M500 Always Fails



  • I'm trying to do initial setup and calibration on my home-built Delta. Every time I try to issue an M500 command, I get this error message:

    M500
    Error: Operation failed (Reason: NullReferenceException in SimpleCode: Object reference not set to an instance of an object.)

    This is on a Duet 3 6HC with RPi4 and the latest stable updates. Everything else is working fine, and I can modify files manually to add the parameters, but M500 would save a whole ton of time through this tedious process. Searching Google yielded no results. I get the same error message whether I try to do it directly on the RPi4 (through the attached RPi display) or remotely from a web interface over the network.


  • Moderator

    It would help to know what firmware version. If you're running from the pi running sudo apt update and sudo apt upgrade would be in order. Please send M122 and post the results to verify firmware version and some other info.



  • I did that. That's what I meant when I said "the latest s6able updates".

    M122
    === Diagnostics ===
    RepRapFirmware for Duet 3 MB6HC version 3.1.1 running on Duet 3 MB6HC v1.01 or later (SBC mode)
    Board ID: 08DJM-956L2-G43S8-6J9D2-3SJ6P-1A0LG
    Used output buffers: 1 of 40 (13 max)
    === RTOS ===
    Static ram: 154604
    Dynamic ram: 162536 of which 44 recycled
    Exception stack ram used: 224
    Never used ram: 75808
    Tasks: NETWORK(ready,1972) HEAT(blocked,1188) CanReceiv(suspended,3820) CanSender(suspended,1488) CanClock(blocked,1436) TMC(blocked,204) MAIN(running,4552) IDLE(ready,76)
    Owned mutexes:
    === Platform ===
    Last reset 00:04:48 ago, cause: power up
    Last software reset at 2020-10-10 20:23, reason: User, spinning module LinuxInterface, available RAM 75696 bytes (slot 2)
    Software reset code 0x0010 HFSR 0x00000000 CFSR 0x00000000 ICSR 0x0444a000 BFAR 0x00000000 SP 0xffffffff Task MAIN
    Error status: 0
    MCU temperature: min 30.6, current 32.7, max 32.8
    Supply voltage: min 26.9, current 27.0, max 27.1, under voltage events: 0, over voltage events: 0, power good: yes
    12V rail voltage: min 12.0, current 12.0, max 12.1, under voltage events: 0
    Driver 0: standstill, reads 60081, writes 0 timeouts 0, SG min/max not available
    Driver 1: standstill, reads 60081, writes 0 timeouts 0, SG min/max not available
    Driver 2: standstill, reads 60081, writes 0 timeouts 0, SG min/max not available
    Driver 3: standstill, reads 60081, writes 0 timeouts 0, SG min/max not available
    Driver 4: standstill, reads 60081, writes 0 timeouts 0, SG min/max not available
    Driver 5: standstill, reads 60081, writes 0 timeouts 0, SG min/max not available
    Date/time: 2020-10-10 22:04:47
    Slowest loop: 3.94ms; fastest: 0.21ms
    === Storage ===
    Free file entries: 10
    SD card 0 not detected, interface speed: 37.5MBytes/sec
    SD card longest read time 0.0ms, write time 0.0ms, max retries 0
    === Move ===
    Hiccups: 0(0), FreeDm: 375, MinFreeDm: 375, 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 = 2 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1, chamberHeaters = 3 -1 -1 -1
    Heater 1 is on, I-accum = 0.0
    === GCodes ===
    Segments left: 0
    Movement lock held by null
    HTTP* is ready with "M122" 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
    LCD is idle in state(s) 0
    SBC is idle in state(s) 0
    Daemon* is idle in state(s) 0
    Aux2 is idle in state(s) 0
    Autopause is idle in state(s) 0
    Code queue is empty.
    === Network ===
    Slowest loop: 0.47ms; fastest: 0.01ms
    Responder states: HTTP(0) HTTP(0) HTTP(0) HTTP(0) HTTP(0) HTTP(0) FTP(0) Telnet(0), 0 sessions Telnet(0), 0 sessions
    HTTP sessions: 0 of 8
    - Ethernet -
    State: disabled
    Error counts: 0 0 0 0 0
    Socket states: 0 0 0 0 0 0 0 0
    === CAN ===
    Messages sent 901, longest wait 0ms for type 0
    === Linux interface ===
    State: 0, failed transfers: 0
    Last transfer: 17ms ago
    RX/TX seq numbers: 8255/8256
    SPI underruns 0, overruns 0
    Number of disconnects: 0
    Buffer RX/TX: 0/0-0
    === Duet Control Server ===
    Duet Control Server v3.1.1
    Code buffer space: 4096
    Configured SPI speed: 8000000 Hz
    Full transfers per second: 31.83
    


  • No help with this? It's still plaguing me.


  • Moderator

    Waiting for @chrishamm to take a look.



  • 2 things i see from the m122.

    I could be totally wrong as I don't have a RPI4 to test. I run mine in standalone.

    First, in the initial line, it says SBC mode. Should it not show the other mode? RPI mode?)

    Second, it says SD Card 0 not detected. Isn't M500 trying to write configoverride.g on the SD card? (again, could be wrong in the RPI mode)



  • nevermind, I just read some more and SBC (I thought SBC standed for single board computer aka standalone mode, I was wrong) is the RPi mode and the SD card isn't supposed to be in for the RPi mode.



  • I tried re-imaging the micro SD card with a downloaded image of the OS (rather than the one that came pre-loaded on the card). The OS from the downloaded image looks very different. It uses a different desktop environment, and it presents me with a setup wizard on first boot for configuring location, networking, password and initial updates. The pre-loaded image never did that.

    However I still can't run M500 without getting the error message listed above. I'm not sure what I'm doing wrong.


  • Moderator

    Yes the latest image is based of an updated version of the recent pi image, so it's a bit more polished.

    Did you do a sudo apt update sudo apt upgrade after?

    Can you try capturing some extended debug information?

    https://duet3d.dozuki.com/Wiki/Getting_Started_With_Duet_3#Section_Monitoring_optional



  • @Thalios said in M500 Always Fails:

    I thought SBC standed for single board computer

    that bit is correct, but its the Pi and not the Duet that is an SBC.

    (I suppose you could argue PanelDue is a graphics port and the Duet is a single board computer, but its commonly used for more general purpose computers like the Raspberry Pi, with the Duet being a specialized embedded computer



  • @Phaedrux Yes, I made sure all packages were up to date and I rebooted. Here's a log output when I try to run M500:

    Oct 16 18:05:08 duet3 DuetControlServer[1464]: [error] Code M500 has thrown an exception
    Oct 16 18:05:08 duet3 DuetControlServer[1464]:    System.NullReferenceException: Object reference not set to an instance of an object.
    Oct 16 18:05:08 duet3 DuetControlServer[1464]:    at DuetControlServer.Files.ConfigOverride.WriteModelParameters(StreamWriter writer) in /home/christian/Duet3D/DuetSoftwareFramework/src/DuetControlServer/Files/ConfigOverride.cs:line 77
    Oct 16 18:05:08 duet3 DuetControlServer[1464]:    at DuetControlServer.Files.ConfigOverride.Save(Code code) in /home/christian/Duet3D/DuetSoftwareFramework/src/DuetControlServer/Files/ConfigOverride.cs:line 34
    Oct 16 18:05:08 duet3 DuetControlServer[1464]:    at DuetControlServer.Codes.MCodes.Process(Code code) in /home/christian/Duet3D/DuetSoftwareFramework/src/DuetControlServer/Codes/MCodes.cs:line 652
    Oct 16 18:05:08 duet3 DuetControlServer[1464]:    at DuetControlServer.Commands.Code.ProcessInternally() in /home/christian/Duet3D/DuetSoftwareFramework/src/DuetControlServer/Commands/Code.cs:line 479
    Oct 16 18:05:08 duet3 DuetControlServer[1464]:    at DuetControlServer.Commands.Code.Process() in /home/christian/Duet3D/DuetSoftwareFramework/src/DuetControlServer/Commands/Code.cs:line 400
    Oct 16 18:05:08 duet3 DuetControlServer[1464]:    at DuetControlServer.Commands.Code.ExecuteInternally() in /home/christian/Duet3D/DuetSoftwareFramework/src/DuetControlServer/Commands/Code.cs:line 336
    Oct 16 18:05:08 duet3 DuetControlServer[1464]: [error] IPC#46: Failed to execute SimpleCode
    Oct 16 18:05:08 duet3 DuetControlServer[1464]:    System.NullReferenceException: Object reference not set to an instance of an object.
    Oct 16 18:05:08 duet3 DuetControlServer[1464]:    at DuetControlServer.Files.ConfigOverride.WriteModelParameters(StreamWriter writer) in /home/christian/Duet3D/DuetSoftwareFramework/src/DuetControlServer/Files/ConfigOverride.cs:line 77
    Oct 16 18:05:08 duet3 DuetControlServer[1464]:    at DuetControlServer.Files.ConfigOverride.Save(Code code) in /home/christian/Duet3D/DuetSoftwareFramework/src/DuetControlServer/Files/ConfigOverride.cs:line 34
    Oct 16 18:05:08 duet3 DuetControlServer[1464]:    at DuetControlServer.Codes.MCodes.Process(Code code) in /home/christian/Duet3D/DuetSoftwareFramework/src/DuetControlServer/Codes/MCodes.cs:line 652
    Oct 16 18:05:08 duet3 DuetControlServer[1464]:    at DuetControlServer.Commands.Code.ProcessInternally() in /home/christian/Duet3D/DuetSoftwareFramework/src/DuetControlServer/Commands/Code.cs:line 479
    Oct 16 18:05:08 duet3 DuetControlServer[1464]:    at DuetControlServer.Commands.Code.Process() in /home/christian/Duet3D/DuetSoftwareFramework/src/DuetControlServer/Commands/Code.cs:line 400
    Oct 16 18:05:08 duet3 DuetControlServer[1464]:    at DuetControlServer.Commands.Code.ExecuteInternally() in /home/christian/Duet3D/DuetSoftwareFramework/src/DuetControlServer/Commands/Code.cs:line 336
    Oct 16 18:05:08 duet3 DuetControlServer[1464]:    at DuetControlServer.Commands.Code.ExecuteInternally() in /home/christian/Duet3D/DuetSoftwareFramework/src/DuetControlServer/Commands/Code.cs:line 383
    Oct 16 18:05:08 duet3 DuetControlServer[1464]:    at DuetControlServer.Commands.Code.<Execute>b__27_0(Task`1 task) in /home/christian/Duet3D/DuetSoftwareFramework/src/DuetControlServer/Commands/Code.cs:line 277
    Oct 16 18:05:08 duet3 DuetControlServer[1464]:    at DuetControlServer.Commands.SimpleCode.Execute() in /home/christian/Duet3D/DuetSoftwareFramework/src/DuetControlServer/Commands/SimpleCode.cs:line 136
    Oct 16 18:05:08 duet3 DuetControlServer[1464]:    at DuetAPI.Commands.Command`1.Invoke() in /home/christian/Duet3D/DuetSoftwareFramework/src/DuetAPI/Commands/BaseCommand.cs:line 67
    Oct 16 18:05:08 duet3 DuetControlServer[1464]:    at DuetControlServer.IPC.Processors.Command.Process() in /home/christian/Duet3D/DuetSoftwareFramework/src/DuetControlServer/IPC/Processors/Command.cs:line 63
    
    


  • Is there some other kind of official support medium than this forum? Because I spent a lot of money on these control boards and I really don't think I'm trying to do anything fancy or outside of reasonable use. It's literally been over a week now.



  • @GoremanX said in M500 Always Fails:

    Is there some other kind of official support medium than this forum?

    This is "it", the developers do frequent the forum, but what you seem to be after seems to be "officially" not supported

    https://duet3d.dozuki.com/Wiki/RepRapFirmware_3_overview#Section_M500



  • @bearer Thank you!

    That would've been nice to know right off the bat. Especially since none of the guides take it into account. Seems like I could've saved a whole lot of head-banging if that had been cleared up immediately.



  • Also, that's a super bizarre omission that makes no sense at all. I hope it gets rectified soon. Having only M500 and M501 not work in SBC mode is seriously odd



  • It boils down to differences in the virtual sd card used on the pi which isn't fully compatible with the code that uses the real sd card when in stand alone mode.

    I think it was scheduled for 3.2 but haven't kept up with stuff lately (also, its possible the Wiki is out of date, but it doesn't work odds are its still at thing)

    Edit: Calling it an omission isn't quite fair, is clearly been on display in the bottom of a locked filing cabinet stuck in a disused lavatory with a sign on the door saying ‘Beware of the Leopard.”



  • Do you need any of the features the Pi offers? Might be better to switch to stand alone mode where M500 is supported while they implement the filesystem support for the SBC mode? The Pi/SBC doesn't really offer much at the present?



  • @bearer The main thing it gives me right now is the ability to have the Pi 4 outside of the electronics enclosure, which gives me functional wifi without requiring any additional adapters (the base of my delta printer is all aluminum). I also have it hooked up to a Pi touchscreen, which gives me a much more complete interface at the printer itself, rather than the limited interface of a PanelDue. Plus I have a Bluetooth keyboard and touchpad paired, which has been convenient. And having the Pi 4 right there makes it super simple to have a camera hooked up for monitoring progress and/or capturing time lapses. Honestly, I'm loving the SBC thing compared to my other Duet-powered setups. If it's only the lack of M500, I'll deal with that until it's fixed. I just wish I hadn't wasted a week on trying to resolve this.

    I haven't seen any mention of M500 or M501 in the recent 3.2 beta fixes and changes, so it doesn't look like it'll be making it into this release.



  • If you replace the ribbon cable with ethernet and stick an sd-card in the duet, you can use the pi to bridge ethernet to wifi and keep using the screen to access DWC running on the duet's ethernet interface. Should -give you the same-ish functionality + M500 while the devs fix the file system stuff that is missing

    (edit: suppose you don't have to remove the ribbon cable actually, it can supply power or just sit there unused as long as the Duet has a sd-card with a config file it will ignore the SBC interface afaik)



  • I don't want to spend more money on an ethernet bridge. Pi4s and touchscreens I have littered about the workshop practically for free 😂 All I need to do is put my heater autotune parameters and delta auto-configure results manually in config.g. I run auto-config before every print anyways. I can't think of anything else I use M500 for. It's only tedious initially because of the initial configuration which requires adjusting those settings multiple times until I zero in on the right ones.



  • It's also super comforting to know that I'M NOT DOING ANYTHING WRONG and there's nothing wrong with my setup that'll bite me later. That was my main concern.



  • @GoremanX said in M500 Always Fails:

    I don't want to spend more money on an ethernet bridge

    you can use the pi for that


  • Moderator

    @GoremanX said in M500 Always Fails:

    @bearer Thank you!

    That would've been nice to know right off the bat. Especially since none of the guides take it into account. Seems like I could've saved a whole lot of head-banging if that had been cleared up immediately.

    Sorry about that. I should have clued into checking the unsupported list first. I hope the road to feature complete isn't much longer.


  • administrators

    @GoremanX Thanks for the report, I could confirm this is a bug in DSF. It will be fixed in the next software version.

    The reason it is happening is because you have configured heaters with gaps (i.e. for example heater 0, 1, 3, 5). You can work-around this problem by configuring the heaters sequentially.



  • @chrishamm Thank you for that clarification. I configured the heaters in the order that seemed logical to me to keep them organized compared with sensors and tools. I tried re-organizing the config file so that sensors and heaters are in numerical order (1,2,3), but it didn't seem to have fixed the issue.

    I skipped heater 0 since I'm using an AC bed heater and the SSR doesn't need vast quantities of current so it's being powered by heater 2 instead, which simplifies wiring. But I did have a sensor 0 configured as a general purpose sensor that was purely informational. So I went ahead and created a heater 0 (that won't do anything) and assigned it to sensor 0, and now M500 works as expected.


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