Exclusion Zones — grblHAL Plugin

A multi-zone 3D exclusion/inclusion plugin for grblHAL. Define axis-aligned 3D boxes that restrict G-code moves, jogs, and tool-change macros from entering protected areas of your machine's work envelope.

Compatible with the Sienci ATCi keepout plugin hook architecture and designed for integration with FlexiSender.

How It Works

Zones are axis-aligned 3D boxes defined by X/Y/Z min and max coordinates. Each zone carries per-operation permission flags:

Bit	Flag	Description
0	allow_gcode	G-code moves may enter the zone
1	allow_jog	Jog moves may enter the zone
2	allow_toolchange	Tool-change macros may enter the zone
3	enabled	Zone is active

• G-code moves that would enter a forbidden zone are rejected.
• Jog moves are clipped at the zone boundary instead of rejected outright.
• If the spindle is already inside a zone, jogs are frozen until the zone is disabled.

Commands

Command	Description
$EXCLUSION=1	Enable exclusion zone enforcement
$EXCLUSION=0	Disable exclusion zone enforcement
$ZONE	List all defined zones
$ZONE=n,xmin,ymin,zmin,xmax,ymax,zmax[,flags]	Set or update zone n
$ZONE-n	Delete zone n

If the flags byte is omitted or the enabled bit (bit 3) isn't set, the zone is automatically enabled.

Example

$ZONE=0,-100,-100,-50,100,100,0,8

Creates zone 0 spanning X[-100,100] Y[-100,100] Z[-50,0] with only the enabled flag set (no operations allowed inside).

$ZONE=0,-100,-100,-50,100,100,0,9

Same zone but G-code moves are permitted inside (flags = enabled + allow_gcode).

Build

Add EXCLUSION_ZONES_ENABLE to your build defines and include the plugin source in your grblHAL driver build:

// In my_machine.h or your board map
#define EXCLUSION_ZONES_ENABLE 1

Call exclusion_zones_init() from your driver's plugin initialization.

Realtime Report

When enabled, the plugin appends |EZ:EZ to the status report:

• E — exclusion zones are globally enabled
• Z — the machine is currently inside an active zone

Configuration

Define	Default	Description
EZ_MAX_ZONES	16	Maximum number of zones
EZ_TOLERANCE	0.5	Boundary tolerance in mm to avoid false positives on grazing moves

Both can be overridden at compile time.

Files

File	Description
exclusion_zones.h	Public header — types, defines, and API
exclusion_zones.c	Plugin implementation

License

Same license as the grblHAL project this plugin is built for.