Novamill - Mach3

[Deck36]

I noticed they aren't the strongest when they just keep going if I hit the hard end stop.

Looks like I have some fixing to do. In the meantime I've managed to get all the axes to jog and found the pins/port combination to get the spindle to run, but I have no control over it.
Keep getting the PWM bumped to minimum warning even when I enter big numbers.
Any clues on how I get control? The screen overrides won't work but I can start it from there or the F5 key.

[m_c]

It's been a long time since I've used Mach3, so can't really help you there, but it'll depend on exactly how the speed control is being done. You'll probably have to trace the wiring to establish how it's wired in, as going by your photos, it doesn't look like it's using the BOB's 0-10V output.

[Deck36]

Thanks for your help. Seems like I've hit a wall at this point

Think I'll just have to leave it now as I've pretty much run out of time. Back to knife and fork to make my final components

B

[JohnHaine]

Are you using the original Sprint speed controller? If so do NOT try connecting the BoB 0-10v output to it as the controller is isolated from ground and its 0v floats at something round half mains voltage. An isolation circuit is needed. I've got a Novamill with a slightly different Bob but happy to share xml when I'm back home. Also can possibly help on the isolation.

[Deck36]

Thanks John

I took some more photos earlier which might show what's what. Spindle was running fine before the dead HDD, so it my just be a case of the right pins/outputs.
Like I said before, the spindle will start with the pins I've picked but there's no control like before. I ned to take a closer look after m_c pointed out the lack of control connections to the 0-10v outputs on the BOB

[Deck36]

If you think your XML might work I'd be very happy to give it a try

Thank you

[m_c]

Are you using the original Sprint speed controller? If so do NOT try connecting the BoB 0-10v output to it as the controller is isolated from ground and its 0v floats at something round half mains voltage. An isolation circuit is needed. I've got a Novamill with a slightly different Bob but happy to share xml when I'm back home. Also can possibly help on the isolation.

The machine has been running, so I'm guessing there must already be some form of isolation.
Going by the photos, I'm guessing P17 is being used to control the SGR (Spindle Go Relay aka switches on power to the Sprint drive), and then the little red wire next to it from the P1-PWM terminal is being used to control the speed.

However to use that, I'm guessing there is another PCB mounted somewhere, because as far as I can remember, the Sprint drive only accepts a 0-10V supply, which must be isolated. Unless it happens to have an isolated Sprint drive, but AFAIK Denford didn't use isolated drives.


Just to be clear what we mean, due to the design, SCR motor controllers (which the Sprint is), the speed control voltage sits at roughly half mains voltage, which is why it needs to be treated with caution. You do risk giving yourself a tingle if you touch those pins/wiring with it powered, but the equipment risk is by connecting them to a non-isolated circuit, magic smoke will be released.

Can we get a full photo of the Sprint drive (lower right corner of your photo)?
And where does that little red wire go to?

[Deck36]

The little red wire goes here:

Close up of the Sprint drive

[m_c]

Looks like they've patched the PWM signal into the original interface board, in which case you just need to work out the PWM settings to control the spindle speed.


You'd need to confirm, but if you wanted, you might be able to connect the Sprint direct to the BOB, as I think the 0-10V circuit on the BOB is isolated from the 5V control circuitry.
You could confirm by removing the 12/24 wires to the BOB and checking everything else still works, and also checking that the Gnd for the 12/24VDC supply isn't connected to the other BOB Gnds, and only connects to the 0-10V Gnd. If that's the case, then you'd just need to add an isolating DCDC converter to get an isolated 12VDC supply to provide the required isolation.

[Deck36]

Given that it was working well before the drive died, I'm reluctant to make any big changes right now.
If all I need are the right PWM settings I stand a chance of being able to finish my work in time.

Just a case of figuring out what they are