Duet 3 6HC Rev. 1.01 Faulty

NeueKlasse

@Phaedrux
Yes the Board works in Standalone mode.. see above

Phaedrux

When in standalone are you able to update to 3.2 Beta 4.1?
Then once updated are you able to start with a fresh pi image and update to the unstable branch to match?

NeueKlasse

@Phaedrux

update to the unstable branch to match.. you mean via apt update/upgrade?
i could try..

Phaedrux

Yes, once the board itself has the 3.2 beta 4.1 firmware flashed on it via USB/Bossa.

Then a fresh Pi image install. https://pkg.duet3d.com/DuetPi.zip

And then update to the unstable branch to match the firmware on the duet.
https://duet3d.dozuki.com/Wiki/Getting_Started_With_Duet_3#Section_Software_Installation

NeueKlasse

@Phaedrux
The DuetPi Update with or without connection to the board via ribbon cable?

Phaedrux

@NeueKlasse I think you can update without the board being connected.

NeueKlasse

@Phaedrux

I've done everything that was mentioned.

Board Updated to 3.2 Beta 4.1 (Tested in Standalone Mode, no Problems)
DuetPi freshly installed (+added ssh.txt, +added wpa_supplicant)
and Updated via unstable branch to 3.2 Beta 4.1 => OK!
DuetPi Connected to Duet3 Board => Again, no Problems while Hotends heating (M303) or Movenments, Homing etc.
BUT when i start M303 for the Hotbed => it's exactly like the Picture from 1.Dec.2020 above. Many Many Connection Losses.....

When i Turn on the Hotbed i get Errors like DCS Stopped, Connection Lost and Connection established again...
as soon as i set the Bed Temp to 0 (off) the Problems STOP! Immediately!

i don't understand!...

Phaedrux

Can you give some more details on your bed, the mosfet, and the wiring?

NeueKlasse

@Phaedrux

Bed is the Original 24V Bed from Anycubic.
Mosfets are the Original Ones either..

Today i made the conversion from Mosfets to the V_OUT Connections on the
Duet itself... maybe the Mosfets are faulty....
but after Powering the Printer and looking on DWC now i get
lots of Communication Lost Errors (see above...) WITHOUT Powering the bed?! i Checked everything again... no Issue there.

dc42

It sounds to me that there is a ground loop in the power wiring. Please provide photos showing how you are providing power to the Pi, the Duet, and the bed heater circuit. Also please confirm that you do not have any independently-powered devices (for example a PC) connected to the Duet or the Pi via USB.

NeueKlasse

@dc42 Thanks, below some Pictures of the Wiring!

Power Supply 3 Rows 24V

Row Bed Heater Mosfets
Row Pi Powersupply 15W
Row to Duet Board

!

on Bottom Right you see the Power Supply for the Pi, i also tried another Pi Power Supply
direct driven from the Wall Outlet without any Changes....

Now i've the Mosfets back in the Cabinet... the 15A Fuse of the Duet seems to weak for the bed and blows after 10-20 degree heatup....
after having the Mosfets back in the Printer the Connection Loss Issues are still
high frequently.....

!

Nothing else is powered / Connected from the Pi or from the Duet! only everything
on the Photos...

NeueKlasse

I Have disconnected everything from the Board except the Ribbon Cable to the Pi
and the PanelDue.
The Communication Errors are still coming every Second!
Connection Lost, Connection Established... and so on and so on...

Tried with another Pi and another Ribbon Cable! Same Thing

I am wondering why they doesn't came that frequently yesterday night....????
they almost just came when i heated up the bed.... but now it's horrible

is it possible to get another Board to confirm that's not the Board? maybe Repair?

dc42

Thanks for the pictures. Your power wiring looks OK to me. I really don't think it's the Duet that is the problem.

Are you sure that the PSU is capable of driving that bed heater? If it was blowing the fuse on the Duet quite quickly, it must have been taking 20A or more. Perhaps the PSU is cutting out and the Duet is resetting.
Could there be a short in the bed heater, or between the bed heater element and the aluminium bed plate of you have one? What type of bed heater is it?
When the connection is lost, does the bed heater turn off?

NeueKlasse

When the communication gets lost the Heater is still Heating, although M303 is working with all that Communication Loss Errors (no Header)

The PSU is the Original One so i think there must be plenty of Room for the Power...
(1000W 24V)
i was also surprised that the fuse was blown... i dont measured the Bed Amps but
i found that the Bed must have around 300-400W (i hope that's correct)
so around 12-16A

The Thing is it doesn't matter if all is connected to the board or when i disconnect everything from the Board.... i have Communication loss Errors every second!

So the Bed Heater doesn't have to Play with it to get hundreds of Errors...
(yesterday i thought so... but today i'm not sure what to think...)

Veti

@NeueKlasse said in Duet 3 6HC Rev. 1.01 Faulty:

i found that the Bed must have around 300-400W (i hope that's correct)
so around 12-16A

the max current on the bed is 15A. So you ware most likely exceeding that.

measure the resistance of the bed and subtract the resistance of the multimeter with no connection

NeueKlasse

@Veti

Yep the Fuse is only 15A (Mosfet on the Duet is rated for 18A i think) but even with
that (i had just tested the Option without extra Mosfets...) i had Communication Errors..

Measured the Bed... 1.5 to 1.6 Ohm, so at 1.6 V/A ... the Bed drawn Current must be around 15A

NeueKlasse

This post is deleted!

NeueKlasse

What does the Point SPI Overruns/Underruns say? (M122)

NeueKlasse

Although, is it possible to exchange the board? I need the Printer to work..

NeueKlasse

I remembered that i had connected the Duet and Pi4 in that way that the Duet supplies the Pi 5V before i put everything in the printer...
Then i wanted a extra Powersupply to not overload the Duet...

Today i disconnected the Pi Powersupply and added the needed Jumper... et voila... problems seem gone.

I don’t understand why? I tried the original Pi power supply and even with this i had communication losses ....

I hope the board is tough enough...