THCAD-10 + hypertherm 45 (nonXP)

Rod,
Sorry it has taken so long to get back...
There is no loss of steps in Z...You are correct that the issue seems to lie in software...
We have more information now that we have had time to use the machine and evaluate what is going on...To further clarify the actual machine setup I provide the following:

We are using SheetCAM TNG for G-code generation...The post processor we use in SheetCAM is the post developed by John Thornton...We have made no changes to his post with one minor exception of raising the Z torch upon completion of the final cut (next to the last line of code) instead of sending the torch to Z0...For all intents and purposes this works perfectly...

Next is the subroutine (also developed by JT) which is called for touch-offs, pierce height, starting torch, etc...This sub has only been modified in the switch hysteresis (had to increase to 0.23" based upon machine design) and when using this sub when importing the created G-code into LinuxCNC the objects to be cut by the torch when viewed from any view except the Z top view appear on different layers...When doing the actual cut it all works okay, but I get an error message box stating that the code exceeds minimum Z limits when there are more than 3 cuts to be done, do you want to proceed anyway...Clicking yes starts the cutting process and completes properly...

From within the subroutine code I commented out the G92 setting the Z to zero, by doing that when viewing the objects to be cut in all the various views all objects appear on the same elevation...I have tested this without doing actual cutting and it seems to go through all processes properly, but I am a little nervous about running it this way...

As a work-around I have envisioned setting the Z limits in the ini to a larger number to avoid the error from appearing and setting the default view to Z (top view) while leaving the G92 code active in the subroutine...

We still do not have the THCAD-10 functional...I may need to ask for some guidance on the THC setup on another subsequent post, but I would like to get some resolve to this situation first...

Any suggestions or comments will be appreciated...

Thanks in advance

kb8wmc

I think you have a several issues here.

Please post your .ini and all .hal and .tcl files your configuration is using. We need to see your actual copies! Are you using any user generated components? If so please post the source here.

Then hand write a simple gcode file that cuts a single straight line. Run all subroutines first from MDI to verify they work. You also may wish to rewrite them leaving out the o<subroutine> sub and o<subroutine> endsub lines and see if the resulting code will load without errors, to use as actual subroutines you will need to add the lines back in. With the plasma power supply off (you don't want the torch to fire!) verify that it is working correctly, MEASURE the pierce height and the cut height and make sure they are as set. While doing this look at your GUI does the Z DRO value make sense for the moves you just made? Once this is all working, you may need to adjust gcode, and actual subroutines to get it working correctly on your equipment. Now turn on your plasma power supply and try 5 or so test cuts in a row using your hand generated code, did they work ok? If not what was the failure? Now modify your hand coded simple line cutting program to have 5 separate lines and run. Did it run ok? If so you now have machine and example gcode running to compare to the SheetCam generated code. If not what was the failure?

Now onto your SheetCam problems. First for trouble shooting help you really need to post the text of the PP you are trying to use and the problematic code it generated. Again it is important that we see the code you are using. Try this on the SheetCam forum and here. Les is really good at looking after SheetCam problems.

What part of getting your THCAD-10 going isn't working? It should be easy on any newer Hypertherm box. There are several users here that have working systems as well and PCW that can help. Read the THCAD manual all the offset and scaling instructions are there. First step is to read a simple 9V battery connected to the THCAD, until this works reading the cutting voltage is a dream.

John

I have exactly the same situation with SheetCam and the produced g-code.

Attached please find the screenshot, all cuts start at different heights. Attached the relevant sample g-code program and touchoff subroutine.
The issue is, that LinuxCNC "assumes" that each probing with G38.2 Z-30 needs to go maximum depth of 30 machine units (mm in my case) therefore sooner or later, depending on your machine setup the Z height will be too small to accommodate all those probings.

This topic was raised on this forum, and other ones too, but I could not find any solution.

Guys

I am running what I consider to be an Alpha prototype system to run my table, read not yet ready for production use. I am using a THCAD card to measure the arc voltage for torch height control. Look in the general section for Grotius's thread about the external offsets branch and you will find a description of my system. The other day I cut out 3 sheets of parts with 487 pierces per sheet and had none of the problems you are describing. I do have problems ( look in the Gmoccapy section) with the Gremlin preview screen but not what you are describing. I have to fish for the next 3 days and then weekend markets so I can't go into this in depth until this time next week. I will post example of working (but very complex to deal with my system) gcode with probing subroutine. I am surprised by how well it is apparently working at this point. I am sure there are bugs in there I just haven't found the right set of conditions yet. I will get together a simplified version of my probing code without all of the error checking and retries that will be much simpler to understand.

John

bjames28 wrote: I have exactly the same situation with SheetCam and the produced g-code.

You could try asking on the emc-users mailing list. The SheetCAM developer is subscribed to that (or was in January)

(That's the LinuxCNC mailing list, it still uses the old name). You can find the subscription information from the "Community" link on the main LinuxCNC web site. ( www.linuxcnc.org , link at the top of this page)

Guys

SheetCam questions are usually dealt with promptly by Les (the SheetCam developer) on the SheetCam Forum. I know most of the questions there are focused on Mach3 and the CandCNC user base but with CommandCNC growing I am sure he is watch LinuxCNC users now.

John