Dual Z motors, the REV setting only works on one side

[colcolcheese]

Bug Description

define INVERT_Z_DIR false => Z&Z2=right rotation

define INVERT_Z_DIR true => Z=left rotation Z2=right rotation

Version of Marlin Firmware

bugfix-2.1.x

Printer model

Don't forget to include

• [X] A ZIP file containing your Configuration.h and Configuration_adv.h.

Additional information & file uploads

Marlin.zip

[ellensp]

tested

./buildroot/bin/opt_enable Z2_DRIVER_TYPE A4988 ./buildroot/bin/opt_enable REPRAP_DISCOUNT_FULL_GRAPHIC_SMART_CONTROLLER ./buildroot/bin/opt_set INVERT_Z_DIR true

good 4b4d98d282f2760e760b9f2ccca8dcc8831f7f8d bad 3e9848f49c6565ea1c630c272e32e27b0858d85a

says commit d93aa0c38449bcbc38aeca7eac506297270546c8 introduced this issue.

but its not the whole story....

[thisiskeithb]

says commit d93aa0c introduced this issue.

That patch was pushed to fix the motion bug(s) reported in https://github.com/MarlinFirmware/Marlin/issues/25785

[ellensp]

Looking into the code, and getting rather confused, but I think I see the issue

The code is correct, but some defines are missing.

when #define INVERT_Z_DIR true then this should also be set

define INVERT_Z2_DIR true

same with INVERT_Z3_DIR and INVERT_Z4_DIR for when you have 3 or 4 Z's simply adding the line will fix the issue, but it should be done automatically

I purpose the following, which fixes it in my testing

diff --git a/Marlin/src/inc/Conditionals_adv.h b/Marlin/src/inc/Conditionals_adv.h
index 7ea12f0493..855218ab37 100644
--- a/Marlin/src/inc/Conditionals_adv.h
+++ b/Marlin/src/inc/Conditionals_adv.h
@@ -875,6 +875,18 @@
 #endif

 // Multiple Z steppers
+#ifdef INVERT_Z_DIR
+  #if NUM_Z_STEPPERS > 3
+    #define INVERT_Z4_DIR INVERT_Z_DIR
+  #endif
+  #if NUM_Z_STEPPERS > 2
+    #define INVERT_Z3_DIR INVERT_Z_DIR
+  #endif
+  #if NUM_Z_STEPPERS > 1
+    #define INVERT_Z2_DIR INVERT_Z_DIR
+  #endif
+#endif
+
 #if NUM_Z_STEPPERS < 4
   #undef INVERT_Z4_VS_Z_DIR
   #if NUM_Z_STEPPERS < 3

[ellensp]

@colcolcheese can you try this on your system?

If it also fixes your issue, ill turn it into a PR to fix it for all.

[colcolcheese]

The test was successful. Thanks for responding.

[ellensp]

PR created, closing this as fixed. (as soon as its is committed)

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