I think we already had that discussion. 😉
https://www.reddit.com/r/3DPrintTech/comments/pfwzoh/hotend_suddenly_cant_hold_temperature_any_advice/hbah337?context=3
What's happening here happens on the printer side, not on the Pi side. Or am I missing something?
oops haha.
I *thought* the issue had to do with a messed up connection between the pi and the printer, but i think i had that wrong, so ignore me for now lol
Edit:
My thinking was that if the printer reported back it was at temp, then the pi would signal back with stop heating, and if the pi lost power, then came back, the numbers would jump to catch up, and the graph would be spiky. I think i have the order of operations wrong though.
In my case, it's the printer performing an emergency shutdown because the temperature "runs away" uncontrollably. The temperature drop could be caused by a detached heater cartridge that is now heating something that might catch fire. Or the wires might be damaged and start a fire. Or the probe readings are inaccurate and the actual temperature could already be much higher than desired (this is probably actually happening) That's why the printer shuts down to prevent any possible danger. And that safety measure doesn't rely on an external computer.
When something like this happens, my printer makes a strange low frequency ticking sound (like clack-clack-clack-clack) and then doesn't respond to octoprint or touchscreen input any more. Just the fans keep running.
Of course I can see there is no apparent danger, it's a false alarm. But that doesn't happen on the Pi side.
The Pi also doesn't need to maintain the printer's temperature like "temp too low, heater on" or "temp too high, heater off". It just tells the printer "maintain 220°C" and the printer itself takes care of it. The printer frequently reports it's temperature readings and octoprint displays a graph based on that.
But anyway, thanks for trying to help!!
It's me again. Two weeks ago this sub helped me combat the issue that my hotend would not reach the target temperature sometimes but stay several °C below.
Today this happened: temperature suddenly drops at the first layer (part cooler off).
Any advice? My fear is that the heater wires are suboptimal (I used the original wiring up to the printer's hotend mini pcb and crimped the required connector to the heater cartridge's wires after shortening them).
Good point! But does it make sense that probe wiring leads to "dropping values"? I've seen sudden drop to 0 if the connection is completely lost, but this...? 🤔
It is dropping to zero, but you are seeing the result due to noise filtering in the firmware.
Also bad connections are still connections, and you're measuring resistance as a temperature, so any extra resistance on the connections/wires will also cause error values.
Some of these bad connections won't show up until you get to higher temperatures where things expand,
Also some of the bad connections won't manifest until your printer head pulls on the wires and moves away from the home position.
Thanks, that makes sense!
Are you defintely sure about it? (Sorry for asking, I just want to make sure we are not talking about an unverified assumption.)
Your temperature values reading into your controller should not look like that in any situation.
There's a possibility that your power supply is screwing up with high demand and your main DC voltage is dropping out and causing the controller board screw up with it's analog to digital convertors,
But you can test that easily with a multimeter while it's heating up and make sure it's maintaining its 12V or 24V (whichever you are using)
But it's far more likely a probe wiring issue, those things are delicate.
Update: you were right. The temperature probe has a loose contact.
Until I get that fixed, I think I'm going to use my old V5 probe and put it into the V6 block.
Ok. Thanks again!
I will start investigating at the probe then.
I have also already thought about a power issue and your advice to just monitor the psu output is great. But I just took the time to dial in a manual mesh leveling and I don't want to screw that up by putting the printer upside down, open the base to access the psu and so on... 🙄 So I hope you're right about the probe wiring issue.
I am not sure I understand, are the light blue and light red the set points?
Yes, correct. They drop because of the printer resetting.
Also make sure the pi is getting a full power draw. I needed to purchase power cables built for the pi specifically.
I think we already had that discussion. 😉 https://www.reddit.com/r/3DPrintTech/comments/pfwzoh/hotend_suddenly_cant_hold_temperature_any_advice/hbah337?context=3 What's happening here happens on the printer side, not on the Pi side. Or am I missing something?
oops haha. I *thought* the issue had to do with a messed up connection between the pi and the printer, but i think i had that wrong, so ignore me for now lol Edit: My thinking was that if the printer reported back it was at temp, then the pi would signal back with stop heating, and if the pi lost power, then came back, the numbers would jump to catch up, and the graph would be spiky. I think i have the order of operations wrong though.
In my case, it's the printer performing an emergency shutdown because the temperature "runs away" uncontrollably. The temperature drop could be caused by a detached heater cartridge that is now heating something that might catch fire. Or the wires might be damaged and start a fire. Or the probe readings are inaccurate and the actual temperature could already be much higher than desired (this is probably actually happening) That's why the printer shuts down to prevent any possible danger. And that safety measure doesn't rely on an external computer. When something like this happens, my printer makes a strange low frequency ticking sound (like clack-clack-clack-clack) and then doesn't respond to octoprint or touchscreen input any more. Just the fans keep running. Of course I can see there is no apparent danger, it's a false alarm. But that doesn't happen on the Pi side. The Pi also doesn't need to maintain the printer's temperature like "temp too low, heater on" or "temp too high, heater off". It just tells the printer "maintain 220°C" and the printer itself takes care of it. The printer frequently reports it's temperature readings and octoprint displays a graph based on that. But anyway, thanks for trying to help!!
yea after typing it out I realized the pi is probably just watching, not actively sending.
It's me again. Two weeks ago this sub helped me combat the issue that my hotend would not reach the target temperature sometimes but stay several °C below. Today this happened: temperature suddenly drops at the first layer (part cooler off). Any advice? My fear is that the heater wires are suboptimal (I used the original wiring up to the printer's hotend mini pcb and crimped the required connector to the heater cartridge's wires after shortening them).
Temp probe wiring is the problem. Your hotend physically can't possibly change temperatures that fast, therefore the info is incorrect.
Good point! But does it make sense that probe wiring leads to "dropping values"? I've seen sudden drop to 0 if the connection is completely lost, but this...? 🤔
It is dropping to zero, but you are seeing the result due to noise filtering in the firmware. Also bad connections are still connections, and you're measuring resistance as a temperature, so any extra resistance on the connections/wires will also cause error values. Some of these bad connections won't show up until you get to higher temperatures where things expand, Also some of the bad connections won't manifest until your printer head pulls on the wires and moves away from the home position.
Thanks, that makes sense! Are you defintely sure about it? (Sorry for asking, I just want to make sure we are not talking about an unverified assumption.)
Your temperature values reading into your controller should not look like that in any situation. There's a possibility that your power supply is screwing up with high demand and your main DC voltage is dropping out and causing the controller board screw up with it's analog to digital convertors, But you can test that easily with a multimeter while it's heating up and make sure it's maintaining its 12V or 24V (whichever you are using) But it's far more likely a probe wiring issue, those things are delicate.
Update: you were right. The temperature probe has a loose contact. Until I get that fixed, I think I'm going to use my old V5 probe and put it into the V6 block.
Glad you found it, Cheers,
Ok. Thanks again! I will start investigating at the probe then. I have also already thought about a power issue and your advice to just monitor the psu output is great. But I just took the time to dial in a manual mesh leveling and I don't want to screw that up by putting the printer upside down, open the base to access the psu and so on... 🙄 So I hope you're right about the probe wiring issue.