@jvp79 Good news!

Yes, probably. In many ways setting up basic LEDs is the same as setting up a fan. Since duet switches pwm on the negative side you can source your voltage elsewhere and then use a fan or heater pin to control it.

https://duet3d.dozuki.com/Wiki/Connecting_and_configuring_fans

In fact if you configure it as an actual fan it can show up as a slider on the web interface for dimming.

@Gerrard said in Consolidating supply and GND for hotend:

Can I run 2 laser filament sensors from the 3.3V and GND of one pin (say E0), then use the input (E0/1 STOP) pins from E0 and E1.

Yes the filament monitors can both be powered from the same 3.3V and ground connection

Then, can I run a 12V and GND from the Power In terminal to the hot end to power the fans and LEDs, and run the Fan's PWM signal pin to the FAN0- and FAN1- pins?

Assuming you are using 12Vs to supply the whole system then you can use a single source of 12V, and switch the -'Ve sides (i.e use the FAN0- and FAN 1- for the two fan 've connections, possibly use fan 2- to control the LEDs.

caveats

You need to ensure you don't exceed the limits of the fan mosfets (1.5A max) There is a potential failure mode where the VIN voltage shorts onto 3.3V. this is more likely if you bundle all the wires up into the same bundle. You mention you are using a ribbon cable. This can be a good solution but be careful to manage the strain relief and flexing to it does not break and short. Also check the max current rating of each of the conductors in the ribbon cable (probably 1A max or less). If you end up putting 12V and the return GND over multiple conductors then if one breaks, the other ones will end up carrying more than they are rated for, and get hot.

It seems I have not read the docs as good as I thought. The L Parameter of the M106-Command fixes my problem. This is the minimum Power for this fan.

M950 F1 C"duex.fan8+^duex.pb6" M106 P1 C"HeatSinkFan" S0 H1 T45 L255

I found this out when investigating the fan status by running M106 P1. It only turned with 50% power.

@dc42 wow, thats a good thing to know. As I understand when I open the valve, I can just after few second use same comand with half of power just to keep everything open. Amazing 🙂

Your schematic should work for low PWM frequencies, your 'screaming', whatever that might be, is probably caused by a wiring error. Are you sure you connected the GND's of the 12V supply and the uC board together?

Other than that the circuit is suboptimal; it takes R3 a long time to charge the gate of M1 which increases dissipation. Replacing R1/R2/R3/Q1 with something like a TC4427 would be a better solution.

Regarding PWMming TEC's: you can do that as long as you keep the PWM frequency above 1kHz or so. If you PWM with a low frequency there is too much stress on the thermocouple joints due to them thermally expanding and contracting many times a second.

@3ddevil said in Configure 4 Pins for PWM Output (Analog Voltage) On Maestro:

The heater needs to be disabled and not referenced by a tool "using M307 H# A-1 C-1 D-1 to make the pin available." Is there any such requirement for the fans/servo?

Yes, see https://duet3d.dozuki.com/Wiki/Using_servos_and_controlling_unused_IO_pins.

Finally, if buffered correctly (F=10KHz) and routed into a proper RC buffer can we expect to an analog output from 0-3.3V for Servo and 0-Vin for Heater and 0-Fan Voltage Set? Can you confirm this is possible?

If using a heater or fan output, you would need to add a pullup resistor to +3.3V if you want a 0 to 3.3V output.

are there any more outputs / alternative pins natively supported by the Maestro or is that all we can do with the chip as currently routed?

The available pins on the Maestro are listed at https://duet3d.dozuki.com/Wiki/Using_servos_and_controlling_unused_IO_pins. Only the heater, fan, and Z probe control/servo pins are PWM-capable.

Interesting pump. Looks like the 6 litre-per-minute brushless version with pwm and tachometer. At $9.50 each, I may have to grab a few to play with.

@fallenhorseman Glad I could help.

Note to all guys: Yeah 4k7Ohm Pullup to 5V is resolving that issues

Funnily, I dont need a pullup between 5V and the PWM of the FAN, but I need one between GND and Z-Probe (as you can barely see in my picture 😉 . I use the 'old' version of BLTouch which is not 3.3V 'tolerant'. Am I missing something or is that a typo on your side?