Z probe wrong direction unless I zero Z
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I've notice that my core xy gets mixed up when trying to probe Z.
If the printer powers up with the bed fully lowered, and I manually raise it (G1 Z-600 F6000). Then initiate a home all, the bed lowers.
If I reset the printer while the bed is up, or set Z to 0 in the web interface, it probes as expected.
I presume this is because it thinks the bed is at -600 Z when starting the Z probe?
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Well you don't mention it but if the printer is in "absolute move" mode and G1 Z-600 moves it up that suggests you have something wrong with your Z axis settings.
On my printer Z=0 has the bed near the top, just touching the nozzle.
The lowest Z position is a positive value of 350.
What do your M208 command(s) in the config.g file look like?
Frederick
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Post your files. Config.g and your homing files.
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; Configuration file for Duet WiFi (firmware version 3) ; executed by the firmware on start-up ; ; generated by RepRapFirmware Configuration Tool v3.1.4 on Sat Sep 05 2020 23:57:30 GMT+0100 (British Summer Time) ; General preferences M80 ; Turns on the ATX power supply G90 ; send absolute coordinates... M83 ; ...but relative extruder moves M550 P"BLV MGN Cube" ; set printer name M669 K1 ; select CoreXY mode ; Network M552 S1 ; enable network M586 P0 S1 ; enable HTTP M586 P1 S0 ; disable FTP M586 P2 S0 ; disable Telnet ; Drives M569 P0 S0 ; physical drive 0 goes backwards M569 P1 S1 ; physical drive 1 goes forwards M569 P2 S1 ; physical drive 2 goes forwards M569 P3 S0 ; physical drive 3 goes backwards M584 X0 Y1 Z2 E3 ; set drive mapping M350 X16 Y16 Z16 E16 I1 ; configure microstepping with interpolation M92 X200.00 Y200.00 Z800.00 E415.5 ; set steps per mm M566 X600.00 Y600.00 Z24.00 E300.00 ; set maximum instantaneous speed changes (mm/min) M203 X20000.00 Y20000.00 Z600.00 E2000.00 ; set maximum speeds (mm/min) M201 X3000.00 Y3000.00 Z100.00 E5000.00 ; set accelerations (mm/s^2) M906 X1600 Y1600 Z1600 E1300 I30 ; set motor currents (mA) and motor idle factor in per cent M84 S30 ; Set idle timeout ; Pressure advance ; M572 D0 S0.05 ; Axis Limits M208 X-23 Y0 Z0 S1 ; set axis minima M208 X305 Y332 Z350 S0 ; set axis maxima ; Endstops M564 H0 ; allow jog without homing M574 X1 S1 P"xstop" ; M574 Y2 S1 P"ystop" ; M574 Z1 S2 ; configure Z-probe endstop for low end on Z ; Z-Probe M558 P1 H5 C"^zprobe.in" H5 F200 T9000 I0 R0.5 ; set Z probe type to switch and the dive height + speeds G31 P500 X-2 Y-16.4 Z1.33 ; set Z probe trigger value, offset and trigger height M557 X10:292 Y5:300 P8 ; define mesh grid ; Heaters M308 S0 P"bedtemp" Y"thermistor"T100000 B3950 C0 R4700 A"Bed Temp" ; configure sensor 0 as thermistor on pin bedtemp M950 H0 C"bedheat" T0 ; create bed heater output on bedheat and map it to sensor 0 M140 H0 ; map heated bed to heater 0 M143 H0 S100 ; set temperature limit for heater 0 to 120C M307 H0 A466.3 C1262.5 D12.8 S1.00 V24.0 B0 ; Set PID for heated bed values M308 S1 P"e0temp" Y"thermistor" T100000 B3950 C0 R4700 A"Hotend Temp" ; configure sensor 1 as thermistor on pin e0temp M950 H1 C"e0heat" T1 ; create nozzle heater output on e0heat and map it to sensor 1 M143 H1 S260 ; set temperature limit for heater 1 M307 H1 A340.0 C140.0 D5.5 S1.00 V24.0 B0 ; Set PID for hotend values ; Fans M950 F0 C"fan0" Q500 ; create fan 0 on pin fan0 and set its frequency M106 P0 S0 H-1 ; set fan 0 value. Thermostatic control is turned off M950 F1 C"fan1" Q500 ; create fan 1 on pin fan1 and set its frequency M106 P1 S1 H1 T45 ; set fan 1 value. Thermostatic control is turned on ; Tools M563 P0 D0 H1 F0 ; 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 ; homeall.g ; called to home all axes ; ; generated by RepRapFirmware Configuration Tool v3.1.4 on Sat Sep 05 2020 23:57:30 GMT+0100 (British Summer Time) G91 ; relative positioning G1 H2 Z5 F500 ; lift Z relative to current position G1 H1 X-355 F6000 ; move quickly to X axis endstop and stop there (first pass) G1 H0 X5 F6000 ; go back a few mm G1 H1 X-355 F360 ; move slowly to X axis endstop once more (second pass) G90 ; absolute positioning G91 ; relative positioning G1 H1 Y355 F6000 ; move quickly to Y axis endstop and stop there (first pass) G1 H0 Y-5 F6000 ; go back a few mm G1 H1 Y326 F360 ; move slowly to Y axis endstop once more (second pass) G90 ; absolute positioning G1 X152.5 Y152.5 F6000 ; go to first bed probe point and home Z G30 ; home Z by probing the bed -
@nick9one1 said in Z probe wrong direction unless I zero Z:
M564 H0 ; allow jog without homing
It's best not to use this on a regular basis and could be hiding other issues. It's meant to save you from a crash.
G1 H0 X5 F6000 ; go back a few mm
Remove the H0 from your homing files. It's the default, so you don't need to specify it.
When you jog your Z axis normally after homing (after you remove the M564) does Z+ move the bed away from the nozzle and Z- towards the nozzle?
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From the documentation when using your Z probe for homing:
The S2 option of M574 is intended for use only when axes other than Z are using the Z probe for homing. The only printers known that do this using Duet electronics are the RepRapPro Ormerod, Huxley Duo, and Mendel Tricolour machines. When using the Z probe to home Z, M574 Z0 should be used.
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Remove the H0 from your homing files. It's the default, so you don't need to specify it. Done
M564 H0 ; allow jog without homing It's best not to use this on a regular basis and could be hiding other issues. It's meant to save you from a crash. I will do after this issue is resolved - at the moment I need to raise the bed at least 300mm to home successfully.
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When you jog your Z axis normally after homing (after you remove the M564) does Z+ move the bed away from the nozzle and Z- towards the nozzle? Yes, the jog buttons work as expected, and I get good prints.
G1 Z5 F6000 lowers the bed
G1 Z-5 F6000 raises the bedWhen the bed is fully lowered at power on, I have to send this before a home;
G1 Z-500 F6000
G92 Z0If I dont send G92 Z0 the printer seems to attempt a probe in the wrong direction (Z+ instead of Z-). I think this is because it thinks the bed is at Z-500 (my G1 Z-500 command).
If I attempt to home when the bed is fully lowered at power on, the bed raises about 1/2 way (Z-), then starts going to other way (Z+).
It seems to me like there is a timeout or travel limit safety. -
M574 now looks like this;
; Endstops M564 H0 ; allow jog without homing M574 X1 S1 P"xstop" ; M574 Y2 S1 P"ystop" ; M574 Z1 S1 P"zstop" ; not
; Endstops M564 H0 ; allow jog without homing M574 X1 S1 P"xstop" ; M574 Y2 S1 P"ystop" ; M574 Z1 S2 ; configure Z-probe endstop for low end on Z Unfortunately the behaviour is still the same
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What fcwilt meant was remove the M574 line for the endstop, unless you still have one on Z maximum.
Your M558 included an I0, which is not supported as part of RRF3.
Your Z maximum is set as 350mm. How large is it as you seem to be issuing a -600mm move which would indicate your Z axis is larger than 350mm
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@nick9one1 this came up recently in another thread, where the M208 Z limit was much smaller then the actual Z movement. If the probe move has to move more than 1.1 times the M208 Z limit, probing is cancelled and it will try to move the bed back to Z0. So set you M208 Z limit to much closer to the actual size, eg Z600. You can always set up a fast Z home move, then slow Z home, if it’s painful to watch it home 600mm at slow speed!
Ian
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@jay_s_uk said in Z probe wrong direction unless I zero Z:
What fcwilt meant was remove the M574 line for the endstop, unless you still have one on Z maximum.
Your M558 included an I0, which is not supported as part of RRF3.
Your Z maximum is set as 350mm. How large is it as you seem to be issuing a -600mm move which would indicate your Z axis is larger than 350mm
Thanks!
I will remove I0 frm M558
I guess Z max here is probably the cause of the bed getting to half way then reversing. I will change to Z650 (Z is 650)
M208 X305 Y332 Z350 S0 ; set axis maxima -
@droftarts said in Z probe wrong direction unless I zero Z:
@nick9one1 this came up recently in another thread, where the M208 Z limit was much smaller then the actual Z movement. If the probe move has to move more than 1.1 times the M208 Z limit, probing is cancelled and it will try to move the bed back to Z0. So set you M208 Z limit to much closer to the actual size, eg Z600. You can always set up a fast Z home move, then slow Z home, if it’s painful to watch it home 600mm at slow speed!
Ian
I like the idea of a faster Z home, so will try that.
I'm also using a mini IR Z probe which seems to have similar behaviour when Z gets close.
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I use
M558 F250 ; Set the probing speed G30 ; Probe a single point M558 F30 ; Set a slower probing speed G30 ; Probe a single point In my Z homing file. That sets the first homing speed to just over 4mm/s and then 0.5mm/s. A similar change to your homing file would work for you.
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@droftarts I thought it sounded familiar
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All working as expected now thankyou.
I think the key change was setting the correct Z height
M208 X305 Y332 Z350 S0 ;now;
M208 X305 Y332 Z950 S0 ;Full Gcode;
950 ; Configuration file for Duet WiFi (firmware version 3) ; executed by the firmware on start-up ; ; generated by RepRapFirmware Configuration Tool v3.1.4 on Sat Sep 05 2020 23:57:30 GMT+0100 (British Summer Time) ; General preferences M80 ; Turns on the ATX power supply G90 ; send absolute coordinates... M83 ; ...but relative extruder moves M550 P"BLV MGN Cube" ; set printer name M669 K1 ; select CoreXY mode ; Network M552 S1 ; enable network M586 P0 S1 ; enable HTTP M586 P1 S0 ; disable FTP M586 P2 S0 ; disable Telnet ; Drives M569 P0 S0 ; physical drive 0 goes backwards M569 P1 S1 ; physical drive 1 goes forwards M569 P2 S1 ; physical drive 2 goes forwards M569 P3 S0 ; physical drive 3 goes backwards M584 X0 Y1 Z2 E3 ; set drive mapping M350 X16 Y16 Z16 E16 I1 ; configure microstepping with interpolation M92 X200.00 Y200.00 Z800.00 E415.5 ; set steps per mm M566 X600.00 Y600.00 Z24.00 E300.00 ; set maximum instantaneous speed changes (mm/min) M203 X20000.00 Y20000.00 Z600.00 E2000.00 ; set maximum speeds (mm/min) M201 X3000.00 Y3000.00 Z100.00 E5000.00 ; set accelerations (mm/s^2) M906 X1500 Y1500 Z1500 E1100 I30 ; set motor currents (mA) and motor idle factor in per cent M84 S30 ; Set idle timeout ; Pressure advance ; M572 D0 S0.05 ; Axis Limits M208 X-23 Y0 Z0 S1 ; set axis minima M208 X305 Y332 Z950 S0 ; set axis maxima ; Endstops M564 H0 ; allow jog without homing M574 X1 S1 P"xstop" ; M574 Y2 S1 P"ystop" ; M574 Z1 S1 P"zstop" ; configure Z-probe endstop for low end on Z ; Z-Probe M558 P1 H5 C"^zprobe.in" H5 F250 T9000 R0.5 ; set Z probe type to switch and the dive height + speeds G31 P500 X-2 Y-16.4 Z1.40 ; set Z probe trigger value, offset and trigger height M557 X10:292 Y5:300 P5 ; define mesh grid ; Heaters M308 S0 P"bedtemp" Y"thermistor"T100000 B3950 C0 R4700 A"Bed Temp" ; configure sensor 0 as thermistor on pin bedtemp M950 H0 C"bedheat" T0 ; create bed heater output on bedheat and map it to sensor 0 M140 H0 ; map heated bed to heater 0 M143 H0 S100 ; set temperature limit for heater 0 to 100C M307 H0 A466.3 C1262.5 D12.8 S1.00 V24.0 B0 ; Set PID for heated bed values M308 S1 P"e0temp" Y"thermistor" T100000 B3950 C0 R4700 A"Hotend Temp" ; configure sensor 1 as thermistor on pin e0temp M950 H1 C"e0heat" T1 ; create nozzle heater output on e0heat and map it to sensor 1 M143 H1 S260 ; set temperature limit for heater 1 M307 H1 A340.0 C140.0 D5.5 S1.00 V24.0 B0 ; Set PID for hotend values ; Fans M950 F0 C"fan0" Q500 ; create fan 0 on pin fan0 and set its frequency M106 P0 S0 H-1 ; set fan 0 value. Thermostatic control is turned off M950 F1 C"fan1" Q500 ; create fan 1 on pin fan1 and set its frequency M106 P1 S1 H1 T45 ; set fan 1 value. Thermostatic control is turned on ; Tools M563 P0 D0 H1 F0 ; 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