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Struggling connecting Mach3 to a controller
« on: July 24, 2009, 07:29:19 PM »
I got a mid size mill a with controller (professionally built) but still struggling to get any connectivity PC-to-Controller. Standard parallel connection, straight through cable. Tried 4 different computers with onboard parallel ports and 2 plug in PCI parallel cards no luck. So decided to test parallel port pins on the computer side with an occilloscope.

Launch Mach 3, scope charge pump pin (pin 9 in my case) = 6.8Khz !?!?! Close Mach3, reopen charge pump = 11.83Khz !?!? Sometimes it comes to 12.2Khz but never 12.5Khz claimed by Mach manual. My pulse freq reported by Mach in diagnostics is about 23656 to 24500 Hz.

I tried to output a frequency on stepper X (pin 7 in my case) and it comes out properly each time and is inline with Mach freq. So when I dial 25000Hz on stepper X it shows exactly Mach 3 pulsing frequency, say 23656 Hz.

But I am a little confused on the charge pump as it obviously way out of range. Does that mean my parallel port is no good? What is charge pump used for anyway? Can I disable it at all? How else can I ensure that the parallel port has suitable characteristics? How can I debug the problem?

I tried 3 different computers and on board parallel ports and they all output charge pump at 6.8Khz (sometimes jumping to 11.8Khz).

Any ideas?
Re: Struggling connecting Mach3 to a controller
« Reply #1 on: July 25, 2009, 02:29:58 AM »
You can use the "DriverTest" under the c:\mach3 folder to see if you have good timing on the parallel port. Gives you the required information about frequency and timing.

Offline Hood

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Re: Struggling connecting Mach3 to a controller
« Reply #2 on: July 25, 2009, 05:12:05 AM »
The Charge pump is primarily used to stop any motor movement whilst the computer is booting. It has been seen as a safety feature whilst running Mach but is not meant as such. I dont use the chargepump on my machines, but you may need to if your computer manically polls the parallel port on boot up.


Offline Jeff_Birt

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Re: Struggling connecting Mach3 to a controller
« Reply #3 on: July 25, 2009, 09:17:40 AM »
What are the specs of the computers you have tried? Did you do a fresh install of Windows on the computers and run through the Mach optimization steps? Then run the driver test as mentioned above.

I like to recommend the SmoothStepper to folks: http://soigeneris.com/Warp9.aspx, it takes care of all the timing critical pulse generation for Mach freeing up PC resources.
Happy machining , Jeff Birt