Choosing a Breakout Board

[Barbs]

So I'm currently aspiring to build a 3-axis router. I'm new to the software/controller end of CNC building and am doing some research.

I was looking into a GREX as an end all solution. I wouldn't mind investing the $400 dollars for the G100 if it was vastly superior to the $100 BOB's that are out there, but from what I've gathered it hasn't lived up to its expectations.

So I am currently considering the PMDX-122, C11X, and the Campbell Combo board.

The PMDX board is the cheapest option. What does this board lack that the other have?

There is the C11, C11G, and the C11T.
Apparently the G11G is designed for Geckos in some way, how?
I like that the C11 is fully isolated. What is the difference between it and the G11G?
And I just don't know about the C11T.
There is a comparison chart on their site but I didn't find it very useful.
What are the pros/cons of each board?
There is also mention of a C23 but I couldn't find any info about it.

The Campbell boards are pretty steep, what features make this board so special?

Finally, I've heard a little info about this Smooth Stepper USB-to-Dual PP controller.
Apparently this device will allow you to connect two breakout boards allowing for more I/O ports.
The smooth stepper will be able to generate 4Mhz signals, but are the previous BOB's compatible with this?

I would think the BOB hardware would need updating in order to start receiving signals at a faster than usual rate.

Thanks

[keebler303]

First off, the GREX is a motion controller, not a breakout board. It generates all the pulses to control the machine by itself, it just needs the computer to tell it where to go. This is similar to motion controllers offered by Galil (www.galilmc.com) or others, albiet much cheaper. There are no problems with the GREX, the problem is it is designed for OEM applications primarily where an application is developed to control the GREX. The hobby market has not been pleased with the GREX because they don't understand what it is meant for. It is not Geckodrive's business to write applications to control it, nor is it Artsoft's (Mach's) main objective to write plugins to make their software, which is designed to work with parallel ports, work with the GREX.

In short, the GREX is still in beta stage as far as mach is concerned and so undoubedly there will be bugs/problems.

I'm not familiar with any of the boards you mention but I might be able to offer some insight.

You want to look at:

isolation
power supply
relays- if you need them for coolant, router on/off, etc.
screw terminals, connections are easier than with pin headers.

The geckos already have isolated inputs so it is redundant to use isolators on the BOB as well, that may be the "gecko" option on the Campbell board. Search the forums and you will find tons of discussion on breakout boards, everyone has a favorite. You need to get a better understanding of what your needs are and then go shopping for aboard which fulfills your needs.

Good Luck
Matt

[Barbs]

Thanks for the info. I knew the G100 was a stand alone controller but I just wondered why I should spend the extra cash when I can use software and a computer as a controller. If there is a significant advantage then I would still consider it.

Is there software that is better suited for coupling with a G100?

[CoAMarcus]

Barbs,

Keebler303 is right about what the G100 is meant for. For the majority of hobbyists, the G100 will be overkill. It comes down to situations where you KNOW you need the G100 as opposed to situations where you THINK you need one. Generally speaking, there are only four situations where you will NEED one:

1.) When you need a high step pulse frequency, and the 45kHz of Mach3 won't cut it for you.

2.) A parallel port connection is absolutely not an option, and Ethernet is the only way you can go.

3.) When you need more than 4 axes, which is typically what most breakout boards provide.

4.) You require lots of I/O's, 16 general purpose inputs and 22 general purpose outputs to be specific.

Because it is meant for a job where the user would ideally have their own program for it, the only hobby program available is Mach3. If you are not going to be requiring one of the above things, then it will just be a very expensive breakout board. I look at it as buying a car when a bike will do; if you can't justify the extra cost, then there is no need to spend it.

If you think I sound like I am trying to talk you out of buying a G100, you are most certainly correct. We never like people feeling ripped off or having buyer's remorse after purchasing one of our products, so we try to be as straight forward as possible. If you don't need it, don't get it. If you do need it, then you will be very happy with it.

-Marcus Freimanis