Ajax CNC Mach3 3-axis mill conversion thread

[skyg]

Hello -

My friend and I have a fairly large - 70"X36"X36" 3 axis mill that was custom made for making plugs for composite tooling. It was made by another friend, who used it for a number of years and then passed it on to us. It currently has a Galil card in it, running on the parallel port and Mach3. The theoretical travel speed of this mill should be ~400 ipm, but we're having trouble running it much faster than 80 ipm w/o the motion quality suffering. Also we're having a lot of stability issues on the parallel port - at least we think that's why the computer that runs the machine seems to crash quite frequently. So, we made the decision to upgrade to the new Mach3 kit that AjaxCNC makes. I figured I would start a thread on the conversion for two reasons. First, I'm sure I'll have plenty of questions along the way. Second, I figure someone might benefit from a step by step thread.

Since the mill is up and running, and we'd like to minimize the amount of down time, I decided to mount the breakout boards to a piece of insulating board. That way I can do as much wiring as possible before swapping out the electronics inside the cabinet. I bought some 0.25" electrical grade fiberglass sheet to mount everything to. Then I used some 6-32X3/4" machine screws and t-nuts to mount the breakout boards and power supplies to the sheet. I've got all the power connections made, just need to get a wall socket plug to hook up the two power supplies to.

Next I'll take care of the plugs for the servo drivers. I've got 3 Baldor TSD servo drivers, and so I just need to make the connections from the GPIO4D to the Baldors. I'm not exactly sure which connections I should be making (this is my first conversion, so if I ask/say anything dumb......). I've attached the manual for the servo drivers. If you look at page 7 you can see the inputs/outputs for the drivers. What I'm guessing the connections should look like are as follows:

GPIO4D Baldor TSD
ANALOG DIFF+
ANALOG COM COMMON
ENABLE OUT ENABLE

Since the Baldor TSD manual says "Input Speed Command -- Differential or single ended analog input signal (± 10 VDC) which is directly proportional to desired operating speed." I'm guessing that there does not have to be a connection between the GPIO4D and the Baldor DIFF- input - Is this correct?

-Sky

[skyg]

I just realized that instead of wiring the Enable Out of the board to the Enable input of Baldor, I should be sending that signal through the E-Stop contactor, correct?

-Sky

[diycncscott]

Sky,

After briefly reviewing the pdf you posted, I'd guess that diff- would be wired to the analog common of the gpio4d and the diff+ should be wired to the axis analog output.

I'll try to look it over a little more closely and get back to you

[skyg]

Scott -

It could also be that it gets wired how you say, and then on the Baldor I jumper the DIFF - to the COMMON. Thoughts?

-Sky

[diycncscott]

Hi Sky,

Just to be sure: We are talking specifically about the axis analog common on the GPIO4D and no other common. As far as I can tell, the DIFF- for an axis should be connected directly to the Analog Common for that axis on the GPIO4D. That should be the only connection, it should not be "jumpered" to any other common on either the Baldor or the GPIO4D.


Regards

Scott

[skyg]

Ok - so there should be nothing connected to the COMMON input on the Baldor, correct?

[skyg]

So I've got the power supplies all hooked up, and it's connected to my computer. A few questions -

1. Is there a manual for installing with the GPIO4D instead of the DC3IO? If there is I can't seem to find it.
2. Instead of having the "DSP Debug" LED solid green, and the "DSP-OK" LED flashing, it's the other way around. What could be causing this? Is this a problem?
3. How do I determine the correct SIP value for the inputs? I'm planning on using the +5VDC from the PS1 - just want to make sure that's ok - that I don't need a stand alone power supply just for those inputs.

-Sky

[skyg]

I've figured out the answers to 1 & 3, just need your input on 2. Please let me know what it means that DSP Debug is flashing, and DSP OK is solid. Was that a typo in the manual or is something wrong??

Also, I'm bench testing the setup right now and having one issue with the limit inputs. When I set any of the limit inputs to Active Low in Ports and Pins, they start flashing, in a irregular fashion. Any idea why this would be?

[diycncscott]

Hi Sky,

You are correct, DSP debug flashes and DSPok should be solid.

You should be using normally closed limit switches (closed when the limit is NOT tripped).

If the limit inputs are flashing erratically in Mach, I would guess that the inputs are open and are "floating" between states.

The correct configuration for you limits in Mach is "active low" and the plugin should have selected that when you installed. Was that not the case or did you change them?

[skyg]

OKay, good to know the boards are ok, thanks.

I can configure my limit switches to be NO or NC, so for safety's sake I'll of course set them up as NC. I don't believe that "Active Low" was set when I first installed the plugin, but it doesn't much matter that they are floating, since I won't be running them in that configuration anyhow.

Attached is a pic of the current setup. There's a 5V bus along the bottom right that's partially obscured by the wiring. Above it is a terminal strip for all the +/-/home switches, and the e-stop switch. Everything is now behaving properly in Mach, so I'm just about ready to do the install. Just waiting on one more connector to show up, which should be here this week.