Messages

511

General Mach Discussion / Re: THC Codes upset corners???

« on: April 13, 2014, 01:26:03 PM »

sounds cute Terry but I wonder if it's really practically useful.

As you know V and F are not a linear relationship so you'd have to define curve data for it to work on. Sounds like a lot of work for dubious advantage (IMHO) - less of course you can convince me otherwise.

Ian

512

General Mach Discussion / Re: THC Codes upset corners???

« on: April 12, 2014, 12:39:34 PM »

Yes - modbus. SetV can be changed on the fly either by screen control or via gcode. There's an option to use ArcOK via pin or without (freeing up a pin for G31 if you want). You can do the SetV as a function of F in the (SCam) post.

No magic about the plug - as I said - just legal begal stuff (over this side of the Pond anyway - don't know about Floyda).

Cheers Terry

Ian

513

General Mach Discussion / Re: G-Code streaming VIA USB

« on: April 11, 2014, 08:44:39 AM »

Also I'm talking about a DIY level here with smaller table top machines, not people that converted older CNC or Non-CNC machines over.

OK so we're most likely talking about steppers then because if we're talking servo we wouldn't be concerned with $200 for a SS.

The Smooth Stepper is capable of driving at 400KHz the stepper motor drivers.
The Arduino Due is capable of driving its digital outs at 12MHz ( Ben Hack on Youtube tested the Arduino Mega which is slower than the DUE and was able to hit 8MHz ) which is twenty times faster, however with the TRE and you even run Embedded mode under Linux or Android which would take it to a whole new level of development.

Not sure why you've latched onto the output switching speed as being of any particular importance to your point but as you have let's take a look...

Hmmmmm 12Mhz.... let's do the maths....

10 microsteps - so 2000 step/rev for your stepper motor (if you don't know why I've picked 10 then look it up)

12000000/2000 = 6000 revs/sec

multiply by 60 = 360000 - yes indeedy - that's a stepper doing THREE HUNDRED AND SIXTY THOUSAND rpm

Now that I'd like to see.

Let's take your figure for the SS

400000 / 2000 = 200

multiply by 60 = 12000 rpm

Now that I'd like to see

So let's come at it from the other way

I don't know what sort of definition you get with your repraps but would 100th of a mm be reasonable to discuss?

I pick that because it just happens to be the "theoretical" resolution of my router.

I have my rapids set to 10m/min - not unreasonable I'd have thought.

So at 10 microsteps that's 10000 * 100 = 1000000 steps/min or 16666 steps/sec i.e. ~16KHz. That's WELL within Mach's slowest kernel speed.

So please  - make whatever points you like but let's have less of this nonesense about output switching speed.

514

General Mach Discussion / Re: Reset pop open window?

« on: April 11, 2014, 06:32:32 AM »

Must be missing something I guess. Why would you want it back? it's an error message. It only pops up when you don't have your limits set right.

515

General Mach Discussion / Re: THC setting up assistance...

« on: April 11, 2014, 05:29:36 AM »

There you go - got it in one.

(or upgrade to a PM45 and use a THC that can be configured to send ArcOK by magic instead of using a pin)

516

General Mach Discussion / Re: THC Codes upset corners???

« on: April 11, 2014, 05:11:44 AM »

As to Stirlings HT connector it is just a connector right ?

Nope - it's the solution to a whole legal nest of vipers.

I was hoping that Stirling would bring his stufF to the USA but as HOOD suggested I think he is hiding it from us (;-) Probably does not want us to pick on him.

Check your PM inbox around August 2011 Terry. That's the one where I offered you one for free in return for testing it out for me. You declined. You had the chance then to pick on me for FREE - now if you want to do it it's going to cost ya.

517

General Mach Discussion / Re: THC setting up assistance...

« on: April 11, 2014, 04:31:19 AM »

I'll dig into the sheetcam post, the one paragraph in the manual is practically useless BTW

Which is probably why Terry and I (more Terry than me BTW) have spent a LOT of time and a LOT of hard work figuring all this out.

518

General Mach Discussion / Re: THC setting up assistance...

« on: April 11, 2014, 04:12:03 AM »

Yes that's exactly how my inputs are wired.

How does G28.1 work if it does not use the probe input??

Time to RTFM Dave (Hint: look at the posts in Sheetcam)

If i move the limits to the e-stop input, does the home-all feature still recognise them ok?

Nope

Just one reason why E-stop should be E-stop and nothing else.

519

General Mach Discussion / Re: THC setting up assistance...

« on: April 11, 2014, 03:35:23 AM »

By the way Mach is working with it, I am guessing that the up and down signals will affect the z-axis regardless of THC on or off settings.

Then something's wrong. Whilst the fire's lit, your THC will always be sending UP/DOWN signals - BUT - with Mach's THC set to OFF it should ignore those UP/DOWN signals. With THC OFF there should be NO, ZERO, ZILCH, NADDA movement of Z.

I am not using arc-ok as I have no more inputs on my board.

I'm guessing you have 1) E-Stop, 2) limits/home, 3) probe (G31), 4) UP, 5) DOWN.

IMHO you'd be better ditching 2) limits/home and using it for ArcOK.

OR

Ditch 3) and use G28.1

I can see the z motor turning slightly as it cuts when the THC button in mach is off

Then as I said above you have a problem. This shouldn't be happening

if I turn this (THC) on, the torch will pierce but then do nothing presumably as it is waiting for arc-ok?

Indeed - with THC ON Mach will not command any movement UNTIL it gets ArcOK. ArcOK is important - you "can" frig the system to work without it but I wouldn't recommend it. ArcOK or limits? - to me it's no contest (especially on a small table).

The only way I can see to use the arc ok signal is to move the e-stop button to the limit inputs, I think that will do a similar job, then I can use the unused e-stop input for arc-ok.

You can't not use E-stop - you could move the limits to the same pin as the E-stop and free up the limits pin - if that's what you meant - but I'd suggest you consider my suggestions above.

520

VB and the development of wizards / Re: VB Script for toolchanger

« on: April 11, 2014, 03:13:01 AM »

OK, I think I understand the Mod function (Modulus) in Mach3 VB script, figured I'd post it here in case someone else needs to reference;

For 'a Mod b',

If a<b, uses full 'a' value as product.  i.e. '2 mod 3' = 2.  (this is what was confusing me).
If a > or = b, divide 'a' by 'b' and the remainder is your product.  i.e. for '9 mod 4', 4 goes into 9 twice evenly (8 ), with a remainder of 1 so 1 is the product.

Hope this helps, it was confusing me, but now it is all clear!   

And Stirling, you are absolutely right, it all works out correctly! 

Nick

Hi Nick - Pleased it's working for you.

However - your mod understanding is still incorrect.

It's simply INTEGER division.

In INTEGER division (by definition) there are no FRACTIONAL parts. So it's as simple as dividing the a by b and taking the INTEGER result. Whatever is "left" after that INTEGER division is the MODULUS.

at NO point is it of ANY RELEVANCE WHATSOEVER whether a<b or a>=b

Ian