Don’t go their yet we don’t know that is the problem…
Oh, I won’t. I’m not touching anything unless told to do so, hah!
In that 2nd thread, Ray seems to be looking for a Red LED on the board when the laser fires.
I just checked with the following conditions:
- LV connector plugged into LPS and C3D (24v and 5v not plugged in on the C3D side)
- C3D powered on with supplied power supply
Power On to the K40
Results:
- Laser fires automatically
- No LED indicating laser fire on the C3D board
Keep in mind, these results are reported based on NOT being connected to the computer and NOT running commands via LightBurn.
No LED from laser automatically firing and no LED when pressing test fire on LPS.
Not sure what this means though.
I think it means that the C3D is not firing the laser.
The 3V we measured on that line suggested to me that the C3D was not firing the laser.
The C3D should not assert lasserfire (and the Red LED) unless there is a job running.
The control panel is not connected to the C3D so the test fire at the panel should do nothing to the C3D.
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On my smoothie clone connected to my K40 from 2017, I have output pin 2.5 being used and the pin in the config.txt is defined for ACTIVE LOW operation. ie, 2.5^ which is defined as the switch.laserfire.output pin and it has worked well for years. Recent work with LinuxCNC had me looking at this signal on a scope and it is active low meaning no fire=high/5V(or 3.3 I forget) and pulses to 0V turns the laser on.
I do see that pin 2.4 is defined as laser_module_pin and it is NOT inverter but I am also not using it. If I were to use it, I would expect to have to invert that signal( 2.4^ ) just as I inverted pin 2.5( 2.5^ ).
Did we verify that without the L signal connected to the LPS, with both Laser powered and C3D powered, the L signal level is high? 3.3V-5V on both the LPS and the C3D?
also wondering if the M2Nano is a 5V device as opposed to the LPC1768 being a 3.3V device and therefore the L signal gets 5V from the M2Nano to turn/keep the laser off while the C3D only asserts 3.3V and somehow does not have enough drive power to turn the laser off.
If that’s the case, maybe a 4.7K resistor between L and 5V would help assert the L signal High.
I meant that I used the test fire button on the LPS itself, not from the control panel.
I just powered up my M2Nano and there is 4.9V on L when powered up.
our measurements show the L and Laserfire signal as >3V when the machine comes on yet the laser comes on at power up. This means that the LPS-L is not at ground and should not cause a fire condition.
The L on the LPS is the ground leg of the input diode in an optocoupler anything other than ground will not turn that diode on (no current) and therefore not fire the laser.
Clearly something is …!
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Agreed and yet the M2Nano works fine. Perplexing for sure.
The test button on the LPS doesn’t do anything externally.
The led you are referring to is on the C3D board?
Right. That 2nd thread seemed to be suggesting the red LED indicating laser fire would result from running commands to move / fire laser from Lightburn. Note that I have not done any of that yet, simply gleaning info from that thread.
@dougl my Nano works fine as well.
I would expect that because the open collector driver on the Nano is turned off you reading close to the the supply voltage.
I am assuming that the C3D reads +3.41V when the LV cable is plugged in because there is a drop on the optocoupler.
Then again if there is no current being drawn on the LPS-L line the voltage at the C3D should be higher than +3.41V or closer to the supply? Then again what is the Vcc for the optocoupler?
I need to see the schematics … flying in the blind.
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That’s what is so odd. All the other wiring on the LPS is external to the firing of the laser and if wired correctly have no effect on what we are seeing, ie power up of C3D with the K40 starts firing the laser. And Don has the LPS schematic which shows a photo diode in the LPS with one side pulled to 5V through a resistor or two and the other side goes to the L pin. If nothing is connected to the L pin then no power flows through the photodiode and laser will not turn on. If 5V is applied(M2Nano) to the L pin also no power/current flows through the photodiode and no laser firing. But if 3.3V(C3D) is on the L pin then there is a ~1.7V differential on the photodiode and it seems to fire.
It shouldn’t be firing.
I just measured mine and L is floating at 22.6V both disconnected and connected to the controller board.
Mmmmm
why would L be floating at 22.6 the opto’s diode anode is connected to 5V.
What LPS are you using??
@Dkwells what Voltage does your L pin on the LPS read without the LV connector plugged in.
4.99V with LV unplugged and machine powered on
If the opto’s output transistor on the C3D has a pullup and was partially turned on then the open line voltage would be lower than the supply voltage …