over-powered message.

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Firefly
Posts: 42
Joined: Tue May 30, 2017 10:29 am

over-powered message.

Post by Firefly » Sat Feb 10, 2018 3:30 pm

I have a message that appears on the Duet WiFi PanelVue Console page , it says: Heater 1 appears to be over-powered. If left at full power, its temperature is predicted.

what does this mean? and is there any concern?

cscheuer
Posts: 17
Joined: Wed Jan 10, 2018 9:22 am

Re: over-powered message.

Post by cscheuer » Sat Feb 10, 2018 5:20 pm

I just logged in to ask the same question, nice to find that someone else is having the same issue at the same time. Attaching an image of the Panel Due output.
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File Feb 10, 6 17 18 PM.jpeg

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UltiBots
Posts: 602
Joined: Fri Apr 21, 2017 10:18 am

Re: over-powered message.

Post by UltiBots » Sun Feb 11, 2018 8:57 pm

The Duet is calculating the Max Temp of the hotend. In several hotend designs, the thermistor is not mechanically attached to the hotend. If the thermistor separated from the heat block, the result could be a runaway hotend where temps get really hot. Our current kits include the newest E3D hotend where the thermistor is retained with a set screw. This minimizes the risk of the thermistor becoming separated. Regardless... we DO NOT recommend unattended printing.
Brad - UltiBots LLC

cscheuer
Posts: 17
Joined: Wed Jan 10, 2018 9:22 am

Re: over-powered message.

Post by cscheuer » Mon Feb 12, 2018 12:30 pm

Is it possible (or advisable) to dial back the power supplied to the hot end, in order to address this warning message (and presumably make the printer a little safer)?

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UltiBots
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Re: over-powered message.

Post by UltiBots » Mon Feb 12, 2018 3:19 pm

The E3D hotend and Duet controller are the "Best in Class" components. That is why we choose them. The kit was not tested with lower current. Please post results if you dial back the power. Regardless... we DO NOT recommend unattended printing.
Brad - UltiBots LLC

cscheuer
Posts: 17
Joined: Wed Jan 10, 2018 9:22 am

Re: over-powered message.

Post by cscheuer » Tue Feb 13, 2018 11:43 am

For those looking at this thread in the future, I found this post to be helpful: https://www.duet3d.com/forum/thread.php?id=3610

It looks like the best way to dial things back would be to decrease the PWM value. This would help in the case of your thermistor coming undone, but probably wouldn't help with a worst-case-scenerio thermal runaway situation where your heater was stuck in the 'on' position, not PWMing at all.

I'm having trouble digging up flash points of various 3D printing materials though; Makerbot puts their ABS's flash point at 404 degrees C, so it might make sense to dial down the PWM so that there's not a risk of going over 400 in the worst case scenario.

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