Apologies if this response is all over the place.

@bearer the laser power (L_PWR) traces are for 12v up to 5A vs the heater which is 24v @ <2A.

The DB connector I selected has a 6A/pin rating. I didn't see anything in the data on it about derating. The wires for HE_0 and L_PWR will be a separate (2 pair) run from the others due to the multi-conductor derating from the manufacturer.

For now, the board will be attached to the tool as-is, and I don't have any plans for an enclosure at this time. That said, if I did want to put this in an enclosure, I could see a simple 'U' shaped lid being fine, letting the tool connectors come in the bottom while the DB15 goes out the top.

@Danal That's an interesting design, but there are a few things about it I don't like. First, I'm not a fan of someone that puts "Git Gud" on something they want to sell in this field. I get some people think it's funny, but it seems tacky to me. That aside, my goal is to have everything going to the board on a single connector, rather than the 3 connectors (20pin +2-2pin) like his design.

Thanks for the input. Here's a rework. Some of the traces aren't pretty, but I want to keep the thermistor connector next to the hotend heater connector. Some clarification: L_PWR is 12v power for a laser and L_PWM is the PWM signal for said laser.


(Edit: slightly tweaked the routing)

If this is the wrong place for this, forgive me. This is my first attempt at designing a PCB so I wanted to get some feedback before I have it made in case I went full noob on it. Except for the hotend connector (pheonix) they are all XH connectors. L_PWR and L_PWM are for laser control. So how did I do? (I'd share the easyeda link but it says I'm too new to share files yet). Thanks in advance! (One small change since these images is I moved the TEMP plug back from the screw hole a bit so give more space.)

@dc42 I forgot to mention in that post that I was wrong about the TTL being active low. S255 is full power and S0 is off.

@resam I'm going to get a separate switch for the laser's power so it won't be powered until I'm ready to start a 'print'. That way when I power the laser on, the config will already be loaded and there shouldn't be a full power spike.
I should have one for other safety reasons anyway.

I think I did something in a prior attempt that buggered the PWM on the one in the picture because I wasn't getting any voltage out of the header when I sent the M42 P7 S255 command. Switched to P5 and it's working beautifully.

Probably nothing that can be done about this, but it does ping the laser to full power for a fraction of a second when powered on. I'm guessing that's just the delay from reading the firmware. Mostly a non issue though as long as it isn't pointed in someone's face since it is such a short burst.

Thanks for the guidance!

Sorry for the late update.

Deleting the M307 in the override fixed that issue.

My replacement TTL circuit arrived today and I just wanted to run the config by you before powering it up just to make sure I'm not doing anything obviously wrong.

In the picture below, you can see the green and black wires going from the Duex PWM header going to the TTL circuit (green->pwm ; black-> -- ) From what I understand, the TTL circuit uses 0v on signal, 5v off signal. I'm assuming that means that the logic for the pwm would be reversed (S0 being on and S255 being off)

The plug above the TTL header is 12v in from a buck converter and the two on the oppostie side are the fan and laser outputs.

Never even looked at that file. There's a M307 H7 A340.0 C140.0 D5.5 S1.00 V0.0 B0 heater config there. Should I change it to M307 H7 A-1 C-1 D-1 or just delete it?

Don't have any tools assigned to H7 and I'm using the exact M307 as posted in the first post. Here's what my config.g looks like from the Tools section to the custom gcode.

; Tools
M563 P0 D0 H1                                      ; Define tool 0
G10 P0 X0 Y0 Z0                                    ; Set tool 0 axis offsets
G10 P0 R0 S0                                       ; Set initial tool 0 active and standby temperatures to 0C
M563 P1 D1 H1                                      ; Define tool 1
G10 P1 X0 Y0 Z0                                    ; Set tool 1 axis offsets
G10 P1 R0 S0                                       ; Set initial tool 1 active and standby temperatures to 0C
M563 P2 D2 H1                                       ; Define tool 2
G10 P2 X0 Y0 Z0                                    ; Set tool 2 axis offsets
G10 P2 R0 S0                                       ; Set initial tool 2 active and standby temperatures to 0C

; Automatic power saving
M911 S22 R23 P"M913 X0 Y0 G91 M83 G1 Z3 E-5 F1000" ; Set voltage thresholds and actions to run on power loss

; Custom settings
M307 H7 A-1 C-1 D-1
M207 S50.0 F5000

I'm waiting on a replacement TTL circuit (I think I killed mine).

In the meantime, I tried putting the M307 line in the config.g custom gcode section, but I still get the pin not available message when I use M42 until I manually send the M307. Is there somewhere else I should be putting it or do I just have to manually send the M307 each time I want to use the laser?

Just got my Duex2 and want to use the servo connector to drive the TTL (5v signal) for a laser using the last heater (PWM5/E6_PWM).

Let me know if this seems right.

TTL controller + to Duex servo 5v
TTL controller - to Duex servo PWM

Use M307 H7 A-1 C-1 D-1 to disable the heater.

From here, would I use M42 P7 S### (0-255) to control the PWM signal for the TTL controller?