Bridgeport Series 1 Boss3 LinuxCNC Conversion

[rwm]

Definitely watching your progress!

 

[rabler]

The currently hurdle is getting the VFD to work via RS485 commands from LinuxCNC. This is where the cheap VFD from a Chinese company called 'Mollum' demonstrates why you should buy an expensive American one, if you've got the cash. So far, I've been able to get the spindle to run in the forward direction.

Any particular reason you went RS-485 over an analog output (10V) RPM signal and forward/reverse contacts?

 

[Shotgun]

Any particular reason you went RS-485 over an analog output (10V) RPM signal and forward/reverse contacts?

Feedback and control of the other outputs. The VFD has a couple relays that might yet prove to be useful, and I could get back info like current and torque and such.

 

[Shotgun]

Well, I think I've reached an impasse.
I was able to add a USB-RS232 converter to communicate with the VFD, and using the mb2hal component of LinuxCNC, I could get the spindle to turn in the forward direction if I sent a '1' to address 2000H, or I could get reverse by sending a '2' to the same address. No other value would do anything, and it would only accept the input once.
I was able to get a few messages from Mollum. They said that I could control the speed sending the desired frequency to 1000H. Nope. Didn't do anything. And now, Mollum tech support appears to be ghosting me.
I'm going to give them a little more time to respond, but it looks like I may have to re-engineer the control section of this project.

 

[Shotgun]

Well, I'm backed into a corner. Most of the other VFDs are much larger than the Mollum, and space is tight in my project box. Another brand just won't fit unless I redesign from the ground up. The only good spot in all this research is that this one appears to be a duplicate of the EV200 sold by StepperOnline. I'm hoping there might be someone might have gotten one working.

 

[rwm]

I know its not ideal, but what about mounting the VFD outside of the project box? Maybe attached to the side?
Oops, I see you have receptacles on the side. Maybe on top? It would look good and give you easy access and visibility of the display.

 

[Shotgun]

Not ideal, @rwm . I would prefer to keep anything with fans in a place with filtered air. But, I may have no choice.

 

[Shotgun]

This is strange.

The USB-485 adapter I'm using to talk to the VFD has Power, RX and TX lights. Just the Power is on until I get LinuxCNC going. The RX and TX light up like Christmas then.

I'm able to send one command, and then it is back to just the Power light. If I power cycle the computer, the TX flashes once when LinuxCNC comes up. And, then nothing except the Power again.

Looking for ideas on what might be causing this. Something from the running VFD feeding back into the adapter, maybe?

 

[rabler]

This is strange.

The USB-485 adapter I'm using to talk to the VFD has Power, RX and TX lights. Just the Power is on until I get LinuxCNC going. The RX and TX light up like Christmas then.

I'm able to send one command, and then it is back to just the Power light. If I power cycle the computer, the TX flashes once when LinuxCNC comes up. And, then nothing except the Power again.

Looking for ideas on what might be causing this. Something from the running VFD feeding back into the adapter, maybe?

I’d suggest opening the serial connection with something like putty, and seeing what happens when you send commands that way. That eliminates any questions of what linuxcnc is doing.

 

[rwm]

I’d suggest opening the serial connection with something like putty, and seeing what happens when you send commands that way. That eliminates any questions of what linuxcnc is doing.

For those novices among us, this make little to no sense. Unless you are talking about plumbers putty???