End of job problem

[kered]

I registered T2Laser yesterday and have just started to use it so please be patient.

Today i made a disposable base plate and went to burn a grid using Steve's Youtube video(thanks Steve) at the end of the burning the laser head switches off and homes, all good so far so i took of my protection glasses to inspect the work which turned out fine, i had left the control window open in case i needed to do another pass as I'm still learning the power curve.
All looked good so i closed the control window and to my surprise the laser turned on full for about a second or 2 before switching off and returning to the design pane. Luckily i was not looking in the direction of  the laser but i might have been.

Do i have it setup wrong or is it a bug?
Thanks
Derek

[ggallant571]

Please post specifics of your equipment. Sounds like the controller could use a pull-down resistor. At a minimum, make sure the 12V power is OFF prior to starting any burn activity and is turned OFF prior to exiting. A large number of users have reported this problem with units purchased in the previous 6 months. Supposidly fixed with the latest controller.
 

[ThothLoki]

No. This is not a software bug but instead a hardware bug.
When the software is connecting or disconnecting from the grbl firmware, the laser pin is left floating and not controlled with a pull down resistor. This causes the laser to turn on.

You can try to fix this by installing a resistor from the S pin on your laser to GND. In theory, that should keep the laser off when the Arduino pin is floating. I tried it myself but did not have any luck. It did lessen the intensity though. I just press the power button on my controller whenever I am not burning.

[kered]

Please post specifics of your equipment. Sounds like the controller could use a pull-down resistor. At a minimum, make sure the 12V power is OFF prior to starting any burn activity and is turned OFF prior to exiting. A large number of users have reported this problem with units purchased in the previous 6 months. Supposidly fixed with the latest controller.

Eleksmaker A3 pro 2500ma,(its in my sig) mana SE control board.

I was not exiting the program just changing from the machine control to design in T2laser, it does not happen in the Elekscam or laserGRBL software so i thought it would be some setting i overlooked.
Before exiting i switch to the weak laser using the button on top of the laser control board. Now i know what happens i'll just switch to the weak laser using the button.
cheers
Derek

[Zax]

I've never heard of it when exiting the Laser Controller, but if you pull the USB out it does the same thing so I understand how it would do that. When entering it connects to your machine which powers up Grbl. Due to a hardware design flaw the floating output turns the laser on until Grbl boots up and sets the output pin.

This isn't a software or firmware issue, and can only be "fixed" by a simple hardware mod. You need to add a pull down resistor from the TTL S-pin to GND. EleksMaker have corrected it in their latest laser modules.

It must do the same in other programs, as it has nothing to do with software. Perhaps you haven't had the laser on when connecting with other software?

[kered]

I expected the software to stay connected to the hardware when moving between modes, i did not realise that when you come out of control mode to design mode it disconects from the machine as if i closed down the entire program. As i say, now i know its no big deal, just click the button on the laser module and done. (and remember to click it again before starting to burn     i bet we all forgot, at least once) 

What size resistor is neaded and wattage?
Thanks
Derek

[ggallant571]

I use a 4.7K surface mount 0603. It just needs to pull the CPU floating I/O pin to GND.

[Zax]

I used a 1kohm.

[kered]

Thanks, so 1/4 or 1/2w would be enough if you have SM, my eyes are not so good to use that atuff,  almost

[Zax]

There is practically no current, 1/8 or 1//4 W would be sufficient.