NPN Inductive Z Probe

[Dizzwold]

Hi Guys,

Could I ask for some assistance?

I'm upgrading my Tronxy X5sa Pro with a Duet3 6HC running RRF 3.4.2 and I using the Tronxy TR Glass sensor which I believe is a NPN inductive sensor.

I've not found any actual guidance on this, but with using the RRF Config tool and looking around at what others have used (different boards and firmware), This is what I have in my config.g;

; Z-Probe
M574 Z1 Z2 S2									   ; set endstops controlled be probe
M558 P5 C"^!io3.in" H5 F120 T6000                  ; set Z probe type to switch and the dive height + speeds
G31 P500 X-41 Y-17 Z2.5                            ; set Z probe trigger value, offset and trigger height
M557 X41:325 Y17:330 S20                           ; define mesh grid

The idea is that X and Y move to accommodate for the probes offset, then raises the bed until the z probe activates, but I get no movement in the X or Y prior to the bed lifting?
The probe is triggering if I wave my hand under the probe and then the bed stops rising, it's just not moving the probe over the bed?
Should G31 be before M558?
Dizzwold.

[Norder]

@dizzwold said in NPN Inductive Z Probe:

Should G31 be before M558?

No, G31 must come after M558 and after M584, so all OK.
I'm more worried about the command line M574 Z1 Z2 S2 because there you have Z1 and Z2, i.e. end stop for the lower end (Z1) and for the upper end (Z2).

You can find more detailed information about the G and M commands on this page (Duet3D Docs).

PS:
Also check out the M557 info.
The values in your command line do not result in whole numbers with S20, so the specified area is not completely scanned with the probe.
Rather than S20, take the parameter Pn, where n is the number of probing points.
Pn automatically calculates the distance between the probing points and the specified area is completely probed.
You have about 15 probing points if you use S20, so the parameter would be P15.
The complete line would be: M557 X41:325 Y17:330 P15

I just wrote a comment on this topic yesterday where I explain it a little more closely.
Here is the thread

[Dizzwold]

@norder

Thanks for the input, and I've taken your advice as stated in you link to what you wrote yesterday. I've already been reading the GCode dictionary, but as a complete newb...

Am I correct in stating, that after I've homed X and Y, I then goto home Z, and the machine should first move in the X and Y to account for the probe offset and put the probe over the bed, then the bed raises?

; Z-Probe
M574 Z1 S2									   ; set endstops controlled be probe
M558 P5 C"^!io3.in" H5 F120 T6000                  ; set Z probe type to switch and the dive height + speeds
G31 P500 X-41 Y-17 Z2.5                            ; set Z probe trigger value, offset and trigger height
M557 X41:325 Y17:330 P15                           ; define mesh grid

Am I even correct to have the probe listed as an "S2"?
I believe "Z1" is correct as the probe is with the printhead and the bed lowers with printing (a +positive number increases the distance between bed and nozzle), therefore it's at the lower end.

Dizzwold.

[Phaedrux]

@dizzwold said in NPN Inductive Z Probe:

Am I even correct to have the probe listed as an "S2"?

If you're using a probe, you can leave out the M574 for the Z axis entirely. The S2 option to use the probe is actually meant for rare special cases when a probe is used for an X or Y axis. It doesn't hurt to have it in there, but it's not actually doing anything.

@dizzwold said in NPN Inductive Z Probe:

Am I correct in stating, that after I've homed X and Y, I then goto home Z, and the machine should first move in the X and Y to account for the probe offset and put the probe over the bed, then the bed raises?

Yes. After the X and Y axis is homed, you would want to use a G1 X Y move to position the probe where you want it, usually the center of the bed, and then use G30 to activate the actual probing.

[Dizzwold]

@phaedrux

Thank you for your reply, but further confused.

@phaedrux said in NPN Inductive Z Probe:

Yes. After the X and Y axis is homed, you would want to use a G1 X Y move to position the probe where you want it, usually the center of the bed, and then use G30 to activate the actual probing.

Okay, so even though I've entered the offset for the probe with the RRF Config tool, if I want it to probe, I've got to tell it again where to go?
Forgive my naivety but coming from a box standard Tronxy, I don't know this?

[Norder]

@dizzwold
It is in the homeall.g and in the homez.g file in the system folder what the probe should do to home the z-axis.

Feel free to post the contents of these two files for the forum to look at.

In the command line M557 X41:325 Y17:330 P15 you have already included the offset of the probe.
This is not necessary because the G29 command that does the MeshBedLeveling has already calculated this offset.

You have a 330mm x 330mm print bed... check where the probe goes anywhere on the print bed.
Often it cannot quite reach one side of the print bed. Measure this area and make a border that goes around the entire print bed.

Example:
The probe still has a distance of 11mm to the extreme right edge of the print bed when the print head can no longer be moved to the right, i.e. it hits the frame. Now make it a 15mm margin so the command line looks like this.
M557 X15:315 Y15:315 P15
(DO NOT accept the command line 1:1. Measure first and then edit the old values)

In the linked thread from my first comment I tried to explain how it is with me.
You don't have to factor in the probe's offset into the M557 command line.

I hope the Google translator translates this text so that you can understand it.
Sometimes it goes horribly wrong.
For this reason, I always post the original text in the hope that someone can clear up a misunderstanding caused by a cryptic translation.
I'm too old to learn English anymore. I can do it a bit, but it's not enough for long texts.

Google Translate
-- Original Text --

Es steht in der homeall.g und in der homez.g Datei im System-Ordner was die Sonde machen soll um die Z-Achse zu homen.

Poste gerne den Inhalt dieser beiden Dateien damit sich das Forum sich es ansehen kann.

In der Befehlszeile M557 X41:325 Y17:330 P15 hast Du bereits den Offset der Sonde mit eingerechnet.
Das ist nicht nötig da der G29 Befehl der das MeshBedLeveling macht, diesen Offset bereits mit berechnet hat.

Du hast ein 330mm x 330mm Druckbett... prüfe bis wo die Sonde überall auf dem Druckbett hingelangt.
Oft kann sie eine Seite des Druckbettes nicht ganz erreichen. Messe diesen Bereich aus und mache daraus einen Rand der um das ganze Druckbett geht.

Beispiel:
Die Sonde hat noch einen Abstand von 11mm bis zum außersten rechten Rand des Druckbettes wenn der Druckkopf nicht mehr weiter bis rechts bewegt werden kann, er also an den rahmen anschlägt. Jetzt mache daraus einen Rand von 15mm, so das die Befehlszeile wie folgt aussieht.
M557 X15:315 Y15:315 P15
(Die Kommandozeile NICHT 1:1 übernehmen. Erst ausmessen und dann die alten Werte editieren)

In dem verlinkten Thread aus meinem ersten Kommentar habe ich es versucht zu erklärt wie es bei mir ist.
Du musst den Offset der Sonde nicht in die M557 Befehlszeile einberechen.

Ich hoffe der Google Übersetzer übersetzt diesen Text so dass man ihn auch versteht.
Manches mal geht es gewaltig in die Hose.
Aus dem Grund poste ich auch immer den Original Text, in der Hoffnung das jemand ein Missverständnis aufklären kann das durch eine kryptische Übersetzung entsteht.
Ich bin zu alt um noch Englisch zu lernen. Etwas kann ich es, aber es reicht nicht für lange Texte.

[Dizzwold]

@norder

Thank you again for your help, I'm very grateful.

I'll have a look at the home all and homez files.

@norder said in NPN Inductive Z Probe:

This is not necessary because the G29 command that does the MeshBedLeveling has already calculated this offset.

I'd been advised in a previous thread that this wasn't calculated and had to allow for this myself, but was also told that the probe would just report "Unreachable", and continue.

I'll go and look at the files and see what I can do.

[Dizzwold]

@norder

Hmm, tinkering (to start), with homeall to home X and Y and then place the probe over the front left corner of the bed to home the Z. The probe is 41mm (X axis) and 17mm (Y axis) from the bed, yet I'm having to enter around 90mm for the X and 10mm for Y probe to cover the corner of the bed.
Also when it moves in the Y, it goes past the point required and the returns, like going +30mm and then -20 mm to get to 10mm?

I'm getting very strange behaviour when I change the figure further.

Is it that when I'm selecting homeall it's also looking at homez which is untouched and confusing things?

Also looking at homeall for example, my home points (endstops), are -337 and -343. Shouldn't theses be 0 (zero)?

; homeall.g
; called to home all axes
;
; generated by RepRapFirmware Configuration Tool v3.3.13 on Mon Sep 19 2022 16:04:20 GMT+0100 (British Summer Time)
G91                     ; relative positioning
G1 H2 Z5 F6000          ; lift Z relative to current position
G1 H1 X-337 Y-343 F1800 ; move quickly to X or Y endstop and stop there (first pass)
G1 H1 X-337             ; home X axis
G1 H1 Y-343             ; home Y axis
G1 X5 Y5 F6000          ; go back a few mm
G1 H1 X-337 F360        ; move slowly to X axis endstop once more (second pass)
G1 H1 Y-343             ; then move slowly to Y axis endstop
G1 H2 X41 F1500			; move X to edge of bed before Z home
G1 H2 Y17 F1500			; move Y to edge of bed before Z home
G1 H1 Z-405 F360        ; move Z down stopping at the endstop
G90                     ; absolute positioning
G92 Z0                  ; set Z position to axis minimum (you may want to adjust this)

; Uncomment the following lines to lift Z after probing
;G91                    ; relative positioning
;G1 Z5 F100             ; lift Z relative to current position
;G90                    ; absolute positioning

[Norder]

@dizzwold
Can you please also post your complete config.g here ?

[Dizzwold]

@norder

Thank you for looking;

; Configuration file for Duet 3 MB 6HC (firmware version 3.3)
; executed by the firmware on start-up
;
; generated by RepRapFirmware Configuration Tool v3.3.13 on Mon Sep 19 2022 16:04:20 GMT+0100 (British Summer Time)

; General preferences
M575 P1 S1 B57600                                  ; enable support for PanelDue
G90                                                ; send absolute coordinates...
M83                                                ; ...but relative extruder moves
M550 P"Duet 3"                                     ; set printer name
M669 K1                                            ; select CoreXY mode

; Drives
M569 P0.0 S0                                       ; physical drive 0.0 goes backwards
M569 P0.1 S0                                       ; physical drive 0.1 goes backwards
M569 P0.2 S1                                       ; physical drive 0.2 goes forwards
M569 P0.3 S1
M569 P0.4 S1                                       ; physical drive 0.3 goes forwards
M584 X0.0 Y0.1 Z0.2 Z0.3 E0.4                           ; set drive mapping
M350 X16 Y16 Z16 E16 I1                            ; configure microstepping with interpolation
M92 X80.00 Y80.00 Z400.00 E330.00                  ; set steps per mm
M566 X900.00 Y900.00 Z60.00 E120.00                ; set maximum instantaneous speed changes (mm/min)
M203 X6000.00 Y6000.00 Z180.00 E1200.00            ; set maximum speeds (mm/min)
M201 X500.00 Y500.00 Z20.00 E250.00                ; set accelerations (mm/s^2)
M906 X900 Y900 Z900 E800 I30                       ; set motor currents (mA) and motor idle factor in per cent
M84 S30                                            ; Set idle timeout

; Axis Limits
M208 X-2 Y-8 Z0 S1                                 ; set axis minima
M208 X330 Y330 Z400 S0                             ; set axis maxima

; Endstops
M574 X1 S1 P"!io1.in"                              ; configure switch-type (e.g. microswitch) endstop for low end on X via pin !io1.in
M574 Y1 S1 P"!io2.in"                              ; configure switch-type (e.g. microswitch) endstop for low end on Y via pin !io2.in


; Z-Probe
M574 Z1 Z1 S2									   ; set endstops controlled be probe
M558 P5 C"^!io3.in" H5 F120 T6000                  ; set Z probe type to switch and the dive height + speeds
G31 P500 X-41 Y-17 Z2.5                            ; set Z probe trigger value, offset and trigger height
M557 X41:325 Y17:330 P15                           ; define mesh grid

; Heaters
M308 S0 P"temp0" Y"thermistor" T100000 B4138       ; configure sensor 0 as thermistor on pin temp0
M950 H0 C"out0" T0                                 ; create bed heater output on out0 and map it to sensor 0
M307 H0 B0 S1.00                                   ; disable bang-bang mode for the bed heater and set PWM limit
M140 H0                                            ; map heated bed to heater 0
M143 H0 S120                                       ; set temperature limit for heater 0 to 120C
M308 S1 P"temp1" Y"thermistor" T100000 B4138       ; configure sensor 1 as thermistor on pin temp1
M950 H1 C"out1" T1                                 ; create nozzle heater output on out1 and map it to sensor 1
M307 H1 B0 S1.00                                   ; disable bang-bang mode for heater  and set PWM limit
M143 H1 S280                                       ; set temperature limit for heater 1 to 280C

; Fans
M950 F0 C"out7" Q500                               ; create fan 0 on pin out4 and set its frequency
M106 P0 C"Part Cooling" S0 H-1                     ; set fan 0 name and value. Thermostatic control is turned off
M950 F1 C"out8" Q500                               ; create fan 1 on pin out5 and set its frequency
M106 P1 C"Extruder Cooling" S1 H1 T45              ; set fan 1 name and 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

; Custom settings are not defined
; Emergency Stop
M950 J1 C"io4.in"
M851 P1 T0 S0 R0


; Miscellaneous
M911 S10 R11 P"M913 X0 Y0 G91 M83 G1 Z3 E-5 F1000" ; set voltage thresholds and actions to run on power loss

[Phaedrux]

@dizzwold said in NPN Inductive Z Probe:

G1 H1 Z-405 F360 ; move Z down stopping at the endstop
G90 ; absolute positioning
G92 Z0 ; set Z position to axis minimum (you may want to adjust this)

You aren't actually using the probe here.

Replace those lines with a G1 XY move to position the probe, and then G30 to activate the probe.

[Norder]

@dizzwold
I wanted to see the config.g to check which axis limits you entered.
But everything seems to be OK.
Except for the X Y values in this line M557 X41:325 Y17:330 P15, there I would... if the homing works... measure an even edge and enter it there as I mentioned before.
At the moment you have the values of the probe offset in there, which is not necessary.
Here you have to try to specify a square area (like the print bed itself) that is as large as possible.

@phaedrux has already advised you to take the Z-height from the middle of the print bed.
He also wrote you that you should drive to the measuring point with a G1 command and then measure the Z height with G30 and delete the three command lines.

I would also like to say... that you have to calculate the offset of the probe yourself with the G1 command.
With the middle of the print bed as the measuring point, it would be...
G1 X206 Y182
G30

Google Translate
-- Original Text --

Ich wollte die config.g sehen um zu prüfen welchen Achs-Limits Du eingetragen hast.
Aber es scheint alles OK zu sein.
Außer die X Y Werte in dieser Zeile M557 X41:325 Y17:330 P15, dort würde ich... wenn das Homing funktioniert... einen gleichmäßigen Rand ausmessen und dort eintragen so wie ich es vorher schon einmal erwähnt hatte.
Zur Zeit hast Du dort die Werte des Probe Offsets drin, was nicht nötig ist.
Hier musst Du versuchen eine Quadratische Fläche (wie das Druckbett selber auch) die so groß wie möglich ist, anzugeben.

@phaedrux hat Dir ja schon geraten die Z-Höhe aus der Mitte des Druckbettes zu nehmen.
Er hat Dir auch geschrieben dass Du mit einem G1 Kommando zum Messpunkt fahren sollst und danach mit G30 die Z-Höhe messen sollst und die drei Kommandozeilen löschen kannst.

Dazu möchte ich noch sagen... das Du bei dem G1 Kommando den Offset der Sonde selber mit einberechnen musst.
Bei der Mitte des Druckbettes als Messpunkt wäre es dann...
G1 X206 Y182
G30

[Dizzwold]

@norder @Phaedrux

Thank you both so much for your help and guidance, I'm most grateful.

So most people homeZ and homeAll to the centre of the bed? (please bear in mind I've only had a Tronxy).
Would this then make the homeall.g identical to homez.g?

Something else I need to consider with creating a bed mesh grid is I still have the original tronxy heatbed and glass build plate, so I'll also have to account for using Bulldog clips to secure the build plate, and to avoid the part cooling ducts from crashing into them too.
When I've completed a bed mesh grid is 0/0 the front left corner (I ask this as the home point being the front left corner is X = -337 & Y = -343)?

M501, Again because I've only had a Tronxy so not familiar with the marlin eeprom. Is this for storing things like the bed mesh grid for use after a power-down, thus not having to re-do when powering back-up? What other practical uses?

I have a lot of reading and learning to do.

[Dizzwold]

@norder @Phaedrux

On the page to calibrate the z trigger height;
https://docs.duet3d.com/User_manual/Connecting_hardware/Z_probe_testing

Number 10, Open config-override.g and check that there are no G31 commands in it. If you find any, delete those lines and save the file.

Where is config-override.g ?

[Norder]

@dizzwold said in NPN Inductive Z Probe:

Would this then make the homeall.g identical to homez.g?

No, the two files do not have identical content. As the file name suggests, homeall.g homs all three axes. With the homez.g ONLY the Z axis is homed. So it's like deleting all lines from homeall.g that meet the x and y axis.

On the topic of clips holding the pressure plate...
Here you should try to capture the largest possible area of the print bed.
In most cases, the probe does not come completely to every edge of a print bed because the print head comes to an end in the X or Y movement, i.e. it hits the frame or something similar. The nozzle gets everywhere, but since the probe is mounted slightly offset on the printhead, it may not reach the very edge of the print bed.
You should measure this area and then place it as a border around the entire print bed and the clips may also be attached in this area.
In my case I have a 330mm x 330mm print bed and leave a margin of 30mm so the area where the probe can work is 270mm x 270mm.
From X30 to X300 and from Y30 to X300.

Subject M501
The best way to do this is to read the description of the GCodes.
You should save this page as a bookmark in your browser because you will need it more often, since very few people can remember all the commands and their meaning.
https://docs.duet3d.com/en/User_manual/Reference/Gcodes

You can find the config-override.g file in the system directory where the files config.g, homeall.g etc. can also be found.

I have a lot of reading and learning to do.

It gets easier over time.
Marlin is more cryptic I think.
If you got along well with Marlin then RepRap won't cause you any big problems.
It's just a bit difficult at the beginning... once it "clicks", everything is easier or a lot easier.

Google Translate
-- Original Text --

Would this then make the homeall.g identical to homez.g?

Nein, die beiden Dateien haben nicht den identischen Inhalt. Mit homeall.g werden, wie der Dateiname schon sagt, alle drei Achsen gehomt. Mit der homez.g wird NUR die Z-Achse gehomt. Es ist also so, als würdest Du aus der homeall.g alle Zeilen löschen die die X und Y Achse getreffen.

Zum Thema Clips die die Druckplatte halten...
Hier solltest Du versuchen den größt möglichen Bereich des Druckbettes zu erfassen.
Die Sonde kommt in den meisten Fällen nicht komplett bis an jeden Rand eines Druckbettes weil der Druckkopf in der X oder Y Bewegung an sein Ende kommt, er also an den Rahmen stößt oder ähnliches. Die Düse kommt überall hin, aber da die Sonde etwas versetzt am Druckkopf montiert ist, erreicht sie eventuell nicht den äußersten Rand des Druckbettes.
Diesen Bereich solltest Du ausmessen und ihn dann als Rand um das gesamte Druckbett legen und eventuell sind auch die Clips in diesem Bereich angebracht.
Ich in meinem Fall habe ein 330mm x 330mm Druckbett und lasse einen Rand von 30mm, so dass der Bereich in dem die Sonde arbeiten kann 270mm x 270mm groß ist.
Von X30 bis X 300 und von Y30 bis X300.

Thema M501
Dazu lese Dir am besten die Beschreibung der GCodes durch.
Diese Seite sollte man sich als Lesezeichen im Browser speichern, weil man sie öfters mal braucht, da die wenigsten sich die ganzen Befehle und ihre Bedeutung merken können.
https://docs.duet3d.com/en/User_manual/Reference/Gcodes

Die config-override.g Datei findest Du im System Verzeichnis wo auch die Dateien config.g, homeall.g etc. zu finden sind.

I have a lot of reading and learning to do.

Es wird mit der Zeit leichter.
Marlin ist kryptischer wie ich finde.
Wenn Du mit Marlin gut zurecht gekommen bist dann wird RepRap Dir keine großen Probleme bereiten.
Es ist nur der Anfang etwas schwer... hat es dann mal "Klick" gemacht, ist alles einfacher bzw vieles einfacher.

[Dizzwold]

@norder

Thank you for your kind words and support, and your efforts as English isn't your native language. I don't know if this was lost in translation;

@norder said in NPN Inductive Z Probe:

If you got along well with Marlin then RepRap won't cause you any big problems.

I've never used Marlin only the Tronxy firmware, which (if I'm correct regarding the translation) is very cryptic, using mm's per step for example rather than steps per mm.

The Gcode reference dictionary page is always in an open tab, along with the wiring page and many more, as is to be expected with a duet novice.

Homez, So would home Z look like this;

G91
G30

Config-override.g, I'm using RRF 3.4.2, but don't see this file listed anywhere?

It's not in __MACOSX, as soon as I click on that, it disappears?

Thank you again for your help.

[Norder]

@dizzwold said in NPN Inductive Z Probe:

don't know if this was lost in translation

Unfortunately, this happens very often because Google translates the words well, but the grammar often falls by the wayside.

... using mm's per step for example rather than steps per mm.

You always have to pay attention to that, because RRF uses both.
In config.g, for example, the maximum axis speed is specified in mm/min and the speeds are displayed in mm/s in the DWC.
Always keep an eye on it when you change something in the settings!

My cascaded printer's homez.g file looks like this:

; homez.g
; called to home the Z axis
;
; generated by RepRapFirmware Configuration Tool v3.3.10 on Sun Mar 20 2022 22:36:03 GMT+0100 (Mitteleuropäische Normalzeit)
G91               	; relative positioning
G1 H2 Z8 F6000    	; lift Z relative to current position
G1 H1 Z-9999 F77 	; move Z down until the endstop is triggered
G4 P500			; 500stel Sekunde Pause
G92 Z0            	; set Z position to axis minimum (you may want to adjust this)

Don't take over 1:1, because I have an end stop for each spindle for the Z-axis and don't use a probe for positioning like you do.
My homez.g has changed. Normally, a fast ride is made first, followed by a second, slower ride. This doesn't happen with me in homez.g but only in the homeall.g file.

If you don't have the config-override.g file in your system directory, then run the M500 command once... now refresh the displayed system folder contents and then you should see the config-override.g.

Google Translate
-- Original Text --

don't know if this was lost in translation

Das passiert leider sehr oft da Google zwar die Wörter gut übersetzt aber die Gramatik oft auf der Strecke bleibt.

... using mm's per step for example rather than steps per mm.

Da musst Du immer drauf achten, denn RRF benutzt beides.
In der config.g wird zB die maximale Achsgeschwindigkeit in mm/min angegeben und im DWC werden die Geschwindigkeiten in mm/s angezeigt.
Habe da immer ein Auge drauf wenn Du etwas an den Einstellungen änderst !

Die homez.g Datei meines kaskadischen Druckers sieht so aus:

; homez.g
; called to home the Z axis
;
; generated by RepRapFirmware Configuration Tool v3.3.10 on Sun Mar 20 2022 22:36:03 GMT+0100 (Mitteleuropäische Normalzeit)
G91               	; relative positioning
G1 H2 Z8 F6000    	; lift Z relative to current position
G1 H1 Z-9999 F77 	; move Z down until the endstop is triggered
G4 P500			; 500stel Sekunde Pause
G92 Z0            	; set Z position to axis minimum (you may want to adjust this)

Nicht 1:1 übernehmen, da ich für die Z-Achse je Spindel einen Endstop habe und nicht so wie Du eine Sonde zur Positionierung nutze.
Meine homez.g ist geändert. Normalerweise wird erst eine schnelle Fahrt gemacht und eine zweite langsamere Fahrt hinterher. Das passiert bei mir nicht in der homez.g sondern nur in der homeall.g Datei.

Wenn Du die Datei config-override.g nicht in Deinem System Verzeichnis hast, dann führe einmal den Befehl M500 aus... jetzt aktualisiere den angezeigten System Ordner Inhalt und dann sollte die config-override.g zu sehen sein.

[Phaedrux]

@dizzwold said in NPN Inductive Z Probe:

Config-override.g, I'm using RRF 3.4.2, but don't see this file listed anywhere?

That file is only created on the first use of M500 to save the things it tracks.

@dizzwold said in NPN Inductive Z Probe:

Homez, So would home Z look like this;
G91 G30

It could, but a G30 by itself will start probing at whatever location the print head is currently at. So you may want to add a G1 XY move before the G30 to specify a safe location to probe. Or you may not. It depends how you want to use G28 Z.

[Dizzwold]

@phaedrux @Norder

I'm back again, and sorry to be a real pest.

Firstly thank you again for your input and comments.

I'm starting to get the hang of things now, or at least I thought I was.

Nothing major& I now know I can work around it, it's just bugging the heck out off me as to why?

I've moved on to the next stage of calibrating, Bed Plane levelling via means of MBLA M671,
But the X axis/carriage crashes into the back of the frame. I believe I've allowed for the Z probe offset, and I've typed M999 after any changes made.

My previous z probe offsets (x-41 y-17), have changed slightly as these were first calculated more-or-less to the centre of the z probe. So now with my current z probe offset of (x-46 y20), the probe is fully allowed for.

My X axis from home has a full 327mm before crashing into the frame. So my bed.g in the X axis is set to 279 allowing 2mm spare. 327 -46 (-46 offset)=281.
My Y axis from home has a full 333m before crashing into the back of the frame. So my bed.g in the Y axis is set to 310 allowing 3mm spare. 333 -20 (-20 offset)=310.

I can't spot a mistake?

; Configuration file for Duet 3 MB 6HC (firmware version 3.3)
; executed by the firmware on start-up
;
; generated by RepRapFirmware Configuration Tool v3.3.13 on Mon Sep 19 2022 16:04:20 GMT+0100 (British Summer Time)

; General preferences
M575 P1 S1 B57600                                  ; enable support for PanelDue
G90                                                ; send absolute coordinates...
M83                                                ; ...but relative extruder moves
M550 P"Duet 3"                                     ; set printer name
M669 K1                                            ; select CoreXY mode

; Bed Adjustment Screw Positions
M671 X5:279:279:5 Y5:5:310:310 P0.5					; front left, front right, back right, back left

; Drives
M569 P0.0 S0                                       ; physical drive 0.0 goes backwards
M569 P0.1 S0                                       ; physical drive 0.1 goes backwards
M569 P0.2 S1                                       ; physical drive 0.2 goes forwards
M569 P0.3 S1
M569 P0.4 S1                                       ; physical drive 0.3 goes forwards
M584 X0.0 Y0.1 Z0.2 Z0.3 E0.4                           ; set drive mapping
M350 X16 Y16 Z16 E16 I1                            ; configure microstepping with interpolation
M92 X80.00 Y80.00 Z400.00 E330.00                  ; set steps per mm
M566 X900.00 Y900.00 Z60.00 E120.00                ; set maximum instantaneous speed changes (mm/min)
M203 X6000.00 Y6000.00 Z180.00 E1200.00            ; set maximum speeds (mm/min)
M201 X500.00 Y500.00 Z20.00 E250.00                ; set accelerations (mm/s^2)
M906 X900 Y900 Z900 E800 I30                       ; set motor currents (mA) and motor idle factor in per cent
M84 S30                                            ; Set idle timeout

; Axis Limits
M208 X-2 Y-8 Z0 S1                                 ; set axis minima
M208 X330 Y330 Z400 S0                             ; set axis maxima

; Endstops
M574 X1 S1 P"!io1.in"                              ; configure switch-type (e.g. microswitch) endstop for low end on X via pin !io1.in
M574 Y1 S1 P"!io2.in"                              ; configure switch-type (e.g. microswitch) endstop for low end on Y via pin !io2.in


; Z-Probe
M574 Z1 Z1 S2									   ; set endstops controlled be probe
M558 P5 C"^!io3.in" H5 F120 T6000                  ; set Z probe type to switch and the dive height + speeds
G31 P500 X-46 Y-20 Z1.45                            ; set Z probe trigger value, offset and trigger height
M557 X46:325 Y20:330 P5                           ; define mesh grid

; Heaters
M308 S0 P"temp0" Y"thermistor" T100000 B4138       ; configure sensor 0 as thermistor on pin temp0
M950 H0 C"out0" T0                                 ; create bed heater output on out0 and map it to sensor 0
M307 H0 R0.187 K0.192:0.000 D1.89 E1.35 S1.00 B0   ; disable bang-bang mode for the bed heater and set PWM limit
M140 H0                                            ; map heated bed to heater 0
M143 H0 S120                                       ; set temperature limit for heater 0 to 120C
M308 S1 P"temp1" Y"thermistor" T100000 B4138       ; configure sensor 1 as thermistor on pin temp1
M950 H1 C"out1" T1                                 ; create nozzle heater output on out1 and map it to sensor 1
M307 H1 R2.498 K0.275:0.349 D6.79 E1.35 S1.00 B0 V24.0  ; disable bang-bang mode for heater  and set PWM limit
M143 H1 S280                                       ; set temperature limit for heater 1 to 280C

; Fans
M950 F0 C"out7" Q500                               ; create fan 0 on pin out4 and set its frequency
M106 P0 C"Part Cooling" S0 H-1                     ; set fan 0 name and value. Thermostatic control is turned off
M950 F1 C"out8" Q500                               ; create fan 1 on pin out5 and set its frequency
M106 P1 C"Extruder Cooling" S1 H1 T45              ; set fan 1 name and value. Thermostatic control is turned on

; Tools
M563 P0 S"Hemera" 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

; Custom settings are not defined
; Emergency Stop
M950 J1 C"io4.in"
M851 P1 T0 S0 R0


; Miscellaneous
M911 S10 R11 P"M913 X0 Y0 G91 M83 G1 Z3 E-5 F1000" ; set voltage thresholds and actions to run on power loss

; bed.g
; called to perform automatic bed compensation via G32
;
; generated by RepRapFirmware Configuration Tool v3.3.13 on Mon Sep 19 2022 16:04:20 GMT+0100 (British Summer Time)
;M561 ; clear any bed transform
;G29  ; probe the bed and enable compensation

G28			; home
M401		; deploy Z probe
G30 P0 X5 Y5 Z-9999
G30 P1 X279 Y5 Z-9999
G30 P2 X279 Y310 Z-999
G30 P3 X5 Y310 Z-9999 S3
M402

; homeall.g
; called to home all axes
;
; generated by RepRapFirmware Configuration Tool v3.3.13 on Mon Sep 19 2022 16:04:20 GMT+0100 (British Summer Time)
G91                     ; relative positioning
G1 H2 Z10 F6000          ; lift Z relative to current position
G1 H1 X-337 Y-343 F3000 ; move quickly to X or Y endstop and stop there (first pass)
G1 H1 X-337             ; home X axis
G1 H1 Y-343             ; home Y axis
G1 X5 Y5 F6000          ; go back a few mm
G1 H1 X-337 F360        ; move slowly to X axis endstop once more (second pass)
G1 H1 Y-343             ; then move slowly to Y axis endstop
;G1 H2 X202.5 F1500		; move X & Y to centre of bed before Z home
;G1 H2 Y175.5 F1500		; move Y to centre of bed before Z home
;G1 H1 Z-405 F360        ; move Z down stopping at the endstop
;G90                     ; absolute positioning
;G92 Z0                  ; set Z position to axis minimum (you may want to adjust this)

G1 X202.5 Y175.5 F3000		; move X & Y to centre of bed before Z home
G30

; Uncomment the following lines to lift Z after probing
;G91                    ; relative positioning
;G1 Z5 F100             ; lift Z relative to current position
;G90                    ; absolute positioning

; homex.g
; called to home the X axis
;
; generated by RepRapFirmware Configuration Tool v3.3.13 on Mon Sep 19 2022 16:04:20 GMT+0100 (British Summer Time)
G91               ; relative positioning
G1 H2 Z10 F6000    ; lift Z relative to current position
G1 H1 X-337 F3000 ; move quickly to X axis endstop and stop there (first pass)
G1 X5 F6000       ; go back a few mm
G1 H1 X-337 F360  ; move slowly to X axis endstop once more (second pass)
G1 H2 Z-10 F6000   ; lower Z again
G90               ; absolute positioning

; homey.g
; called to home the Y axis
;
; generated by RepRapFirmware Configuration Tool v3.3.13 on Mon Sep 19 2022 16:04:20 GMT+0100 (British Summer Time)
G91               ; relative positioning
G1 H2 Z10 F6000    ; lift Z relative to current position
G1 H1 Y-343 F3000 ; move quickly to Y axis endstop and stop there (first pass)
G1 Y5 F6000       ; go back a few mm
G1 H1 Y-343 F360  ; move slowly to Y axis endstop once more (second pass)
G1 H2 Z-10 F6000   ; lower Z again
G90               ; absolute positioning

; homez.g
; called to home the Z axis
;
; generated by RepRapFirmware Configuration Tool v3.3.13 on Mon Sep 19 2022 16:04:20 GMT+0100 (British Summer Time)
;G91               ; relative positioning
;G1 H2 Z10 F6000    ; lift Z relative to current position
;G1 X202.5 Y175.5 F1500		; move X & Y to centre of bed before Z home
;G30

;G1 H1 Z-405 F1800 ; move Z down until the endstop is triggered
;G92 Z0            ; set Z position to axis minimum (you may want to adjust this)

; Uncomment the following lines to lift Z after probing
;G91              ; relative positioning
;G1 Z5 F100       ; lift Z relative to current position
;G90              ; absolute positioning


G91                     ; relative positioning
G1 H2 Z10 F6000          ; lift Z relative to current position
G1 H1 X-337 Y-343 F3000 ; move quickly to X or Y endstop and stop there (first pass)
G1 H1 X-337             ; home X axis
G1 H1 Y-343             ; home Y axis
G1 X5 Y5 F6000          ; go back a few mm
G1 H1 X-337 F360        ; move slowly to X axis endstop once more (second pass)
G1 H1 Y-343             ; then move slowly to Y axis endstop

G1 X46 Y20 F3000		; move X & Y to front left, home Z at front left
G30

Sorry for all the unneeded stuff in the files, but as I still unsure of myself, I've left some in there.
I've also tried and failed to extrude after M302 P1, and get the error "attempting to extrude with no tool selected". I've tried changing tool number in the tool part of the config.g lines 64, 65 & 66 from P0 to P1 and the drive from D0 to D4, but no luck.

[Norder]

@dizzwold said in NPN Inductive Z Probe:
I have a quick answer to the last question.
I'll watch the rest later because I have work to do.

I'm back again, and sorry to be a real pest.

Yes, that's really bad with you. (fun)

error "attempting to extrude with no tool selected".

At the end in config.g you have to enter T0.
This activates tool #0.

See you later.