SSR and Mech Relay for Mains bed Controlling, Need a doublecheck
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@danal said in SSR and Mech Relay for Mains bed Controlling, Need a doublecheck:
@mangy_dog said in SSR and Mech Relay for Mains bed Controlling, Need a doublecheck:
the way i had it in my head, the master mechanical relay is less likely to fail On...
If the relay coil is fails... the relay will fail open... but this is VERY rare... because the coil is not a moving part. A much more common relays failure is "Welding", which happens when they turn on. Therefore, I would not bother with the relay at all. Just my opinion.
I would do the SSR, AND a one-shot or self-reset thermal cut device as the actual safety net.
+1 on this. Mechanical relays can fail shut due to contacts welding together. I have seen it a few times (not on Printers).
SSR is the easiest way to go, adding a thermal cutoff is the safest way. It's also safer for the duet board. No extra diodes to add.
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Well it didnt exactly work...
Need some advice, regarding the mechanical relay.
I have 1 pin of the coil wired to 5v on the duet3d and one pin wired to PS_ON, when I send M80 nothing happens. The relay is a 5v DC trigger type...
what am i missing? (other than a brain or a clue)
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@mangy_dog which 5V pin are you using? The one next to PS_ON is an input. You need to use one from any of the extension headers.
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The PS_ON pin sinks to ground when M80 is called up.
Basically it completes the circuit to ground.
You are using a 5V relay right? The coil is rated at 5 volts?
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@wilriker said in SSR and Mech Relay for Mains bed Controlling, Need a doublecheck:
@mangy_dog which 5V pin are you using? The one next to PS_ON is an input. You need to use one from any of the extension headers.
You sure? Looking at the wireing diagram its just a pin to the 5V rail on the board. So when the boards powered it should be able to provide 5v, alternatively can be used to give 5V off a supply...
PS_ON sinking to ground makes sence tim, thats how i thought it should work...
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Well circuit tester out... ok that pin doesnt read any voltage.
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Ok, So that 5v is the external 5v input...
Am i right to assume if i put a connector on the EXT 5v EN jumper that 5v pin is then connected to the 5v rail on the duet?
So the normal use of using an external 5v PSU would be to disconnect the internal 5V header so external can be used...
But If I connect both headers am I right to assume that the 5V pin on the PS_ON header is just directly conencted to the 5V rail so just turns into a simple 5V pin for me to run the coil on?Or is there some other circuitry going on that might mess up things?
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OK last thing last night I found the circuit diagram... And there's a zener between the 5v in pin and the 5v rail... That's why it didn't work....
I'm not prepared to void my warranty and solder jump that Zener.... -
@mangy_dog Just take any of the three (or actually four) available 5V output pins on the expansion headers. There is one on the Panel Due header, one on the large expansion header and on on the
CONN_SDheader. And in the unlikely case of all these pins used by something else you could also take the 5V from the VFAN select jumper header.P.S.: the latter might be protected by the 1A fuse but I hope your relay won't use that much current.
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With mech relay working, having to manually do m80 m81 to trigger it... but my keenovo heater is heating up nicely
Now all i need to do is tie M80 to trigger when the bed is set to active... and M81 when the bed is set to off and in thermal runway detection...
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@mangy_dog said in SSR and Mech Relay for Mains bed Controlling, Need a doublecheck:
Now all i need to do is tie M80 to trigger when the bed is set to active... and M81 when the bed is set to off and in thermal runway detection...
How+1 on that
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@mangy_dog said in SSR and Mech Relay for Mains bed Controlling, Need a doublecheck:
Now all i need to do is tie M80 to trigger when the bed is set to active... and M81 when the bed is set to off and in thermal runway detection...
HowThe part for thermal runaway protection is already in place while doing a print AFAIK but not in idle (see this thread for a current discussion on this topic).
EDIT: I just checked the source code and the PSU is shut down on a heater fault while printing or while a print is paused.
I am not sure if there is a method to automatically connect
M80|M81to bed heating. -
is there a way to make custom .g scripts to happen in certain events?
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@mangy_dog Not yet -
