Author Topic: LaserGRBL doesn't switch the Laser ON  (Read 1860 times)

ggallant571

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Re: LaserGRBL doesn't switch the Laser ON
« Reply #15 on: January 16, 2018, 07:49:51 PM »
I was unaware that it is possible to control the power on the USB port from an application running on a host computer. Perhaps this explains the difference in behavior.
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rpt007

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Re: LaserGRBL doesn't switch the Laser ON
« Reply #16 on: January 17, 2018, 04:09:51 AM »
@Zax:
Quote
Eleks have already fixed the issue and acknowledged it was a poor design

I only got last week an SE board as I had already understood from some comments in the forum, that the Eleksmaker guys pretended to have fixed the issue on the hardware side and I want to build a bigger machine now.

Didn't have the time yet to test it a bit more with different software but T2Laser switched the Laser ON ...

To avoid getting an "old" board from stock I bought it directly from Eleksmaker to hopefully get the SE board with the fixed design and NOT via a third party seller. Unfortunately they apparently keep selling the old stuff as my board came still with the LaserON problem onboard.

Will contact them and ask for a fix - maybe I can do it by myself having an electronic laboratory at hand.

« Last Edit: January 17, 2018, 04:14:33 AM by rpt007 »
Do you have already thought about a solution yourself or is a part of the problem sitting in front of the screen?

Zax

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Re: LaserGRBL doesn't switch the Laser ON
« Reply #17 on: January 17, 2018, 12:56:04 PM »
The fault is not with the Eleks board, it's the laser driver that is designed poorly.

Disconnect the S-pin from the laser and see what happens. It will go full power!

mauriceman

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Re: LaserGRBL doesn't switch the Laser ON
« Reply #18 on: January 17, 2018, 03:46:27 PM »
The laser drive boards that I use all incorporate a pull-up resistor on their TTL input.  Originally I added a parallel resistance on the input to lower internal input voltage (to go low) but now I remove the input pull-up resistor and then have no issues with start-up laser firing. I'm thinking that these controller boards were originally designed for other applications (ie. laser light show) and the front end controller (light sequencer for the show) most likely has an optocoupler at their output. This would keep the 2 sections isolated from ground loop issues. Here you can unplug the laser driver input to test and plug it in  to run (now off). This too would require a proper power sequence when initiallizing though. Applies the same to pro-audio, pre-amp first then power amp.

I really do not think there is a design flaw, just a different use for these boards and logic interfacing has to be addressed.

I can vouch for these boards from Techhood. I have 4 of them, and after removing the input pull-up resistor, work jim-dandy up to 3 amps.
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