What pin should I use to switch my router relay?
-
Sorry to be so active asking questions, but I'm going through this process and really appreciate the online help... so
My CNC router uses a 5V relay to switch the router power on/off. I've set my system up as CNC with a fan pin for the 'spindle' (relay). The relay current requirement is about 100mA so a fan output makes sense.
M453 C"fan1" R1000 ; use the fan1 port for spindle / CNC mode
The problem is that when the board is reset (such as updating the config.g or a software bug) the relay triggers on for a short time causing the potentially dangerous router to turn on.
Is there any way to not have the relay trigger at reboot? Must I use a different method to trigger the relay?
My system is a Duet2 with a breakout expansion.
Thanks.
-
@markz use a heater instead. The fan outputs are set to on before the config has loaded incase the hotend has been on and needs cooling.
-
@jay_s_uk Hmmm, i looked at the schematic and doc and don't see a way to run the bed heater at 5V for the relay. I hate to run 2W into a dropping resistor (I have a 24V supply) but I guess I could do that. Is there another way to get 5V there?
Thanks for the info about the reset. I suppose I could change the startup code since I have to do firmware changes any way. I don't define it as a a fan and deliberately didn't use fan0... sigh.
-
@markz what's it switching at the other side?
Most mains solid state relays support 5v-32v input to activate them.
An SSR is probably better than one of those cheap little pi blue ones.Owns various duet boards and is the main wiki maintainer for the Teamgloomy LPC/STM32 port of RRF. Assume I'm running whatever the latest beta/stable build is
-
@jay_s_uk It's a physical relay, specifically an IDEC RJ1V-AH-D5, see here:
For $5 I can buy the 24V version at Digi-key...
-
@jay_s_uk Nice! Thanks to your hint I decided to look at the source code and found that on the Duet2 only fan 1 is turned on at power on - and of course that's the one I was using - so I just swapped my two relays (the other controls the spotting laser - no big deal) and now it no longer turns on at reboot.
Thanks.
