Unexpected token a in JSON at position 251



  • Has anyone seen the following before... ?
    json error.PNG

    I editted config.g to tweak my steps/mm on extruders, rebooted and then this happened

    Running 2.02 and DWC 1.22.6, WiFi server 1.23
    (I know it's old but my CoreXYUV only wants to work on 2.02)



  • M122 Dump from YAT - In case anyone can help ?
    (It says 2.03 now as I updated FW, DWC and DWS in desperate attempt to get it going)

    === Diagnostics ===
    RepRapFirmware for Duet 2 WiFi/Ethernet version 2.03 running on Duet WiFi 1.02 or later + DueX5
    Board ID: 08DGM-917DA-G4MS8-6J9FL-3SN6K-TVV39
    Used output buffers: 1 of 24 (15 max)
    === RTOS ===
    Static ram: 25680
    Dynamic ram: 94640 of which 112 recycled
    Exception stack ram used: 260
    Never used ram: 10380
    Tasks: NETWORK(ready,524) HEAT(blocked,1180) DUEX(suspended,156) MAIN(running,3808) IDLE(ready,160)
    Owned mutexes:
    === Platform ===
    Last reset 00:04:04 ago, cause: software
    Last software reset at 2020-07-16 10:54, reason: User, spinning module GCodes, available RAM 10380 bytes (slot 2)
    Software reset code 0x0003 HFSR 0x00000000 CFSR 0x00000000 ICSR 0x00433000 BFAR 0xe000ed38 SP 0xffffffff Task 0x4e49414d
    Error status: 0
    Free file entries: 10
    SD card 0 detected, interface speed: 20.0MBytes/sec
    SD card longest block write time: 0.0ms, max retries 0
    MCU temperature: min 45.6, current 45.9, max 46.1
    Supply voltage: min 0.4, current 0.5, max 0.6, under voltage events: 0, over voltage events: 0, power good: no
    Driver 0: ok, SG min/max not available
    Driver 1: ok, SG min/max not available
    Driver 2: ok, SG min/max not available
    Driver 3: ok, SG min/max not available
    Driver 4: ok, SG min/max not available
    Driver 5: ok, SG min/max not available
    Driver 6: ok, SG min/max not available
    Driver 7: ok, SG min/max not available
    Driver 8: ok, SG min/max not available
    Driver 9: ok, SG min/max not available
    Date/time: 2020-07-16 10:58:23
    Cache data hit count 908644412
    Slowest loop: 3.47ms; fastest: 0.06ms
    I2C nak errors 0, send timeouts 0, receive timeouts 0, finishTimeouts 0, resets 0
    === Move ===
    Hiccups: 0, FreeDm: 169, MinFreeDm: 169, MaxWait: 0ms
    Bed compensation in use: none, comp offset 0.000
    === DDARing ===
    Scheduled moves: 0, completed moves: 0, StepErrors: 0, LaErrors: 0, Underruns: 0, 0
    === Heat ===
    Bed heaters = 0 -1 -1 -1, chamberHeaters = -1 -1
    === GCodes ===
    Segments left: 0
    Stack records: 1 allocated, 0 in use
    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
    serial is ready with "m122" in state(s) 0
    aux is idle in state(s) 0
    daemon is idle in state(s) 0
    queue is idle in state(s) 0
    autopause is idle in state(s) 0
    Code queue is empty.
    === Network ===
    Slowest loop: 201.12ms; fastest: 0.08ms
    Responder states: HTTP(0) HTTP(0) HTTP(0) HTTP(0) FTP(0) Telnet(0) Telnet(0)
    HTTP sessions: 1 of 8
    - WiFi -
    Network state is running
    WiFi module is connected to access point 
    Failed messages: pending 0, notready 0, noresp 1
    WiFi firmware version 1.23
    WiFi MAC address b4:e6:2d:60:e2:9a
    WiFi Vcc 3.36, reset reason Turned on by main processor
    WiFi flash size 4194304, free heap 24824
    WiFi IP address 192.168.50.43
    WiFi signal strength -46dBm, reconnections 0, sleep mode modem
    Socket states: 0 0 0 0 0 0 0 0
    ok
    
    


  • What issues were you having when you upgraded to RRF3?



  • @jay_s_uk I haven't tried RRF3 yet, But with 2.05 and 2.04 my second set of motors didn't move as expected
    in this post here...
    link text



  • have you thought about trying a newer version of DWC? I believe 2.07 should work ok.
    If you don't like it, you can easily go back to 1.22.6 as well.


  • administrators

    @curlypaul said in Unexpected token a in JSON at position 251:

    @jay_s_uk I haven't tried RRF3 yet, But with 2.05 and 2.04 my second set of motors didn't move as expected
    in this post here...
    link text

    I can't tell from that thread what actually changes when you upgrade from 2.02 to 2.05. Please start a new thread about that, and include the config.g and homing files that work with 2.02 in that thread.



  • @dc42
    When i get it up and ruuning again I will certainly do that with the seperate thread.

    Still the same issue with DWC 2.07...
    Checked through config.g to see if messed anything, but literally all i changed were E steps/mm
    json error 2.PNG



  • can you get an output of M122? It would be interesting to see what your wifi signal is



  • @jay_s_uk
    M122 dump is in the second post.
    It's about 3m away from Unifi access point, i have another printer (duet) right next to this printer running ok



  • Missed that.
    -46db is perfectly fine so that's not the issue.
    Best to follow dc42's advice and work out where the issues lie when upgrading from 2.02 to 2.05.1



  • @curlypaul said in Unexpected token a in JSON at position 251:

    Checked through config.g to see if messed anything, but literally all i changed were E steps/mm

    Long shot here but logically, if all you did was edit something in config.g, then the issue must either be something to do with that edit, or it's just an unfortunate co-incidence. If it was me, I would comment out the line that was edited, then carefully type it again. Just in case a hidden character has crept in somewhere that is screwing things up. Maybe post your config.g just in case one of us can spot something that you might have missed.



  • I changed the E steps on second extruder from 802, to 401 as swapped from 0.9 to 1.8deg motor

    M584 X3 Y4 Z2 E7:6 U0 V1 P4                       		; set drive mapping
    M350 X16 Y16 U16 V16 Z16 E16:16 I1                  		; configure microstepping with interpolation
    M92 X160 Y160 U160 V160 Z2560 E402:401   			; set steps per mm
    M566 X1200 Y1200 U1200 V1200 Z25 E2500:2500			; set maximum instantaneous speed changes (mm/min)
    M203 X20000 Y20000 U20000 V20000 Z600 E9000:9000		; set maximum speeds (mm/min)
    M201 X1000 Y1000 U1000 V1000 Z500 E3000:3000      		; set accelerations (mm/s^2)
    M906 X1200 Y1200 U1200 V1200 Z1500 E900:E900 I30   		; set motor currents (mA) and motor idle factor in per cent
    M84 S60                                         		; Set idle timeout
    


  • Deleted the lot and typed it all in again

    Working now

    Goodness knows what that was all about

    Thankyou to those that chipped in 🙂


  • administrators

    @curlypaul said in Unexpected token a in JSON at position 251:

    Deleted the lot and typed it all in again

    Working now

    Goodness knows what that was all about

    Thankyou to those that chipped in 🙂

    I recall that a few RRF versions ago, I fixed a bug which caused invalid JSON to be generated in some configurations. Looks like you hit it.



  • @dc42 - thanks i think !? 🙂

    I kind of hope i 'hit 'it' in a way


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