### Compile error since Release 1.1 if G38 enabled

[sergioausrio]

Got a Compiler Error if i enable the G38 Support in Configuration_adv.h. Need this for my MPCNC Error from Arduino IDE;

sketch\Marlin_main.cpp: In function 'void process_next_command()':

Marlin_main.cpp:10527: error: 'subcode' was not declared in this scope

       if (subcode == 2 || subcode == 3)

           ^

exit status 1 'subcode' was not declared in this scope

[thinkyhead]

Will patch shortly. Here's the fix:

if (parser.subcode == 2 || parser.subcode == 3)
  gcode_G38(parser.subcode == 2);

[sergioausrio]

Thank you. The Compiler error is gone but G38.2Z-99 dont stops on Probe Contact (Z Min Endstop on Ramps). G28Z0 works fine with the same Probe

[thinkyhead]

Hmm, there haven't been any logical changes to G38 (as far as I know). I will take a look at 1.1.3 and compare to see what might have broken.

[thinkyhead]

Seems not to have changed since 1.1.3 — so does it not work in 1.1.3 either?

[sergioausrio]

No. G38 doesn't work since the 1.1 release. I tried every release. I have one of the last RC8 Bugfix Version with working G38

[thinkyhead]

So, RC8 seems to be the last? I will compare to that instead…

[thinkyhead]

Are you using ENDSTOP_INTERRUPTS_FEATURE?

[sergioausrio]

No

[thinkyhead]

What is your Z_MIN_PROBE_PIN setting? The old G38 used the Z_MIN_PIN while the current G38 requires the use of Z_MIN_PROBE_PIN.

[sergioausrio]

Ok. If have only #define Z_MIN_PROBE_USES_Z_MIN_ENDSTOP_PIN enabled. Is this my Problem ? What should i enter on Z_MIN_PROBE_PIN for a normally open switch (Probe with a CNC Bit)

[Bob-the-Kuhn]

The idea is to use Z_MIN_PIN for homing and Z_MIN_PROBE_PIN for setting your work piece origin.

I believe that this set of definitions will get G38 working:

//#define Z_MIN_PROBE_USES_Z_MIN_ENDSTOP_PIN
#define Z_MIN_PROBE_ENDSTOP
#define Z_MIN_PROBE_ENDSTOP_INVERTING true

Some of the CNC bits are not very conductive if you're probing in the X or Y directions. You may need to lightly rub some fine grit sandpaper on the side of the bit.

[thinkyhead]

@Bob-the-Kuhn

I see that #5897 is also concerned with G38. It looks like it can be closed, as I believe you can probe in any direction now.

Can G38 be made to work with Z_MIN_PROBE_USES_Z_MIN_ENDSTOP_PIN? There may be some obscure reason someone is homing Z to max and choosing to use the Z min pin as the probe pin.

[sergioausrio]

I got it working in the Z Direction only with

define Z_MIN_PROBE_ENDSTOP

define Z_MIN_PROBE_ENDSTOP_INVERTING true

but in X or Y Direction the Probe does not stop...

[Bob-the-Kuhn]

My robot is down so I can't verify this.

Please do a sanity check on the X & Y movement. Assuming you have an alligator clip on the bit and a touch plate similar to the triquetra system, issue a G38.2 X100 F200 and then touch the clip to the plate.

If the head doesn't stop then there's a software problem.

If the head stops immediately then the problem is poor electrical contact on the side of the bit.

[sergioausrio]

I tried it with a Alligator Clip direct on the Touchplate for many Times. It works only in both Z Directions. The crazy Thing is: Marlin throws allways the "Error: failed to reach target" Message even if the Probe stops in Z Direction on contact.

The optional PROBE_DOUBLE_TOUCH does not work either with G38

[Bob-the-Kuhn]

That's not what I was expecting to hear.

Time to jerry rig something so I can test.

[sergioausrio]

This morning i give the latest 1.1.4 Bugfix a try.... and IT WORKS !!! G38.2 is full functional! All directions working.

I put this in Configuration.h:

#define Z_MIN_PROBE_ENDSTOP
#define Z_MIN_PROBE_PIN Z_MIN_PIN

[Bob-the-Kuhn]

GREAT!!!

[sergioausrio]

Is it normal that a G28Z0 does not work in this configuration ? I dont need a G28 for CNC but i tried it and the Z-Axis does not stop on contact. (G38.2, G29 and G30 woking fine) On the other hand, the MPCNC is a multitool and can be used for 3D printing and Lasercutting. A G28Z is needed...

[thinkyhead]

Does G28 Z work, but G28Z does not?

[sergioausrio]

No. G28 works only with my regular Microswitch Endstops on X-Min & Y-Min but not on the Z-Axis with the Probe wich is on Z_MIN_PIN

[Bob-the-Kuhn]

It's really strange that G28 Z doesn't work but the others do.

I think the easiest thing to try is to replace #define Z_MIN_PROBE_PIN Z_MIN_PIN with #define Z_MIN_PROBE_PIN xx where xx is the number of the Z_MIN_PIN. Sometimes the first method doesn't work.

I think the long term fix is to change the G38 code to use either the probe pin or the Z_MIN pin. Try this: a) change configuration.h

//#define Z_MIN_PROBE_ENDSTOP 
//#define Z_MIN_PROBE_PIN Z_MIN_PIN
#define Z_MIN_PROBE_USES_Z_MIN_ENDSTOP_PIN

b) in endstops.cpp replace #if ENABLED(G38_PROBE_TARGET) && PIN_EXISTS(Z_MIN_PROBE) && !(CORE_IS_XY || CORE_IS_XZ) with #if ENABLED(G38_PROBE_TARGET) && (PIN_EXISTS(Z_MIN_PROBE) || PIN_EXISTS(Z_MIN)) && !(CORE_IS_XY || CORE_IS_XZ)

[thinkyhead]

It's really strange that G28 Z doesn't work but the others do.

It only homes with the probe if Z_MIN_PROBE_USES_Z_MIN_ENDSTOP_PIN, because it then assumes you have no Z min endstop.

#define HOMING_Z_WITH_PROBE (HAS_BED_PROBE && Z_HOME_DIR < 0 \
        && ENABLED(Z_MIN_PROBE_USES_Z_MIN_ENDSTOP_PIN))

[sergioausrio]

I changed

#define HOMING_Z_WITH_PROBE (HAS_BED_PROBE && Z_HOME_DIR < 0 \
        && ENABLED(Z_MIN_PROBE_USES_Z_MIN_ENDSTOP_PIN))

to

#define HOMING_Z_WITH_PROBE (HAS_BED_PROBE && Z_HOME_DIR < 0 && ENABLED(Z_MIN_PROBE_USES_Z_MIN_ENDSTOP_PIN) || ENABLED(Z_MIN_PROBE_ENDSTOP))

and G28Z (G38 too) works now with Probe:

#define Z_MIN_PROBE_ENDSTOP
#define Z_MIN_PROBE_PIN Z_MIN_PIN

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