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Question EBB36 thermistor spike when restarting

Dajosco

New member
When restarting Klipper I get sometimes (4/10 times) a spike of a random value on the extruder thermistor. This value can be either negative or positive and usually of a huge magnitude. Other than this everything works perfectly.
Is anybody else experiencing the same or similar?

My configuration is:
  • Raspberry PI4 --> BTT U2C 1.1 --> EBB36 1.2
  • 500000 kbps
  • PT100
  • Mainsail or Fluidd

EBB36_Spike.png
 
Is your can bus set up as hot plug?
From: https://www.klipper3d.org/CANBUS.html
  • Whenever the "bridge mcu" is reset, Linux will disable the corresponding can0 interface. To ensure proper handling of FIRMWARE_RESTART and RESTART commands, it is recommended to replace auto with allow-hotplug in the /etc/network/interfaces.d/can0 file. For example:
allow-hotplug can0
iface can0 can static
bitrate 500000
up ifconfig $IFACE txqueuelen 128


If do have the canbus config set for hotplug, then I would assume it is the EBB36 MCU booting, establishing the SPI bus for the PT100, and establishing the canbus network connection.
 
Is your can bus set up as hot plug?
From: https://www.klipper3d.org/CANBUS.html
  • Whenever the "bridge mcu" is reset, Linux will disable the corresponding can0 interface. To ensure proper handling of FIRMWARE_RESTART and RESTART commands, it is recommended to replace auto with allow-hotplug in the /etc/network/interfaces.d/can0 file. For example:
allow-hotplug can0
iface can0 can static
bitrate 500000
up ifconfig $IFACE txqueuelen 128


If do have the canbus config set for hotplug, then I would assume it is the EBB36 MCU booting, establishing the SPI bus for the PT100, and establishing the canbus network connection.
Thanks for your answer. Yes, I do have the hotplug option enabled. What you mention is kind of my theory, it might be a bug while initializing where is not reading properly the value.
I wonder if somebody else has the same problem.
 
Thanks for your answer. Yes, I do have the hotplug option enabled. What you mention is kind of my theory, it might be a bug while initializing where is not reading properly the value.
I wonder if somebody else has the same problem.

sudo apt install can-utils
canbusload can0@YOURDATARATEHERE I.E. 250000 -b -c
Control +C to stop the window scroll.

You can do pull this canbus load utility up on the PI and see if it's struggling during start up. Even on 250000, and one device on the network I only every reach 24% max during probing, etc.
 
I Only had this with PT100. It would spike and came back "slowly" to normal values. Same board with Semitec 104GT-2 no spike.
 
Thanks for your answer. Yes, I do have the hotplug option enabled. What you mention is kind of my theory, it might be a bug while initializing where is not reading properly the value.
I wonder if somebody else has the same problem.




I'm in the same situation as you
 
My setup is as following:
  • Raspberry PI4 --> BTT U2C 1.1 --> EBB36 1.1 (canboot)
  • 500000 kbps
  • Thermistor Generic 3950
  • Mainsail
  • I do not have the CAN interface set to hotplug
I am not seeing any spikes.
 
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