Wierd issues with my duet wifi



  • Hello All,

    I have been having some weird issues with a duet wifi that i am currently configuring for a machine that i build (a fluid handling robot for operation in a laminar down flow cabinet). I have already ordered a new duet but i want to fix potential issues as to no fry another duet.

    First the MCU is reporting strange readouts in voltage and temperature:
    86b5db98-35dd-487a-a997-55d043863fc3-image.png

    The voltage should be 24v and the temperature is obviously false. Earlier before i disabled all heaters i did also see reported temperatures of 2000°C which is also bull as i do not have temperature sensors connected.

    In the second more important issue: the DUET web control is becoming unresponsive if i move certain axis. I have 3 mini axis driven by M3 lead screws 15mm 16 step steppers that pull 0,5A. If i move one of these web control disconnects but the WIFI signal stays up. This is very weird as i have several days of testing without this issue. Furthermore its just web control that crashes if i run the home all command all axis home without issues even though small problematic axis home before the x and y axis. The problem is not in G code execution and the axis seem to be wired fine otherwise the homing commands would not work.

    Some back ground on the design which may point to some issues:

    The system once finished will use a separate controller which is connected using a 64 pin ribbon cable which connects into a breakout board which splits in the different connections on the duet. There is another breakout board on the X carriage that connects the different motors and end stops. As this introduces extra connectors and points of failure i triple checked all connections and they are fine. However this makes the cable length very long (~2m).

    To get enough power to the X and Y motors they are all double wired and a 24v power supply is used. The smaller steppers use only one lead each.

    The connected hardware:
    X axis 2.5A stepper (set for 1500ma)
    Y axis double 2.5A stepper connected in series (set for 1500ma)
    3 mini linear actuators of which two move with different tools in the Z axis and one will be configured as a mini syringe pump

    On the DUEX 5 at 12v
    5 peristaltic pumps driven by stepper motors which are (not yet connected)
    3 additional endstops for the small axes to check if tools are present.
    1 electromagnet driven by an H bridge controlled by three fan pins (not yet connected)
    3 solenoid valves that i want to drive with fan/led outlets these pull 0.66A at 12v
    3 1.5A air pumps that i want to drive with heater outlets Is it possible to run motors this powerfull on the heater outlets? Or is the EM noise to much?

    Thanks in advance for the helpfull responses!

    With regards,

    Eric Wieland

    Diagnostics if it helps...
    M122
    === Diagnostics ===
    RepRapFirmware for Duet 2 WiFi/Ethernet version 3.1.1 running on Duet WiFi 1.02 or later + DueX5
    Board ID: 08DGM-9T6BU-FG3SJ-6J9DD-3SN6P-TVYRG
    Used output buffers: 3 of 24 (15 max)
    === RTOS ===
    Static ram: 27980
    Dynamic ram: 93836 of which 56 recycled
    Exception stack ram used: 264
    Never used ram: 8936
    Tasks: NETWORK(ready,460) HEAT(blocked,1456) DUEX(suspended,160) MAIN(running,1880) IDLE(ready,80)
    Owned mutexes:
    === Platform ===
    Last reset 00:01:40 ago, cause: power up
    Last software reset at 2020-08-27 15:01, reason: User, spinning module GCodes, available RAM 8728 bytes (slot 3)
    Software reset code 0x0003 HFSR 0x00000000 CFSR 0x00000000 ICSR 0x0441f000 BFAR 0xe000ed38 SP 0xffffffff Task MAIN
    Error status: 0
    MCU temperature: min -71.4, current -64.4, max 235.8
    Supply voltage: min 15.4, current 15.6, max 15.8, under voltage events: 0, over voltage events: 0, power good: yes
    Driver 0: standstill, SG min/max not available
    Driver 1: standstill, SG min/max not available
    Driver 2: standstill, SG min/max not available
    Driver 3: standstill, SG min/max not available
    Driver 4: standstill, SG min/max not available
    Driver 5: standstill, SG min/max not available
    Driver 6: standstill, SG min/max not available
    Driver 7: standstill, SG min/max not available
    Driver 8: standstill, SG min/max not available
    Driver 9: standstill, SG min/max not available
    Date/time: 2020-08-27 15:30:01
    Cache data hit count 173840482
    Slowest loop: 7.99ms; fastest: 0.12ms
    I2C nak errors 0, send timeouts 0, receive timeouts 0, finishTimeouts 0, resets 0
    === Storage ===
    Free file entries: 10
    SD card 0 detected, interface speed: 20.0MBytes/sec
    SD card longest read time 4.0ms, write time 0.0ms, max retries 0
    === Move ===
    Hiccups: 0(0), FreeDm: 169, MinFreeDm: 169, MaxWait: 0ms
    Bed compensation in use: none, comp offset 0.000
    === MainDDARing ===
    Scheduled moves: 0, completed moves: 0, StepErrors: 0, LaErrors: 0, Underruns: 0, 0 CDDA state: -1
    === AuxDDARing ===
    Scheduled moves: 0, completed moves: 0, StepErrors: 0, LaErrors: 0, Underruns: 0, 0 CDDA state: -1
    === Heat ===
    Bed heaters = -1 -1 -1 -1, chamberHeaters = -1 -1 -1 -1
    === GCodes ===
    Segments left: 0
    Movement lock held by null
    HTTP is idle in state(s) 0
    Telnet is idle in state(s) 0
    File is idle in state(s) 0
    USB is idle in state(s) 0
    Aux is idle in state(s) 0
    Trigger is idle in state(s) 0
    Queue is idle in state(s) 0
    Daemon is idle in state(s) 0
    Autopause is idle in state(s) 0
    Code queue is empty.
    === Network ===
    Slowest loop: 15.75ms; fastest: 0.00ms
    Responder states: HTTP(2) HTTP(0) HTTP(0) HTTP(0) FTP(0) Telnet(0), 0 sessions
    HTTP sessions: 1 of 8

    • WiFi -
      Network state is active
      WiFi module is providing access point
      Failed messages: pending 0, notready 0, noresp 0
      WiFi firmware version 1.23
      WiFi MAC address 62:01:94:2e:1b:47
      WiFi Vcc 4.36, reset reason Unknown
      WiFi flash size 4194304, free heap 23264
      WiFi IP address 192.168.1.11
      Connected clients 1
      Socket states: 0 0 0 0 0 0 0 0
      === DueX ===
      Read count 3, 1.79 reads/min

  • Moderator

    @Eric said in Wierd issues with my duet wifi:

    reported temperatures of 2000°C which is also bull as i do not have temperature sensors connected.

    2000c is what it shows when no sensor is connected (open circuit) as a safety precaution in the event a sensor is disconnected. Jumping to 2000c triggers the thermal exceedance protection.

    The voltage should be 24v

    Is that what you measure at the PSU terminals?

    How do you have the Duex5 wired? Particularly the power and ground connection.

    See example here: https://duet3d.dozuki.com/Wiki/Duex2_and_Duex5_Features#Section_Wiring


  • Moderator

    @Eric see this thread, especially @dc42’s posts, which explains how the PSU voltage is calculated, and what you can test: https://forum.duet3d.com/topic/17583/duet2-wifi-overvoltage-issue
    As your voltage is low, I’d expect the 3.3V to be reading high. Possibly you have a short somewhere of 5V to 3.3V, but with enough resistance that it only raises the voltage a little.

    Ian



  • @Phaedrux

    Good info i see i missed a very important point there. I am planning to drive the DUEX5 at a different Vin (12v instead of 24v) that the DUET. Currently the setup is not jet in the the final controller and i indeed made the mistake to not connect the grounds of the duet and the DUEX together with a separate wire. I have only tested driving a single pump en a few endstops with the duex 5 so far but it could be that the damage is done.

    The measured Vin at the terminals of the duex is 23.8v

    @Ian,

    Thank for the info. I will check the reference voltage on the board on Monday as i am working from home today.

    As for the other issue do you know anything that could cause web control to become unresponsive from driving a stepper? But still lets planned G Code be executed?

    These issues started popping op after a badly crimped connection on the X axis caused the stepper driver to report that only 1 phase was driven. Strangly the error happens when i drive one of the other 3 axis. As i said before i have some small 15mm steppers connected to these:
    0655ae9b-ce31-451d-97b6-fb68ab1c2d78-image.png



  • @droftarts

    The 3.3v rail measures 4.9v so there is indeed a short between the 5 and 3.3v rails.

    Apart form external equipment what damage does this do to the board? And would this damage also extend to the DEUX5?

    Should i write of the board and expect weird issues if i use it? Or is their a likely cult-print and an component replacement that can be done to fix these issues?



  • @Eric said in Wierd issues with my duet wifi:

    The 3.3v rail measures 4.9v

    the absolute max ratings for the main cpu is only 4.0v - how confident are you with that reading?



  • I am confident that the CPU is still working. As webcontroll is working normally.

    But i did measure 4.96 volt on both the endstop 3.3v pin and the probe 3.3v pin. I could not find the Vref pin.

    stupid me... i just found the problem... There was an used crimp terminal lodged in the solder pins of the expansion connector.... So much for keeping a clean work place 😵

    I narrowed down the other issue (connectivity to web controll lost) to the E2_STOP and E3_STOP pins. If there are end stops connected to these and the small steppers are powered the connectivity to the duet is lost. This is either damage form the short or an an cross talk issue between the steppers lines and the end-stop lines.

    Could i reduce the noise on these by adding small (ceramic) capacitors over the end-stop lines? With a low capacitance this should have a minimal effect on the homing accuracy.



  • @Eric said in Wierd issues with my duet wifi:

    I am confident that the CPU is still working.

    thats why i asked how confident you were in the voltage reading, as it shouldn't have worked (but I'm not inclined to try:D)

    anyways, moving on

    @Eric said in Wierd issues with my duet wifi:

    If there are end stops connected to these and the small steppers are powered the connectivity to the duet is lost. This is either damage form the short or an an cross talk issue between the steppers lines and the end-stop lines.
    Could i reduce the noise on these by adding small (ceramic) capacitors over the end-stop lines? With a low capacitance this should have a minimal effect on the homing accuracy.

    are the switches normally closed or normally opened?



  • Yes I can be happy that the CPU still works after this... Tony and Co make a very robust board

    The switches are normally open. But as these are used to detect the
    presence of a tool and they are activated a lot of the time.

    Strangely if i use the E5_Stop and E6_stop connectors there is no problem. And i am planning to use the other two connectors with setups that will not have any electromagnetic interference as they will be used as buttons on the controller (confirm/continue and pause button).



  • couldn't find the post i was looking for but

    https://forum.duet3d.com/post/107742
    https://forum.duet3d.com/post/160304



  • It looks like one of the possible fixes is a 10uf capacitor to tone down the noise as i can easily implement that i will try that.

    Thanks for the help to everyone



  • I'm happy with my wifi right now. No issue there I found so far. LOL!


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