Connecting to Atomstack P7 M40, port not opening

I’ve done several YouTube reviews on Ortur lasers and now I’ve been sent the Atomstack P7 M40. I got it set up OK but Lightburn couldn’t find it. Finally after setting the port to (Choose) it found it and let me set a name and dimensions. I had a little more trouble and restarted Lightburn. Now it just says “Port failed to open, already in use?”. Could it be something to do with also using Orturs on this laptop?

I’ve got it set up now but it won’t do anything besides Home. It guves this message. I’ve double checked that the limits are correct. Should be 200x200 for this laser


Homing fail. Could not find limit switch within search distance. Defined as 1.5 * max_travel on search and 5 * pulloff on locate phases.


Grbl 1.12930h [‘$’ for help]

[MSG:Check Limits]

[MSG:‘$H’|‘$X’ to unlock]

[MSG:Caution: Unlocked]


I’ve never gotten a straight answer on this but I’m almost certain your machine does not have homing switches. In which case you should refrain from homing.

Start the laser with the laser head at front-left. That should be your 0,0. The other thing to watch out for is the orientation of the laser. I believe the expected orientation is with where you are able to read Atomstack on the gantry right side up.

Try the starting procedure above and see if you are able to use the jogging controls in the Move window. Do they move the laser head appropriately?

I will look into it. It does have homing switches though, you can see them here.

When I click any of the Move buttons it immediately jumps over to the console and says the following,


Hard limit triggered. Machine position is likely lost due to sudden and immediate halt. Re-homing is highly recommended.

On or near line 4:

Stream completed in 0:00

[MSG:Reset to continue]

[MSG:Pgm End]


Grbl 1.12930h [‘$’ for help]

[MSG:‘$H’|‘$X’ to unlock]

[MSG:Caution: Unlocked]


Okay. Interesting. I’m trying to get my bearings in that picture. Does that mean the machine homes to top left?

Does the machine automatically attempt to home at power-on? It should move slowly toward the homing switches, engage, pull-off slightly, re-engage, and pull-off one more time before coming to a final rest.

Is there anything preventing this sequence from occurring?

If the machine does home properly, can you check position in Move window? What are the coordinates?

This means you’ve triggered one of the switches. It’s in alarm state at that and will require a reset to be responsive again. You will then need to rehome at that point. So try each direction in turn after resetting to see if any will move away from the switches.

Here’s a quick video of it homing when I power on. It’s hard to tell in the video but it looks like it presses and releases the (left in video) homing button 6 or 7 times, the displays the message I posted above.

The position in Move says X51.84, Y148.01, z0.02, U 0.0

How do you reset?

Thanks for the video. Here’s what I think is happening.

At power on, the laser attempts to home but cannot complete the procedure. Then you get the “ALARM:9 Homing fail.” message. You’re still in alarm state which is likely preventing you from moving using jog buttons.

It looks like the X-homing is completely successfully but Y-homing is not. Check to see if the button is actually getting articulated. Is there anything impeding the switch from getting triggered. Couldn’t tell if the cord was possibly blocking the way.

You can try manually moving the laser head around to feel where and if the switches get activated. Can you feel that for the Y-axis? By the way for reference, Y is running left and right in the video you sent.

If the switches are actually getting triggered try manually triggering the Y-switch during homing and see if stops the laser and completes homing. You may need to trigger them twice. If manually triggering does not stop the motion check to see if you have a good electrical connection from the switch to the controller. Make sure the connectors are on in the correct orientation and securely. If you don’t see anything unusual, try swapping the cables between X and Y. Does the problem stay on the same axis or shift? I can’t quit tell from your pictures if swapping will be a possibility.

Either way, the goal is to find out why the switch is not behaving.

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OK thanks much for the help. I was checking all the connections and I unplugged the Y endstop cable, seemed OK so I plugged it back in. Tried again and everything worked perfectly. It no longer makes the loud grinding noise, it Homes and the Move buttons all work. I even did a quick test burn and got a square on wood. Thanks again.

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