Hello Guest it is March 29, 2024, 07:32:16 AM

Author Topic: THC setting up assistance...  (Read 15918 times)

0 Members and 1 Guest are viewing this topic.

Offline Davek0974

*
  •  2,606 2,606
    • View Profile
THC setting up assistance...
« on: April 10, 2014, 10:38:43 AM »
Would I be right in my belief that unless I am using the ARC-Ok input from a THC, I will not be able to turn THC on or off within Mach3???

That seems to be the way it behaves, just confirming.

Offline stirling

*
  • *
  •  2,188 2,188
  • UK
    • View Profile
    • www.razordance.co.uk
Re: THC setting up assistance...
« Reply #1 on: April 10, 2014, 11:50:11 AM »
What do your THC manufacturers say?  ;D

It depends on exactly what you mean. More detail needed on what you're trying to do and how your trying to do it.

Offline Davek0974

*
  •  2,606 2,606
    • View Profile
Re: THC setting up assistance...
« Reply #2 on: April 10, 2014, 02:17:31 PM »
The manufacturers say very little (but I'm sure you knew that :) ) This is simply a voltage comparator THC, it outputs three signals - up, down and arc ok, there are no inputs apart from torch voltage.

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

I can see the z motor turning slightly as it cuts when the THC button in mach is off, if I turn this on, the torch will pierce but then do nothing presumably as it is waiting for arc-ok?

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.

Offline stirling

*
  • *
  •  2,188 2,188
  • UK
    • View Profile
    • www.razordance.co.uk
Re: THC setting up assistance...
« Reply #3 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.

Offline Davek0974

*
  •  2,606 2,606
    • View Profile
Re: THC setting up assistance...
« Reply #4 on: April 11, 2014, 03:45:53 AM »
Yes that's exactly how my inputs are wired.

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

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

Thanks

Offline stirling

*
  • *
  •  2,188 2,188
  • UK
    • View Profile
    • www.razordance.co.uk
Re: THC setting up assistance...
« Reply #5 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.

Offline Davek0974

*
  •  2,606 2,606
    • View Profile
Re: THC setting up assistance...
« Reply #6 on: April 11, 2014, 04:14:42 AM »
I'll dig into the sheetcam post, the one paragraph in the manual is practically useless BTW

Offline stirling

*
  • *
  •  2,188 2,188
  • UK
    • View Profile
    • www.razordance.co.uk
Re: THC setting up assistance...
« Reply #7 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.

Offline Davek0974

*
  •  2,606 2,606
    • View Profile
Re: THC setting up assistance...
« Reply #8 on: April 11, 2014, 05:02:18 AM »
Ok, am i on the right track...

Move my probe switch to the limit switch circuit.
Remove the probe input entry in ports & pins and use it for the arc-ok input.
Reverse my Z homing direction.
Remove the Z axis from the home-all button.
Switch sheetcam post to use G28.1

This will free up an input for Arc-OK but means my Z axis will now home downwards??
« Last Edit: April 11, 2014, 05:04:18 AM by Davek0974 »

Offline stirling

*
  • *
  •  2,188 2,188
  • UK
    • View Profile
    • www.razordance.co.uk
Re: THC setting up assistance...
« Reply #9 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)