How do I connect a servo on Duet 2 with Duex 5 Expansion board?

trobison · 10 Oct 2021, 07:53

How do I connect a servo to E3D Tool changer / Duet 2 with Duex 5 Expansion board?

I am trying to configure a “Pebble Wiper” on my E3D Tool Changer. When I add the following lines, the hot end fan on tool 3 will stop. I have tried e1stop and get the same result. My goal is to connect a servo and control it. The lines below work, but I fan stops on Tool 3. I have been using a 9g micro-servo for testing.

M950 F7 C"^duex.e2stop" Q600 ; Set up Wipe Servo
M106 P7 C"Wipe" ; Set up Wipe Servo

config.g

Board: Duet 2 Ethernet (2Ethernet)
Firmware: RepRapFirmware for Duet 2 WiFi/Ethernet 3.3 (2021-06-15)

o_lampe · 10 Oct 2021, 08:18

@trobison "F7" is already defined as a fan in config.g. You can use M950 "S1" for servos and they don't need a Q(600) parameter.
Also check here about further details, like using M280 instead of M106

droftarts · 10 Oct 2021, 09:14

@trobison you can’t connect the servo to an endstop pin. Use the PWM pins on the Duex. See https://duet3d.dozuki.com/Wiki/Using_servos_and_controlling_unused_IO_pins

Ian

trobison · 10 Oct 2021, 23:37

Thank you for your help. I think I have it working. Yes, the F7 was already defined as a fan and that stopped the fan. The servo did work on the endstop pin, but the fan stopped. What I did in the end was:

M950 S0 C"duex.pwm5" ; assign GPIO port 0 to pwm5 on expansion board, servo mode

and use:
M280 P0 S80 ; set 80deg servo position on GPIO port 0
to move the servo. This is all very new to me, thank you for your help.