[trogan]

I found the documentation slightly unclear regarding exactly which power connections should come from the PC vs. which should come from my dedicated machine power supply. Best I could figure out, this was the correct way but can someone who knows for sure confirm? Thanks!!

[john-100]

Hi trogan

to me it looks like you need to swop the 5v supplies over

your "external 5V " ground is connected to the PC printer port ground

I don't think you will be able to take this from a USB port -
I think A USB port is limited to 250 mA until the PC detects a USB device , then the limit is increased to 500 mA ( 1/2A)





John

[trogan]

Thanks, john-100. I see what you mean about where it says "these GND terminals are common to PC GND". I suppose I didn't immediately recognize that text as instruction to supply PC +5v at that location. But I guess that makes sense now that you mention it. Also, I've tapped straight into my PC's power supply; I'm not using a severed USB cable for power so I should be in good shape there.

EDIT: OK, I'm confused again. Looking at some wiring documentation again, I'm seeing conflicting data.

This suggests I have it right: http://cnc4pc.com/Tech_Docs/C11R8WG.pdf
This suggests that perhaps I do not: http://cnc4pc.com/Tech_Docs/WG_C11TR2.pdf

[trogan]

OK, I think I have this figured out now. The tl;dr is that I think I have the wiring correct as shown in the picture of my original post.

Here's the nitty gritty of why I think I have it correct. I had to get out the multimeter and check continuity between some things to make sense of it.

1. In the attached picture, all arrows of the same color are points which are common to one another (0Ω).

2. The power terminal at the bottom, marked with the orange and gold arrows, is tied to the +5v and GND pins on that big chip on the board. Based on that, I'm asserting that this should be fed by the PC +5v.

3. The power terminal at the right, marked with the purple and red arrows, is tied to +5v and GND pins that go with the IO pins of the breakout board itself. The jumper which decides whether your 4 axis COM pins (lines in blue) are GND or +5v is also tied to the same place. Based on that, I'm asserting that this should be fed by the machine's +5v power supply.

I feel pretty confident about it now, but if someone in the know disagrees, I'd love to hear. (Does Arturo Duncan from cnc4pc lurk in these forums?)

[john-100]

Hi trogan


you diagram is not exactly what I expected

the 0V / +5V jumper for the common terminals for the outputs outputs is the same used on some of the other CNC4PCs breakout boards

I had expected the AT89C51 to be powered by the 5V supply connected to the printer port
and the low current 5V supply to power the input side of the 4 opto isolators used for input pins 11,12,13 and15

does this mean you need yet another 5V power supply for any limit switch you have ?




john

[hub]

From the first pic,
Connect +5V (external PSU or wired from PC PSU +5V) to "left", marked as "+5V from PC". NOT from LPT port.
Connect a +12V PSU (or from PC PSU +12V) to "external +12V".
The connector marked as "External +5V" is an +5V output IMO.

Connect all 0V/(GND/COM) together, PSU, BOB & LPT & other I/O devices.

[arturod]

Trogan,

Use a [email protected] A to power the board. This goes in the main power connection, the one on the end of the boards with two sets of +5vdc and GND terminals. This is what powers the board. The other power terminal is optional, is for powering the outputs circuit in case you need to keep the isolated. Most drivers are optoisolated, but if using the G320, you need the optoisolation as the ERR/RES terminal is not optoisolated. The +12vdc terminal is just for the analog circuit. If using a VFD, you can power this with the +10vdc reference from the VFD.

Let me know is clear enough.

Arturo Duncan
:: CNC4PC :: iNtRo

[trogan]

Thanks for commenting, Arturo! Instead of trying to type a description of why I'm still confused, I decided to make a short youtube video to explain it more effectively. https://www.youtube.com/watch?v=wiJcYZekv80

[arturod]

I am sorry, I certainly misspoke, I meant that it was optional to use additional power supply, if you do not need to isolated the outputs circuit, you can power it with the same power supply that is powering the board. What drivers are you using? There are some wiring diagrams in our website that I am sure you can use.

Arturo Duncan
:: CNC4PC :: iNtRo

Trogan,

Use a [email protected] A to power the board. This goes in the main power connection, the one on the end of the boards with two sets of +5vdc and GND terminals. This is what powers the board. The other power terminal is optional, is for powering the outputs circuit in case you need to keep the isolated. Most drivers are optoisolated, but if using the G320, you need the optoisolation as the ERR/RES terminal is not optoisolated. The +12vdc terminal is just for the analog circuit. If using a VFD, you can power this with the +10vdc reference from the VFD.

Let me know is clear enough.

Arturo Duncan
:: CNC4PC :: iNtRo

[trogan]

No problem at all, Arturo! I appreciate that you took a few minutes to help me out. I have found the documentation on how to wire my drives up, and that all makes sense. Given that I had been previously suspecting EMI from the VFD to be the cause of some problems for me, I just wanted to fully understand what the differences were between the two sets of power terminals. I think I have a sufficient understanding at this point.

I am sorry, I certainly misspoke, I meant that it was optional to use additional power supply, if you do not need to isolated the outputs circuit, you can power it with the same power supply that is powering the board. What drivers are you using? There are some wiring diagrams in our website that I am sure you can use.

Arturo Duncan
:: CNC4PC :: iNtRo