Please Help - How to Configure a 5 Axis Head-Head

It seems to be working, I could cry lol  .  Yeah 100 inches is a long pivot haha.  

So if you don't mind, let me tell you about my plan to set pivot length/tool height.  I have attached an image showing a diagram for calculating the pivot length of an arbitrary height of a lollipop (probably solder a ball bearing to the end of a piece of brass).  So the diagram would give me the arbitrary length of the lollipop, then I would write down the g53 (machine coordinate) z height for that lollipop, then I would add or subtract the change in height of my measured tool to that distance.  Then I need to set that height as my new pivot length.  Does that make sense? So my question to you is, what is the best way to set that height without modifying the .ini file? Is a tool length offset the best way to go? Is there some other method or do you have any other suggestions? Is it possible for me to write some kind of little script or something to probe/measure my tool length and write it somewhere to effect my pivot?   I have a collet system on my machine so I have to probe in the length every time I change tools. 

Okay, I am going to go mess with halshow and my endstops now and see if I can't get something working.  I'll make a new post if needed. Thank you.

Glad you got it working.

As for pivot-z and tool-length, for the kinematic model it does not matter much since both are always collinear to each other so one simply gets added to the other. For machine operation I think it would make sense to define pivot-z as the length from the a-rotation axis to the end of the collet taper (ie with collet nut removed) and the tool-length is measured from there to the end of the tool. If you do it all as tool-length and you forget to activate tool-lenght compensation then strange things could happen (I think). Also this way you can measure the end of the spindle taper on machine startup as a reference.
So basically you would measure the spindle taper, then insert your lolly and measure again (which gives you the length of the lolly) then do your measurement with the angled spindle and do the math.
At least that is what I think should work, but it's late and I need to go and listen to my pillow now.

So I got the homing switches all working. The issue was that the input common on the Mesa was not plugged into +24V, which it needs to be for NPN sensors.  Mesa support helped me out with this. The issues now is that I wanted my probe (probes really) to work on 5V.  My probe is just a simple circuit closing upon metal to metal contact.  The reason that I don't want it to run on 24V is that I am worried there could be some arcing and therefore erosion through the bearings of my spindle (the entire machine is on one leg of my probe circuit, and then the probe is insulated and is on the other leg of the circuit).  Maybe this isn't a concern though, after all the bearings are probably coated in a grease or oil. What do you guys think?  

All day today I tried wiring the 5V of my probe to the gate of a MOSFET to turn on 24V.  But I tried everything and no matter what I did, I could not get the MOSFET to pull low on 24V volts (so the probe input pin was always on when the MOSFET is wired).  I tried using a pulldown resistor to both 5V gnd and 24V gnd, as well as moving my pins all over the place, I tried two different brands of MOSFETs, nothing worked.  

Right now I see three possible options.  Simply run the probe at 24V, put an electrical wiper on the spindle so the voltage bypasses the spindle bearing, or purchase or build a 24V z height probe that works off of touch only.


Aciera 
I think the end of the spindle is a very logical place to set the z pivot length.  Tomorrow I hope to try messing with the tool offset to effect pivot distance.  I want to make sure I can get it loaded and working well.  I'm sure it is not too hard, but just want to make sure I know how to do it and that it works smoothly.  Hope you got some rest. 

Tommy
Thanks for that. I think what was occurring is that I simply had a bad MOSFET.  I replaced it and it seems to be working (I hear FETs are sensitive to static and such).  I did get some really weird behavior when I tied the negative of my 24V, 5V and my ground together (this was per Mesa support suggestion). I would shake the machine and some of the motors would start stepping, just one step.  Very odd but seemed to resolve itself when I removed the tie to ground (the -5V and -24V are still wired). 

Anyway, now that this seems to be working, does anyone know how to set up a probe in HAL? I'm sure it is just a couple lines of code.  My input pin on the Mesa for probe is 6. Is there a probe module or anything like this for LCNC?  

Thank you

Tommy
Sorry I am a little confused, I have not programmed a HAL input before. I found the pin you were describing inside of LinuxCNC (I attached a photo).  Then I found this line of code all ready in my HAL file

So, does it need to be changed to something along the lines of: net my_probe <= probe-in => hm2_7i96s.0.inm.00.input-06 ? 

Why do I need to to include "my probe"?

That worked! Thank you. I am going to get some parameters dialed in, play with probing in my Z height and hopefully make some test cuts soon!

I will let y'all know the results of the testing!

What is the best way to probe in LCNC? It looks like there are a couple of different probe modulus and probe guis, is there one that is the most supported or most recommended?

Edit: it seems like not all the probe modules work with LCNC 2.9?