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Hi All,

I wonder if I can get some help from some expert in the forum. I am connecting an OptLaser 15W to the AXBB-E using the “Laser Pin” in UCCNC

I connected the “Power Out 5V0 “of the AXBB-E to the “GND” of the Laser Adapter. A second cable “O17” of the AXBB-E to the “ANALOG” input of the Laser Adapter. This way the laser appears to work OK using M3+M10QXXX commands.

However, OptLasers recommend to connect it to the “TTL/PWM” input of the laser adapter instead for the “ANALOG” input. If I do that that laser even without a M3 command appears to be ON all the time at minimum power. The only way to completely turn it OFF is with a second cable (O16 for instance linked to M3 Relay pin in UCCNC) to the “ENABLE” input of the Laser Adapter.

So the first question is, does anybody know what the laser can be turned OFF completely with the ANALOG input but not with the TTL input unless a second ENABLE cable is connected? OptLasers mentioned a “possible leakage current of the board”? I just don't understand why the same cable works on the analog input but it doesn't on the TTL input.

The second question is, after I finished the testing, and since I have all the Non-Isolated outputs in Port 1 taken with X, Y1,Y2 & Z + ENABLE for the stepper motors, I connected the Laser directly to Port 3/LPT port. I connected the cables with just 2x single female Dupont connector to pins 1 & 2 (Port 3). Is there a problem with connecting the laser to the LPT port without a Breakout board?

Thanks in advance for your help.

The TTL input seems to be active low, so set the active low checkbox at the laser output in UCCNC. Using the enable input with the M3 output makes it a bit more safe, so I recommend using it. Also, with the active low TTL input you need the enable, because when you turn on the controller and UCCNC is not running then the outputs are low and the laser turns on, so the enable input will prevent the laser from starting with full output power.

The manual does not say a word about the inputs, however, most of the modern devices have isolated inputs. Maybe, you should ask the manufacturer of the laser to be sure.

Hi dezsoe,

Thank you for replying. I will check the active low option (I cant remember if I am using it or not)

dezsoe wrote:The manual does not say a word about the inputs, however, most of the modern devices have isolated inputs. Maybe, you should ask the manufacturer of the laser to be sure.

Does this refer to my question regarding Port 3/LPT Port?

Yes. It's always a good practice to connect a device to isolated I/O.

Hello iOne,

There is a detailed manual at the Opt Lasers website showing how to connect a laser module to the AXBB-E:

Home/Support/Laser Upgrade Instructions/ AXBB-E CNC Controller Connection

TheNigerian wrote:There is a detailed manual at the Opt Lasers website showing how to connect a laser module to the AXBB-E:

Home/Support/Laser Upgrade Instructions/ AXBB-E CNC Controller Connection

Hi TheNigerian,

Thank you for your reply. Yes, I saw that manual and it was the first wiring that I tried. Unfortunately, that wiring diagram appear to be out of date, reason why there is also some confusion even in this forum as how to connect the laser. The way I understand it, the connection shown there has 2 problems:
1- It assumes that you want to use the "analog" spindle output of the AXBB-E which is not my case as I am already using it for an actual spindle control thru a VFD. Also, OptLaser themselves recommend to use a TTL signal instead of an analog one.
2- I think those instructions were created for an old version of UCCNC. Now UCCNC has a dedicated "Laser Pin" which you cannot direct it to the "analog" spindle output, and for what I read in this forum it only works with ports 1 & 3 of "non isolated" pins. If you read thru the forum, I think that is why people confuses the "PWM Spindle" with the "Laser Pin" when they try to control the laser.

So in conclusion, my understanding is, use port 1 OR 3 non isolated pins, one for the TTL Signal and one for a ENABLE. The ENABLE pin gets linked to the "M3 Relay" and the TTL Signal pin to the "Laser Pin" in UCCNC. The GND of the laser goes to any of the 5V0 of the AXBB-E. I hope this helps somebody and feel free to correct if there is something wrong on what I am writing.

Thank you iOne.

I'll see how to use that information to connect my plh3d-6w to the single port UCSB bob.

Additional general information from OptLasers I hope it helps someone too:

"Yes, your connection is correct. However, if I were you, I would start by simply generating signals on the O1 output of your CNC controller and, using a multimeter, I would focus on making sure they are in the appropriate range (by simulating a signal that is meant to make the laser engrave a long straight line for say 5-8 seconds and then no engraving [rest movement of the router] for another 5-8 seconds). For this set-up, the signal on O1, (measured against the GND) measured when the laser is meant to engrave should be 0 - 0.8 V. If you measure the signal on O1 when the laser would be meant not to engrave should be 3-24 V (with respect to the GND).

Please remember to put on and wear laser safety glasses, before starting to work with the Adapter (before arming the Adapter) and the laser. "