This simple coding scheme allows us to control the laser system, without having to implement a complete GCode interpreter.
It is based on simple integer numbers that are communicated over a line (RS232, USB or TCP/IP).

<command> [arguments]


Command Function Description
0 MoveXY <x> <y> Absolute move to (x,y), laser OFF
1 LineXY <x> <y> Absolute move to (x,y), laser ON
2 MoveZ <z> Absolute move to (z), asynchronous
4 SetPosition <x> <y> <z> set current position
5 Nop No action
6 HomeXY Move to end switches and set zero position
7 Set parameter <index> <value> Set the requested parameter to a value. (100=Speed, 101=Power, 102=Frequency)
8 Get parameter <index> Report the value of parameter nr <index>
9 Bitmap data <bpp> <width> <data-0> .. <data-n> Load bitmap data line of <width> pixels with each <bpp> bits per pixel. This is followed by [n] 32-bits datawords. Where [n] is rounded up to 32 bits using n = ceil(bpp*npixels/32). These pixels are clocked out during the next mark command (1). Pixel 1 is located at the LSB of the first dataword.
10 Drill mark <time> Turn laser on for <time> msec on the current location.

Note: Command 1 and 2 are synchronous. They wait until the the final position is reached before the next command is processed.
Command 3 is processed independent of the XY movement, and it is asynchronous (the next command is processed immediately, it does not wait to reach the commanded z position)

A response is always in the form:

<index> <value>

Index can vary and is predefined and fixed (e.g. 0 state, 1time, 2==x, 3==y, 4==z, 5==laseron)
This allows a constant stream of variable data to be reported. Responses are optional. Some commands will not respond anything. Also: responses are asynchronous, they can occur at any time, and at any pace.
See the table with index values for valid indexes. Unknown indexes and associated values should be silently ignored


The length of all the command arguments is (can be) encoded in the command. This allows backwards compatibility, as unknown commands can be parsed and its arguments ignored. To implement this, a 16 bit size field is included in the commands 16 significant bits. Add [length]<<16 to the command. The lower 16 bits are used for the actual command code.


No CRC or other error checks are implemented. It is assumed that a guaranteed data stream is implemented at a lower protocol level. A TCP/IP socket implements CRC, retransmissions and flow-control.


Comments lines in the file are supported. Comments start with a ';' character, and extend all the way to the EOL character.
the comment character should be the first character on the line.

The content of the comments have no exact predefined format. However, the laser system may store the first comment lines, and display them on the LCD screen to identify the job.
So these lines might include something like "Title: ", "Owner:" and "Date:".

Index values

The following index values are defined at the moment (not all are implemented yet).

Index Value R/W Description
0 State R Current equipment state (0=not initialized, 1=initializing, 10=initialized, 20=job received, 30=marking, >100=error)
1 Time R Current time in [msec] after poweron
2 X R(W*) Current X position in [incr]
3 Y R(W*) Current Y position in [incr]
4 Z R(W*) Current Z position in [incr]
5 LaserOn R Status of the laser (1=on)
6 VentOn RW Status of the ventilation(1=on)
7 PurgeOn RW Status of the Purge(1=on)
8 CoolOn RW Status of the Water cooling (1=on)
100 MarkSpeed RW Set Speed in [1/10000 units] of the mark lines (100% = 10000)
101 MarkPower RW Set power in [1/10000 units] of the mark lines (100% = 10000)
102 MarkFreq RW Set frequency in [Hz] of the mark lines
200 UserAction W If written with a value != 0, the system pauses, to allow the user to interact (e.g. reposition)
201 JobXmin RW Minimum X position of the current job (bounding box)
202 JobXMax RW Maximum X position of the current job (bounding box)
203 JobYMin RW Minimum Y position of the current job (bounding box)
204 JobYMax RW Maximum Y position of the current job (bounding box)

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Updated by peteruithoven almost 11 years ago · 3 revisions