CNC4PC C23 Power Connections

[TravisR100]

I've got a C23 board from cnc4pc.com. I looked and didn't see a specific forum for their products so I'm posting this here. I apologize for the long-winded, very detailed post. I simply want to make sure I provide all the information to answer my questions.

The documentation for power hookups leaves something to be desired. Here are the issues. I'll be referencing two documents.

Document 1
http://cnc4pc.com/Tech_Docs/C23-Dual...Board_Rev2.pdf

Document 2
http://cnc4pc.com/Tech_Docs/C23R2WG.pdf

Document 1 says, "When using the Smooth Stepper board there is no need to use an additional power supply to power the optoisolators, the board will draw power from the Smooth Stepper board."

Document 1 says, "The signals are transmitted through light and not through physical connections. In this way, a power surge has no way of reaching your computer. That is the reason why this card has two power connections. One power connection is power powering the circuit that interacts with the PC, the other connection is for powering the circuit that interacts with your cnc system."

Document 1 says "Requirements: A power supply with 5vdc@ 2 amps. If not using the Smooth Stepper Board it will ALSO requires a connection to your PC power supply. A USB cable could be used fir this, but it is not provided with this board. You can also wire it directly to your PC power supply."

Document 1 says, "Connect the Smooth Stepper Board or an isolated power supply to power the optoisolated side of the circuit." So it doesn't necessarily need power from the computer after all? It can take an "isolated power supply?" Isolated from what?

All this would lead me to the following:
There is a "computer side" of the board and a "cnc side" of the board. They are separated by optoisolators. So far, so good.

The computer side of the board will get its power either from the SmoothStepper (which I'm using) or from the PC power supply which must be brought in from the PC. This all makes sense. I assume it's wanting the computer side to share a common ground.

Now on to Document 2.

Document 2 has a section labeled "Power from your PC." It says, "Provide +5V from your PC. You can use the provided USB power cable or wire it directly to your PC's power supply. No need to use this if using a SmoothStepper. The SS will power the optos." Yes, this statement references the "provided USB power cable" that document 1 states isn't provided. No big deal. OK, so this connection on the board is obviously not used if I'm using the SmoothStepper, which I am. It obviously is an input connection for power from the PC power supply. I'm going to call this Power Connection 1. Moving on.

Document 2 has a section labeled "Power Connections." It says, "Provide +5vdc at 2 amps. There are extra terminals to ease powering of external devices." Now, zoom in real close to the connections this section is pointing to. It says on the PCB, "+5vdc@ 2 amps must be provided to the power card. Use additional power connections to external devices." I can only assume he meant to say "...must be provided to power the card" not "must be provided to the power card." On this section of the PCB there are 2 ground terminals and three 5v terminals. I'm going to call this Power Connection 2. Moving on.

Document 2 has a section labeled "Analog Output." It says, "The analog output is optoisolated. An external +12vdc power source is required. This circuit consumes less than 10 milliamps. Use the pot for fine tuning the output voltage..." The PCB here has "external power" connections for 12v and gnd. It also has connections for the analog output to the speed controller. There is a warning note here. It says, "These grounds must be common with the grounds of the speed control connection, but must be kept isolated from the grounds of the board." I will call this Power Connection 3.

All of the above statements raise a lot of questions for me. Here are the questions and my assumptions.

Power Connection 1 I shouldn't need to deal with since I'm getting power from the SmoothStepper. This is the "computer" side of the board and should share a common ground with the PC since it's getting power from the USB cable to the SS.

Power Connection 2. This connection seems to need an input to the board of 5vdc at 2 amps. The confusing part is there are 2 ground connections here and 3 5v connections. Can I simply apply 5v to any one of them? Do the others then become outputs for 5v? This seems like a built in terminal block of sorts. Is this correct?

Power Connection 3. This connection seems to be for yet another, third, power supply. It requires 12v and has a ground connection as well. It also notes in the warning that this (these it says, although there's only one) ground should be common with the ground of the speed control connection.

Ok, all the questions.

In previous posts I've read by Al everything should have a common ground. I'm taking the earth ground from the AC power connection from the wall and tying it to a grounding board in the electronics cabinet.

If I'm supposed to tie all grounds to this common grounding board how would the 12v power supply to Power Connection 3 (which would go to this grounding board), the 5v power supply to Power Connection 2 (which would go to this grounding board), and the motor control ground (which would go to this grounding board) be isolated from each other? It just doesn't make any sense to me.

The C23 notes as well as the speed control notes are very adamant about the fact that this connection between the two should be isolated.

For Power Connection 2 which requires 5v 2a could I use a 5v 3a power supply instead? Could I use a switching supply here or must it be linear?

Could I use a dual output power supply that supplies both 5v 3a and 12v 2a to provide power to Power Connection 2 and Power Connection 3?

So confused here. Again, apologies for the very lenthy, detailed post!

[TravisR100]

Did I make this too detailed to get a response?

[dirtdiggler]

Hi Travis,

Have you sent these Q's to Arturo at CNC4PC. He usually gets back within a day or two. He will set you stright on the power. It's pretty simple. I think in manuals he doesn't keep some of the info consistant so it gets confusing on some parts.

I have the same board (C23) and I'm ordering a smooth stepper today. I already have the C23 board powered though for testing.

The 12V side is if you are using the VFD control part. I haven't needed to power this yet. I power the 5V 2Amp side with my computer power supply wires, and the other 5V with USB wires from the computer. Just take an old USB cord and splice out the ground and pos and wire it to the board. You could also just find an old 5V power supply, like a phone charger and it will usually do the trick. Just make sure the amps are low.

I'm interested in what how your setting yours up. Maybe we can help each other. Mine is going retro'ing a BP Boss 9 series II



Kirk

[TravisR100]

I believe I've pretty much worked through all the questions myself or got explanation from Arturo. Hopefully I'll have time to post a build log at some point.