Trying to move from UCCNC to Linuxcnc and using 7i96s but having trouble

I’m reaching out to the forum to hopefully get some guidance.I’ve spent the past several days working through a LinuxCNC setup with a Mesa 7i96S for what should be a fairly straightforward retrofit on a :Bridgeport Series 2

• XYZ mill
• X & Y steppers
• Z servo (knee)
• No exotic kinematics, just a basic mill configuration

I’ve gone through many iterations and changes (largely guided by ChatGPT), and while I’ve learned a lot, I’m currently back near square one. I did manage to get one motor oscillating back and forth, so I know signals are getting through at some level.At this point:

• I do have solid communication between the PC and the Mesa card
• Network issues are resolved (static IP for Mesa, internet via USB dongle)
• Latency issues were addressed by disabling several BIOS features
• Debian installation and networking are now things I actually understand, which is a win

That said, I’m struggling with what feels like a high barrier just to get basic motion. My main question to the community is:

Is it realistic to expect a simple XYZ mill (2 steppers + 1 servo) to at least jog without days of trial-and-error, or is this learning curve typical?

For context, I’m not new to CNC:

• I previously had this machine running under UCCNC
• I had:
  • A 4th axis
  • VFD spindle control
  • Spindle brake
  • Mist, air to the knee, and lube pump
• All of that worked reliably

The only reason I switched to LinuxCNC was:

• I want true rigid tapping
• I’m interested in the QtDragon / QtPlasma ecosystem
• I also have a router and another plasma table I’d like to potentially convert

So this is not a casual experiment — I’d really like to make LinuxCNC work long-term.I’ve learned a lot in the last few days:

• Installing Debian cleanly
• BIOS tuning for real-time performance
• Static networking for Mesa Ethernet cards
• Separating “GUI motion” from real hardware motion
  …but I’m still not confident I understand the correct minimal path to first motion.

I’m hoping for reassurance that:

• This transition is doable
• There is a clean, recommended workflow for initial bring-up
• I’m not fundamentally missing something obvious

Any perspective, advice, or “yes, this is normal / no, it shouldn’t be this hard” would be greatly appreciated.Thanks in advance,
Mark

 
ChatGPT is not particularly useful with Linuxcnc. I worry when I ask AI a question and it quotes into I wrote on this forum back to me.
now you have communication to the Mesa card, I would create a new config with pncconf and see how it goes. If it fails, share your hal and ini file and somebody will help. Also some rules.
1. Stick to the default axis user interface until you get a working  machine
2. Always start linuxcnc from the command line. That way you will see any error messages. Usually messages are fairly clear and refer to the file and line number 

I think the main difference with Linuxcnc is linuxcnc is a blank canvas where other systems have specific wiring terminals for specific purposes. That means you have a bit more work to do  as you have to define a bit more of your machine here. eg for coolant, you need to select a random pin on the 7i96s and then connect it to the appropriate internal signal. Also note if you have not defined your spindle, you won't see coolant/mist controls in axis. 

Proceed something like:
Get x,y,x morion working
Set up home/limit switches. If you did not have these, take the time to wire in a shared home/limit switch an all axes. It is much easier
Get estop working.
Work on your spindle. pin spindle.0.on needs to connect to the 7i96s pin you chose for the spindle on signal (spindle relay)
Set up your 0-10 volt speed control and scale it correctly
Get your encoder working (or do it later so you have something you can use)
Then set up coolant and mist. Test these with MDI commands M7,M8,M9
OIler then follows. I have not done anything with it but the pins are here
linuxcnc.org/docs/html/man/man1/halui.1.html#Lube

Main thing is to share console output and hal and in files here as you work through this so we can help

 

To echo what rodw said:

Create a simple configuration with pncconf or MesaCT

Test this configuration by launching it from the command line

if there are issues you cannot resolve, post your error messages,  hal/ini files here

So I stopped trusting Chat gtp and started to think more for myself .   I started using the error log at the end of a mistake.  I finally figured out that i had mistakenly set the estop pin to invert and that was what was causing the hard limit and qtdragon not coming online(despite what chat said that it would not cause this is decided to try and uncheck it anyway).  SUCCESS.  I got xyz working and even ran the excellent facing wizard.  How exciting. After days of chat having me cut and paste(I really learned how to cut and paste in Nano and learned the shortcuts)  Wild goose chase.  I think I learned most from someone just going through the settings on Youtube, but it just seemed like everytime i did something and got somewhere something else happened.  Chat told me I should switch to the Axis Gui to do the calculate steps wizard I am used to using in uccnc and mach3 a long time ago.  When i went to change the name in the ini for axis instead of dragon it didnt work and then it said oh yeah that doesnt work.             What is the best way to get the xy and z calculated, like I mentioned in uccnc there is a calculator that tells you to enter a value and you measure that and it adjusts the steps per rev.         If it is only in axis i could make a new config and use it and copy the values.            Will linux compensate for slow down in the cut by changing pwm?  I will have a spindle encoder.     Is there a tutorial on halcustom files?  From my understanding using them for custom I/0s is the best way so I can have a base pncconf.      Should I try to get all the inputs and outputs I have wired so that i can use the pncconf as much as possible?   Which things should be put in the Hal custom?    Is there a button to overide limits to jog off in case they are tripped in QT Dragon?
  Last question.   Is there another AI that is better for linuxcnc than Chat?   My machine is a Bridgeport Series 2 I have had for 15 years and I started off retrofitting it with Mach 3 then moved to UCCNC.  I recently replaced the 4 hp original motor and made some custom mounts for a 7.5 HP motor hoping to be able to face mill more aggressively and hoping that will help with ridgid tapping.    Thank you in advance for your help.
 

Mark wrote:

So I stopped trusting Chat gtp and started to think more for myself

 

great! pncconf will calculate out the step calibration but there is a shortcut if you dare!
You can review you mach3/uccnc and look for what Mach3 calls steps-per (steps per inch or steps per mm)
This directly equates to what linuxcnc calls STEP_SCALE in the ini file. so just edit your ini file to use your known values. But at this point you will be doing stuff manually in a text editor from here on. Which is not a bad thing in my book! Also try using geany for text editing. Our ISO's install it but otherwise type sudo apt install geany. Its very similar to notepad++ in Windows.

I often use pncconf to create a basic config and edit it by hand to correctly scale the axes and set velocities and acceleration.

slowing down in a cut is done by the motion controller. It knows from your ini file what the velocities and accelerations are and will adjust them accordingly. G64 is probably new to you but it sets the closest distance away from a corner you want to allow and should be in every gcode file (and set in the ini file). Without it, the motion will stay at your maximum velocity which cause you to cut corners significantly. Read up on it.

Yes, buttons to allow you to override limits should appear if you violate them.

This forum is far better than any AI as its where the AI's come to get their info. I prefer Elon Musk's Grok as it lies less even though it has quoted info I wrote here back to me a week later   

rodw wrote:

 
ChatGPT is not particularly useful with Linuxcnc. I worry when I ask AI a question and it quotes into I wrote on this forum back to me.

And then knowing the ratio between "dangerous half knowledge" and "expertise" for a fact makes it even scarier.
Suddenly your own work hypothesis becomes a fact and "best expert advise" one can find on the internet.
 

Good news.  Having some success.  I have xyz moving and i have spindle brake and mist toggling on and off in halshow(which i have learned to use); I even got my mist working but grok says i have it backwards and i hope i have not damaged the board because wired 24 v + to solenoid    and solenoid - to output +    and out - to   ground.  It did not work when i wired it solenoid - to out - 

I have a huanyang gt 7.5 kw vfd  it is different from the non gt and its pins i had been using with uccnc are
s1    s2   grnd(may have been +10 the wire pulled off as I was looking at it)  Ai1 and comm     I am going to the shop soon and will post my files I will see if i get any led light on the board when I m3 if there are any.  Is there someone else who has wired a gt vfd that could tell me what worked for them.  Also ready to do encoder wiring. what pins would those be? Thanks in advance and i will be posting soon.   In uccnc  I had a custom button to put the spindle brake on when changing tool because i have a quick change nut on my Bridgeport series 2.

Got it .  Spindle running and all axis running now just need to tune axis and get limits and encoders set up this is amazing after so many days I think this is going to be worth it because I have more of these conversions to do and I have learned so much it is amazing.  Without even tunning the spindle is behaving really well with no feedbac yet.  I was having trouble in uccnc wtih overshooting and taking awhile to get settled.  Has anyon e noticed smoother operation with linuxcnc vs other s when they switched?  The exciting thing for me is the prospect of ridgid tapping.  .  My liimit switches are only two wire.  Is this going to work?  I have a threee wire home swithc set up hall sensor
 

If you have the limit switches, keep them. It does make for a safer machine. I used seperate min/max/home on my first machine but my next one I used a combined home/min limit switch only with no max limit.