Initial Config Query
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@chrishamm The bed heater is giving me a resistance of 147.9 , how would i check the input voltage?
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@deckingman
Thanks Ian , I believe the SSR is turning on , I agree it seems no power is reaching the heater beyond the SSR output. I did look into the bed and there was no markings or serial numbers however previously I asked about this in the forum.
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@900turbo "check the voltage across the heater itself but be very careful as you are likely dealing with mains voltage." How would I do this correctly?
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@900turbo @chrishamm
This may help but thought I’d show a photo of what’s going on control wires on the SSR input running to the MB , then the power from the SSR output to the heated bed and another power running into a relay and then the PSU. -
@900turbo said in Initial Config Query:
@900turbo "check the voltage across the heater itself but be very careful as you are likely dealing with mains voltage." How would I do this correctly?
With a multi-meter at the same point that you measured the resistance but be careful as you are likely dealing with mains voltage. If you are in any doubt about your competence, ask an electrician to do it for you.
You haven't told us if this is 110V mains as used in the US, or 220 -240 V as used in the UK and Europe. But using your measured 148 Ohms resistance, from Ohms law we can deduce that the current draw is 1.6 Amps if using 240 V and 0.7 Amps if using 110V. Wattage is voltage x current so we can say that if using 240 V, the wattage is around 390, and if using 110V, then it is a mere 81 Watts.
If the bed is 700mm x 700mm, then it would need to reasonably thick so I'd say that the heater is under powered for this application. There are formulas for calculating the heater power required - do an internet search. But as a guide, I use a 400Watt heater on my 400mm x 400mm x 10mm thick bed and your 700mm x 700 mm bed is 3 times the area, which would indicate that you ought to be using around 1200 watts.
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@900turbo looks like the SSR is feeding into the relay on the right on the DIN rail? If so, whats activating that?
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
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@deckingman I do not think I could as the wiring loom is a series of shielded lines with screw end terminals so how I would measure the resistance at the heater I am unsure on. This is 220-240v UK
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@jay_s_uk I'm not sure the PSU turns on and simply runs power through them. I believe they're there as a failsafe to protect the system from a surge?
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@900turbo if you don't know what they're doing I really think you should get someone qualified involved
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@900turbo Can you tell us a little more about the machine itself?. I get the impression that this is one that you are converting. Is that correct?
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@deckingman Yes I am , Its a Builder Extreme 2000 from 2017. It originally had dual extruders but just didn't perform all that well. Upgrading it with the duet products and hemera xs would hopefully give a very reliable albeit single extruder large format printer that could be accessed wirelessly. The following components are new Hemera xs , duet tool board 1lC ,Duet MB6XD , Panel Due 5i yet to be installed ( just want to get it printing first!) as well as a BL touch and a raspberry pi 4. I contacted builder to see if i could have wiring diagrams and the specs of all the components. However they wouldn't release anything despite the printer no longer being produced after 2018.
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@900turbo Do you happen to know if the bed heater actually worked before you started the Duet modifications?
From what I have read of this thread, it seems that any configuration issues that you may have had, have been resolved. In which case, the fault must lie elsewhere. I'm afraid there are no easy solutions if the original manufacturer can't or won't help. It could be that the heater itself is faulty, or it could be that SSR isn't outputting the necessary mains voltage, or it be that one or more of the relays or fail safe devices has failed, or possibly some other reason. Somehow or other, you need to ascertain if the correct voltage is being applied to the heater, and if not, then you need to identify the reason for it.
I'm not familiar with that machine but if it was me and getting at the wiring was as difficult as you say, then I'd be tempted to run new wires. Initially, I'd connect the heater directly to mains via a switch to see if it actually heated when power was applied. If that was the case, then I'd run the live from the SSR ad check again. But it all means cutting into the existing looms and great care needs to be taken.
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@deckingman The company I work for has 2 other identical machines both of which bed heaters do In fact work so I was debating swapping one of those in. The few config issues I had have been resolved bar the steppers not working at all but then again that may be a Relay related Issue. If I swap in a different heater there is at least a possibility of finding out if it is just a faulty heater. I agree the SSR or the other Relays may have issues. I'm not a electrician so its something that most likely needs to be professionally looked at. I guess there aren't many people running 24v and 240v in one printer. Anything powered of the Duet MB eg extruder fans and a end stop has worked perfectly I ran new wires for the tool board ( 24v and Can ). The way the loom works means it wouldn't be easy to run a switch in line to the heater in the bed. The bed loom itself is 3 sections connected with something similar to this https://www.amazon.co.uk/Waterproof-Electrical-Cable-Connector-Depth/dp/B06XS5WNKM/ref=asc_df_B06XS5WNKM?tag=bingshoppinga-21&linkCode=df0&hvadid=80539283534604&hvnetw=o&hvqmt=e&hvbmt=be&hvdev=c&hvlocint=&hvlocphy=&hvtargid=pla-4584138858708446&psc=1
bit long winded but just wanted to try explain things a bit more.
Thank You for all the help and advice. -
@900turbo Well actually, there are quite a lot of us that run mains heaters with everything else being 24V. Swapping the heater sound like a good idea. Best of luck.
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@deckingman I swapped the bed out and nothing happened , started going over every single bit of wiring I will keep it short but basically there's a emergency stop switch on the case and one of the wires was not on all that well. Reconnected it then tried to heat the bed and it heated straight up. I still cannot move my any of my axis but the steppers LEDs now come on so i assume Its just an issue with my g code.
Major relief anyway as I thought there was a far more serious issue with a broken SSR or Relays. -
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