Laser turns off after following code is sent after M3

dc42

Both Smoothieware and GRBL use the S parameter to control laser power, so you could look for a plugin that works with one of those firmwares. If you can't find one, I guess I could add a parameter to the M452 command that selects how the laser is controlled.

ericlmccormick

I will look around for a Smmothieware/GRBL plugin.

I'm confused on what I would change in the M452 command. I have set the P, R and F parameters and I don't see anything else besides inverting the signal that you can do with the command. From other places on the forum, it looks like people have had success using the M452 with M3 commands when using a fan pin to control. However, I need to use a 5V TTL signal. Is there something inherent to how the HEATER3 pin is controlled? Is there another pin I might try instead?

dc42

No there is nothing inherent to heater 3, it's just the first PWM-capable output on the expansion connector.

I'm wondering whether it would work to have M3 preset the laser power (without actually turning it on) in laser mode. Then the power you set with M3 would be used on subsequent G1 commands with no S parameter (but not on G0 commands). Do you think that would work for you?

Meanwhile you could try using CNC mode (M453) which lets you map M3 to an output for spindle motor control in a similar way to M452. Note, in CNC mode, G0 commands ignore the feedrate and always use maximum speed as set by M203.

bishop86

Hi. Im using LightBurn for generating gcode. Most of preset machine have persistent power so gcode have S power only on change. It will be good if M5 lock the output so none of G1 movements turn on laser. M3 without without Sxxx could unlock laser with previously setup power or with S to set new power. But Laser would only turn on with G1 movement. If S is included in G1 new power is set up. G0 cannot reset power.

Now im using custom written program convert gcode. It reads line by line and if S power param is in this line i stor it, If G1 line without S i add S with stored power at the end.

dc42

@bishop86 said in Laser turns off after following code is sent after M3:

Hi. Im using LightBurn for generating gcode. Most of preset machine have persistent power so gcode have S power only on change. It will be good if M5 lock the output so none of G1 movements turn on laser. M3 without without Sxxx could unlock laser with previously setup power or with S to set new power. But Laser would only turn on with G1 movement. If S is included in G1 new power is set up. G0 cannot reset power.

Are there any other firmwares that behave in this way?

devleon

@dc42 I've tired a lot of software (lightburn, laserweb4, lasergrbl) in the last few days that generate GCode using G1 Xnnn Ynnn Snnn to set the laser power. However, as @bishop86 mentioned, the S parameter is only included when the S is supposed to change, meaning G-Code will look like this:

G1 X33.73 Y16.07 S255.00
G1 X36.89 Y19.23
G1 X36.94 Y19.30
G1 X36.96 Y19.38

This means that S is supposed to stick, and I doesn't do that currently. That's why @bishop86 wrote a script to append the S paramter to G1 lines that have it missing.

In the meantime, would you be able to share the script you wrote @bishop86 ?

dc42

Which firmware version are you running? The G1 S parameter is already sticky in 2.03beta2 (although I regard this as dangerous, and a very bad decision on the part of those who introduced the S parameter and made it sticky).

devleon

@dc42 Oh, I haven't tried the beta yet, still running 2.02. Will give it a try in the next days!

dc42

Advance warning: in 2.03beta3 the G1/G2/G3 S parameter will only be sticky if you add parameter S1 to your M452 command.

nelho

Hi @bishop86 it's possible to send me your program please ?
Thanks

morokolli

Hi,
Any progress on this?
I ran in same situation with following code with Release 2.04 (Duet 2) and 1.25 (Duet 06/085).
Tested also with 3.0beta12 (2019-11-02b1) using M452 C"exp.heater3" Q200.
Config is in attached file.config.g
Seems that heater3 output is turned off.
gcode:
;Project bugbug
; *** START begin ***
G90
G21
M84 S0
G92 X0 Y0 Z0
G00 X0.0000 Y0.0000 Z5.0000

;No. 2: Engraving 1
G00 X25.7569 Y48.9645 Z5.0000
G00 Z0.5000
G01 Z0.0000 F1200
M3 S255
G01 X19.7518 Y30.6457 F750
;bug hits here. previus move is lasered ok, next 2 moves not.
;if run line by line (pasting one by one to console) all works ok.
G01 X1.1829 Y30.6942
G01 X16.1260 Y19.5851
M5
G00 Z5.0000
G00 X0.0000 Y0.0000
M05

dc42

@morokolli, I'll test that when I get time.

Are you able to configure your GCode generator to generate S parameters on the G1 commands instead of using M3? That's the modern way of doing laser engraving, and it benefits from velocity ramping in RRF3.

morokolli

Tested with S parameter -> works like it should.
I had to ask from CAM software developer is it possible. I'm using ESTLcam at moment.
Waiting answer from there also.

morokolli

I did more testing.
While using attached G-Code error hits in even with S255 parameter.
First square is burned ok, then on another part start and goes well until light turns off after couple moves (somewhere around line 30-32) and comes back after next move.
Using Release 3.0beta12
Sample G-code:
[0_1573400684875_peukku.nc](Uploading 100%)

dc42

Did you select sticky laser power in your M452 command?

Your file upload to this forum doesn't appear to have worked. Please try again.

morokolli

Reload of sample and config.g.
config.g.txt
peukku.nc.txt

dc42

@morokolli said in Laser turns off after following code is sent after M3:

Reload of sample and config.g.
config.g.txt
peukku.nc.txt

M452 C"exp.heater5" Q200 ; laser uses heater3 pin, PWM frequency 100Hz

You didn't select sticky laser power. https://duet3d.dozuki.com/Wiki/Gcode#Section_M452_Select_Laser_Printer_Mode

morokolli

Still same thing while using:
M452 C"exp.heater5" Q200 S1
Here's video:
https://www.youtube.com/watch?v=2FMmwe_Vmpk

morokolli

More debug info:
If F value in G1 F300 is more than F1015 All lines are done as they should. If i's lower, piece is missing. And if speed is added over F1200, next line starts to suffer. Hopefully picture explains better:

craigb244

any update on this? im having the same issue.

M452 is set to sticky in the config but (quite randomly) it forgets the Gcode "stickiness" and only restores after it hits the next G1 Sxxx