Messages

581

General Mach Discussion / Re: Limit rapid speed from a digital input

« on: February 18, 2014, 04:47:00 AM »

I may be wrong here but the one detail I see is that I don't think you can change the speed of a rapid that's already executing. i.e. when you open the door, if there's a rapid in motion it won't slow down but the next one will. Maybe not an issue to you but thought I'd mention it.

582

General Mach Discussion / Re: Soft limits info please...

« on: February 17, 2014, 09:47:09 AM »

Fair enough. I just never really see the point of limits on a small stepper machine - never mind soft limits - but that's just me.

Thing is that if you hit a soft or hard limit when you're running you more than likely just screwed the job - so the best approach is not to do it. Plus limits of either kind in plasma do nothing to stop the machine when you get a tip-up and that's FAR more likely AND far more likely to cause damage.

583

General Mach Discussion / Re: Soft limits info please...

« on: February 17, 2014, 09:28:16 AM »

An alternative way of looking at this is to ask why you're using soft limits at all. On a small light machine they really don't bring much to the party. If you DO want them for some reason then they're perhaps most useful to prevent jogging into a limit but personally I'd just turn the bloody things off (at least) when you're running code. Why would you reduce the size of an already small work area for no particular gain?

584

General Mach Discussion / Re: Modbus / MPG help...

« on: February 17, 2014, 08:46:53 AM »

OK - cheers - still seems like a dog's breakfast to me 

Ian

585

General Mach Discussion / Re: Modbus / MPG help...

« on: February 17, 2014, 07:18:18 AM »

Makes me wonder if the macropump is actually not being used at all. If it IS then it seems whacky to use keyboard emulation for some keys and the macropump for others - doesn't make sense.

Ian

586

General Mach Discussion / Re: Modbus / MPG help...

« on: February 17, 2014, 06:33:36 AM »

Nice one Hood - how did you ascertain it uses a keyboard emulator? I assume it's using the USB for that i.e. it's emulating a USB keyboard - yes? So why's it using the macropump and modbus for a select few keys at all? i.e. why not handle them all via keyboard emulation? and what's handling the handwheel i.e. the MPG clicks?

Ian

587

General Mach Discussion / Re: Modbus / MPG help...

« on: February 16, 2014, 09:39:51 AM »

I agree with Hood - there is nothing in that macropump that operates the togo button. In fact all that macropump does is set the jog modes and axis selection. Forgetting buttons for a moment - if your machine jogs when you turn the handwheel it has nothing to do with that macropump so either it's not the one that is actually running or you MUST have either a Brain or a Plugin running.

Why not post a link to what you downlaoded.

588

General Mach Discussion / Re: Shield grounded at one end only

« on: February 08, 2014, 07:28:33 AM »

RICH - understood - but my question was about specifically trying to get a handle on the AMPLITUDE (Vp2p/Vrms/dB) of the noise we might typically see. After all if we're happy to talk about signal level and we're happy to talk about signal to noise ratio then we MUST be happy to QUANTIFY noise in the amplitude domain - yes? I know it's kinda like asking how long is a piece of string - but just trying to get a picture. We hear all the time about "noise" in "general terms" but no-one ever quantifies it. That's my interest in asking is all.

Ray - thanks - but see my answer to RICH.

Tweakie - Interesting you mention USB because I tried to find if the USB spec specified how the SCREEN is connected on those also. All I could find was one link that said the screen is NOT connected at the USB device end. So it looks (though not conclusively) like USB is in the one-end-only camp.

Brett - perfect - exactly what I was after - thankyou.

589

General Mach Discussion / Re: CV Control Help For Beginners....

« on: February 08, 2014, 06:05:30 AM »

TBH I have no idea what "plasma mode" actually does over plain vanilla CV. All it says in the manual is:

Plasma Mode, if checked, this controls Mach3's implementation of constant velocity moves
to suit the characteristics of plasma cutters.

and

In Plasma mode (set on Configure Logic dialog) the system attempts to optimise corner
motion for plasma cutting by a proprietary algorithm.

So your guess is as good as mine 

I've never use it and just make sure I'm in G64 and that all CV "options" are off - works for me.

The route to CV nirvana? Like a said (IMHO) - acceleration. (and a stiff enough system to handle it).

590

General Mach Discussion / Re: CV Control Help For Beginners....

« on: February 07, 2014, 12:47:30 PM »

In plasma CV is king. You don't want to be restricting it in any way or your cut quality will suffer. Bottom line is if you find yourself having to tune CV you're in trouble before you start. Acceleration, acceleration, acceleration - you can't have enough of it.