "XGND" digital ground connection, or is there a way to make these connections with my current hardware?

Basically, my VFD seems to need: FWD, XGND, GND, and VI1. My breakout board has FWD, COM (GND) and AVI (VI1), but no XGND. When I connect the GND and XGND it doesn't work. Any solutions? Thanks, folks!

Current breakout Board:


New VFD:


New VFD Schematic:


Similar Threads:

• Need HELP connecting Hypertherm 105 to Breakout Board
• Need Help!- Connecting spindle to breakout board
• Need Help!- Connecting Breakout board to Stepper Drivers
• Need Help!- Connecting Breakout board to Stepper Drivers
• Need Help!- need help connecting breakout board to relay to vfd

[Al_The_Man]

What is the nature of your break out board outputs, do you have a diag of it?, the VFD inputs are just simple opto isolators.
You can drive them with either a contact closure or a open collector fet or transistor.
You just need to connect the XGND to the common of the BOB output.
Al.

[FranKrause]

Thanks, Al! I tried connecting the XGND to the COM of my BOB but it seemed to lock up and didn't spin. I'll check out the outputs of my BOB tonight with my multimeter and see what I can do. I think that I might try controlling the connection between my VFD's FWD and XGND with a transistor, and use my BOB's FWD signal to control the connection.

[FranKrause]

Okay, sitting here with my multimeter, here's what's going on with the wires coming out of the BOB:

When the spindle is off in Mach3:
FWD is connected to COM

When the spindle is running in Mach3:
FWD and COM are not connected.

The existing AVI and COM outputs from the BOB seem to be controlling the spindle speed just fine, but I basically need the FWD output to act as an on-off switch between the FWD and XGND on the VFD. Any thoughts on how that sort of thing could be achieved?

[ger21]

Toggle the Active Low setting?

[FranKrause]

Thanks, but that doesn't seem to have an effect.

[FranKrause]

Ah-HA! I mean... Ah-ha? I think I may have found a solution, but I'm not sure if it will lead to the eventual meltdown of any of my components. If I connect everything like it is in the photos, but I run a jumper from FWD to XGND, the VFD will always be in "RUN"mode, but the spindle won't be moving since Mach3 is telling it that the frequency is "0". Will this cause any strain on the VFW to be in "RUN" mode all the time but not actually spinning the spindle?

One other question: with this setup, in Mach3 -> Ports & Pins -> Spindle Setup -> Relay Control, should I enable or disable Spindle Relays? It doesn't seem top have an effect.

Thanks!

[mactec54]

Ah-HA! I mean... Ah-ha? I think I may have found a solution, but I'm not sure if it will lead to the eventual meltdown of any of my components. If I connect everything like it is in the photos, but I run a jumper from FWD to XGND, the VFD will always be in "RUN"mode, but the spindle won't be moving since Mach3 is telling it that the frequency is "0". Will this cause any strain on the VFW to be in "RUN" mode all the time but not actually spinning the spindle?

One other question: with this setup, in Mach3 -> Ports & Pins -> Spindle Setup -> Relay Control, should I enable or disable Spindle Relays? It doesn't seem top have an effect.

Thanks!

Most likely nothing is happening because you don't have the correct output pins set to use it

Yes that will work, but is not very safe to do it like this, this is Ok for testing, as you should have a relay to turn it on and off, FWD run on the VFD is just switched, so the output from the Breakout Board should be turning ON / OFF a Relay, or if your Breakout Board already has a Relay, set up the correct output Pins to drive it, so you can use this to switch the FWD On / OFF

[FranKrause]

Thanks! I finally had some time to sort this out. I figured out how use the relay switching on my breakout board. It was switching the connection between my FWD and COM wires. The AVI was providing the 1-10V speed control. I connected my FWD wire from my BOB to the FWD wire on my VFD, the COM wire of my BOB to the XGND of my VFD, the AVI wire on my BOB to the Vl1 on my VFD. Then I ran a jumper from the XGND to the GND on my VFD.

When it's running, the relay switches on the spindle by connecting FWD to XGND, and the speed is controlled via the Vl1 and GND connections.

The last thing I had to set up was the deceleration speed. I kept getting overvoltage warnings whenever I turned off the spindle. It turns out the default acceleration & deceleration times were 2 seconds, so I switched them to 9 & 8.6. For some reason, it lists 9 & 8.6 in the manual as the "user set value" and 2 as the "factory settings." I'm not sure why those are different, but giving it more time to slow down has fixed my problems.

Thanks, everybody!