Mesa 7i96s.ini settings issue.

Hi All. I’m familiarising myself with my 7i96s on a RasPi-4 (rpi-4-debian-bookworm-6.1.54-rt15-arm64-ext4-2023-11-17-1731) before choosing a dedicated computer.TB3 I/O & mesaflash are working.Pncconf wizard not completing & Mesa configuration tool fails to start. I’d rather avoid problem solving a temporary computer issue if I can finish editing configuration files by hand.I have a partly formed (?) by_interface.mesa.hm2-stepper config.Can anyone suggest appropriate values for 7i96s.ini?
[EMCMOT]
SERVO_PERIOD (currently 1000000)?[JOINT_0]
SCALE (currently 1000)?
DIRSETUP (currently 200)?
DIRHOLD (currently 200)?
STEPLEN (currently 4000)?
STEPSPACE (currently 4000)?
My system (simple xyz mill):
Nema23’s wired bipolar parallel.
‘Generic stepper drivers’
Peak current 4.25A.
Half current mode.
3200 steps/rev.Mill lead screw 20tpi giving 2519.685 steps/mm.
Previously I used: velocity < 500 mm/min, acceleration < 250 mm/s/s.Latency stress test (RasPi-4).
             max interval (ns)   max jitter (ns)
sever thread   (1ms) 1913640     999630
base thread   (25us) 304292      279292

Thanks...

What errors do you get from pncconf or mesact?

For the latency test you should not run a base thread so either

latency-test 1ms
or
latency-histogram --nobase --sbinsize 1000

pncconf error example:
 
Latency (4xGlxGears & 360pYoutubeVideo&4xGlxGears) 
 

I reinstalled mesact again, this time sucess! I configured:
7i96s_xyz metric.ini
Scale 1574.80315
Step time 3500ns
Step space 3500ns
Direction setup 5000ns
Direction hold 5000ns

LinuxCNC starts, I am able to jog in small increments (0.1mm) but larger (& continous)  movements halt with "joint 0 following error".
I can jog 9 x 0.1mm, the tenth jog puts me back to the origin with the "joint 0" error.
I occasionaly get "Unexpected realtime delay on task 0 with period 1000000".

Changing the size of ferror & min_ferror makes no difference.
Also I should note that I'm trying the board with no stepper drivers connected at the moment.
Well it's progress? 


 

You might try increasing the servo thread period to 2 ms
(2000000ns).

Also make sure you have force turbo enabled in the config
as CPU speed switching causes latency issues.

To get an idea what the actual peak latency is, run:

halcmd show param *.tmax

In a terminal when LinuxCNC is running, the numbers represent
the peak times of all LinuxCNC functions (in ns on ARM)

 

Thanks for the advice PCW. My intention was to try the 7i96s on a RPi4 prior to rewiring it's box. Given the unexpected config-learning-curve for the RPi4 I think I might as well look for a dedicated computer and spend my time on that.
I was planning to get a new PC anyway so I'm considering my old Dell first - does this machine sound a likely candidate?
Dell Precision T1700?

The Dell is a reasonable host to try

I think pncconf will run to run if you setup a EN_us locale

If you are using an image from the downloads page. please type sudo menu-config
to fix yor locale and any other settings shown.

rodw - I'm using linuxCNC downloads rpi-4-debian-bookworm-6.1.54-rt15-arm64-ext4-2023-11-17-1731
I set menu-config options:
4) Locales: en_US.UTF-8 & 6) Governor: Conservative - still gives locale error...
 

Seems like there is still a locale issue
Here is my (en_US) locale:  (type "locale" in a terminal)


LANG=en_US.UTF-8
LANGUAGE=en_US
LC_CTYPE="en_US.UTF-8"
LC_NUMERIC="en_US.UTF-8"
LC_TIME="en_US.UTF-8"
LC_COLLATE="en_US.UTF-8"
LC_MONETARY="en_US.UTF-8"
LC_MESSAGES="en_US.UTF-8"
LC_PAPER="en_US.UTF-8"
LC_NAME="en_US.UTF-8"
LC_ADDRESS="en_US.UTF-8"
LC_TELEPHONE="en_US.UTF-8"
LC_MEASUREMENT="en_US.UTF-8"
LC_IDENTIFICATION="en_US.UTF-8"
LC_ALL=

 

Locale en_US.UTF-8 accepted (user error [ass]umed).