Home Z-Axis Twice
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Hello guys,
The X & Y Axis can be homed in two steps. First it hits the endstop fast then it goes a few mm back and hits the endstop again while driving slower. This works perfectly with my Printer.
But how can I programm the Z-Axis to do the same? At the moment it just hits the endstop and stops without turning back etc.
Thanks for your help!
; homez.g
; called to home the Z axis
;
; generated by RepRapFirmware Configuration Tool v2 on Tue Jan 15 2019 15:02:03 GMT+0100 (Mitteleuropäische Zeit)
G91 ; relative positioning
G1 Z0 F12000 S2 ; lift Z relative to current position
G1 S1 Z805 F3000 ; move Z up stopping at the endstop
G1 Z-2 F1000 ; go back a few mm
G1 S1 Z550 F100 ; move slowly to Z axis endstop once more (second pass)
G92 Z531.7 ; set Z position to axis minimum (you may want to adjust this)
G90; homeall.g
; called to home all axes
;
; generated by RepRapFirmware Configuration Tool v2 on Tue Jan 15 2019 15:02:01 GMT+0100 (Mitteleuropäische Zeit)
G91 ; relative positioning
G1 Z0 F12000 S2 ; lift Z relative to current position
G1 S1 X355 Y355 F3000 ; move quickly to X or Y endstop and stop there (first pass)
G1 S1 X355 ; home X axis
G1 S1 Y355 ; home Y axis
G1 X-5 Y-5 F12000 ; go back a few mm
G1 S1 X355 F360 ; move slowly to X axis endstop once more (second pass)
G1 S1 Y355 ; then move slowly to Y axis endstop
G1 S1 Z805 F3000 ; move Z up stopping at the endstop
G1 S1 Z536
G1 Z-2 F1000 ; go back a few mm
G1 S1 Z536.1 F100 ; move slowly to Z axis endstop once more (second pass)
G90 ; absolute positioning
G92 Z536.1 ; set Z to axis minimum (you may want to adjust this) -
Please post your config.g file, in particular I need to see the M574 and M208 commands.
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; 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 movesM667 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? -
@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?
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@dc42 we will change M574 command!
Our bed is moving and the gantry is fixed in z (only moving x/y).
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@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?
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@dc42 exactly, that´s right!
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@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.
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@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
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@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
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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?
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@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?
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@dc42 yes we had already ...second hit is really slowmo but it doesn't help.
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@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
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We are using mechanic switches with a push bar.
I've ordered a bem break now to try if its working better.
@fcwilt -
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?
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@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
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