mach2 home switches

[kong]

I've just downloaded the demo of Mach2, having just set my home switches up for emc - nc switches wired in series to one input. I just can't figure out how to get all of the axes to home. I can see the button that says "ref all" which sends all axes to home, but when one hits it's switch, mach2 thinks they are all at home. Is there a ref x or ref y button somewhere?!

[balsaman]

My home switches are working. Mine are NO. Perhaps you need to change that in the software somewhere (uncheck active low?). I don't see a ref x, y, z. I also can't figure out how to send an axis to a location...

Eric

[HuFlungDung]

I am not sure how you have your machines set up, but logically, the setup is impossible if you are calling your home position that location where the switch opens. You should not. You should home to a given number of steps from where the switch changes state again. This will allow the continuity of the circuit to home another axis in sequence.

For machines with encoders, they never home on something as crude as a switch opening. That is merely a signal to mark the approximate position, after which the encoder index is sought in a given range from the switch break.

[HomeCNC]

Kong, I have attached some setup screen shots of my Mach 2 setup. Look over the screen shots and compair them to yours.

[HomeCNC]

Next one.


Also check out the Mach 2 PDF manual

[balsaman]

Hu,

You are correct that the best way is to use the encoder's marker pulse for homing after you hit a home switch. I think there is a circuit for doing that on the CAD_CAM yahoo site. It's just another thing on my to do list that will never get done!

Eric

[kong]

Thanks guys, I've wired each one on a seperate pin now, so they work ok when I use "ref all". Balsaman, the only way I can see to send an axis to a location is to use the MDI screen to input a seperate line of g-code. I'm liking this software now, will purchase at the weekend I think.
Just out of interest, what sort of pulse stream should I expect to get from an AMD 500Mhz pc, as the demo is limited to 25000Hz.

[balsaman]

Originally posted by kong Thanks guys, I've wired each one on a seperate pin now, so they work ok when I use "ref all". Balsaman, the only way I can see to send an axis to a location is to use the MDI screen to input a seperate line of g-code. I'm liking this software now, will purchase at the weekend I think. Just out of interest, what sort of pulse stream should I expect to get from an AMD 500Mhz pc, as the demo is limited to 25000Hz.

Are you sure? I thought it was user selectable. Up to 35000 hz...

Maybe you are right. 25 khz is enough for my machine.

My Pll 233 puts out the 25 khz no problem.

Hey this is my 1000th post! You guys must be sick of my rambling. LOL

Eric

[kong]

Originally posted by balsaman Hey this is my 1000th post! You guys must be sick of my rambling. LOL Eric

yawns, only joking!

Seriously, the demo will allow you to change the settings, but they seem to have no effect. In the motor tuning screen, the max speed stays the same. I can remeber reading this somewhere too. My machine requires 9500ish pulses per inch/second.

[HomeCNC]

Balsaman,

I was wondering the date you would hit 1000 posts. Wow you do talk alot

I thought you were using TurboCNC not Mach 2.

[High Seas]

Kong -
My PIII/500hz machine "seemed" to be ok at 35000. I say "seemed" as I was trying to work some motor problems - steps lost/gained and thought a re-tune would be usefull to explore all rates and pulse width allternatives. BUT - the problem seems to really be the motors. All indications were the system was running at 35,000 +/- but the symptoms remained the same- so off for another set!
Jim

[kong]

HighSeas, it's probably no help, but I have just read about on-board graphics interupting the pulse-stream. It seems in the older systems these graphics chip sets may have a higher system priority than Mach2, which I take it may cause lost steps or jerkiness in motion. Just a thought.