G54 - Work Coordinate Systems

G54 selects work coordinate system 1. Smoothieware supports nine total work coordinate systems (G54-G59.3), allowing you to define different coordinate origins for multiple work pieces or machine setups. This is essential for CNC machining workflows and multi-part production runs.

Overview

Work coordinate systems (WCS) provide a way to set different coordinate origins for different parts or setups. Instead of recalculating coordinates for each part, you can define a WCS for each part (each at its own 0,0,0 point), then switch between them with a single G-code command.

What Are Work Coordinate Systems?

Coordinate Transformation:
Machine coordinates = Work coordinate system offset + Commanded coordinates
Machine_Position = WCS_Offset + Commanded_Position

Available Work Coordinate Systems

Smoothieware supports nine work coordinate systems:

Command	WCS Number	Name	Default
G54	1	Work Coordinate System 1	Yes
G55	2	Work Coordinate System 2
G56	3	Work Coordinate System 3
G57	4	Work Coordinate System 4
G58	5	Work Coordinate System 5
G59	6	Work Coordinate System 6
G59.1	7	Extended WCS 7
G59.2	8	Extended WCS 8
G59.3	9	Extended WCS 9

Syntax

G54      ; Select WCS 1
G55      ; Select WCS 2
G59.3    ; Select WCS 9 (extended)

Parameters

Work coordinate system selection has no parameters. The command simply selects which WCS is active for subsequent moves.

Behavior

Modal command: Once selected, a WCS remains active until a different one is selected
Default on power-up: G54 is the default active WCS
Applies to all axes: X, Y, Z, and any additional axes use the same WCS offset
Persistent: WCS offsets are stored in configuration and persist across power cycles

Setting Work Coordinate System Offsets

Use the G10 command to set WCS offsets:

G10 L2 P1 X0 Y0 Z0         ; Set G54 offset to 0,0,0
G10 L2 P1 X10 Y20 Z5       ; Set G54 offset to X=10, Y=20, Z=5
G10 L2 P2 X100 Y0 Z0       ; Set G55 offset to X=100, Y=0, Z=0
G10 L2 P5 X0 Y0 Z-5        ; Set G58 offset to X=0, Y=0, Z=-5

The P parameter specifies which WCS to modify (1-9). See the G10 documentation for detailed offset setting.

Examples

Example 1: Two Parts on One Table

; Part 1 positioned at machine X=10, Y=20
G10 L2 P1 X10 Y20 Z0      ; Set G54 (WCS 1) to part 1 location
G54                        ; Select G54
G0 X0 Y0 Z0               ; Move to part 1 origin (actually machine 10,20,0)

; Part 2 positioned at machine X=110, Y=20
G10 L2 P2 X110 Y20 Z0     ; Set G55 (WCS 2) to part 2 location
G55                        ; Select G55
G0 X0 Y0 Z0               ; Move to part 2 origin (actually machine 110,20,0)

Example 2: Setting WCS After Probing Bed

G28                        ; Home all axes
G0 Z5                      ; Move to probing height
G30                        ; Probe bed and set Z=0
G10 L2 P1 Z0               ; Set G54 Z offset to current position

Example 3: Querying Active WCS

$G                         ; Report current modal state (includes active WCS)

Output will show which WCS is currently active.

G10 - Set WCS offsets via G10 L2 P[number]
G53 - Use machine coordinates (bypass WCS for one move)
G92 - Set position offset (adds to WCS offset)
M500 - Save WCS offsets to SD card (config-override)
M501 - Read WCS offsets from SD card

G10 - Set WCS offsets via G10 L2 P[number]
G53 - Use machine coordinates (bypass WCS for one move)
G92 - Set position offset (adds to WCS offset)
M500 - Save WCS offsets to SD card (config-override)
M501 - Read WCS offsets from SD card

Use Cases

CNC Machining:

Multiple parts on one machine bed, each with their own WCS
Rotating workpieces through multiple operations
Tool change positions in machine coordinates

3D Printing:

Less common (usually just G54)
Can be used for multi-part beds

Pick and Place Machines:

Each feeder position can have its own WCS
Each board position on the table can have its own WCS

Important Notes

Offset Addition: G92 offsets are ADDED to WCS offsets. Both transforms apply.
Machine Coordinates: G53 bypasses WCS offsets for a single move, useful for absolute positioning.
Persistence: WCS offsets are saved in configuration and restored on boot (with M500).
Machine Coordinate System: G54-G59.3 are offsets from the machine coordinate system (MCS) established by homing.

Video Tutorial

Resources

For more detailed information about work coordinate systems:

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