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Messages - bjr

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General Mach Discussion / Re: hard real time with Windows XP
« on: October 02, 2010, 03:16:59 PM »
Thanks for the insight.

Interesting you mention the motion control cards.   Does the Galil card act as a buffer between Mach3 and the servos?  I mean, does it store the pulses and generate it's own timing so you would not have to worry too much about Windows XP processes interfering with Mach3?

Are there any cards out there that buffer and generate their own timing for ultra smooth operations?


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General Mach Discussion / hard real time with Windows XP
« on: October 02, 2010, 08:28:25 AM »
Just thought I'd throw this out there.... was browsing the web on real time systems and Mach3, and came across this website:
http://www.intervalzero.com/rtx.htm

Seems to be some sort of addon to Windows XP that allows a programmer direct access to the API and hardware functions in real time. 

Not sure if Mach3 would benefit from this, but using an addon like this would certainly up the price of Mach3.

Comments, anyone?

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I Know the legacy cards don't work with Mach3

Is there a list of Galil cards that are confirmed working?

thanks
Brian

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Galil / Re: Galil/Mach3 stepper motor accuracy confusion
« on: August 05, 2007, 05:38:17 PM »
Thank you very much for your input. 

I see that I need to figure out how my machine will operate with the stepper motor, driver, ball screws and linear guides.

I'm amazed that you can achieve an accuracy of 0.0005" .... that's half a thousandth or just over 0.01mm!   Did you do anything special to your bridgeport setup to eliminate any linear deviance in the x,y,z planes? 

Thanks for clearing that up about the microstepping.... I really need to start looking at the total system components and how they will work together... at the moment I don't know how to calculate the amount of travel per microstep. 

Regards
BJR





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Galil / Re: Galil/Mach3 stepper motor accuracy confusion
« on: August 04, 2007, 10:35:01 PM »
Thanks for your reply.

I'm a little green when it comes to designing a micro milling machine (think really finely detailed waxes and engravings with a cutting area of at most 4X4X4" xyz)

I just thought that by going with a native motor that can do 0.45 degree steps (it was designed to do this), that the performance and accuracy will be better than a 1.9 degree motor driven with a 1/2 step.  I was under the impression that stepping modifies the signal, and depending on the quality of the step driver circuitry, may not be so accurate.

So the chain goes like this:

Mach3 -> Galli controller card -> microstepping driver -> stepper motor

I'm still hoping someone will help me understand how I can change the microstepping on the fly - is it through Mach3, a dip switch on the microstepping driver, a feedback loop from the microstepping driver to the Galli card, or what?????

Doesn't seem practical to build an entire workpiece at 1/64 step from start to finish.... I'd like to think I can remove some bulk material faster initially at 1/2 step then do the finer detail in the last stages of cutting.  Anyone?

thanks




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Galil / Re: Galil/Mach3 stepper motor accuracy confusion
« on: August 04, 2007, 03:58:55 PM »
Well, I can answer some of my own questions now - amazing how much I can learn by surfing the web.

1) The step motor I purchase will usually be mated (optionally) with a corresponding microstep driver.  This is nice, because it ensures that the two devices were tested and will work correctly with each other.  And I will most likely end up purchasing the power supply from the same folks.

2) Yes, I will get twice the resolution out of a 0.45 degree stepper over a 0.9 degree stepper.  By purchasing a 0.45 degree stepper, I've eliminated many of the el-cheapo junk brands out there... doesn't seem like a lot of companies make the 0.45 degree steppers.  Great way to narrow down the choices and keep my sanity.

3) Still don't know how Mach3 software will integrate and let me control the microstep driver that comes with the stepper motor, and how it will perform with 0.45 degree stepper motors.

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Galil / Galil/Mach3 stepper motor accuracy confusion
« on: August 03, 2007, 07:32:46 PM »
Can someone please help me... I'm confused on this one:

I just received some info from Galil tech support, but there are lingering questions I have:

DMC-18x6 is only outputting step pulses. Once the steps leave the controller we really have no idea what happens to them. What this means is that the only limitation that the controller could have is the maximum frequency that this step train runs at, which for the DMC-18x6 is 6Mhz. Also keep in mind that the 6Mhz is the limitation for our steps, if the amplifier then takes those steps and microsteps then the maximum speed for the motor will be less then 6Mhz depending on the number of microsteps.

1) What is a "step train"?  Is it a microstepping amplifier that goes between the output of the Galil card and the actual stepper motor?  If so, where do I get this microstepping amplifier/device?  Seems like just Galil card/Mach3 combo alone will not do microstepping.

2) If I have a 0.45 degree stepper motor capable of doing 800 steps per revolution, and I employ microstepping with it, then does this mean I will get twice the accuracy of a 0.9 degree stepper motor?

3) How does the Mach3 software take into account and handle microstepping??  If the above is true, then it seems like Mach3 has nothing to do with microstepping and that microstepping is achieved through some kind of hardware device....

Please, if anyone (Brian?) can help, I would appreciate it.



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