Jtech 24w Laser Always Firing - Cannot turn off

LightBurn Hardware Compatibility
1

Have you all experienced an issue where the laser is always ON (firing) when turned on. Double checked connections. It was working at one point but not anymore. The TTL switch is active and cannot send GCODE commands to turn the laser off with the M5 command. Tried using UGS, Lightburn to send commands but nothing. I was using Vectric Vcarve for a CNC project and then tried using the Jtech laser and that is when I started having problems. I can jog the machine using UGS and Lightburn. Here are my GRBL settings.

$$
$0=10
$1=255
$2=0
$3=2
$4=0
$5=0
$6=0
$10=0
$11=0.010
$12=0.002
$13=0
$20=0
$21=1
$22=1
$23=1
$24=50.000
$25=800.000
$26=200
$27=5.000
$30=1000
$31=0
$32=1
$100=57.288
$101=57.288
$102=200.000
$110=16510.000
$111=16510.000
$112=4570.000
$120=1470.000
$121=1470.000
$122=700.000
$130=900.000
$131=900.000
$132=100.000
ok
2

What controller is this using? And does the Jtech have a separate laser module driver or adapter box?

Has anything changed from the time it was until now?

How are you determining this?

Please confirm. The GCODE command cannot be sent, or it’s not being respected? Want to clarify if you’re describing a communication issue or a function issue.

Are you swapping the laser for a spindle when you did this? If so, what is the procedure for making the change?

3

What controller is this using? And does the Jtech have a separate laser module driver or adapter box?

I have the Millright Mega V CNC machine which uses (I believe an Arduino UNO) and the Jtech 24w Laser uses its own, what they call a safety interface board driver that connects to the Millright controller. Using the multi-meter, I was able to verify that the cable connection (ohmed out) between the two controllers were good.

Has anything changed from the time it was until now?

They only thing I had “changed” was switching to using the Vectric Vcarve software, other than that, nothing was really changed via the connections, GRBL settings, etc. I did disconnect the cable that leads from the laser module to the Jtech laser driver board when I use the CNC machine.

The TTL switch is active

There is a switch on the Jtech driver board where you can switch between using the CW (continuous wave) or TTL. Switching to CW should enable the laser at 100% automatically whereas switching to TLL should take an input such as a GCODE command to turn on/off. The laser is always on at 100% if switched to CW or TTL. The switch via inspection is the only thing I can determine if the TTL is active or not. Perhaps, the switch is bad. I will try to verify this with an multi-meter.

Please confirm. The GCODE command cannot be sent, or it’s not being respected? Want to clarify if you’re describing a communication issue or a function issue.

Sending the GCODE command via UGS or Lightburn results in “SUCCESS” or “OK” via the software. I am not sure if it is a communication issue since I can successfully jog the CNC machine using UGS or Lightburn.

Are you swapping the laser for a spindle when you did this? If so, what is the procedure for making the change?

I am swapping the laser for a spindle but I am not making any changes to the GCODE settings when making the change. I just disconnect the laser module (magnetic mount) from the spindle housing and disconnect the cable that leads to the laser module driver and set it aside so it does not collect dust when the CNC is in use. Perhaps, Vectric Vcarve software overwrites something in the GRBL settings but I am not seeing any changes to the GRBL settings when viewing the “$$” output via the console.

According to the Jtech laser documentation, the mode input switch from CW to TTL mode should disable the laser and enable the laser switching from TTL to CW. Unless, somehow the Jtech laser driver board remembers the last settings - i.e. the laser somehow was still on when the system went down. Not sure about that though.

I am also using GRBL version 1.1f.

Thank you for helping me out!

4

I’d suggest isolating if the issue is occurring coming out of the controller or coming out of the safety interface board driver.

Check that you’re getting modulated voltage out of the controller. I assume your controller generates 5V TTL logic if it’s Arduino based. Voltage should be proportional from 0% power to 100% power between ~0V and ~5V. If you can confirm proper function from controller then proceed to Jtech interface and check with TTL setting that you’re getting modulated power.

From what I’ve seen in the past it’s almost always the interface board that hiccups in these scenarios.

5

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