Flakey Behaviour from Duex 5



  • Background Info:

    I've have the Duet Ethernet Duex 5 setup running for many months. This on my bigger printer, so I don't run it a bunch, but enough to know it was functioning fine. I was cleaning up the electrical panel a few days ago (adding some cooling fans to the boards because I was getting temp warning from the drivers and removing some unused hardware). In cleaning up the panel, I removed the Duet and Duex to remount them on some tall standoffs to get better airflow underneath the boards. I had also intermittently had issues with the ethernet module not starting (very intermittently maybe once or twice in the last few months, usually a power cycle or two would resolve the issue.

    Once I restarted after cleaning up the panel, I have had some really flakey results from the system. I struggled for about 2 hours trying to get the ethernet working, I finally pulled the module and re-seated it and that seams to have done the trick. The only mistake I made was I connected a thermistor to the always on fan, thinking it was a fan. I blew the thermistor. After it was replaced, no issue, temp reads fine.

    The Problem:

    • Sometimes the board powers up and does not recognize the Duex. Under the settings screen, it does not say Duet Ethernet + Duex 5, just Duet Ethernet. A power cycle or two and unit will detect the Duex again. I cannot seem to get it to reliably detect the Duex. I have replaced the ribbon cable with a new one. Seemingly no change to the problem. Sometimes it is detected, sometimes not.
    • The endstop for E2_Stop is not changing state. Although the lights on the board are changing state, the settings screen is not showing the endstop as changing state. This is when the Duex is being detected. The drivers on the Duex are functioning and the temp inputs on the Duex are working properly.
    • I was having issues with my V and W Axis homing as the drives were not moving, but I think this was because the Duex was not being detected properly.
    • The thermostatic control on the extruders is no longer working reliably. The fans on the 2 extruders on the main board (Duet Ethernet) are set to run once the hotend gets above 45deg C. This keeps the unit from making a bunch of noise in my office when it is not actively printing. Now, once the temp gets above 45 degrees, they turn on, but only for a few minutes and then cut out even though the temp is 245 deg. I have checked the meter going back to the board and no power from the board.

    I am concerned that I have damaged the electronics in some way. I have ordered a new Duet and Duex5 last night. I have another printer that I would like to convert to these electronics. So, not a waste if the issue on the current ones can be resolved.


  • administrators

    Do you have a short thick wire directly between the ground sides of the VIN terminals of the Duet and DueX, as instructed in the DueX wiring instructions? This is vital.

    I am surprised the you blew a thermistor by connecting it to a fan output. The thermistors used in 3D printers normally have a resistance of 100K or more at room temperature, and should easily survive 24V.



  • Well I actually blew 3 of them trying to test different fan outputs before I realized that I had the wrong plug.

    I had originally run the separate power from the din rail fuse holder to each of the Duet and the Duex, likewise the ground were run separately to a din rail mount terminal strip (about 500mm away). In troubleshooting over the last couple days, I saw the wiki about wiring them together. I fixed it last night as per the wiki, but no change in the results. Could having it the boards connected incorrectly have permanently damaged either of the boards?


  • administrators

    @dougjones said in Flakey Behaviour from Duex 5:

    Could having it the boards connected incorrectly have permanently damaged either of the boards?

    If the DueX is sometimes recognised and sometimes not, I think it's unlikely that this is due to damage, although not impossible. OTOH having separate ground wires from the PSU to the Due and DueX is known to cause problems, especially after motors connected to either board have been energised.

    Which firmware version are you using? I made a change a few versions ago made to increase the reliability with which the DueX was detected at power up.



  • Firmware version 2.02 RC2
    web version 1.22.3



  • I have upgraded to 2.02 (RTOS) and Web Version 1.22.6 and still have the same problem.

    E2_STP is not being seen by the board. The light on the board is changing state, but the screen under Settings->Machine Settings is not changing state when I move my carriage over and back.


  • administrators

    Is it just E2_STP not working, or all of the DueX endstop inputs? Are the DueX fans working?



  • I appears to be all the end stops on and the fan outputs on the Duex. I confirmed the sensors used and fans used to test work on the Duet. I used M106 and M107 to turn the fans on and off on fan 0 then moved that fan to fan 7 and 8 and could not get them to turn on.

    The endstops are working on the main board and then moved to the Duex and the lights come on on the board, but the state does not change on the Settings page on the web interface.

    The 3 extruder fans that are acting up are also on the Duex (not on the main board).

    So I am gathering that I have a Duex that is goosed, correct? But the main board seems to be functioning properly.


  • administrators

    @dougjones said in Flakey Behaviour from Duex 5:

    Sometimes the board powers up and does not recognize the Duex. Under the settings screen, it does not say Duet Ethernet + Duex 5, just Duet Ethernet.

    If it doesn't recognise the DueX then the DueX endstops and fans will not work.



  • When it does connect, This is happening.

    The stepper drivers appear to work thermister inputs work. The Endstops and Fan outputs do not seem to be working.


  • administrators

    @dougjones said in Flakey Behaviour from Duex 5:

    When it does connect, This is happening.

    The stepper drivers appear to work thermister inputs work. The Endstops and Fan outputs do not seem to be working.

    That indicates that I2C comms between the Duet and the DueX has broken down, even though it must have been working well enough when the DueX was recognised at startup. If you run M122, I expect you will see a lot of I2C errors reported.


 

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