# Hooking up a laser



## Kiiski (Dec 16, 2020)

Hello all,
I have a sainsmart 3018 pro with a Woodpecker v.3 board. I also have a NEJE laser module with a separate NEJE laser module tester. The woodpecker board has a three wire plug for a laser labeled 12v PWM and ground, but the laser module tester has two wires labeled TTL and ground. There are four wires that go from the laser to the module tester. What are my options?


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## old55 (Aug 11, 2013)

Welcome to the forum.


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## Kiiski (Dec 16, 2020)

old55 said:


> Welcome to the forum.


Thank you


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## difalkner (Jan 3, 2012)

Welcome to the forum! Photos always help in cases like this. Were there instructions with the unit?

David


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## marecat3 (Nov 30, 2010)

Welcome to the forum


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## gwilki (Nov 12, 2012)

I am not familiar with either your CNC controller or your laser, but I can offer some general information. 

Do you have a separate power supply for your laser? If so, it should have a 2-conductor output, + and - running from it to your laser control board.

Then, you should have 4 wires from the laser control board to the laser module. Two for the laser and two for the cooling fan. Each set has a + and - conductor. Is that what you have?

From the CNC controller to the laser control board, you need a 2-conductor wire, again + and -. These run from the PWM port on your cnc controller to the pwm input on your laser control board. Is this what you have, or is this what you talking about when you mention a 3-wire plug?

What software are you planning to use to run the laser? No matter what you use, you need to set grbl controls for it to operate properly.


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## Kiiski (Dec 16, 2020)

Thank you everyone for the warm welcome. I have attached a picture of what I have.. I plan on using Laser GRBL. I know I could hook the laser up (without the temp wire) to the control board, I just wanted to use the temp board for an easy way to use the separate power supply.


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## gwilki (Nov 12, 2012)

I'll take a stab at this, but I will repeat that I am not familiar with your particular laser.

Some of this you already know. The power supply plugs into the temp/control module. Then from that module, you use the 4 conductor wire to connect the module to the laser.

Now, you need to connect the temp/controller module to your cnc controller. You only need 2 conductors to do this - pwm/ttl and ground. I understand that your cnc controller board (woodpecker v.3??) has a 3-pin output. So, I would simply plug in a 3-pin plug, with only 2 conductors running from it - one each to pwm and ground. You don't need the 12v since you are getting that from the temp/controller board. Make sure you respect polarity.

If your cnc controller is outputting pwm signals, when you turn everything on, there should be no light coming from the laser. It is waiting for a pwm signal to set the laser's strength.

Unfortunately, I am not familiar with lasergrbl either. I use Lightburn. The basics, though, are that you must set laser mode in your grbl controller to "on" and you must set a maximum "speed", which is translated to power on the laser. A recommended speed/power is 1000. Then in your laser software, you set the max speed to the same 1000. That way, when you set power in your laser software for a specific project, it is a percentage of the max = 1000, and the max is the same in your software and in grbl.


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## Kiiski (Dec 16, 2020)

gwilki said:


> I'll take a stab at this, but I will repeat that I am not familiar with your particular laser.
> 
> Some of this you already know. The power supply plugs into the temp/control module. Then from that module, you use the 4 conductor wire to connect the module to the laser.
> 
> ...


Thank you so much for the information. I didn't know if it was okay to plug a TTL line into a PWM port. What is the benefit of the temperature module if any?


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## gwilki (Nov 12, 2012)

I really don't know anything about a temperature module. I have never heard of one before you posted. From your pics and your description, I understand that the wiring scheme of your laser pretty much forces you to have it in the loop. You may want to read up on just what it does.


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## Kiiski (Dec 16, 2020)

I would think I could bypass the temperature module and plug the 12v, Ground and PWM to the control board. The fourth wire seems to be just for the temperature sensor.. I've looked for information on the temperature sensor and have found very little on it.


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## gwilki (Nov 12, 2012)

FWIW, I would think that you're correct.


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## Kiiski (Dec 16, 2020)

gwilki said:


> FWIW, I would think that you're correct.


I went ahead and bypassed the temp module and it works great. I was expecting a few hiccups but it lit right up, ran a test file and there seems to be full power level control. Let the fun begin. Thank you for your help with this, it's much appreciated.


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## gwilki (Nov 12, 2012)

@Kiiski I'm glad you got things working. We both learned something.


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