powering a 24v brake with the heater outputs (duet2 wifi)?
-
I have two stepper motors using power off brakes which operate at 24v <1a. I was thinking of using a relay to turn them on/off with a simple i/o pin, but just realized that I am not using any heaters on this machine. Is it possible to feed the correct power through the heater terminals at a steady rate and switch off/on similar to a relay setup? I already run 24v on my board.
From what I have read in the documentation this seems possible, but I can't figure out how to set it up in firmware.
I can always just use the relay but thought this might be a cleaner/elegant solution.
Best,
T -
Yes if you're using RRF3 you can define a pin with M950 and then switch it with M42.
https://duet3d.dozuki.com/Wiki/Gcode#Section_M950_Create_heater_fan_or_GPIO_servo_pin
https://duet3d.dozuki.com/Wiki/Gcode#Section_M42_Switch_I_O_pin
-
Which Duet are you using? Duet 2 doesn't have back diodes on the heater outputs, so you would need to connect an external flyback diode in parallel with the brake solenoid. Duet 2 does have built in flyback diodes on the fan outputs. Duet 3 has them on heater outputs too.
Duet WiFi hardware designer and firmware engineer
Please do not ask me for Duet support via PM or email, use the forum
http://www.escher3d.com, https://miscsolutions.wordpress.com -
I'm using the 1.04c. Duet 2 wifi
-
This post is deleted! -
@dc42 I am a bit confused since the duet 3 pin out diagram description says this:
2-pin JST VH OUT_1 thru OUT_3: these are intended for extruder heaters or fans. Maximum recommended current 6A each. If you connect inductive loads to these outputs, you must use external flyback diodes.
Does heater outputs has flyback diodes built-in?. I am trying to control 24VDC contactor via out9 but it seems it draws too much power and thus resets the whole system. I am going to give it a try with heater outputs but I am not sure if there are flyback diodes on them.
