Anton thanks a lot it will help me so mutch
when i will have all my parts i will probably to contact you again lol
thanks
Francois
Sorry for the long silence. I was only recently able to get to the workshop. My connection looks like this:
the yellow wire is TTL, I control through the commands M106 P1 S250
thanks but i dont used this board i used rambo 1.4 sorry
Any chance you can post your marlin code for pins. Greatly appreciated.
Here is a bit of info I’ve collected from the forum for a laser in my future (so not practical knowledge). I’m assuming given the title of this post that you have a Rambo board and are planning control your laser using g-code fan commands. If your laser control logic is 12v compliant, you don’t have to make any Marlin changes. You just pick one of the three fan pins and use M106 and M107 to control the laser. You can find the connections labeled on in this photo: https://www.v1engineering.com/wp-content/uploads/2018/02/Ramboboard.png
If you need 5V logic, then you can reassign one of the fan pins to a 5V PWM pin. You will be modifying this section in pins_Rambo.h:
#ifndef FAN_PIN
#define FAN_PIN 8
#endif
#define FAN1_PIN 6
#define FAN2_PIN 2
The typical advice on this forum is to reassign FAN_PIN by changing ‘8’ to ‘45’, but you should be able to use any of the three fan pins, and you can reassign them to any of pins 44, 45 or 46. Pins 44, 45, and 46 are all PWM pins. Here is a photo of the pins you would then use for the control logic on your laser: Rambo laser pin.
Note if your laser is controlled using a 3.3v signal, you will have to take steps to bring the voltage down using a voltage divider or some other circuitry between the 5v pin and your laser.
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I’m trying to connect my Sculpfun S9 (12v PWM) to a Rambo 1.4 so can’t use pin 45 as that is 5V. Anton has connected his VCC to a PWM pin but I have no idea about the pin numbers. Do I connect the power to fan 0 + and - and leave the VCC cable off like what Robert is saying (I think) or try and do what Anton has done and use the VCC (I’ll need to find a 12V PWM). I’ve read a lot of posts but am totally confused.
Any help would be much appreciated.
Are you sure you need 12V PWM? In this post, Cristian used a 5V pin to drive his Sculpfun S9. A lot of lasers these days can be controlled by a range of PWM voltages. With PWM, the time spent on or off controls the laser, not the voltage.
The second thing you need to figure out is power. The 6A power supply that V1 specifies for the Primo is not enough to run both your laser and your MPCNC. If you have a 6A power supply, you either have to upgrade, or you can use a separate power supply. If you use a separate power supply, you will need to “split” your ground so that both your control board and your extra power supply share a ground connection with the laser.
As for driving your laser with 12V PWM, I think you will have issues. On the Rambo board, the 12V fan connections have their PWM on the ground side rather than the 5V side. This causes issues with most laser control boards and often requires additional DIY circuitry to make it functional.
If you elect to drive your laser from the control board, there is a 12V pin pair in the corner of your Rambo board for VCC and ground for your laser. I’ve called them out in the blue square below, or you can wire VCC and ground to the connections where you bring power to the Rambo board.
In summary, the path of least work (assuming 5V PWM will work) is to have a big enough power supply to your Rambo board (I suggest 10A since they are common), use pin 45 for PWM, and use the two pins I called out for your VCC and ground.
Edit: I did a bit of searching. According to the picture in this post, your laser will take 5V PWM input
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Hi Robert,
Thanks a lot for getting back to me. Please forgive my ignorance as I’ve read so much information that it’s messed my thinking up. I’ll give the 5v pwm a shot. Reading another post I put a 10k resistor inline on the PWM cable, shall I remove this or would it not make a difference?
You don’t want the 10K resistor, and on the other posts it is likely it was to be wired between the PWM pin and ground, not inline. The typical use I see for resistors on laser circuits is to pull the PWM pin down to ground before the firmware is fully booted. This avoids a flash of laser light from a floating pin. So, if after you have your laser working you see your laser briefly flash on when you turn on your control board, consider adding a 10K resistor between pin 45 and a ground pin.
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Thanks that all makes sense. I’ll have my new power supply tomorrow so should be working by the weekend. 
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Hi Robert,
You where correct, the Sculpfun S9 works on pin 45 and the X30 pins do provide the power.
Thank you for your kind help
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Hi. Help me connect the PLH3D-series laser to the 1.4A RAMBO control. I found a connection to a Mini-Rambo on the Internet. Please look at the photo. The pictures there show 12 volts and I have a 24 volt power supply. Also, the picture shows how to create a cable, I don’t quite understand why and what kind of bifurcation is on the cable?
First off, you have a full-sized Rambo board, not the MiniRambo correct? Currently I don’t believe there are enough pins to run the display and a laser on the MiniRambo. Assuming a full-sized Rambo, the first step will be to upgrade to the latest firmware. Firmware is released here.
Second is the PWM/TTL hookup. The V1 maintained firmware uses pin 45 for laser PWM. You will find pin 45 is the left-most pin in the middle row:
Power is a little trickier since you need to make sure that your 24V power supply provides enough current for both your Lowrider and your laser. According to the sales page for one of the PLH3D models, the laser will take 24V as input. I would recommend pulling the power from the screw terminals, not from any of the pins on the board.
As long as you pull the power for the control board and the laser from the same power supply, you can get away with just three connections: power, ground, and PWM. If you go with a separate power supply for your laser, then you will also need to tie the grounds of the two power supplies together.
Yes, I have a Rambo 1.4. My laser has its own adapter and a separate power supply. The adapter can be configured for different CNC machines. I set it up for a Mini-Rimbaud (Since there is an explanation of the setup in the manual) and connected the PWM 45 and the grounding as in your photo. The laser began to turn on but there is no power. It glows, but it doesn’t burn out the lines. I did it as in the photo. All via LightBurn.
So how are you driving it from the Lightburn side? I assume you set it up for Marlin? For commands you want:
Then you need to put the following at the top of any g-code files you send:
M3 I
You can put it in Device Settings/GCode/Start Code and it will be added automatically.
As for testing your laser, if you want to be absolutely sure what is going on, you can directly manipulate pin 45 using M42. For example, sending the following should turn your laser on at quarter power:
M42 P45 S64
I tried different codes. I did the initial and final as in the picture. This is a screenshot from the laser manual. It doesn’t work((((
M42 P45 S64 Do you need to enter these codes in the command line? I did it, nothing comes out. I also tried to insert these codes into the start window. Not like((((