PID Tuning help needed
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@deckingman Yes, read the whole thread. @Reefwarrior said "The graphs show spikes". While I'm sure the heater can create a spike up in temperature, it probably can't create a drop as quickly! But a dodgy thermistor can, though I guess it could be a power drop across the board when the heater switches on, if the PSU isn't up to it.
@Reefwarrior A screenshot of the temperature graph misbehaving would go some way to disambiguate the cause of the "spikes". Try wiggling the thermistor wires, see if that causes the spikes, too.
Ian
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@droftarts I guess it depends on the definition of "spike". I read this (quote)
Other strange thing is, there are quite a lot of oscillations with regards to the temperature being sensed. (Up to 3 to 4 degrees up and down)
As you say, we need a picture of the graph......
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A picture of the graph would be nice, but don't don't run that 12v heater at 24v just to make a graph for us. You're liable to melt something. Just replace the heater with a 24v version before you do anything else.
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Hi all,
OK so I swapped the cartridge for a 24V one. Did the PID tuning... results:
Warning: heater behaviour was not consistent during tuning
Auto tuning heater 1 completed after 4 idle and 25 tuning cycles in 1494 seconds. This heater needs the following M307 command:
M307 H1 R3.064 C165.3 D10.06 S1.00 V24.3
Send M500 to save this command in config-override.gBothers me a bit with the 'warning'. Also it seems the temperature sensing thing is a PT1000 I think? It's a little silver cylinder that connects directly to the board, no daughterboard. Chinese brand.
there is the picture that I am referring to. Look at both the blue and the red - the curves are not smooth - it's like jagged. Even the 'MCU Temperature' seems to oscillate by about 1 degree up and down (including the decimals....)
Also got this after PID tuning my bed:
Warning: heater behaviour was not consistent during tuning
Auto tuning heater 0 completed after 4 idle and 25 tuning cycles in 1536 seconds. This heater needs the following M307 command:
M307 H0 R1.369 C277.3 D5.29 S1.00 V24.2
Send M500 to save this command in config-override.g -
@Reefwarrior said in PID Tuning help needed:
Also it seems the temperature sensing thing is a PT1000 I think? It's a little silver cylinder that connects directly to the board, no daughterboard. Chinese brand.
Why do you think Pt1000? It could be a plain thermistor.
Photos?
Yeah that graph looks a bit fuzzy which would explain the warning.
The overall curve of the graph looks ok though, so I think the values it provides should be usable.
Perhaps a good time to replace the temp sensor with something better quality.
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@Phaedrux Unfortunately I am not in a position to be able to do that. I'm one of 70 pilots that got retrenched when our government decided to liquidate the national airline.
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I'm not sure that that means, but if you want to continue to roll with the equipment on hand, you can verify that the tuning results are accurate by setting a printing temp and seeing if the graph and reported temps are stable.
The fuzziness in the graph may also be a result of noise from running near other cables. You could verify that by temporarily isolating the thermistor wiring and seeing if that makes a difference.
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@Phaedrux hi, yeah it's a plain thermistor NTC 100k; 3950B.
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@Reefwarrior said in PID Tuning help needed:
NTC 100k; 3950B
These are known for being pretty cheap, poor thermistors, which might explain your fuzzy readings.
Ian
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Ok, seems I got it fixed, somehow. Next issue is now the heatbed....
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Ok, bed issue solved too. Seems the algorithm is too sensitive in my case.
How do I mark this as 'SOLVED' ?
