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Author Topic: Computer Load Vs Hardware.. Smooth stepper etc.  (Read 6461 times)

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Computer Load Vs Hardware.. Smooth stepper etc.
« on: July 29, 2009, 03:59:54 AM »
Hello,
I'm New to MACH3 I've had a look for this info so sorry I've missed the thread.
I have read it is not recommended to run anything other applications while the MACH3 is running a job on the computer as it will mess up the pulse train out of the Motors  etc etc..... The reasons for this i understand and why this happens... My Question is.

IS THERE Hardware that SIGNIFICANTLY Buffers the stream so that This is no longer an issue ???
I want to be able to run other apps while MACH3 is Machining with out things going pear shape.

I Have been looking at the smooth stepper but is there any thing else out there that people recommend?

I AM Running Servos and Granet Controllers so want a fast Pulse rate.

Regards
Bart




vmax549

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Re: Computer Load Vs Hardware.. Smooth stepper etc.
« Reply #1 on: July 29, 2009, 01:59:40 PM »
Please don;t take this wrong as it comes up all the time.

What you are asking mach to do is akin to a BRAIN SURGEON talking on the cell phone AND watching a SoapOpera on TV while doing brain surgury on YOUR head.

IT can be done but why take the risks (;-)

(;-) TP
Re: Computer Load Vs Hardware.. Smooth stepper etc.
« Reply #2 on: July 29, 2009, 02:30:23 PM »
you can have a decent used computer for 100$, you better buy another computer to run your other stuff. it will still be cheaper then investing in some other hardware.

Offline RICH

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Re: Computer Load Vs Hardware.. Smooth stepper etc.
« Reply #3 on: July 29, 2009, 04:51:52 PM »
Your computer should be dedicated to CNC. Yes, you can have other stuff loaded on it,
but don't run other porgrams while machining.

RICH
Re: Computer Load Vs Hardware.. Smooth stepper etc.
« Reply #4 on: July 29, 2009, 05:31:01 PM »
Thank you all for your replys,
Mostly this machine will be CNC only however it is on a network and will be connecting back to a server.
to get the Cut files etc. I'm running 4000 count servos over 5mm lead ball screws so i will need i high pulse rate so will be looking at a hardware interface such as smooth stepper.

My main question really is Which hardware out there provides the best buffering etc
Regards
Bart


vmax549

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Re: Computer Load Vs Hardware.. Smooth stepper etc.
« Reply #5 on: July 29, 2009, 10:40:19 PM »
SO far there are only 2 that are advanced enough to be dependable and have support SS (step and direction)and dspMC (analog)
Just a thought, (;-) TP
« Last Edit: July 29, 2009, 10:44:49 PM by vmax549 »

Offline Jeff_Birt

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Re: Computer Load Vs Hardware.. Smooth stepper etc.
« Reply #6 on: July 29, 2009, 11:36:42 PM »
Mach's parallel port drive is amazing. It is limited by the underlying PC hardware. No software generated pulse stream (on PC hardware) will be as accurate/smooth/jitter free as that from dedicated hardware. I've had decent luck with the parallel port but it can be a struggle on some PCs to get it working right and on some it will not work at all.

Using a PC for all the things it is good for (crunching numbers, nice display, etc) and a HW based pulse generator gets you the best of both worlds. It also completely eliminates the parallel port issue that many new users struggle with. I am a big fan of the SmoothStepper and reccomend them. Everyone I have sold them to have been really pleased.
Happy machining , Jeff Birt
 

Offline simpson36

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Re: Computer Load Vs Hardware.. Smooth stepper etc.
« Reply #7 on: July 30, 2009, 05:56:44 AM »
If you are running w2K or XP, and you have dual processors (real, virtual or core), you can set the affinity and priority of each process. If you put MACH on one processor and any other heavy program on the other and set MACH priority to real-time, the OS will make every other running process wait on MACH, effectively making Mach the only program running (excepting memory use).

Other things to look at are using the drivertest to see how fast your computer can run the port. Note this doesn't mean the software can actually keep up with that speed.

The big thing it to get the task manager up and watch the CPU usage while Mach is running. If the CPU pegs, you're dead meat. A huge buffer is not useful if you are pumping garbage into the front of it.

Also note that not all processors are the same. I am using an old dual P3 processor server to run Mach. With no overclock, the processors run at only 850mhz. Mach is not multi threaded so one processor runs it without breaking a sweat whereas a 1.2ghz VIA chip would peg if you moved the mouse while Mach was runing g-code.

Disable your network while mach is runing and re-enable it to move files around. Use great caution with wireless networks. I find that for tiny g-code files, a thumb drives works beautifully as a transfer/backup mechanism.

Offline Jeff_Birt

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Re: Computer Load Vs Hardware.. Smooth stepper etc.
« Reply #8 on: July 30, 2009, 09:24:30 AM »
 
Quote
Mach is not multi threaded


Oh yes it is! Among other things the toolpath display now runs in its own thread, any serial coms are also run in their own thread...
Happy machining , Jeff Birt
 

Offline simpson36

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Re: Computer Load Vs Hardware.. Smooth stepper etc.
« Reply #9 on: July 30, 2009, 10:29:46 AM »
Jeff,

You must be using something special, then. When I run .026 of Mach, only one new process opens, even when the toolpath is active.

In any case, an application opening multiple processes is not the same thing as being multi threaded.


I can't comment on serial communication as I do not have any running with mach. Presumably you are referring to modbus?
« Last Edit: July 30, 2009, 10:39:09 AM by simpson36 »