Issues with Spindle/VFD Modbus 'Timedout' status

OK, so I have been scouring the forums for ideas on how to get my spindle up and running. I purchased a PWNCNC spindle and VFD combo as I was looking for a plug-and-play solution and wanted to get up and running as soon as possible.

The spindle combo arrived and I hooked up as per the instructions and with the knowledge gained from this forum. I tested it manually and everything work, I was even able to do a test carve. Then when I went into the tool menu to select the VFD and hit save the status changed from Disconnected to Timedout indicating no serial communication going on.

I tried to swap the wires in the breakout plug with no success. I checked the continuity of the wires in the cable and no success. The cable is shielded and I checked the breakout plug to ensure all the wires were seated properly. PWNCNC has been awesome through all of this and they have even sent out a new cable and a different VFD, but unfortunately, this is still not resolved so I think they have done everything they can from their end to help but I am still stuck.

I recently removed the breakout plug I was using with an IOT powerstrip for my makita router so I know that at least pin 15 is currently working.

What else can I check? I believe the VFD is programmed correctly as we have tried two different ones and no luck. Is there anyway to verify other pins from the DB25 are working? Is there a way to “ping” the VFD from the controller/interface (I believe this is what the status is?)?

Please help, I need to get this running.

Check that the plug is seated properly . I had trouble whereby the screws to tightened and hold the plug on place were preventing the plug properly engaging in the socket.

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Try this. I think i did similar.

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Hey makermatt,

Thanks for the ideas and links to other things to try. I will dive in tonight or tomorrow and see what progress I can make. It was very clear from OF support that they do not provide ANY support for spindles even when I was asking about verifying that the BB controller was working correctly and testing pinouts for correct/expected behavior or signal. Honestly it was the first time I have been disappointed in my interaction with OF support but I guess they drew a line and are sticking to it.

In terms of the RS485 wires being swapped around, I am not sure if this is what is in the DB25 connector or something else, but if it is not in the DB25 breakout and is in the VFD itself, that was setup by PWNCNC and I can check with them on this being a step to try.

@Aiph5u thank you for pointing me to those other threads, I have checked the first with the breakout board as I swapped it to one that I had used previously that I know is making contact (at least pin 15) and was able to measure a perceivable voltage with my multimeter so it seems that there is a connection there to some degree just not sure if it is what is expected or needed for the modbus comms to work.

I will open up the BB controller next and check each of the solder joints for the dsub connector. I am assuming that a continuity test will work here with a probe on the pin and a probe on the trace on the board that leads to the soldered connector? I will dig in to that thread and see what else to try. Thanks for the link.

OK, I spent some time tonight removing the PCB from the black box and checking all the pins for the DB25 connector and they are all soldered well and I have even traced the leads back from where the connector is soldered on to the PCB back to the chips where they connect to make sure the traces were solid and conducting. Everything seems to be connected just fine. I used the schematic and PCB layout to trace all pins back to their source up to the point where ohms or a continuity tester wouldnt detect which was typically a leg of an IC, a resister, diode or a capacitor.

I plugged in the Breakout connector and made sure there was a signal all the way through the cable to the connector where it plugs into the VFD and that has continuity all the way through so I believe I have eliminated that as a possibility where the issue is coming from.

I have not changed the baud rate as another forum article mentioned so I was going to try that next to see if that makes any difference, but I need to figure out how to change that on the PWNCNC VFD before I can try that.

Any other ideas on what to check?

This is tough and must be frustrating.

It has been a while since set my spindle up and that before the PWNCNC offering around.

All i can think of is things you’ve probably tried.

I bought, but never needed to use in the end ( it wasnt cheap) an unit that plugged into the vfd so that i could set and view my settings as tapping through the screen was prone to error and long winded. Not sure if you have this option with your vfd.

My comms issues were all DB connector issues once i got vfd configured.

I do remember having issues with setting the BB config (e.g. signs) but i didnt have a preconfigured BB set up. You could, if you havent, try configuring BB yourself. For me, it was some trial and error once all other paths failed.

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Hey makermatt,

did you understand that the first link describes that the screws of the breakout board adapter were too long and removing them solved the problem?

Also you have to consider that you are not forced to use a breakout board adapter. Such adapters with screw terminals are for people that have no opportunity to solder. If you can solder, you can use just a D-Sub connector and solder the wire directly to it so that you have a custom cable, with connectors matching your VFD’s terminals at the other end. You can also use a 25-pin D-Sub extension cable to have the breakout board adapter at a more comfortable location.

See also this RS-485 VFD connection instruction page.

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Thanks for asking, yes I understood this and checked on that. I also reported above that I had tested the continuity from the chip to the end of the cable indicating that the connector is plugging in and doing its job to provide the connection.

In terms of your second point, that is helpful to point out, but I am not sure that would fix anything as I am getting measurable voltage at the end of the cable that plugs into the VFD from the BlackBox (through the DB25>breakout>cable assembly)

Hey Makermatt,

did you already go through #Troubleshooting

Hey Makermatt,

also I would check for

  1. correct grounding and shielding,
    and for
  2. RS-485 bus termination (my VFD (Omron MX2) has an internal termination resistor that can be switched on with a DIP switch)
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yeah, I went through this already and unfortunately with the PWNCNC vfd being pre-programmed I am hesitant to dig in to their program. I have gone through everything that I can find in regard to the BB box itself

I will dig into these articles and see if I can make any progress. Also I will check with PWNCNC and ask about the termination.

Hey makermatt,

the most important thing is that the VFD is set up to communicate via Modbus. Daniel @PwnCNC offers VFDs with different settings, e.g. the one for Masso is not set up with Modbus interface capability as the MASSO G3 is unable to communicate via Modbus.

Also the parameters like baudrate, stop bits, parity bits, slave bus-id must be exactly the same on the VFD and on the (buildbotics-derived) Onefinity controller under TOOL > Modbus Configuration as described here. The PwnCNC VFD manual is here, but don’t ask me, Daniel @PwnCNC knows this VFD better

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