LinuxCNC on Raspberry Pi 5

Booting from MicroSD or NVME?
If first, try a different one, if you can.
Or a USB stick...
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If NVME, skip the above.
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Also, in a terminal
sensors
should show temperatures, if the processor is above 60-65C, slap some cooling on it.

So....... this morning the Pi 5 has been quite stable in terms if ethernet comms. I might naively be thought to have caused this because I added 1x 0.1 uF and 1x 47 uF/16 V electrolytic capacitor across the blue terminal block (photo a couple of pages back) which is across the +5V / 0V rail.

I did this for a few reasons. First, because yesterday I plugged in the 7i96s while the Pi was running which may have caused the Pi to reset. Possibly the voltage at the Pi dipped due to 7i96s capacitance. I don't know if the Pi has any decent amount of power supply capacitance -- perhaps it is hidden under the heatsink (not a good place for electrolytic capacitors to live).

Second, the 5V/3A Meanwell PSU datasheet does not specify the output capacitance (or stability if you add capacitance). But in any case, the resetting of the Pi could suggest it doesn't have a lot of output capacitance.

Third, the 5V rail wiring is a bit long and all over the place, so could be picking up noise from other appliances, so this could suppress it a bit.

I also raised the Meanwell 5V rail voltage from 5.0 to 5.1V at the PSU terminals. Voltage drop in the wiring is about 100 mV according to my dodgy DMM, thus perhaps the rail was causing instability.

Well, things were quite stable, so I reversed all of the above and things are still stable !!! I can repeatedly send 50,000 packets with 1 ms spacing and get 0% loss.

Micro SDCard.

I ran

/opt/vc/bin/vcgencmd measure_temp

So the Pi is sitting at 48.8. Running

sudo chrt 99 ping -i .001 -q 10.10.10.10 -c 50000

50000 packets transmitted, 50000 received, 0% packet loss, time 50045ms
rtt min/avg/max/mdev = 0.102/0.112/0.197/0.006 ms

/opt/vc/bin/vcgencmd measure_temp
temp=50.5'C

So the wee fan and large heatsink appear to be holding the temperature down with a 50 s length increased load.

To try encouraging packet loss, I have plugged in a brushed electric drill into the same plugbox and revved it, and then plugged in a desktop PC with SMPSU. Still 0% packet loss over 10x sends of 5000 packets. Capacitors are not fitted.

Looks fine so far.

Ok, maybe this helps...

Originally I was using 10.10.10.1 as the IP on the Pi 5.

sudo nmcli con mod "Wired connection 1" ipv4.addresses 10.10.10.1/24

ip addr /* returned 10.10.10.1/24 */

For the past day however I have been using 10.10.10.11 because I read somewhere never to use the dot-1.

So I changed back to dot-1 and was able to get intermittant packet loss -- usually 0%, sometimes 1 packet if I used Ctrl+C (see previous posts). In one instance I was able to lose 7 packets.

Further, I was able to lock up the ethernet again.

What happens is I run this command

sudo chrt 99 ping -i .001 -q 10.10.10.10 -c 50000

and I note that the green LEDs on the ethernet are no longer flashing at some point. So I Ctrl+C and there are lots of lost packets (23% or something like that).

But running a ping 10.10.10.10 also now fails, but if I run this again

sudo nmcli con mod "Wired connection 1" ipv4.addresses 10.10.10.11/24

then the ping starts working again and we are all good to go again.

So........ is my sin that I used 10.10.10.1 and it is conflicting with the default gateway that I have not set anywhere but is perhaps defaulting to that IP address?