Mach 2 On a Shopbot

[podunk]

Hello,

I have been shopboting for about 5 years. Recently I rebuilt an engraver to expand by business. I now send step and direction signals over printer port via Mach2 Software. http://www.artofcnc.ca/Mach2.html
I love this software and it's capabilities. Instead of upgrading my brain box I was wondering how & where to send step and direction signals to my current unit using this software.

[wayneo]

Hi Gavin, I would be interested to know more about what you are doing with Mach2. Are you using the additional axis?
Thanks

Wayne

[stevem]

Gavin,

You will need to purchase third party stepper motor drives, like Geckodrives, that operate on step and direction signals. I would suggest going with 10 microstep drives for a major improvement in smoothness. As an aside, the Alphastep drives from Oriental Motors will also work with step and direction signals.

For those not familiar, this is a straight forward conversion that will allow the Bot to be used with G code.

[podunk]

Wayne,

No I am not using Mach2 to add axis although that would be a simple thing with the software. I want to use Mach2 on my shopbot because that is what I am using to run my engraver. I like the features available in this package. Things like on the fly speed control & motor tuning. Also the ability for future expansion and robust continuing development.

[podunk]

Steve,

Doesn't the shopbot software pass step and direction signals to the controller at some point? The G code itself is handled by Mach2 then converted to step and direction signals sent via printer port as High -Low states. There must be a place within the controller where the printer port outputs could be wired to accept the step and direction signals. Am I overlooking something?

[stevem]

Gavin,

My understanding is that the drives supplied with the ShopBot controller will not work with step and direction signals. My Bot now operates with Geckos and Mach2.

[podunk]

Wayne,

Did you need 4 Gecko Drives (two syncronized)? How did you wire it? Do you notice smoother motion & increased accuracy? Any other things that might be helpfull to me as I am considering going with the Gecko 210's for both my Shopbot and my engraver, that way replacement parts would be interchangeable.

Thanks for your input

[jlawren6]

For those of you who have switched from the Shopbot control software to something else like Mach2, DeskCNC, etc, what lead you to make the change?

Were there limitations with the Shopbot control software or additional functionality you were looking for? Or was it just a personal preference/familiarity thing?

I'm still in the process of determing what route I'm going to take to get into CNC and Shopbot is one of the options. I'm just not sure if I would be limiting myself from a control software point of view by going the Shopbot route. Your insight would be appreciated. Thanks.

[Brady Watson]

Jon,
There are a few reasons that someone would consider switching to a Mach2-type setup.

1. Speed - which is now a moot point with the Alpha.

2. To run raw G-code to call routines for toolchangers, coolant and other specialized functions. This can also be done within the SB software with some custom programming and a simple relay.

3. To run both steppers and servos on the same machine or to speed up and smooth standard steppers. This is again, not applicable to the new Alphas because they are plenty fast and have feedback to prevent lost steps...

At this point, the path of least resistance and headaches....is still to buy a new ShopBot. There is absolutely nothing out there on the market at this price that even comes close to the performance/value of the new Alpha machines.

-Brady

[jlawren6]

Thanks Brady. That's exactly the kind of answer I was hoping for.

I guess I was a little concerned that people may be switching to Mach2 to run G-code directly because they were having issues converting that G-code to SBP format (if their CAM program would produce only a G-code post and not SBP directly). Not having any CNC experience myself and going only off what I have read on multiple forums, it's difficult to get a grasp on where the pitfalls may be (if any) in going with a proprietary system like Shopbot. My gut tells me that it's probably not that big of a deal as there is almost always a way to get it done.

[podunk]

As far as buying a new shopbot, I already have one. It will be considerable cheaper at this time to convert to Mach2 and will add several functions to my shopbot such as on the fly speed control, simpler operation, and the ability to run in Windows XP. I know I could upgrade my control box and or upgrade to alpha but the cost of doing so would be more by at least a factor of around 10.

Also my design software does not export Sbp as Jon mentioned meaning xtra steps when preparing output.

[Brady Watson]

Gavin,
You already have the ability to run XP if you use the Windows software.

You can expect a 10-30% increase in speed and smoother operation over the PRT factory setup. However...there are a few things to point out with the Mach2 setup that may not be immediately apparent.

First, you are going to need a breakout board to properly wire up the parallel port to the drivers and any other in/outs you may have. There is a Mach2 board made by another vendor than the Mach2 software. I believe they are in the $150-200 range. You will need to purchase 4 drivers, either Geckos or other brand to drive the steppers at a cost of about $125 each. In my reasearch I found that some Gecko users complained of the driver going into a fault mode and not able to communicate with the Mach2 (Gecko not Mach2 problem)...so check that out before you delve in. You will also need to fabricate your own power supply for the steppers, or find one that can do the job.

Software-wise, you will need to write a routine to do the Z-zero function, and probe routines if you plan to use the SB probe.

To me, converting to Mach2 isn't something that I personally want to do. I rely on my machine to make me $, and don't have time to play mad scientist (at least not with the SB!) For the small increase in speed, it doesn't make sense to spend almost $1000 on something that I can't call support about. Not only that, but less than a handful of SB owners run Mach2, which means that if you do encounter a problem, who is going to support it?

Mach2 may be right for you and your situation, but upgrading to an Alpha with greater speed & closed loop feedback is something that I would hold out for.

JMHO
-Brady

[podunk]

Brady,

My understanding is that in order to use the windows software I would be required to upgrade my control box ($795 last post I saw). I already have a PMDX breakout $77 and my Geckos cost $114 including heatsinks & fan. As far as power supply goes the research I've done shows the power supply I already have (came with the SB) should work just fine.

I own a sign shop so I hear ya on the making "$" issue. Due to the age of my machine & the limitations of my control box I already feel like a mad scientist when I fire it up. I don't reccomend the solution that I and others are taking for people who don't like to tinker but I also believe that if you were all about turn key simplicity Shopbot would not have been your first choice.

As far as support goes check out Arts site http://www.artofcnc.ca/ & forum http://groups.yahoo.com/group/mach1mach2cnc/. The Mach2 community is much larger than the SB brotherhood & there are lots of people more than willing to help out. The development rate on Mach2 is constant and bugs get worked out quickly.

With that said I agree that if you're not a little adventurous, willing to learn, and are not afraid to go down a road that may lead to some frustration than you should stick with the SB method of upgrading mentioned above.

Forgive me any typos & spelling it's early as I type this.

Gavin