The PK296A1A-SG3.6 motors have 7.7mH inductance when wired half-coil, so they can handle over 80VDC. The Gecko's limit of 80V means that you'll get maximum advantage of those motors if you can wire them half-coil. (Some motors supplied to Shopbot only have four wires Black/Green Red/Blue. Those must be wired series.) The SG gearbox limits the torque, so half-coil connection is not a penalty.

The PK268-02AA motor is one of my favorite motors. I've installed dozens and dozens of them over the years in non-CNC projects, but they are small and not ideal for use on a large CNC router. I would not use a 23 frame size motor on a CNC router unless I were stranded on a deserted island and had no other motors available. The PK268-02A motors are rated 3.6mH half-coil or 14.4mH series. I use a 50VDC power supply when I connect that motor half-coil. If you used a 70V to 80V power supply, you would have to wire the motor using the series connection. Wiring the motor series would give you excellent torque, but it would also limit the speed to around 200 - 300 RPM. With a 5-tpi ball-screw, that would give you a maximum speed of about 1-ips.

Running two power supplies, a 70V for the PK296A1A-SG3.6 motors and a 50V for the PK268-02A motor is a possibility, but it would probably cost about the same to replace the PK268 motor with a PK296 motor. Even then, the problem is that a high-performance 34 size motor (motor with low inductance) works best when wired half-coil and a power supply in the 35-40V range.

Those PK296A1A motors just have the wrong inductance when compared to most other motors being used on a CNC router.

http://blog.makezine.com/archive/200...heir_code.html

Apparently ShopBot has open sourced their code. ... Interesting.

This happened some time ago, I guess I just missed it!

Their input .sbp code (the stuff you see in the file with Notepad/wordpad etc.) has always been freely accessible and they promote it as better than g-code. This official "open source" announcement is just another push to get more recognition for their .sbp code, as opposed to g-code.

Their control software (actually firmware), serving a similar function to Mach3, LinuxEMC, etc., is definitely not open source

http://www.opensbp.com/

For people to use ShopBot machines they have to feed it a non-standard code (with .sbp extension). ShopBot is resisting a full swing to the internationally recognised g-code. (G-code is also very much "open-source", although their isn't an "official" site for it)

After visiting the OpenSBP web site, I fully agree with Gerald. The OpenSBP movement seems to be to "allow" anyone to use Shopbot "defined" instructions without worrying about getting a call from a lawyer for copyright infringement.

To RUN that code, you would still have to have a Shopbot controller. That code is not opensource.

I have written a lot of OpenSource code. OpenSource means that the source code, the actual code used to create the program, is included so that anyone can modify that code to allow the program to do whatever is desired. The only stipulation on OpenSource code is that it must remain OpenSource, meaning that if you modify my code and then pass that code on (sell or give) to someone else, you MUST include my source code and your source code.

Now, back to Shopbot. They have NOT released the code that they use to create the SB3 program; therefore, their code is not OpenSource. All they have done is to allow anyone to use their syntax and to encourage others to create tool pathing files using their code - so that they can sell more machines that use their proprietary controller hardware.

The OpenSBP "movement" seems totally self-serving to me. Frankly, I'm very disappointed with Shopbot for pretending that OpenSBP is something that it is not.

Now we just wait for a nice geek to do a SB to G-Code converter!

If someone did and got it really working, at least SB couldn't complain that they are ripping off SB code! :)

Still, nothing to lose sleep over at this point, one way or the other.

Shopbot actualy released one, I have a copy but cant seem to find it on their web page right now, go there and do a search.

UX_SBP.exe. It is a utility included with their control software.