zero out work offsets: Marlin

[rflulling]

#### Description
When this function is invoked it generates a command G10 L20 P1 Z0.
In marlin this command directs a firmware controlled filament Retraction.
If a machine is set up with FW retraction not used since this is a CNC, then a user will see a "Unknown Command" in serial.

What we really need is a G92 Z0, or G92 X0 Y0
Use of this command will set a virtual zero from wherever the head position is.
https://marlinfw.org/docs/gcode/G092.html
There is also M428, but I am not familiar with it's use.
https://marlinfw.org/docs/gcode/M428.html

Sadly this is one of a few very specific differences between marlin and old school CNC specific gcode.
Thankfully, it is not a show stopper and the needed commands can be built into a file or entered manually.

#### Versions

• CNCjs: 1.10.2
• Node.js: 14.8.3
• NPM: 5.x

#### How Do You Install CNCjs?

• NPM
• Download the CNCjs Desktop Application

#### CNC Controller

• Grbl
• Smoothieware
• TinyG/g2core
• Marlin 2.x

#### Hardware

• Raspberry Pi
• Desktop or Laptop
• Mobile Device

#### Operating System

• Not Applicable
• Windows
• Mac
• Linux

[wilcomir]

I too have the same issue. I have fixed this with a couple of macros, but it would really be great to build this into cncjs.