First steps linuxcnc 7i76E

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10 Jan 2018 10:33 - 10 Jan 2018 10:37 #104231 by kor
First steps linuxcnc 7i76E was created by kor
Hi,
I installed linux Mint 18.1 the preempt kernel 4.9.4-RT2 with this great tutorial: How To Linux Mint 18.1 PREEMPT .
I followed the tutorial for the linuxcnc aswell.
The manual of the Mesa 7i76E is pretty confusing to me, but fortunatly I found this great work:
7i76E connection sheet
where I also printed the labels for the connectors. (to make my live easier eventually)
Now I attached the 24V power supply to the TB1 connector pin1 gnd pin4 24V (counted from top side starting with 1)
And I got no error so far.
I also attached the same 24V power to TB3 connector pin 2 (GND) and 3 (24V)
when I power the card the two yellow(-orange) LEDs light up after some blinking which indicate everything runs OK. (CR8 Field power and CR13 logic power)
The W3 jumper was changed to the up position, in order to change from the standard IP Address to the 10.10.10.10 address. (which hasn't been tested since I have not jet connected the ethernet cable.)

But now I am lost. Everything I could find so far is fairly non step by step. thats why I am asking for help. I hope This can eventually help someone else to get this card up and running. To the point where at least one stepper runs one input and one output is connected.
From the things I read so far one has to start the PNCConf wizard next. I can only start linuxcnc which has some sample configurations but nothing I can modify, I think that is for simulation of Gcode. I found a picture somewhere (don't remember) where a cnc menu in the linux start menu is present showing the pncconf.
Sry for my beginner questions but I am fairly new to linux and it is not as easy as it sometimes appears.
Last edit: 10 Jan 2018 10:37 by kor.

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10 Jan 2018 12:49 #104234 by rodw
Replied by rodw on topic First steps linuxcnc 7i76E
Create a config with PNCCONFand take the time to specify your stepper motor gearing etc.
Edit the generated hal file to change the IP address to 10.10.10.10 address as the wrong IP will be inserted.
Save the hal file and open the config using Linuxcnc. You should be able to jog each axis. From the menus, you will be able to open halshow.. The menu might say "Show Hal configuration" or something similar. find the 7i76e in the tree structure and get to know the pin names. You can even connect a wire to +24 volts and touch it to an input and watch it change state in halshow.

From here, I recommend editing the hal and ini files in a text editor.

When I started, I sorted out my estop, a red light when in estop (easy) followed by the home and limit switches for one axis and then played around the ini settings to get that axis running at and set the maximum speed and default velocity for jogging. You have plenty of inputs so use maximum and minimum limits and a home switch for each axis. Shared home and limit switches are OK, but in my experience seperate switches is much nicer. Use the homing offsets to move the axis so the home switch is no longer triggered after homing.
I found the homing configuration documentation to be very well written so I persevered until I got all of the homing etc working..

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10 Jan 2018 14:15 - 10 Jan 2018 16:41 #104235 by kor
Replied by kor on topic First steps linuxcnc 7i76E
Thank you. But my first and most important problem is that i can t find the pncconf wizard. Sry it will probably very obvious but rigt now it is driving me crazy.
The only executable I was able to start so far was /home/linuxcnc-dev/scripts/linuxcnc
which gives me a one page wizard with some sample confs for simulations.
Last edit: 10 Jan 2018 16:41 by kor.

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10 Jan 2018 21:52 - 10 Jan 2018 21:52 #104256 by kor
Replied by kor on topic First steps linuxcnc 7i76E
I build the dep packages and instelled them now I got access to the pncconf wizard. for testing I skipped a bunch just added 2 steppers I will modify that later.
finally I thought I could start linux cnc but I got the following error message:

modprobe: ERROR: could not insert 'ip_tables': Operation not permitted
iptables v1.6.0: can't initialize iptables table 'filter': Table does not exist


any ideas?
Last edit: 10 Jan 2018 21:52 by kor.

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11 Jan 2018 01:08 - 11 Jan 2018 01:08 #104266 by PCW
Replied by PCW on topic First steps linuxcnc 7i76E
I've seen this error on Mint18.1 (Mint 17.x is OK) and LInuxCNC 2.7.X
I believe its fixed with LinuxCNC master, not sure what the fix is for 2.7.x and Mint18.x
Last edit: 11 Jan 2018 01:08 by PCW.

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14 Jan 2018 11:30 #104422 by kor
Replied by kor on topic First steps linuxcnc 7i76E
uninstalled linuxcnc 2.7.x downloaded compiled 2.8.0 pre1 and it works :)
Well at least one switch and I made a stepper turn. only in the pncconf wizard.
in linuxcnc I get an error: stepgen maxvel is to big. for current step timings.
I am fairly certain I have to do those things in pncconf but it is not really clear to me what all the stuff means.
I set for the testing the driver to full steps and 5mm/rev 50mm/min as max speed 4mm/s² as ramp. so there should not be any problems. with those settings I get 50revs per minute in the motor tuning from pnc. without a problem.

Later my goal is 5 microsteps and 1000mm/min max velocity. which should be 1000steps/rev and 200rev/min this should be 200kHz and a step resolution of 0,005mm.

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14 Jan 2018 13:25 #104424 by rodw
Replied by rodw on topic First steps linuxcnc 7i76E
I never really used PNCCONF once I had stepper motors using and just edited the .ini file directly for each joint and axis.
What stepper drivers are you using? Some are better than others.

Sounds like you need to give some thought to these settings (mine are very, very short but they work for my stepper driver). Try 4x the figures I am using and then bring them back by trial and error.
DIRSETUP   = 500
DIRHOLD    = 500
STEPLEN    = 1500
STEPSPACE  = 1500

Sounds like when all of the above timings are multiplied out, your max speed cannot be achieved. Thats odd, as you are not pushing the limits anywhere.

Also your acceleration is very conservative. Depending on your drivers, you can probably get 50mm/s/s ( I think I've run 110mm/s/s OK with a 3:1 reduction drive from a NEMA 23 to a 5mm ball screw.)

You should easily reach your target speeds and velocities as you forgot to convert minutes to seconds so you will only be at 3.33 kHz. I'm running at 20x microstepping and about 90 kHz. The 7i76e can manage 10 MhZ if your stepper controller can handle it. As a guide I can get around 700 rpm out of my steppers.

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14 Jan 2018 14:20 #104431 by kor
Replied by kor on topic First steps linuxcnc 7i76E
thanks rodw. I will try later. I got chineese closed loop 4.5NM stepper nema34 (HSS86). Thats embarrassing that I forgot to convert minutes to seconds, My drivers can handle 200khz thats how I came up with the maximum velocity. Since I wanted to have a resolution which is below 0.01mm and is a multiple of 0.01mm. Now I can even go to the original 10 microsteps I was looking for. and increse the speed. Even though I think that is not necessary.

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18 Jan 2018 20:47 #104699 by kor
Replied by kor on topic First steps linuxcnc 7i76E
I have been trying for hours to get my closed loop stepper to run.
Manual: cnc4you.co.uk/resources/Servo%20Stepper%...20UK%202%20HSS86.pdf
first I was able to turn them slowly in the pncconf with 50 to 100 revs per min. (for testing porpuses I still have full steps.
but now they don't move at all. even if I am using value which worked previously.
So I just dont have any clue what is going on.
So I decided to just finish this setup even if the motor is not running. when I start linux cnc I get 2 error msgs:
unexpected realtime delay at task 0 with period 100 000.
and hm2/hm2_7i76E0 error finish read! iter=7
I really need some help I just got no clue whatsoever what to try next.

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18 Jan 2018 20:52 #104700 by PCW
Replied by PCW on topic First steps linuxcnc 7i76E
if you really have a servo thread of 100000 ns, that's _WAY_ too fast
Standard servo thread period would be 10 times that (1000000 ns)
The following user(s) said Thank You: kor

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