PID Issues 3.4 RC1
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@dc42 Hi; I will provide a photo shortly. I have in the meantime exchanged everything except for the control board - new heater cartridge, new thermistor - and same result. I have changed output of the hotend cooling fan to only 50% of the PWM; and even the part cooler fan I have defined to have a maximum of 70% PWM - still the same issue. Other thing is it takes like 30 to 40 minutes for a single PID session (only to have the warning) --- is that normal?
For what it is worth, here is the printer in action: https://www.reddit.com/r/voroncorexy/comments/snin2s/ender3_converted_to_voron_switchwire_serial
It doesn't have an issue with a short print, however, I have tried a 3 hour print yesterday, just to have it failed basically because the 'rise in temperature' was slower than that which is expected - I forgot the exact wording of the error.
I will provide a photo soon of the hotend itself.
Rgds
Tinus -
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Sorry I have not uploaded a photo yet - been a bit busy- only got the printer fully assembled again this evening - weird thing now is the temperature stays about 10 to 15 degrees HOTTER than requested.
Did a tuning with 200C and PWM of 0.8 and this was the result:
M307 H1 R2.723 K0.545:0.322 D10.96 E1.35 S0.80 B0 V24.1
Rgds
Tinus -
That dead time of 10 seconds seems unusually high for an E3D V6 style hotend.
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@phaedrux That's the 'D' parameter in the line? To what do you suggest should I decrease it?
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It means it's taking 10 seconds for the sensor to register a change in temp between the time heat was requested and when it's detected. For my V6 it's closer to 2 seconds. So I wonder if there is something off with assembly causing that.
Hence the request for photos to see what is happening or if it's an unusual design etc.
Is the hot block in direct contact with the cold end heatsink or something? Or the heater cartridge or sensor not firmly secured?
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@phaedrux Everything is firmly secured - did double check it
The only thing that may be a little weird is the gap between the nozzle and the heat block, may be a tad big.... but that should not be an issue, should it?
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Maybe? We're looking for anything non-standard, so...
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@phaedrux
Have you done a PID autotune with2.4rc13.4rc1?
I'm getting D values in the 10 second range with my E3D V6 as well.
As you probably know I've been experiencing issues with wild temperature fluctuations with later releases. -
@owend you mean 3.4rc1?
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@reefwarrior Yes. My fingers are dyslexic
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Not wanting to hijack this thread......
A search reveals that in November 2021 in V3.4.0b6 , I was getting PID results ofM307 H1 B0 R1.594 C358.1:217.5 D6.05 S1.00 V24.3With same hardware in 3.4rc1
M307 H1 R2.848 K0.325:0.197 D10.51 E1.35 S1.00 B0 V24.3Different algorithm of course, but I wouldn't have thought the dead time would change that much as a result and it may explain the over shoots I now get.
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@owend I will try a different firmware version tomorrow, however 3.4 is needed to keep my mini12864 up and running. My overshoot is typically 10 to 15 degrees at the moment...
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@reefwarrior said in PID Issues 3.4 RC1:
@owend I will try a different firmware version tomorrow, however 3.4 is needed to keep my mini12864 up and running. My overshoot is typically 10 to 15 degrees at the moment...
Overshoot is typically caused by the R parameter being too high. It appears to have increased significantly from earlier. Try reducing it.
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Also:
M307 H1 R2.0 K0.545:0.322 D10.96 E1.35 S0.80 B0 V24.1 ;V3.4RC1
M307 H1 B0 R2.788 C90.8:60.3 D10.93 S0.80 V24.1 ;V3.3 -
My layer 1 printed perfectly. Just after beginning on layer two, temperature exceeded by 15 degrees; and cause a heater fault.
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@reefwarrior Does the part cooling fan turn on for layer two? It seems as if the firmware is anticipating a drop in temperature from the cooling and and tries to compensate.
Do you have a nozzle sock to test with?
Also it seems like your heatsink fan may be acting to cool the hot block as well.
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@phaedrux Hi. Yeah tested with a sock too. Same result. Hot end fan is isolated from heat block - there is like a round 'O' of plastic (like a divider) between the heat block and the fins.
Also what is the approximate time of a PID cycle with defaults? I quite frequently have 30+ minutes. I even swapped out the board this morning. Same result!
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Also changed hot end fans. No difference.
