cooling fan trips heater fault on second layer
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Hello everyone, I'm just setting up my second duet board, this time a duet 2 wifi. I upgraded my ender 5 pro by increasing the build height to 500mm and in doing so I needed a bigger stepper motor for the Z, so I decided to also upgrade the board to a duet 2 wifi. I've been running a duet 3 on my other printer at work for about a year now but I'm still pretty new to the duet world.
I've got everything up and running now but I seem to have small issue with the part cooling fan and the thermal protection. When the part cooling fan turns on 100% at layer 2 it drops the temperature of the hot end too much and the print pauses. Are there best practices for this or do I just need to figure out how to slowly ramp the fan up to 100% over the course of layer two.
I did have a similar issue with the original hardware but it seemed to cope with the fan coming on better than the duet is. Is there a way to tune the PID to be predictive?
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@baird1fa if you are daring, upgrade to 3.2 RC1 (which I would say is stable for every day use) and retune the hotend as a tool (e.g. M303 T0 S220).
The tuning algorithm has been improved and takes into account the effects of the part cooling fan coming on.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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Oh, I'm not sure I am that daring yet; I just got the printer up and running. Perhaps I will in a few days as that sounds like a cool feature and exactly what I would need.
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@baird1fa if not going to the beta releases, maybe try normal PID tuning your hotend with the fan running (at least partially)? It won't help too much with the sudden shock of the fan turning on, but might get it a bit closer to the steady state with the fan on.
Equally you might try adjusting the default heater fault parameters to give you a bit more leeway (M143 I think...). Obviously you don't want to go too far as you're reducing the safety net, but if it only needs a few degrees more, it might be okay?
I'd also suggest getting a silicone sock for your heater block. It'll help the hotend keep a more constant temperature in general
Finally, unless you really need it, why are you running your part cooling fan at 100% from layer 2? Seems lot of cooling very early on. For PLA, I keep my fan off till a few layers later then keep it at ~35% minimum, up to 100% as required by the slicer (bridging, short layers etc). I use prusa slicer if relevant
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For what it's worth, I think at some point the little glass blub thermistor that my ender 5 pro (the printer in this case) worked itself loose/came out of the hole that it is supposed to be inside of. I noticed it the other day when I was clearing a jam and it completely fell out. I put everything back together and I don't seem to have any cooling effect on my nozzle (or any appreciable about) anymore. I did manage to update to the version 3.2 and run the autotune and noticed that there wasn't any effect on the temperature when the fan came on.
Always something unexpected, but it explains why there wasn't this issue before I changed my printer board over to the duet.
