Ohmic and floating head at the same time?

[wilman]

Hello friends, a query, is it possible to have two starting point detection systems installed on a cnc plasma cutting table? Ohmic sensor and floating head ?. in thin plates (less than 1mm) the floating head system can push the sheet and mark an erroneous position, then can the ohmic sensor go into action?

[djreiswig]

Usually it works the other way. The ohmic is primary and if it fails to detect the z overruns and the floating head switch activates. Then the z raises back up a programmed offset to get back to zero.

[TJS]

Usually it works the other way. The ohmic is primary and if it fails to detect the z overruns and the floating head switch activates. Then the z raises back up a programmed offset to get back to zero.

That is exactly the way I have it. After I wired it correctly when the 0.8 update came out from CandCNC.
Here is a snippet of the highlights:

Quick guide to new features in
CommandCNC 0.8.0
Table of Contents
Dual switch probing (touch off)..................................................................................................1
Probe limit now set in Manual tab in CommandCNC................................................................3
Support for Torch off before end of cut......................................................................................4
Dual switch probing (touch off).
Before this release of CommandCNC; for those who had a FeatherTouch Ohmic sense setup, if
the Ohmic touch failed to detect the metal because it was rusty or for any other reason, the floating
head switch would be tripped and would put your machine into E-Stop. This caused many sore
heads and lost hair.
Fortunately, there is now a better solution! With a simple change to your wiring, and a change in
your config, the touchoff can now use the floating head switch for the touch-off if the ohmic sense
misses - and it will automatically apply the switch offset if the floating head switch is the one that
tripped.

[djreiswig]

Mine works this way now too since I wrote a Mach3 Reference macro.

[Maiquem]

Hello friends, I'm trying to make my plasma cut able to interpret both ohmic and mechanized beings, could you share your Macro and how you made your wiring diagram, I also use Mach3.
Thanks

[djreiswig]

I'll see if I can put something together for you. It might be a bit as I don't get out to the shop much in the winter.

[acourtjester]

This may require 2 methods depending on the software you are using and how the 2 operation function. And others may have another setup that may be different from mine and they can comment about that. With Mach 3 I had the ohmic for detection using a Probe input and the floating head as a safety wired into the limit switch circuit. Other software can have it setup as an either or arrangement. With the offset of the floating head switch configured in if it is tripped to have the correct pierce height used. Main difference is Mach 3 stops if the Ohmic fails, the other will keep going using the correction sequence.

[Plasma-art]

Linuxcnc with qtplasmac does that if you have both.
It uses ohmic as main sensing but after that it automaticly uses the float switch to touch off.
Not as easy to setup and get going as mach3 however.

[BTA Plasma]

It is trouble to mix the two. If ohmic fails but picks up between ohmic touch and switch for floating head then you have a recipe for too tall or too short of a pierce distance. So it is nice to have access to both but not run both at the same time.

[djreiswig]

Okay, heres a version of my dual reference macro. I'm not positive that it is the version I'm currently running, but it should be close. I call it M1000.
I am using Z Home for the floating head switch & Digitize for the ohmic. I also have a few custom variables in my Mach settings screen that hold the needed values.

Code: Select all

OhmicLED = 1503 ' LED that indicates OFF
TouchLED = 1504 ' LED that indicates ON
RefFeed = 1120 ' Ref Feed from Settings
PlungeSafety = 1121 ' Plunge Safety from Settings
TrialZ = 1122 ' Trial Z from Settings
SwitchOffset = 1045 ' Switch Offset from Settings
TipSafety = 1123 ' Allowed difference between old Z and new Z
TipLED = 1511 ' LED to turn on tip up detection green = 0 red = 1

If GetUserLED(OhmicLED) Then
  If IsActive(DIGITIZE) Then
    Message "Ohmic sensor jammed."
    MsgBox "Ohmic sensor jammed.  Clear and hit RUN to continue. ", 0 + 48 , "Clear Z Jam"
    Code ("M0")
  Else
    Do
      ret = 0
      Code("G00 Z" & GetUserDRO(PlungeSafety) & " (Start probe touch-off)")
      While (IsMoving())
        Sleep(10)
        If IsActive(ZHOME) Then 'ohmic missed during rapid.  Fatal error.
          Message "Ohmic sensor missed."
          DoButton(3) 'stop
          Sleep(500)
          Code ("M0")
          MsgBox "Ohmic sensor missed on rapid." & Chr(10) & Chr(10) & "Rezero Z higher above material and reference again...", 16, "Fatal Error"
          Message ""
          End
        End If
      Wend
      Code("G31 Z -3.937 F" & GetUserDRO(RefFeed))
      While (IsMoving())
        Sleep(1)
        If IsActive(ZHOME) Then 'ohmic missed
          DoButton(3) 'stop
          Sleep(500)
          Message ("Ohmic sensor missed.")
          If MsgBox ("Ohmic sensor missed.  Use touch?", 4 + 32, "Ohmic sensor missed.", "Missed") = 6 Then
            Code("G92 Z0.0")
            While (IsMoving())
               Sleep(10)
            Wend
          ' 0.07 fudge to make match ohmic position
          Code("G00 Z" & (GetUserDRO(SwitchOffset) + 0.07) & " (Switch offset lift)")
            While (IsMoving())
              Sleep(10)
            Wend
          Else
            Message ("")
            Code ("M0")
            End
          End If
        End If
      Wend
      If (GetDRO(2) > GetUserDRO(TipSafety)) And GetUserLED(TipLED) = 0 And GetOEMLED(804) <> 0 Then 'only check tip ups if running code
        'new z is above old z so possible tip up
        ret = MsgBox ("Possible tip up." & Chr(10) & Chr(10) & "New Z zero is " & GetDRO(2) & " above previous Z zero.", 2 + 48 + 512, "Possible tip up.")
        If ret = 4 Then 'Retry
          Code("G00 Z" & GetUserDRO(PlungeSafety) & " (Retrying)")  'retract to clear switch
          While (IsMoving())
            Sleep(10)
          Wend
        End If
      End If
    Loop Until GetUserLED(TipLED) = 1 Or ret <> 4 'Retry
    If GetUserLED(TipLED) = 0 And ret = 3 Then 'Abort
      Message ""
      Code ("M0")
      End
    Else 'Ignore or no tip up
      Code("G92 Z0.0")
      While (IsMoving())
        Sleep(10)
      Wend
      If GetOEMLED(66) Then 'trial Z offset    
        Code("G92 Z -" & GetUserDRO(TrialZ) & " (Trial Z offset)")
        While (IsMoving())
          Sleep(10)
        Wend
        Code ("G00 Z 0.0")
      End If
    End If
  End If
Else
  If GetUserLED(TouchLED) Then 'touch
    If IsActive(ZHOME) Then
      Message "Touch switch jammed."
      MsgBox "Touch switch jammed.  Clear and hit RUN to continue. ", 0 + 48, "Clear Z Jam"
      Code ("M0")
    Else
      ret = 0
      Code("G28.1 Z" & GetUserDRO(PlungeSafety) & " (Start touch-off)")
      While (IsMoving())
        Sleep(10)
      Wend
      Code("G92 Z0.0")
      While (IsMoving())
        Sleep(10)
      Wend
      Code("G00 Z" & GetUserDRO(SwitchOffset) & " (Switch offset lift)")
      While (IsMoving())
        Sleep(10)
      Wend
      Code("G92 Z0.0")
      While (IsMoving())
        Sleep(10)
      Wend
      If GetOEMLED(66) Then 'trial Z offset    
        Code("G92 Z -" & GetUserDRO(TrialZ) & " (Trial Z offset)")
        While (IsMoving())
          Sleep(10)
        Wend
        Code ("G00 Z 0.0")
      End If
    End If
  End If
End If 
Message ("")

Then I have 2 other macros that run the LED's.
M1001

Code: Select all

'ohmic macro
  'if AutoLED On, turn TouchLED Off & OhmicLED On
  'Define some constants
  AutoLED = 1501 ' LED that indicates AUTO
  OhmicLED = 1503 ' LED that indicates OFF
  TouchLED = 1504 ' LED that indicates ON
  if GetUserLED(AutoLED) then
    SetUserLED(TouchLED,0)
    SetUserLED(OhmicLED,1)
  end if 

and M1002

Code: Select all

'touch macro
  'if AutoLED On, turn OhmicLED Off & TouchLED On
  'Define some constants
  AutoLED = 1501 ' LED that indicates AUTO
  OhmicLED = 1503 ' LED that indicates OFF
  TouchLED = 1504 ' LED that indicates ON
  if GetUserLED(AutoLED) then
    SetUserLED(OhmicLED,0)
    SetUserLED(TouchLED,1)
  end if

Here's what I have for buttons.

Mach Buttons.JPG

Behind the Auto/Manual button sits this code.

Code: Select all

  'if AutoLED On, turn AutoLED Off & ManLED On, else turn AutoLED On & ManLED Off
  'Define some constants
  AutoLED = 1501 ' LED that indicates AUTO
  ManLED = 1502 ' LED that indicates AUTO
  if GetUserLED(AutoLED) then
    SetUserLED(AutoLED,0)
    SetUserLED(ManLED,1)
  else
    SetUserLED(AutoLED,1)
    SetUserLED(ManLED,0)
  end if

Behind the Ohmic/Touch button sits this code.

Code: Select all

  'if OhmicLED On, turn OhmicLED Off & TouchLED On, else turn OhmicLED On & TouchLED Off
  'Define some constants
  OhmicLED = 1503 ' LED that indicates OFF
  TouchLED = 1504 ' LED that indicates ON
  if GetUserLED(OhmicLED) then
    SetUserLED(OhmicLED,0)
    SetUserLED(TouchLED,1)
  else
    SetUserLED(OhmicLED,1)
    SetUserLED(TouchLED,0)
  end if

Basically, these two buttons just flip the LEDs between the 2 modes. The LEDs tell the reference macro what you want it to do.

I also have a button & LED for a tip up check, which I haven't really used much. It just watches for a reference that is much higher than the previous reference.
The Trial Run function uses the Block Delete mode in Mach where lines of code preceded by a \ are skipped when the mode is on. My post inserts the \ before the things I want skipped.
I use this quite a bit to test cuts without firing the torch. It follows the path 1/4" above the actual cut height. I think I have posted about using this mode somewhere else on the forum.
Hopefully this gets you started.

[Maiquem]

Hello, thank you very much for sharing this material, I'm a bit new to the subject of macros, I'm from Brazil, and people here don't have the habit of sharing these subjects, so I'm learning little by little, sorry for my English, but I use it a translator.) I would like some more information to be able to make these configurations on my Mach3, or if you can share these files and macros and Screensets... etc, I would be very grateful. I'll post the macro that I use, with an Ohmic sensor in the PROBE input I call it M3.
If you can share some G-code as an example to see the command structure to call the macros!

M3.m1s
CODE "G92 Z0"
CODE "G31 Z-100 F250"
While ISMOVING( )
Wend
CODE "G92 Z0"
While ISMOVING( )
Wend
CODE "G0 Z3"
While ISMOVING( )
Wend
resetthc( )
DoSpinCW( )
Code"G4P1"
CODE "G0Z2"

[djreiswig]

You basically just have to call M1000 in your code where you normally do a reference. The macro handles the dual reference. Then you have to add the buttons and associated code in mach. The reference macro looks at the LEDs to see what it should do.
I'll see if I can get a screen put together for you. What SheetCam post are you currently using?

[Maiquem]

Hello, I am using the "MACH3" Post-Processor.

I thank you immensely for your help, if you can send me your screen the buttons settings your macros and files and the post-processor you use on your machine, I would be very grateful, I'm struggling to make this work right here, but I'm not giving up now .
hahahahaha

[N2 Welding]

Following along. Do y’all use 2 switches on the z axes in addition to Ohmic sensing. One switch for torch fully retracted at highest point away from material and a switch on floating head so torch will stop diving into the material should the Ohmic fail to detect touch of work surface?

[acourtjester]

I have both a upper and lower limit for the Z (I use the table for router too) and a floating head and Ohmic sensor. The floating head is for safety and the Ohmic sensor is for torch touch pierce height position. the limits and floating switches are all in series to one input for the controller. This is on the UCCNC controlled table. And for the linuxCNC table the switches are each connected to an input pin on the controller board, as it has many input and output pins that can be used.

[Maiquem]

Hello friends,
here I am again, as I said before in other posts, I am finalizing my CNC plasma, I am using a POWERMAX 45 I intend to cut sheets of different thicknesses and for that I am studying how to adapt this ohmic senor + floating head, for that I know that I need MACROS and a post-processor so that all this works in an intelligent way, the friend "djreiswig" shared with me some excerpts of the macros he uses, but as I don't understand anything about programming and MACH3 I would like a more in-depth help on the subject, if Could someone make these MACROS, POST-Porceser, MAch3 SCREEN printa files available to me or something like that.
I'm grateful, here in Brazil no one understands these settings either, so I'm looking for help for you foreigners.
my e-mail is: maiquem.trilha@gmail.com

[acourtjester]

HI Maiquem
I have not used any macros when using a floating head switch and Ohmic sensing together. So you understand the floating head switch is a safety when using a Ohmic sensor, so it is hooked up in series with the other home/limit switches. The Ohmic sensor is now connected as a probe input (pin selected in input section). It also requires a post processor that uses a G31 as the command for moving the Z axis to touch the metal surface.
To test the Ohmic sensor use this simple G-code to work the Z axis down to touch the metal surface, it will do the first down until it touches then repeat at a slower rate and back up to 1.50" You can use Wordpad/Notepad to write and save as a G-code to load into Mach 3.

G31 z -3 f40
g92 Z0.0
g1 z0.8
g31 z-1 f10
g92 Z0.0
g1 Z 1.5 this can be changed to a lower height like 0.50" or MM values.
m30

[Maiquem]

hello acourtjester,
Interesting this option, in fact the floating head is like an end of course for safety in case the ohmic sensor does not recognize the touch of the material, right?

[djreiswig]

In my setup the ohmic & floating head switch are hooked up to separate inputs and are not connected with the limits. The macros I posted above perform the backup function automatically.
I've not been back to my computer lately to get the screen set or macros.

[acourtjester]

Yes that is correct, now other setup can be used as above examples where separate inputs can direct the software to use the floating head as a backup surface sense. In that the Ohmic sense is Z 0.0 and the floating head has a backlash compensation to get to X0.0 if the Ohmic sensor fails (dirt/rust).
The software selects which input does what is needed due to the input signal activation.

[Maiquem]

yes, perfect, in theory I understood perfectly how these options set by the friend "acourtjester" work, but really my interest would be with the connections and the operation in two different inputs, one for the ohmic and another for the floating touch head, if the friend "djreiswig" could take some time and send us this screen with the buttons and LEDs with the macros and details of the settings, I would be very happy.

big hug

[acourtjester]

My Ohmic sensor is connected to the Probe input on the controller, You select the pin for it on the BOB and tell the software that pin in the software for the probe and use a Post Processor which has the G31 command for the Z to look for a probe signal. here is for Mach 3

probe.JPG

[djreiswig]

If you download a mach screen editor you can add the buttons to your current screen set and add the macros I posted to the buttons. Then just edit your post and call the m1000 macro in the onreference section.
It's really pretty simple once you start playing with it. Designing the macros was the difficult part.
It's also a great learning experience.

[Maiquem]

For me, it's a little more complicated than it seems, because I don't speak English, I'm from Brazil, I use the translator to communicate with you here, and since I also don't know how to work with those Mach3 screen editors, much less Visual Basic, it will be difficult for me to be able to develop all this we are debating, really if someone could share a mach3 screen ready for me it would be easier. But I would like to thank my friends for the ideas and the exchange of experiences, who knows, maybe one day I'll get there. hahahahaha