Air Assist Clarification

I have searched but I wasn’t sure of the answer…

Does the air assist toggle switch in Lightburn have any effect with Trocen controllers?
I have an AWC708S and it doesn’t seem to make any difference - my solenoid is connected to Out 2.
It is working fine but the software switch doesn’t seem to make any odds.
Didn’t seem to do anything with my TL-3120 either.

Also not getting the expected output from the Out 1 port. I see ~9.5V between Out 1 and Gnd. Which drops to 0V when a job is started. I’ve seen a few threads on here saying they couldn’t get Out 1 to work. Anyone got any insight about this?


I have an older Trocen controller and was tempted to try to turn my air on that way. Then chose to wire a small electrical outlet into the door. Reason being: simplicity and it’s not like running the air a little longer creates a problem.
Put the exhaust fan on the same box, at least for the winter.

Do you mean so they come when you close the door?
Or are you talking about a switch near the door?
Either could work I guess but not really what I’m hoping for.

Not having a lot to go on here… I’d guess when you state

From this statement I’d guess that it is operating properly and you have it wired incorrectly.

A typical misconception is that the output of the controller ‘drives’ the solenoid.

In actuality the ‘output’ is known as a ‘sink’ and completes the circuit to ground.

You should measure from supply voltage (assuming 24v) to the output pin.

One side of the solenoid goes to 24v and the other side to the controller.

Is this how you wired it up?

Some solenoids have internal diodes, so if the leads indicate polarity, pay attention to them.

Good luck



Is this definitely true for Trocen controllers? I’ve seen the wiring diagram for Ruida controllers and as you say the solenoid is connected to 24V on one side and the wind pin on the other.

As I understood it from the manual the Trocen controllers are different. I currently have my solenoid connected to OUT2 and GROUND and it is working as expected. If I swap it to OUT1 it does not work.

I close the door and a switch turns an electrical box on. Allows me to clear out any lingering smoke after the cut is completed. A simple solution.

1 Like

Sounds good. I have the air extraction on a plug with a remote control.

I don’t want the air assist connected to the door though. I’ve already got it so it come on when the laser fires. Just wanting to add a low flow option for engraving/acryllic. Also need to conserve air as compressor is running near or over duty cycle already.

Since there is conflict, I ran it down.

would indicate that it’s operating as I suggested.

Final truth is the actual wiring manual (or one operating), which probably trumps us all, where I should have looked in the first place…

This link to the TL-3120-PLUS has this illustration…

The wiring shows an OUT3, but I don’t see it in any of the device photos. There doesn’t seem to be any kind of current values. They show a ss switch in the diagram, but I have no doubt people hook solenoids to them…

Showing how they did it, quite the opposite of mine and the other ones I worked on in the 70’s.

The drawback of this is now the components become locked into the operating voltage.

I’m sorry I lead you in the wrong direction… I guess I should just keep quiet.

It also makes me wonder about the output going to 0 volts when it in a ‘run’ status.?

Take care, good luck


No worries. I have an Out3 on mine but it says ‘reserved’ in the manual! It doesn’t appear to do much.

Is it still not operating properly?


I actually looked into it further and answered my question “Does the Software Air Assist Toggle Have Any Effect?”. It does! On my board at least.

I feel like I’m really bad at explaining this stuff and there are quite a few unanswered threads about it so in case anyone ever searches this thread in the future here is what I’ve discovered…

I have a Trocen AWC708S board.
There are 4 Outputs: OUT1, OUT2, OUT3, OUT4
In the manual it says: OUT1 blowing signal (blow all the working time).
OUT2 Blowing signal (blow when laser is powering on).
OUT 3 & 4 Reserved

Unfortunately OUT1 is not working properly on my board but luckily OUT4 appears to behave the same way.
The air assist toggle in lightburn affects OUT4 - and I’m guessing OUT1 - but it has no effect on OUT2.
I confirmed this behaviour by testing the voltage between the OUT ports and Ground. There is a 24V signal when it is active.

Got it. I’m not using compressed air but just a small air pump. Sounds like your on the right track.

It’s compressed somewhere… :crazy_face:

If you cut much, what a difference…

I bump my pressure up engraving backsides of mirrors. Seems to get on everything, around and in the nozzle.

It would be a great addition to your machine.


So blowing air out of a straw involves compressed air too?

I mentioned blowing smoke away from the backside of my lens once and someone shot back that that’s the fault of poor smoke evacuation. But that’s a bit off topic :confused:

The only way the air goes there is your mouth compresses it and it’s only way out is via the straw.

Probably right… :crazy_face:


So, moving forward with my actual thread :smile:

OUT1 is live when the laser fires but the software air assist switch has no effect.
OUT4 is live when a job is running, as long as the air assist switch is on.

This seems strange, and I’m not sure if it’s by design, a bug, or a hardware issue. Can any Trocen users or Lightburn people confirm?

But assuming I have to live with it, my ideal set up is to have high pressure air when the laser fires, when the software air assist switch is on and low pressure all through the job (for engraving/acryllic) when the switch is off.

I don’t think this is possible with my current set up, or is it?

The assist requires you have something that tells you the machine is in ‘run’ mode (‘Status’ with the Ruida). This is generally used to enable low pressure air.

When the laser is working with the ‘Air Assist’ enabled (‘Wind’ on the Ruida), that output bypasses the low pressure restrictor.

You need two signals, one for low pressure or just to enable the air whenever the machine is operating. The other one ‘somehow’ come from enabling the air assist on that layer. Sounds like that is OUT4

if the laser is ‘firing’ does this mean it’s follow the pwm control?

If it’s on for the duration of the layer, you could use that for the Status or enable low pressure, then use the OUT4 to bypass the restrictor…


I have the C version of this controller. I don’t use this feature. My controller has two ports with four pins each.
Here’s how I interpret it:
It talks about ‘blowing’ which means turn the compressor on. Out1 goes high all the time and Out2 goes high only when the laser is firing.
I know your measurements don’t confirm that but I would assume it’s correct for now.
I don’t think you want the air running all the time so I think out2 is what you need to use.
I would get a 24v air solenoid to control the air using out2. Unfortunately the manual doesn’t give you a current rating so pick one that’s low. Maybe solid state?
I would wire that up and if it doesn’t work then you may have to realize that Chinese controllers don’t always deliver what they say. :cry:
Btw I don’t see a way to tell cutting from engraving so good luck with that.

Oh yeah sorry, I got mixed up Out1 is the one which goes high all the time!
I have the Solenoid connected to Out 2 and it is working.
I want to use the high all the time output for the low pressure.
I can do this as well.
And I can select an engraving layer by using this switch in Lightburn
Screenshot 2022-03-06 at 11.45.40

Thing is the switch only seems to affect the ‘on all the time output’, not the ‘on when laser is firing output’
So I think I can only have a system where the air is on all the time (high pressure) when air is selected in software and on when the laser is firing (low pressure). Seems a bit counter intuitive and I guess I need to double check but I think this is my situation!

EDIT**No I think I’ve sussed it out now! I’ll post here if it works.

My guess is that the Out functions in AWC708S are not controlled by any software including LB. It appears to be driven by controller firmware.
So if you want low air when running and high air when laser on and off when off then you will need to create external logic driven by out1 and out2.