Messages

131

General Mach Discussion / Re: mach 3 and encoder

« on: September 12, 2007, 02:38:24 PM »

Just a note, there is a company that boasts that they are the 10 Dollar encoder company. I have used them, they work very well. Best check it out at http://www.usdigital.com
If you are not in the states, you can order from just about anywhere in the world.

Whacko

132

General Mach Discussion / Re: steps per rev

« on: September 12, 2007, 02:26:05 PM »

Amen! That sums it up pretty good. Shout if you need more info. There is a lot on the web too. This 'ere is a good un! http://www.cs.uiowa.edu/~jones/step/

Whacko for real

133

General Mach Discussion / Re: New Computer w/ no parallel port

« on: September 12, 2007, 02:11:27 PM »

I think best to first contact the supplier, as they pre-install the OS. If it is win xp you might have to reactivate the OS when it sees hardware changes at boot up. Microsoft has a automated telephone activation facility, or you can do it online with another pc. Somehow, this doesn't always happen, but more so with branded PC's.

There should be a spare PCI slot, parallel port addon cards are cheap and should fix your problem as the other people said.

Whacko

134

General Mach Discussion / Re: steps per rev

« on: September 11, 2007, 06:30:29 PM »

Yes it will, but it also depends on the electronics driving the motors. If the electronics are up to it, it would increase the resolution of the simulated sinewave that drives steppermotors.

Whacko

135

General Mach Discussion / Re: steps per rev

« on: September 11, 2007, 05:43:01 PM »

By rev do you mean step revolutions or shaft revolutions. You cannot damage steppermotors by running them at high revolutions. They will stall if you go above their max threshold, but that wont damage them, it might put a lot of strain on your drivegear though as they will vibrate when they stall. It is better to microstep a stepper, more speed and smoothness. I microstep motors currently at 2400 microsteps per shaft revolution. The step angle is 1.8 deg for the motors. They are reasonably smooth, enough for the application.
Whacko

136

General Mach Discussion / Re: New Computer w/ no parallel port

« on: September 11, 2007, 05:27:05 PM »

Is your computer a laptop or a Desktop computer?

Whacko

137

General Mach Discussion / Re: How to calculate the kerf width for plasma cutting?

« on: September 11, 2007, 03:40:30 PM »

Ok, this is it! Disregard all I said before in this thread. I got rusty cause I played with the offsets way back. I went through the whole excercise and then everything came back to me, including why I don't use the G40,G41,G42 codes, and it's not just because you cant do reverse or jog in the kerf enabled modes.

To get it to sort of work, you go to the "config" menu. Click on "tool table". A selection box apears. In slot one you can type plasma as the name. The kerf will be the diameter setting. Enter your kerf diameter and save.

Now the kerf is saved in slot 1 of a possible 255 settings. Don't use the G54 command. You use the G41D1 command. The D1 designates the tool number with it's diameter in slot 1 you entered before as I described. So, D1 is TOOL1. D does not mean diameter. I think you cannot use just G41/42, you have to select the tool. Someone who has more experience and watching this thread can correct me on this. But in my setup it won't work unless I specify the tool number. But this is where you will discover that Mach3 don't work kindly for plasma application.
So to cut a square your code could look something like this.

%
G21
G91
G00X10.00Y10.00
G41D1
M07
G01X0.00Y100.00
G01X100.00Y0.00
G01X0.00Y-100.00
G01X-100.00Y0.00
M08
G40
G00X-10.00Y-10.00
M30
%

You might get an error about concave cut in cutter radius compensation or something like that. Then you could do this:
%
G21
G91
G41D1
G00X10.00Y10.00
M07
G01X0.00Y100.00
G01X100.00Y0.00
G01X0.00Y-100.00
G01X-100.00Y0.00
M08
G40
G00X-10.00Y-10.00
M30
%

You won't get the error, but the kerf compensation ramps up to full diameter at second corner of the square. No good, cause you'll be cutting into the job.

That's one of the few reason's I gave up on it, and I did post something about the G41/42 some time ago, but Brian replied that the way Mach3 is written, its a big problem to change the code and I have to compensate for the kerf in the CAD software. I don't use Lazycam, but I did read something about this in an earlier thread.

Well, Sorry for leading you on a goosechase.

Whacko

138

General Mach Discussion / Re: How to calculate the kerf width for plasma cutting?

« on: September 11, 2007, 02:06:05 PM »

To be quite honest, I will have to go back and check how I did it, because I abandoned the kerf compensation because of the no-reverse in g41,g42 code. I will check it out and get back to you.

Whacko

139

General Mach Discussion / Re: online tutorials

« on: September 11, 2007, 01:53:43 PM »

You are welcome Brett.

William

140

General Mach Discussion / Re: Charge Pump Signal Hiccup

« on: September 11, 2007, 01:51:29 PM »

Yes, a capacitor arranged so that you have a charge pump circuit. Only a signal that changes rapidly will build up a charge good enough to switch a comparator. Inductive decoupling would be like a pulse transformer, again only a signal that changes state rapidly can cross the isolated barrier via magnetic flux variance in the transformer. You have to implement this through a current limiting resistor so that if the port state is active high, you will not damage the switching device, like a mosfet, or bipolar transistor.
The example in the download page is apparently good, but I have not used that one.

Whacko