G30 S-1 Single Probe Command Not Responding to FSR Limit

  • Having problems with auto calibration. When I enter the single probe cmd G30 S-1 (at X0 Y0 Z5) the hot end moves down but doesn't stop after the FSR triggers, it continues down until I cut power to the machine. E0 end stop LED (red goes off) and JohnSL LED (green goes off & triggered FSR red goes on) get triggered but nozzle keeps moving down. FSRs seem to trigger easily when the bed is pushed with LEDs on JohnSL and Duet Wifi blinking accordingly. I have reviewed my setup files numerous times and can't find my error. I've readjusted bed/FSR mounts to make sure they are not binding and checked my cabling even tho' the LED lights trigger correctly when the bed is manually pushed.

    Machine is a Mini Kossel (with a shortened overall height, build height is approx 160mm). I've manually calibrated the bed using the 4 point paper test at the center and three tower locations. The nozzle tracks well over the bed when I manually move the effector and the the height measurements are repeatable from day to day. All elements of the machine seem to be operating correctly and move appropriately when commanded.

    One additional note: When I home the towers from a tower base position (i.e. X0 Y56 for the Z-Twr) only one tower is homed, the other two stop short and a second home-all needs to be issued to complete the homing of all three towers. I'm running a reduced build radius of R=56 mm until fully commisioned. My homedelta.g file is copied right from the wiki.

    Any help will be greatly appreciated as I can't find my error after several days of internet searching and physical review of build.

    Thanks, Ed

    Duet Wifi with Panel Due-7
    Panel Due-7.0-1.15c
    Duet Wifi Server-1.03-ch
    Duet Web Control-1.14-b.4
    Duet Wifi Firmware-1.17b


    ; Configuration file for Mini Kossel kit from Think3DPrint3D for testing Duet WiFi

    ;Communication and general
    M111 S0 ; Debug off
    M550 Freyja ; Machine name and Netbios name (can be anything you like)
    M551 duetwifi ; Machine password (used for FTP) (Set by Ed Davis)
    If you have more than one Duet on your network, they must all have different MAC addresses, so change the last digits
    M540 P0xBE:0xEF:0xDE:0xAD:0xFE:0xED ; MAC Address
    Wifi Networking
    M552 S1 ; Enable WiFi

    M555 P2 ; Set output to look like Marlin
    M575 P1 B115200 S1 ; Comms parameters for PanelDue

    G21 ; Work in millimetres
    G90 ; Send absolute coordinates…
    M83 ; ...but relative extruder moves

    ;******Axis and motor configuration
    M569 P0 S1 ; Drive 0 goes forwards
    M569 P1 S1 ; Drive 1 goes forwards
    M569 P2 S1 ; Drive 2 goes forwards
    M569 P3 S1 ; Drive 3 goes forwards
    M569 P4 S1 ; Drive 4 goes forwards

    ;.....End Stop Configuration See M558 Line near bottom for FSR Z Probe endstop config
    M574 X2 Y2 Z2 S1 ; set endstop configuration (all endstops at high end, active high)

    ;.....The homed height is deliberately set too high in the following - you will adjust it during calibration
    ;.......Theo. Values Delta Radius=104.55 Diag Rod=202.56 Print Radius 80 Homed Height 159.96
    M665 R104.0 L202.56 B56 H159.9 X0 Y0 Z0 ; set delta radius, diagonal rod length, printable radius (set at 56 for safety and bed clamps and homed height from page 109 of build notes)
    M666 X0.06 Y0 Z0.13 ; put your endstop adjustments here, or let auto calibration find them

    M350 X16 Y16 Z16 E16 I1 ; Set 16x microstepping with interpolation (Z-axis not initially listed added Z16, Ed Davis)
    M92 X100 Y100 Z100 ; Set axis steps/mm....(80 changed to 100 reflect build)
    M906 X1000 Y1000 Z1000 E500 I60 ; Set motor currents (mA) and increase idle current to 60% (Reduced mA setting on extruder motor from 800 to 500 mA - Ed Davis to reduce chance of chewing filament)
    M201 X1000 Y1000 Z1000 E1000 ; Accelerations (mm/s^2)
    M203 X20000 Y20000 Z20000 E3600 ; Maximum speeds (mm/min)
    M566 X1200 Y1200 Z1200 E1200 ; Maximum instant speed changes mm/minute

    M143 S260 ;Added limit hot end E3D v6 (to max of 280C -20C initial safety margin added by Ed Davis)

    M305 P0 T100000 B3950 R4700 H0 L0 ; Put your own H and/or L values here to set the bed thermistor ADC correction

    ;********HOT END #1
    M305 P1 T100000 B4388 R4700 H0 L0 ;STD THERM B-VALUE for E3Dv6 Put your own H and/or L values here to set the first nozzle thermistor ADC correction H an L not required for Duet Wifi

    ;*******HOT END #2 NOT IN USE
    ;M305 P2 T100000 B3974 R4700 H0 L0 ; Put your own H and/or L values here to set the second nozzle thermistor ADC correction (commented out by Ed Davis)

    M570 S120 ; Hot end may be a little slow to heat up so allow it 180 seconds

    ;*******PID values added by Ed Davis
    ;........PID Tuning Values for Hot End B0 use PID values, B1 to use band-bang mode
    M307 H1 A447.6 C193.4 D5.8 B0 S1.0 ;Modified to 1/10/17 Autotune values with new thermistor

    ;*******PID Tuning Values for Heated Bed Plate B0 use values, B1 to use band-bang mode
    M307 H0 A317.9 C555.4 D10.9 B0 S0.5 ;Modified to 12/29/16 Autotune values S0.5 for safety

    ;.....Always on..Duet Enclosure Fan
    ;.....FAN0.......Layer Fans A&B PWM
    ;.....FAN1.......E3DV6 Cooling Thermo H1 turn on at 45C
    ;.....FAN2.......Base Fan Thermo H0 turn on at 45C
    ;M106 P1 H-1 ; disable thermostatic mode for fan 1
    M106 P1 T45 H1 ;Set FAN1 to thermostatic, on when H1=>45C E3Dv6 Cooling Fan
    M106 P2 T45 H0 ;Set FAN2 to thermostatic, on when H0=>45C Heated Bed Plate Fan

    ;***Tool definitions
    M563 P0 D0 H1 ; Define tool 0
    G10 P0 S0 R0 ; Set tool 0 operating and standby temperatures
    If you have a single-nozzle build, comment the next 2 lines
    ; M563 P1 D1 H2 ; Define tool 1 (commented out by Ed Davis disable 2nd extruder)
    ; G10 P1 S0 R0 ; Set tool 1 operating and standby temperatures (commented out)
    M92 E487:663 ; Set extruder steps per mm (changed from 663 to 487)

    ;******Z probe and compensation definition
    ;........If you have a switch instead of an IR probe, change P1 to P4 in the following M558 command
    ;M558 P1 X0 Y0 Z0 ; Z probe is an IR probe and is not used for homing any axes
    ;M558 P4 X0 Y0 Z0 H5 ; Z probe is a switch & not used for homing any axes from Hackney
    ; H5 set to H20 for initial testing
    M558 P4 X0 Y0 Z0 F25 H20 I1 T1000 ; set FSR probe endstop active low from MHackney

    ;........Hot Bed ; Set the zprobe height and trigger threshold (put meas. values here)
    G31 X0 Y0 Z0 P500 ; Ref temperatures for Cal..TE_200 TB_55 (Z0 was -0.167)

    ;For Reference Only: MHackney's G31 follows: G31 X0 Y0 Z-.05 P500

    ;********If you are using axis compensation, put the figures in the following command
    M556 S78 X0 Y0 Z0 ; Axis compensation here

    M208 S1 Z-0.2 ; set minimum Z
    T0 ; select first hot end
    G1 F2500

  • Usually when an axis doesn't move far enough to hit the endstop, the line that tells that axis to move doesn't have a large enough move specified. For example, the X axis is 400mm long, and the home file only tells it to move X300 and the endstop is actually at X400. If it starts its move at a distance more than 300, then it'll never reach it.

    For the probe, make sure it's triggering as expected, use M119 or check the Settings->Machine Properties tab.

  • One problem down, FSRs still issue.

    1. Homing issue solved. I changed the axis values as suggested and homing issue is solved.

    2. FSR tripping. I went to the Machine Properties tab and the FSRs are triggering, however they do not remain in a triggered state for long. They trigger from an intermittent flash (from green to red back to green on the JohnSL board) to a longer but still short period of being red for approx. 0.5 seconds before returning to a non triggered state. I don't know if this is the proper behavior from the FSR/JohnSL or not. But if the triggered condition is of too short a duration it may not be registering with the duet (altho' the duet LED does flash from red to off in conjunction with the triggering on the JohnSL).

    I played with the P variable in G31 X0 Y0 Z0 P500 but that didn't seem to have an impact. My understanding of P is that it is a trigger sensitivity level and has nothing to do with time delay anyway.

    So, thanks, one issue solved but one still remaining.



  • I executed the G30 S-1 cmd and watched closely as the command was executed. The print head moved slowly to the bed, the triggers (LEDs) indicated on both the JohnSL and Duet that a trigger had occurred the LEDs remained red/JohnSL and out/Duet, but the head continued down into bed until I killed power so I don't believe this is an intermittent triggering of the FSRs being reported to the Duet.

    At a loss for what is causing this.


  • administrators

    If you think that the Duet may not be recognising the short trigger pulse, try reducing the P parameter in the G31 command to 50 or even 20. That will speed up recognition of the signal. But I've never heard of people having problems using the JohnSL board with the Duet before. Check that you still have Z probe type 4 selected by running M558 with no parameters.

  • administrators

    PS - if the Duet endstop LED goes from red to off when the board triggers, that implies that it has an active high output. But the I1 parameter in the M558 command in the config.g file you posted earlier is for an active low output.

  • Ok, I'm still processing all this but it seems to be working. As usual operator error. Thanks to dc42 for providing me with enough information to figure out my mistake on the FSR and StephenRC for the homing issue.

    1. Had endstop plugged into E1 not E0 my stupidity and maybe a bit of dyslexia as I get tired.
    ….....as viewed on board
    E1-Therm E0-Therm E1-Stop [E0-Stop] X-Stop Y-Stop Z-Stop

    2. But I had to change I1 (low) to I0 (high) to get it to work but I thought this had to be inverted (low) to work. Not going to question it at the moment will dig into it later to understand my error in thinking.

    The following is the current LED action and seems correct:
    Now it's green light JohnSL….red light duet when not triggered
    red light JohnSL....off at duet when triggered

    and the G30 and G32 cmds appear to be working.

    Hopefully, I've now got this animal working correctly and I can revert back to reading posts and not making them.

    Thanks to All, its been a big help and learning process.



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