Messages

231

VB and the development of wizards / Re: Better way to stop axis movement

« on: August 20, 2012, 08:02:13 PM »

Depends on what else you want to do while stopped.  Feedhold will stop the machine and allow you to jog.  Pressing cycle start then resumes the program.  I don't think you can just stop one axis whike the others continue running normally.  The only think I can think of might to programmatically inhibit the axis you want to stop.  Something tells me it won't work, but it's something to try.

232

General Mach Discussion / Re: Possible new project pending feedback on LazyCam software

« on: August 20, 2012, 07:44:13 PM »

Another vote for SheetCAM.  We have ArtCAM, RhinoCAM and VisualMill...And I Use SheetCAM 99% of the time.  The ability to use programming logic like if...then...else, etc. in post processors makes it capable of a lot of things that the others are not. 

233

General Mach Discussion / Re: Another help request.

« on: August 14, 2012, 08:56:56 AM »

What are you trying to switch?  SSR's won't work with everything AC.  They usually won't work with motors that have electronic start circuitry or any kind of electronic speed contol.  Older motors that have centrifugal/mechanical start mechanisms work fine.  If the motor doesn't make a clicking sound as it slows down, it has electronic start circuitry.  We've also had trouble switching some solenoids using SSR's.

234

General Mach Discussion / Re: Spindle Motor is the cause of all my problems

« on: August 11, 2012, 06:43:16 PM »

Shielding on both ends works fine as long as EVERYTHING is grounded properly.  There is no room for error.  I know that the newer versions of the ProMotion, Burny and Hypertherm controls ground on both ends.  There are closed loop AC servo systems with high voltage signals.  Grounding on one end DOES seem to work best on Mach systems though.

235

General Mach Discussion / Re: Need to cut a radius

« on: August 11, 2012, 06:32:13 PM »

Or use a cam program like SheetCAM.  Simple things usually fall within the line limit of the trial version.  You would need to draw the arc, but SheetCAM will handle the GCode.

236

VB and the development of wizards / Re: Help! How to Jog Axis till switch Hit Macro

« on: August 06, 2012, 10:59:18 AM »

I haven't tried this but it should work.  Set up one upper switch and one lower switch so they both trigger the "Digitize" input.  For your "UP" routine, do something like G31 Z4.000 and for your "DOWN" routine, do something like G31 Z-4.000.  I'm assuming a negative number drives your Z down.

Create two buttons and put each routine in it's own button, like....

code "G31 Z-4.000"

When the axis hits the switch it will stop.  If you want to do something else after it stops, add that code after the G31.

Just curious....Are you trying to make a floating head work?  Can't figure out why you'd want a switch on the bottom of the Z axis travel....Unless you're using it as a lower limit.  We use an upper travel limit and a floating head with the G31 code on the floating head.

237

General Mach Discussion / Re: How can i JOG during operation ?

« on: July 07, 2012, 06:29:10 PM »

You can't jog, but you can use the THC Up/Down inputs.  Just go to Port & Pin -> Mill Option and under THC Options, elect "Allow THC control even if not in THC mode".  Now just make a remote with two buttons that activates the THC Up/Down inputs.

238

General Mach Discussion / Re: Ohmic Sensor - HOW?

« on: July 05, 2012, 10:00:43 PM »

To do it right, you need two relays.  The contacts on relay 1 will connect to the wire you see on the ohmic sensor and to the coil (-) on relay 2.  The coil (+) on relay two goes to 24V or whatever voltage you're using for relays.  Connect the contacts on relay 2 to the input on your bob you use for "probe".

The first thing you'll do when you want to fire the torch is to close relay 1.  This makes continuity from the ohmic sensor to relay 2 so when the torch touches ground, relay 2 closes activating the "probe" signal.  Before the torch fires, close relay 1.  If you don't...and the arc jumps to the ground cap (ohmic sensor)...and it will...you will send 150+V to the ohmic sensor relay.  The purpose of relay 1 is to isolate the ohmic sensor completely while the torch is fired.   

When you go to HF arc start, you have to go even further as the HF will jump the contacts in relay 1 like it's not even there.

239

General Mach Discussion / Re: External e-stop

« on: June 29, 2012, 05:27:21 PM »

I've never found caps to help all that much with excessive noise.  It can't hurt to try.  You would put the cap across the two terminals that your estop loop connect to on the BOB.  That will filter out a little bit of noise on your estop wiring circuit, but that's probably not where the problem is.  If your BOB is grounded and your PC is grounded, then you could have a ground loop going on.  Ideally, the BOB should not be grounded to the machine chassis.  It should be grounded through the parallel cable at the PC end.  We've even had to replace PC's before.  For some reason, some are more susceptible to noise than others.  We've also found some BOB's to be more resistant to noise than others....which is why I asked which one you had.

If your BOB supports estop hardware disable, you can just set the estop port in Mach to 3 or any non-existent port.  When you hit an external estop, the machine will still stop by disabling the drives, but Mach will keep running.  Don't do this unless your BOB supports hardware disable.

We deal with high frequency plasma every day.  The only real fix for excessive noise is proper grounding.

240

General Mach Discussion / Re: External e-stop

« on: June 29, 2012, 01:04:16 PM »

Further to my problems, when external e-stop has interupted my job, i then try to run from line so as not to start again and mach3 scrolls through my g-code problem and stops randomly at a line no where near where the run from line  should return to !!!!!!!!!!!!!!!!!!!!

When you estop during a job, depending on your feedrate, Mach will lose position.  Estop is not a controlled stop.  Here are some suggestions for your estop issue...

(1) First and foremost, make sure you are properly grounded.  The gantry, Z lifter, table frame and controller should all be grounded to a star ground and that should be grounded to a ground rod driven into wet earth.

(2) If the problem still exists, disconnect all estop switches and jump the estop terminals on your BOB.  Does the problem still exist?  If Yes, the problem is not in your wiring or switches.

(3) Remove your DB25 serial cable going from the BOB to the PC and solder a wire to the metal shield part of the end of the cable.  ground that to the star ground on your machine.  That will dissipate any noise being caught by the serial cable.  The cable should only be grounded on one end....The PC end.  You can also ground the metal chassis of the PC to the star ground.

Just out of curiosity, which BOB are you using?