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Different Power Supply - where to add laser wire?

Only just got around to installing this board, have having some problems right away. Differences between my cables and power supply, and the instructions.

 

All the diagrams showing how add the (extra single) laser wire to the power supply are slightly different to mine.

Where the Laser wire is supposed to be connected I have 2 connectors "K+" and "K-", but the pinout etch on the actual power supply board shows P|G|L|G|IN|5V (6 pins), the actual pins are P|G|K+|K-|G|IN|5V (7 pins).

So the Pinout Diagram etched on the board shows the 6 pins (as in your instructions), but the actual pins there are 7. The "L" pin, seems to be both "K+", and "K-".

Has anyone else dealt with this?

 

Also my control board doesn't have a ribbon cable, but 2 four cable connectors.

Any help would be appreciated.

 

Uploaded files:
  • laser_power_supply_pinout.jpg
  • laser_original_board_pinout.jpg

Hi Lee, from another forum I read that the silk screen K+ and K- are swapped around. You can measure with a ohm/multimeter between K-/+ and Gnd which K is connected to ground. Make sure the machine is turned off when measuring.

The original k40 with ribbon cable has the X and Y endstops and x axis motor all in the ribbon cable connection. The k40 shield on gerbil has separate x and y axis connections so you can plug these straight over. The pwm wire connects to 'IN'.  On the moshi board (last photo you supplied) you see the right connector with the L0, 5V, Gnd and I assume since the silk screen is obstructed in the photo: 24V. So this connector should plug in directly in the Gerbil shield.

What's left are the end stops. I see these are connected on the vertical connector under the label DBF... The labels are YL XL and Gnd so that should plug in nicely in the broken out limit switches on the gerbil shield. Since there is no 5V line on the limit switches, you must have mechanical end switches. Make sure you wire a 100nF capacitor parallel on each switch to limit electrical noise otherwise the end stops might behave erratic (machine never homes properly or never in the same position).

K- and K+ are then just left which I believe is the laser 'on' switch on the K40 control panel (again an ohm multimeter will give you the answer). So k+ and k- can be left connected and you only operate the laser switch when the machine is ready and homed (option on the Inkscape plugins and CNCjs).

Let me know how it goes!

Cheers, Paul awesome.tech

I have a similar setup, a 2 pin connector and a 3 pin connector going to the stock laser power control board.

K+|K-   G|IN|5V 

From what I can tell:

K+ = no wire
K- = laser test button

G = Ground from the stock laser power board
IN = ? (Laser power level signal)?
5V = 5V from the stock laser power board

I am pretty sure the "IN" is the wire that connects to the PMW output of the GERBIL as per the instructions.

I have not been able to get it to work yet. Here is what I have done so far:

Disconnecting all the wires (G,IN,5V) and the laser fires at MAX power.
Disconnecting just eh IN wire and the laser will not fire.
Connecting just IN to the GERBIL PWM ouptut (No GND, No 5V) and the laser will not fire
Connecting IN N to the GERBIL PWM ouptut (with GND and 5V connected to the stock board) and the laser will not fire. - I figured this should be working as it matched the install instructions. I will double check my wiring and connections to see if I did something wrong.

Troubleshooting ideas:

Check my setting to make sure I have things configured correctly.

Check my g code commands on the plug in to make sure they are correct

I could need the GND and 5V to connect to the GERBIL board directly. Though with both boards sharing the same power supply I don't think it should mater?

I may need to use a single adapter. I have found info where other non-GERBIL board had to adapt a +3v PWM signal to +5v. Though I suspect that the GERBIL already does this?

Referance:

https://github.com/gnea/grbl/wiki/Grbl-v1.1-Laser-Mode

I set:
$30=255 (Max RPM/Power)
$31=0 (Minimum RPM/Power)

This did the trick!

Originally it was :
$30=1200
$31 =1200
so I was running it as too low of power to see the effect.

Hi, Glad you found the issue and got it to work. Yes the PWM signal is a 5v signal. You need to set $30 to a value to match the full range for your laser. The default setting for the k40 at $30 = 2048 which means the full 18mA is divided into 2048 steps. By lowering the value you increase the current for each step. I suggest you run some calibration prints to see what works for you. Also it depends on your gcode generation program. The inkscape plugins are generating gcode based on the default $30 value and a dpi of 380. Of course you can change these figures within the raster plugin. Good luck and post your engravings and cut models!

Cheers, Paul awesome.tech

configuration can be found here https://github.com/paulusjacobus/grbl/wiki/Configuring-Gerbil-Grbl-v1.1f

Cheers, Paul awesome.tech

Hi...as there is no 5V line on the limit switches, you must have mechanical end switches. Make sure you wire a 100nF capacitor parallel on each switch to limit electrical noise otherwise the end stops might behave erratic.

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