Home Z-Axis Twice



  • ; Configuration file for Duet WiFi (firmware version 1.21)
    ; executed by the firmware on start-up
    ;
    ; generated by RepRapFirmware Configuration Tool v2 on Tue Jan 15 2019 15:02:01 GMT+0100 (Mitteleuropäische Zeit)

    ; General preferences
    G90 ; Send absolute coordinates...
    M83 ; ...but relative extruder moves

    M667 S1 ; Select CoreXY mode

    ; Network
    M550 P"My Printer" ; Set machine name
    M552 S1 ; Enable network
    M587 S"Faurecia" P"1234abcd" ; Configure access point. You can delete this line once connected
    M586 P0 S1 ; Enable HTTP
    M586 P1 S0 ; Disable FTP
    M586 P2 S0 ; Disable Telnet

    ; Drives
    M569 P0 S0 ; Drive 0 goes backwards
    M569 P1 S0 ; Drive 1 goes backwards
    M569 P2 S1 ; Drive 2 goes forwards
    M569 P3 S1 ; Drive 3 goes Forwards
    M569 P6 S0 T5:5:10:0
    M584 X0 Y1 Z6 E3 ; Apply custom drive mapping
    M350 X64 Y64 Z1 E32 I0 ; Configure microstepping without Interpolation
    M92 X320.00 Y320.00 Z2133.333 E820.00 ; Set steps per mm
    M566 X900.00 Y900.00 Z300 E300.00 ; Set maximum instantaneous speed changes (mm/min)
    M203 X24000.00 Y24000.00 Z800 E3600.00 ; Set maximum speeds (mm/min)
    M201 X5000.00 Y5000.00 Z50 E250.00 ; Set accelerations (mm/s^2)
    M906 X2200.00 Y2200.00 Z800.00 E2000.00 I30 ; Set motor currents (mA) and motor idle factor in per cent
    ;M84 S30 ; Set idle timeout

    ; Axis Limits
    M208 X0 Y0 Z0 S1 ; Set axis minima
    M208 X390 Y490 Z516.10 S0 ; Set axis maxima

    ; Endstops
    M574 Y2 S0 ; Set active low and disabled endstops
    M574 X2 Z1 S1 ; Set active high endstops

    ; Z-Probe
    M558 P0 H0 F2000 T12000 ; Disable Z probe but set dive height, probe speed and travel speed
    M557 X15:0 Y15:195 S20 ; Define mesh grid

    ; Heaters3
    M307 H0 B0 S1.00 ; Disable bang-bang mode for the bed heater and set PWM Limit
    M307 H1 A927.1 C134.5 D5.9 S0.3 B0
    M305 P0 T100000 B4138 R4700 ; Set thermistor + ADC parameters for heater 0
    M143 H0 S120 ; Set temperature limit for heater 0 to 120C
    M305 P1 T100000 B4138 R4700 ; Set thermistor + ADC parameters for heater 1
    M143 H1 S280 ; Set temperature limit for heater 1 to 280C

    ; Fans
    M106 P0 S0 I0 F500 H-1 ; Set fan 0 value, PWM signal inversion and frequency. Thermostatic control is turned off
    M106 P1 S1 I0 F500 H-1 ; Set fan 1 value, PWM signal inversion and frequency. Thermostatic control is turned off

    ; Tools
    M563 P0 D0 H1 ; Define tool 0
    G10 P0 X0 Y0 Z0 ; Set tool 0 axis offsets
    G10 P0 R0 S0 ; Set initial tool 0 active and standby temperatures to 0C

    ; Automatic saving after power loss is not enabled

    ; Custom settings are not configured

    ; Miscellaneous
    T0 ; Select first tool



  • @dc42
    you have an idea?


  • administrators

    @robinfaurecia said in Home Z-Axis Twice:

    M574 X2 Z1 S1 ; Set active high endstops

    That command in config.g says that your Z endstop is that the axis minimum, i.e. bed as high as it can go or gantry as low as it can go.

    G1 S1 Z805 F3000 ; move Z up stopping at the endstop

    That command says you are homing to maximum Z, i.e. bed as low as it can go, or gantry as high as it can go.

    Which are you trying to do? Does the bed move in Z, or the gantry?



  • @dc42 we will change M574 command!

    Our bed is moving and the gantry is fixed in z (only moving x/y).


  • administrators

    @robinfaurecia said in Home Z-Axis Twice:

    @dc42 we will change M574 command!

    Our bed is moving and the gantry is fixed in z (only moving x/y).

    So you trying to home to maximum Z, i.e. bed at the bottom - correct?



  • @dc42 exactly, that´s right!


  • administrators

    @robinfaurecia said in Home Z-Axis Twice:

    @dc42 exactly, that´s right!

    So remove the G92 command from your Z homing sequence, and the M208 Z limit will define the position when the homing switch is triggered.



  • @robinfaurecia said in Home Z-Axis Twice:

    @dc42 exactly, that´s right!

    Hi,

    Why are you wishing to home at Z max (bed at bottom)?

    Frederick



  • @fcwilt
    Because we thought that it is not possible to print the first layer while the endstop is triggered.
    Now we try to home Z at Z max. If this makes to much problems we want to change the endstop position to Z min.



  • @robinfaurecia said in Home Z-Axis Twice:

    @fcwilt
    Because we thought that it is not possible to print the first layer while the endstop is triggered.
    Now we try to home Z at Z max. If this makes to much problems we want to change the endstop position to Z min.

    Thanks.

    Go ahead and home to Z min - it will work fine and save time.

    Frederick



  • Now we can home the Z Axis twice thats good!

    But everytime we home Z Axis (doesn´t matter if at Z max oder Z min) we have a difference of 0,2 to 0,5 mm between nozzle and bed. Maybe the difference is caused by hitting the endstop a little bit different every time we home the Z-Axis. Do you have any idea how we can fix this problem?


  • administrators

    @robinfaurecia said in Home Z-Axis Twice:

    Now we can home the Z Axis twice thats good!

    But everytime we home Z Axis (doesn´t matter if at Z max oder Z min) we have a difference of 0,2 to 0,5 mm between nozzle and bed. Maybe the difference is caused by hitting the endstop a little bit different every time we home the Z-Axis. Do you have any idea how we can fix this problem?

    Have you tried reducing the speed of the second homing move, to see if that gives you a more reproducible result?



  • @dc42 yes we had already ...second hit is really slowmo but it doesn't help.



  • @robinfaurecia said in Home Z-Axis Twice:

    But everytime we home Z Axis (doesn´t matter if at Z max oder Z min) we have a difference of 0,2 to 0,5 mm between nozzle and bed. Maybe the difference is caused by hitting the endstop a little bit different every time we home the Z-Axis. Do you have any idea how we can fix this problem?

    I've never encountered that. I use micro switches with no arm on them and they work fine.

    What sort of endstop are you using? Micro switch? Beam Break? Hall Effect Device?

    Frederick



  • We are using mechanic switches with a push bar.
    I've ordered a bem break now to try if its working better.
    @fcwilt


  • administrators

    If you have multiple Z motors, and you are measuring nozzle height at bed centre but the Z microswitch is at the side of the bed, perhaps your Z motors are getting out of sync and the bed is tilting?



  • @robinfaurecia said in Home Z-Axis Twice:

    We are using mechanic switches with a push bar.
    I've ordered a bem break now to try if its working better.

    "Push bar" - you mean the arm attached to the micro switch that presses on the actuator button?

    Micro switches usually have more than enough accuracy and repeatability for use as end stops.

    I suppose it might be possible that some brands of micro switches are not suitable but I have never encountered any.

    "Beam Break" devices can work but they may not yield the crisp on/off action desired.

    Frederick



  • @dc42 we only use one motor for Z-axis.
    @fcwilt yes, the ones with the arm attached to the micro switch.
    I hope the beam brake will work... it should be compatible.


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