[Tom Kay]

Hi;

I have received my C10 breakout board from CNC4PC. I want to know a bit more about the connections before I hit the power switch. The pull-up or pull-down option has me a bit confused.

I want to run 3 steppers (4 eventually) with Mach3 software from the parallel port. I will use db25 cable pins 1-17 as outputs (pins 2-9 as step and direction).

Can anyone clear up the pull-up/down resistor thing? How do I determine which I need? I know I set this with a jumper, but pull-up or pull-down?

Also, with Mach3 software, is the chargepump connected to the C10 enable pin? Or should I just connect a jumper from +5V to the enable pin to get the whole system running?

I'm just bench testing for now. I don't own a mill yet. To early to hurt myself!

I just don't want that puff of smoke when I switch on.

Thanks, Tom.

[SignTorch]

pullup/down resistors set input polarity when the input circuit is open

such as if you have a button from ground to an input (active low)

when the button is not pressed the input circuit is open, neither high or low is reaching the input pin, so the input polarity is ambiguous

in that case you need a pullup resistor to hold the input high when the button is not pressed

if you were to put a pulldown resistor it would hold the pin low, which would activate the active low input continuously, such that the button to ground would be redundant and ineffective

it lets you set the default (safe) value on each input pin

if an input is open, and has no resistor, it can fluctuate and cause random input signals/errors

[Tom Kay]

Signtorch (and other readers);

I really appreciate the efforts to explain about this. Unfortunately, this is truly some of my weakest knowledge base, and I'm still not fully clued in on the pull-up/down issue (I mean where the actual resistor would be located), especially as it pertains to my new C10 board. Although, I hope the fog is slowly lifting.

I know that there are a number of jumpers on the C10 board that give the user easy-to-use options, such as setting some/all resistors. I've followed the setup guide, but I have not actually checked to see if I'm getting 5 volt step pulses at the step output pins of this powered breakout board.

Before, when I used a "passive" (unpowered) breakout board, the weak 3V pulses from the parallel port were simply distributed to the 3 motors. In effect, the breakout board was just that, a distribution board with lots of paths coming in from the db25 connector, but then neatly distributed to 4 different areas for the 4 motors it could handle. It actually looks like a 16 lane highway broken into 4 four-lane highways. However, with weak signals, sometimes my motors ran reasonably well, sometimes they looked like twitching, dying roadkill.

So the whole point of the new powered breakout board, I assume, was to amplify weak parallel port signals to strong 5V signals, which are in turn input to my stepper driver boards. Sorry about this "tutorial" but it's more for my limited understanding than anything.

In setting up the C10 board, I have placed the jumpers in the (hopefully) correct locations. When I return home tonight, I'll see if I'm getting any voltage at the step pin outputs. If I'm not, then the board isn't outputting any pulses, and this is where I need to focus my attention.

On this board, there are hookups for an E-stop button (normally closed) and also limit switches (normally closed). I didn't have anything connected to these, and I was wondering if I should just connect a jumper wire to act as closed E-stop and limit switches. I do have a wire jumper from +5 Volts to the Enable connection on the board, as the instructions specify.

As far as the pull-up/down resistors, I haven't attempted to even understand these, because the vendor of the board said that if pins 2-9 of the db25 cable were to be used as outputs (for step and direction on 4 motors) then the resistors are not even an issue. Ignore them. Does this sound correct?

Also, my driver boards from Dan Mauch (old kits) have 5 volts supplied to them to function, from a small wall wart. I am using a separate 5volt supply to power the C10 board. Does this sound normal? I noticed in one wiring diagram, that Gecko drives would simply take 5volts from the powered breakout board, but I'm using 2 separate supplies. Any bad issues with this approach?

OK, sorry for the long essay, and thanks to those who might wade through this. Each person who sets up any CNC machine and runs into problems probably knows how frustrating it can be, especially if you have all of the hardware and software, and 99% of the correct setup. I know I'm just overlooking something relatively simple that can be corrected with jumpers, software configuration, etc. Remember, my motors were running (inconsistently) with a non-powered breakout board, so I was essentially confgured and successful. I'd rather get this new board figured out, than buy an old computer with a strong, full 5 volt parallel port.

So please feel free to chime in, especially if you use the C10 breakout board from CNC4PC company.

Cheers all, Tom.

[Tom Kay]

I know that there weren't too many replies to my "Help!", but I understand that my situation was a little different than what most cnc'ers run into.

I was trying to get the C10 breakout board to amplify the weak parallel port signals and feed them to some old driver kits that Dan Mauch at Camtronics used to sell. I've warehoused these assembled kits for years, and before giving up and spending more money on Gecko's I just wanted to see if I could make them work. To be honest, I will probably end up with Geckos anyway, especially if micro-stepping is a good thing. Dan's old kits might do half-stepping, but not X10 microstepping.

Many attempts, swearwords and head scratches later, it simply came down to applying a jumper between the ground pin and the enable pin of Dan's driver boards. Suddenly, the motors behave as well as I could hope, although now it's time to do some tuning with Mach3.

This was a frustrating experience, but the good points are that the C10 board from CNC4PC works very well, lots of people helped me along the way, and at least I have the clean, precise sound of steppers in my head.

Probably the most difficult part was deciphering some poorly written text on setting up the driver boards. I make mistakes too, but clear communication really does matter, especially if you're offering a product to the world that needs extensive assembly.

The text that comes with the C10 breakout board is much, much, MUCH better, but I still had a few questions along the way. Passing grade, though. I'm happier today than I was yesterday.

Cheers, Tom.

[Azalin]

Bump

I own a C11GS from cnc4pc. I did all the wiring and waiting to power up everything but this pull-up/pull-down is confusing me. I just have a C3 spindle indexing board connected to the input pin #15. In this case I don't know if I need the jumper set for pull-up or pull-down.

[CNCMAN172]

Azalin,
The pull up or down down option is normally dictated by your parallel port card. Most parallel port cards have pull up resistors, so they are normally high. I also have the C10 card and set mine to high because that is what my parallel card also uses. This seems to work fine. The CMOS chips they use want the inputs to be pulled one way or the other because you can't just let them float.

Russ

[Azalin]

Hi Russ,

I use an old IBM laptop (T42). I have no idea what it requires on the pins 10, 11,12, 13 and 15. Should I search for some info about the LPT port that T42 uses?

These are the specs of the C3

• Reads an index pulse from the spindle.

• Acts as an optical switch for accurate homing.

• TTL or Open collector output signal.

• Active low or Active high output signal.

• Comes with a Built-in LED that shows the status of the output pin at all times.

• Comes with 6’ pre-wired shielded cable.

• Easy connections.

• Screw-On connections for all terminals.

• Comes with an RJ45 Connector fast installation

Thanks for your reply.

[CNCMAN172]

Azalin,
Those are all input pins, which can be used for various purposes like limit switches or whatever you need. Set them to pull up, the parallel port has traditionally used pull up resistors since it first came out with the first IBM PC. Keep in mind you will not hurt the board if you set this to pull down. Next after you set the board to pull up then go to the MACH3 diagnostic page and make sure when you put a low on those pins the LEDS light up for that given pin. You also have to configure the ports and pins page in Mach to set those inputs as active LOW.

Let me know if you have other questions.

Russ

[Azalin]

Got it Russ. I'll give it a try. Thank you.