[caleb105]

Help me, oh might CNCzone! Grant thee a sliver of thy eternal wisdom.

I am doing an X3 with Nema 23's on X,Y, and Nema 34 on Z. I don't know if it matters, but I'd like to add an MPG (Manual Pulse Generator) in the future as well. Oh, and possibly a 4th axis.

Nema 23's = 387 in-oz 3.5A, 65volt

Nema 34 = 640 in-oz 3.5A, 65 volt

PSU = 65volt/20A (DIY type)

G203V's

Thanks!

[LeeWay]

I think just about any BOB will work. Depends on your needs and how much you want to spend.
I am using C10 BOB's from CNC4PC and I'm happy with both cost and function.

[caleb105]

Leeway,

Yes, I have been looking at cnc4pc.com also. Do you need a C10 BOB for EACH motor?

Thanks!

-Caleb105-

[LeeWay]

No. The single C10 BOB does all four axes. Take a look at the schematics for each BOB you are looking at. Most BOB's will handle 4 axes. Pins 2 thru 9 are generally step and direction pins. One of each per axis.

A BOB mainly breaks out all 25 pins on a parallel port. Many do more than that, but that is a basic BOB.

[hoss2006]

Hey Caleb,
An MPG only needs 2 inputs and power so you could use one on a single C10 along with 4 motors.
If you want to have a manual axis selector switch like is used on cnc4pc's pendant
you'll need another C10 to handle all the OEM trigger inputs (10 on mine).
You'll also have to get the Mach 3 Brain to process the signals.( cnc4pc gives one for 4 axis)
A switch is more convenient than jumping back and forth from the MPG and mouse.
An easier tool might be the Shuttle Xpress or Shuttle Pro, I'm going to use one for my new build.
They've been on Ebay for $45.
Hoss

[caleb105]

Lee, thanks for the BOB info.

and Hoss, thanks for the great info on the MPG's. That shuttle express looks pretty interesting.

So my big question is, which of the following would you recommend? Seems like there are tons of different models, with greatly varying prices, and I really don't understand all the differences between them:

C1
C1G
C10
C11
C11G
C11T
C23
C25 (smooth stepper?)

KL-DB25


What is the "Smooth Stepper"? Keling's got one, but it's $159!! What the heck does this do? And is it necessary?

[caleb105]

From a different thread:

On the BOB, the only one I don't think I've ever heard a single complaint about is the PMDX. I've personally had, and continue to have, frustrating problems with my CNC4PC C11 BOB (I'm on my third revision now).

Regards,
Ray L.

[hoss2006]

The C10 is a simple breakout board, I haven't had a bit of trouble with either one I use.
the other multifunction boards like the c11, c23 have extra features like relays, speed controls etc with some gecco specific.
I like to keep things separate, less complexity to go wrong.
the smooth stepper is a USB driver, his c25 is just a breakout board for it.

[caleb105]

So....looks like my choices are:

C10 = $25.49
PMDX 122 = $81

Is there any reason to spend the extra money on the PMDX? Seems like both the C10 and PMDX are reliable.

[hoss2006]

The PMDX has a charge pump on board the C10 doesn't.
the C4 is $22.

[SCzEngrgGroup]

So....looks like my choices are:

C10 = $25.49
PMDX 122 = $81

Is there any reason to spend the extra money on the PMDX? Seems like both the C10 and PMDX are reliable.

The advantage is, if you accidentally short something, with the PMDX you'll most likely just blow up a chip on the PMDX. With the C10, you'll likely blow up the parallel port on your PC, or worse. Isolation is worthwhile. Most people will never *need* it, but it's cheap insurance.

Also, if your PC has a low-voltage parallel port, the PMDX will work fine, where the C10 might, or might not. This can cause flaky problems that can be very tricky to track down. Or the current capability of the parallel port may be marginal, and one day you'll hook up one more signal, and start getting flaky behavior. The PMDX runs from a separate power supply, so this will never be an issue.

Regards,
Ray L.

[caleb105]

The PMDX has a charge pump on board the C10 doesn't.
the C4 is $22.

C4?

[hoss2006]

C4 is the charge pump from Cnc4pc that works with Mach, like HK said it's cheap insurance just in case.

[cliveastro]

The CNC4pc is optically isolated therefore it wont blow up your parallel port. It also needs a seperate 5v power supply.
The biggest problem with BOBS is getting the software settings set up correctly.

Clive

[cliveastro]

Whoops
Should read CNC4PC C10 board.

[SCzEngrgGroup]

Whoops
Should read CNC4PC C10 board.

The C10 is buffered only, it is *not* opto-isolated.

Regards,
Ray L.

[cliveastro]

Strange that he offers buffers and optoisolators as replacements for the C10 board.
But I am not an electronics expert so I stand to be corrected.
Regards
Clive

[SCzEngrgGroup]

Strange that he offers buffers and optoisolators as replacements for the C10 board.
But I am not an electronics expert so I stand to be corrected.
Regards
Clive

Clive,

There are many errors, omissions and inconsistencies in their documentation....

Regards,
Ray L.

[cliveastro]

Ray
Yes I agree that the documentation is hastily assembled.
I have a reasonable understanding of an optoisolator, so how much protection will a buffer give if any, as I have 2 of these boards, one for my cncmill and one for the cnc lathe I am converting.

Clive

[Crevice Reamer]

For consideration, there is also the $183 PMDX-132 BOB for Geckos. After you mount your Geckos to it this is like a giant G540:

http://www.pmdx.com/PMDX-132/

CR.