Advanced Search

Thanks for the comments - they were very useful.  Here is what is happening when I try running LinuxCNC with my custom kinematics. 

I am running in simulation mode - no hardware is connected or moving
When I launch LinuxCNC, the GUI only lists Joint0 and Joint[1]  - not X and Y (1st image) 
When I "home" the machine, X and Y appear on the GUI however the position of the unit jumps to x1.106, y1.895 (image 2) 
At the same time, the forward kinematics are executing and coverging, but not exactly where I expected them (very close though) 
Am then getting a "Joint Following Error" and the inverse kinematics are executing but returning zeros for every calculation. 
My cablekins.comp file is attached. 

Any ideas?   
 

ATC chip cover.

Top plate is 1/4" polyethelene; white skirt sections are PETG.  Door, slider mechanism, and motor cover are PETG-CF.

Skirt sections have interlocking tabs, and are edge-glued with epoxy.

After 18 months in the making, the ATC just passed a torture test so I feel like I don't have to hide my shame.

 
 

andypugh wrote:

You could try switching to joint mode (halui.mode.joint ) then homing, but I am not sure that is preferable to unhoming then rehoming.

What is the input that prompts this? Are you literally just working at the command line, or is the rehoming prompted by a soft or hard button?

 

For simple MDI type mill control tasks I prefer real buttons to mouse clicks. So I made this little control panel for ease of use. On the control panel side it's just Arduino code so libraries galore and I found some open source code called Arduino Connector (Thanks Alex from Germany) that allows simple messaging between Arduino world and HAL. The display has multiple modes and in the Jog Mode, the home buttons are associated with the three grey buttons just below the screen.


 

Yeah, from a distance I would guess that U5 (the driver chip  for STEP-/DIR- 0 0..3)
has been damaged as it looks like all 0..3 - pins are bad.

If you already have an install of studio, in a terminal
sudo apt update
sudo apt install linuxcnc-uspace
should install everything, except maybe not the real time kernel as Ubuntu had removed it a while back, no idea if it is back.
If the kernel is not installed, do a search for linux-image 6.11 with RT in the name, and install that.
Studio uses a preemptive kernel, LinuxCNC uses a fully preemtable kernel, so not exactly the same thing, again a while back.
The real time kernel should be soon in normal Debian distros.
There was also the option of installing all the studio apps on normal Ubuntu or Mint or Debian, if all else fails.

Moved to "driver boards" section.

If you have differential outputs (A+,A- ,B+,B-for example)
you should jumper the 7I96 encoder inputs to differential mode
and use all 6 wires.

If you want to use single ended mode (only A+,B+)
you need to jumper the 7I96 encoder input for single
ended mode.

Now I can't go and measure, but I just measured with gnd.
outputs 1-2-3 gave the same values, 2.3v and 4.8 V,
output 0 dir- and step-    0.05 V
Output 4   5v and 4.8v

These were approximately the values ​​I found

​​​

Its probably best to measure between STEP+,STEP-,DIR+,DIR- and GND
You should get a positive voltage in one state and a voltage close to ground
in the other

If you measure between say STEP+ and STEP- you should get
a positive voltage in one state and a negative voltage in the other state.
(as you did on channel 4). The fact that channel 4 acted very differently
than channels 0..3 is a pretty clear indication that U5 or U7 are damaged
(and may have been marginal for a long time)

one moment, let's try to understand each other well otherwise I'll make a mistake. should I measure between step+ and step- / dir+ and dir- or gnd - Step + / gnd- step- etc? because then I have different values. Or another way? sorry but I'm not familiar with this, if you tell me precisely what I need to measure I'll be grateful.

I am using linuxcnc 2.9
I am working on simulation but the behavior in the real machine appears as joint following error which i think it’s reasonable error due to sudden change in joint position

A couple of videos from Tom on the IRC





JT

New to LinuxCNC - I added an MPG to the Spindle Encoder of Mesa 7i96.  Initially I had only A+ B+ 5V GND on TB2 Connector and it was having trouble moving and was registering only 1 count in Hal.  Going thru the forum comments, I removed the 5V from TB2 and connected it to the main 5V supply.  I was able to move the axis and able see the counts.  However it would not reverse, so i connected the A- B- and it started working both forward and reverse.

Any reason, I need to connect the A-B-? because the posts mention A+ B+.  The TB2 provides only 4.4V and my MPG says 5V-15V could that be a reason for not able to use the TB2 5V?

Thanks
babu

You have a damaged driver chip (U5 or U7) or incorrect wiring
(did you ground DIR+ or DIR- ?)

You can check it its a wiring error by unplugging the connectors.
If you still don't get a differential output like channel 4 (+ and -  >2.4V))
Either U5 or U7 have been damaged and its surprising channels 1,2,3
still work

I tried but I get very different values


Output 0 (now no connection)

DIR+/DIR-= 4.9/0.03
STEP+/ STEP-=4.9/0.03

Output 1 

DIR+/DIR-= 2.4/0.04
STEP+/ STEP-= 2.4/0.03

Output 2

DIR+/DIR-= 2.4/0.1
STEP+/ STEP-=2.48/0.048

Output 3

DIR+/DIR-= 2.3/0.048
STEP+/ STEP-=2.3/0.048

Output 4 (now use for X)

DIR+/DIR-= +3.9/-4.9         ????
STEP+/ STEP-=+3.9/-4.9    ????