Multiple valve PWM control with DUET

reFlexlab

Hello everyone.

I am currently building a multi-fonctional fabrication plateform. I have plan to control several component.

I noticed that a way to control a selenoid valve with the duet is to wire the valve to a PWM fan control pin .
You can then use the command M571 in order to trigger the PWM output only when the extruder is on.

I would Like to know if I could control multiple 12V selenoid valve. For exemple in the same way you can use multiple extruders.

Is the command M571 is triggered on the selected extruder ?
Can you assign different pin to different extruder ?

Thank you,
Tom

A Former User

Are you needing PWM to partially actuate the solenoids or are you just using the PWM capable fan pins because of the transistors?

You will want to make sure you add flyback diodes to the solenoids in any case.

dc42

Is https://duet3d.dozuki.com/Wiki/Gcode?revisionid=HEAD#Section_M670_Set_IO_port_bit_mapping any use to you?

reFlexlab

Hello,

dc42 : I don't understand how to use in combination the M571 and M670 command and how they influence eachother.

Bearer : I think flyback diodes are already built in isn't it ?

dc42

M670 sets up the mapping of bits to output ports, to turn solenoids or other devices on or off. Then you specify in each G1 command what you want on and what you want off for that move, using the P parameter. Optionally, you can specify a small time advance for switching the solenoids, to allow them to react.

If you don't want to turn the solenoids on/off that often, or you want variable PWM, then use M42 instead. See https://duet3d.dozuki.com/Wiki/Using_servos_and_controlling_unused_IO_pins.

T3P3Tony

@reflexlab said in Multiple valve PWM control with DUET:

Bearer : I think flyback diodes are already built in isn't it ?

Flyback diodes were added to the PWM fan outputs from revision 1.02 of the Duet 2

reFlexlab

Hello, I am coming back to this subject.

Maybe this is a simple question but I am trying to use the unused pin on the DUET wifi.

I plan to use the M670 command, in order to successively control output ports during moving..

They are area of shadow in the use of the M670 command.

For exemple if I want to trigger two output ports : 20 and 22 which are fan output pins (chosen with this help) :

I want pin 20 off and pin 22 on during the moove I will send this command :

M670 P20:22
G1 P0:1 X... Y... Z...

Is it correct. Thank you

reFlexlab