Connecting a DA SSR
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I am in the process of wiring up an very high powered AC heated bed, using a SSR to control it. The printer originally came with the DC bed connected to the Duet's GND terminal and the 12V from the PSU. I am wondering whether I reuse this wiring to connect my SSR. Or is there a good reason to find a place in the delta towers to run an extra wire connecting Duet bed + and SSR + ?
Below, a simple drawing of how I plan to wire it.
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Hi,
If you wire it as shown the bed heater will always be on - I cannot imagine that is what you want.
Check the normal bed heater connector on the Duet.
One terminal is marked with a "-" symbol, the other with a "+" symbol.
Connect those to the SSR control inputs, observing polarity.
BTW what's a TCO?
Frederick
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@fcwilt said in Connecting a DA SSR:
Hi,
If you wire it as shown the bed heater will always be on - I cannot imagine that is what you want.
Check the normal bed heater connector on the Duet.
One terminal is marked with a "-" symbol, the other with a "+" symbol.
Connect those to the SSR control inputs, observing polarity
Why would the heater be always powered? The bed output of the Duet still opens and closes the circuit I imagine.
BTW what's a TCO?
TCO stand for thermal cutout, basically a temperature triggered fuse.
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Mark you different GNDs to be more clear.
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@sigxcpu As requested
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Yes, that will work.
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@dc42 said in Connecting a DA SSR:
Yes, that will work.
Is there any consequence or disadvantage wiring it this way?
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None that I can think of.
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@nxt-1 said in Connecting a DA SSR:
Why would the heater be always powered? The bed output of the Duet still opens and closes the circuit I imagine.
Because the way you had it drawn originally you had the - terminal of the SSR connected to a terminal on the Duet labeled GND. You had the + terminal of the SSR connected to +12, thus the SSR would be on as long as the power supply providing the +12 was on.
Now you have changed the diagram to show using the BED- terminal which is NOT ground. Connecting that way will work.
And as mentioned if it makes things simpler or clearer you can connect the BED+ terminal to the SSR + terminal.
Frederick