I have an MKS DLC32 and an LPS with H or L inputs to activate the laser. I have connected S (PWM) to the IN input, and TTL goes to G. The problem is that when either L is low or H is high, the laser starts at about 20% power regardless of whether there is a PWM signal or not.
Is there a pin on the MKS DLC32 that I can use to activate, for example, a MOSFET and apply 5V to H only during the job, or is there a parameter in GRBL I can use?
Additionally, my milliamp meter shows 32 mA at 80% power, which seems high for a 150W tube.
You only need a single enable, so use only L or H, but not both.
Most of these wired this way – have L wired to a laser enable switch for the operator to allow it to lase.
Make sense?
The reason for this, is larger lasers usually have a more standard controller. The Ruida produces pwm output the entire time it is executing a layer. The Ruida then pulls L active (low) to allow it to lase.
What firmware are you running?
There is only a single signal to the lps or laser module. It is S and is TTL compatible. The center is Ground and should work fine with this going to any common ground.
Sorry if I was a bit unclear. L is used for the “Laser Test” button, so I need to activate H when the laser is performing its job (or alternatively L in parallel with the test button).
I have wired it as shown in the diagram, except that I use V to activate H via a MOSFET. However, V is active as soon as the laser starts moving, meaning both before and after the actual job runs (including travel to and from the home position).
So I need a solution that activates the laser (H or L) only when the actual job is running.
If you enable the laser, it must have a pwm for it to lase. Most of these controllers do not produce a pwm signal when not executing. That makes me wonder about how the rest of this is setup.
All you are doing is applying +24V to the mosfet, which will turn on… There is no software control over the V pin. You should have the mosfet turned on any time the controller is operational or has power.
According to the schematic, V is always at the board supply voltage.
I’m starting to suspect that something is wrong. As soon as I activate H or L, the laser turns on at about 20% power (without PWM), which I also find strange.
The best solution I get is when I connect S on the MKS DLC32 to H on the LPS and TTL to G. This way, I have no voltage to IN on the LPS… However, I can’t reach more than 20 mA at 100% power, so this is not the right approach either.
With this solution, though, the laser tube is only activated during the actual job. I have also set $30 to 25000, but it makes no difference.
This Redsail laser was once controlled by an MPC03 board from a PC, and in that specification, I understand that the PWM should be 25 kHz.
This runs the tube as a digital device, so that’s not what I’d recommend you do with the Signal (pwm). If you want software to control the tube, the only option is to use S to drive the IN terminal of the lps.
TTL → G should be fine, as that’s the ground terminal of the lps. It should be grounded to your machines case also. This help ensure all grounds are at the same potential.
If this is the case, there is a dc voltage or pwm coming into the lps. This is how they work, with 0 voltage to the pwm input, there is zero output when the laser is enabled. If you’re 100% positive, there is no control current, you may have a faulty lps.
Is this standard grbl? Don’t recognize the versioning… but that shouldn’t matter.
I think I have LinuxCNC loaded on mine now… It’s not in a machine at the moment.
For the controller to operate properly, the S-Value Max, in Lightburn and the $30 in the controller need to be the same.
One step closer. First, I started by adding a pull-down resistor between IN and G—no difference. Power still comes out of the LPS.
I then switched to an 80W LPS I had lying around, and everything works.
However, the next problem arises: I’m not getting any power from the laser tube. At 25 mA, it produces less than my 40W laser. I suspect the tube is defective, but it’s relatively new. My knowledge about this is too limited, though. Sigh.
