Sporadic Temperature Changes
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Any hints and tips will be helpful
The sharp spikes originate from electrical/contact problems, either at connectors, crimps, somewhere along the lines, or within the thermistor itself.
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@Bridge-Of-Don From my past experience, this has always happened to me with a bad conection on either side of the thermistor. Check that, it doesnt matter it the conection looks ok at your eye, sometime is a cold soldering problem, a faulty cable having a problem when the cable is moved by the printhead, or even when the temperature is rised and everything is hot. I would bother finding the cause, I would just change the cable, re make all conections, at the end that saved me lot of time.
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By the way: it is a great, GREAT, tool to have such graphics, many time this temperature spikes, imposible to see on the interface number, triggers a fault state, and you just know the cause by looking the graphics. Thanks duet for this tool, it is great!
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I would just change the cable, re make all conections, at the end that saved me lot of time.
Sorry to object, but IMHO, it is better to have a closer look at the root of the problem, just in order to learn what specifically went wrong. The time is not worth the money, but I get more familiar with my printer, and possibly understand that I better improve my crimping skills (or not to buy the cheapo thermistors in the dozens).
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@infiniteloop No worries at all. It is a very valid and good opinion. I myself prefer many times to dig into the causes of a problem in order to learn. But also, we all learn from others experiences, and for examplein this case, to diagnose if the prioblem is a bad crimp, could take hours. I have had this problem in the past: you get these spikes in the graphics, you dont see any spike on the number reported on the interface... and you wonder "what is happening"... You move by hand the cable and the problemis not happening... you heat up the hotend and the hotend reached temperature and the fault never happens... and everything ends up being a bad crimp, just giving a faulty connection only when a particular position of the cable is met, or only when some vibration happens.... It is because of this I gave my advise, but you are very much right: finding the cause always leads us to learning.
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for example in this case, to diagnose if the prioblem is a bad crimp, could take hours.
Things can get tricky at times, but in your second post, you gave a valuable hint at how, using the temperature chart, you can accelerate the diagnosis. Combine this with the observation of the printhead’s movements, and voilà, you can make an educated guess where in your wiring and possibly even why the contact might possibly be interrupted (or become somehow unstable).
Obviously, the case presented by the OP is not static, so the cause of the spurious occurrence relates either to heat or movement (or vibrations) - or to both of them. The single unknown component is the thermistor itself, you can either replace it or leave it in place.
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On the printer I built, I've had several instances of the temperature sensor making intermittent contact. In every case the problem was a broken wire in the bundle that moves with the print head. I thought I was safe using a cable chain, but even with it's gentle bending I had wires break, and it was caused by cheapo insulation on the wires that got brittle and cracked over time and that broke the copper strands inside. This is another possibility of the connectors are not at fault.
I now only use silicone insulated wires that are super-flexible because they have very fine wire strands. One example from Amazon: https://www.amazon.com/BNTECHGO-Flexible-Silicone-Resistant-Electronic/dp/B06Y5L4T86
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Many thanks for all the replies.
I was unsure if what I was seeing was real or an artefact.
I'm pretty used to intermittent faults as drive a 90's car so loads of issues around the connectors to the electronic dashboard etc.I'll re-make the wire up and report back, hopefully with a positive result, but as it doesn't always spike , who knows!
I do like the DWC as a user interface, much better than a 4" LCD screen, abilty to view progress and monitor things makes life easier.
Alan
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Many thanks for all the replies.
I was unsure if what I was seeing was real or an artefact.
I'm pretty used t intermittent faults as drive a 90's car so loads of issues around the connectors to the electonic dashboard etc.I'll re-make the wire up and report back, hopefully with a positive result, but as it doesn't always spike , who knows!
I do like the DWC as a user interface, much better than a 4" LCD screen, abilty to view progress and monitor things makes life easier.
Alan
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We took the multi plug fitted at the themister apart and one of the two connectors just 'fell-out' and no real force to push back in, so hopefully that was the issue, only time will tell!?
Alan
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@Bridge-Of-Don said in Sporadic Temperature Changes:
We took the multi plug fitted at the themister apart and one of the two connectors just 'fell-out' and no real force to push back in, so hopefully that was the issue, only time will tell!?
Alan
Well several prints later and the temperature does seem to be 'rock steady' so another of the teething problems crossed off the list!!
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