My Ormerod burned... January 10, 2014 04:42PM |
Registered: 10 years ago Posts: 13 |
Re: My Ormerod burned... January 10, 2014 05:02PM |
Registered: 10 years ago Posts: 14,672 |
Re: My Ormerod burned... January 10, 2014 05:06PM |
Registered: 10 years ago Posts: 13 |
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dc42
The change made to the thermistor calculation affects the reported extruder temperature. Previously, at around 200C the reported temperature was about 12C too high, so the extruder temp was about 12C lower than you asked for. At temperatures below 25C, the temp reading was too low, which explains why most of us saw the reported temperature as lower than expected when the extruder is cold.
I had a print hang on me once due to the attached computer going into sleep mode. It appeared that the extruder temp climbed to 300C (which is what the web interface was reporting), then the firmware decided it has a temperature measurement error and turned off the heater. So all I had was a ruined print and some burnt PLA on the print and on the nozzle.
Re: My Ormerod burned... January 10, 2014 05:15PM |
Registered: 10 years ago Posts: 578 |
Re: My Ormerod burned... January 10, 2014 05:22PM |
Registered: 10 years ago Posts: 578 |
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rosario
My printer was printing from SD Card (no PC connected) when the problem occurred... So it shouldn't be related to the PC sleep mode either.
Re: My Ormerod burned... January 10, 2014 06:17PM |
Registered: 10 years ago Posts: 135 |
Re: My Ormerod burned... January 10, 2014 06:28PM |
Registered: 10 years ago Posts: 578 |
Re: My Ormerod burned... January 11, 2014 04:16AM |
Registered: 10 years ago Posts: 13 |
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rayhicks
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rosario
My printer was printing from SD Card (no PC connected) when the problem occurred... So it shouldn't be related to the PC sleep mode either.
I use a mac and repetier host (and as I said above not the latest firmware) if I'm printing from SD card and disconnect. the print stalls until I reconnect (I can get it to continue by repeating connection/disconnection but there does seem to be some interdependency so I always leave mine connected and awake - roll on a reliable and useful web interface!)
Ray
Quote
rayhicks
I suggest you try reconnecting using only USB power (with the ATX switched off) and see if the thermistor values have returned to normal, then turn on the ATX and try heating the bed and nozzle to something tame while monitoring their temperatures with an external thermometer (preferably a thermocouple on a compatible multimeter, again Maplins have these for a reasonable priice) and check to see if the measured temperature matches the reported temperature.
Re: My Ormerod burned... January 11, 2014 04:19AM |
Registered: 10 years ago Posts: 14,672 |
Re: My Ormerod burned... January 11, 2014 04:21AM |
Registered: 10 years ago Posts: 13 |
Re: My Ormerod burned... January 11, 2014 04:26AM |
Registered: 10 years ago Posts: 13 |
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rosario
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dc42
Time to get a new thermistor + ptfe sleeving perhaps?
I definitely think so
Re: My Ormerod burned... January 11, 2014 05:42AM |
Registered: 12 years ago Posts: 1,611 |
Re: My Ormerod burned... January 11, 2014 05:52AM |
Registered: 10 years ago Posts: 66 |
Re: My Ormerod burned... January 11, 2014 05:55AM |
Registered: 12 years ago Posts: 1,611 |
Re: My Ormerod burned... January 11, 2014 06:13AM |
Registered: 10 years ago Posts: 578 |
Re: My Ormerod burned... January 11, 2014 07:06AM |
Registered: 10 years ago Posts: 59 |
Quote
droftarts
The PTFE heatshink is quite specialised. It is 1/8" diameter (about 5mm when flat, unshrunk) clear PTFE heatshrink, 4:1 shrink ratio. I don't have another source for this - we get it from China!
Re: My Ormerod burned... January 11, 2014 07:17AM |
Registered: 12 years ago Posts: 1,611 |
Re: My Ormerod burned... January 11, 2014 08:16AM |
Registered: 10 years ago Posts: 14,672 |
Re: My Ormerod burned... January 11, 2014 08:38AM |
Registered: 10 years ago Posts: 59 |
Re: My Ormerod burned... January 11, 2014 08:44AM |
Registered: 12 years ago Posts: 1,611 |
Re: My Ormerod burned... January 11, 2014 09:40AM |
Registered: 10 years ago Posts: 13 |
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droftarts
Hi rosario
Sorry you've had problems! I have received your emails, and I am (slowly) catching up, so I will reply. It looks like the hot end survived, though I think testing it by hand first would be a good idea, once the temperature readings are correct.
I suspect the thermistor has failed. If you have a spare resistor of 100k ohms (or even a range of resistors down to 1k ohms), you can remove the thermistor, and check that the Duet is functioning correctly by putting the resistor(s) in it's place. Don't run the machine like this, though! It's just to check the Duet is working properly. It should report different temperatures with the different resistors. If they all stay at -17C, check the wiring (particularly the hot end plug where it joins the loom) for bad connections.
You can test the thermistor, if you have a multimeter. It's resistance should be around 100k ohms at room temperature (20C) and the resistance will drop as it gets hotter - hold it between your fingers to test.
Send me an email with the parts you need, we will replace them under warranty.
Ian
RepRapPro tech support
Re: My Ormerod burned... January 11, 2014 09:46AM |
Registered: 10 years ago Posts: 14,672 |
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rosario
- I put some different resistors (1k, 10k, 48k, open) in place of the thermistor, and on pronterface nothing changes
Re: My Ormerod burned... January 11, 2014 09:53AM |
Registered: 10 years ago Posts: 59 |
Re: My Ormerod burned... January 11, 2014 11:14AM |
Registered: 12 years ago Posts: 1,236 |
Re: My Ormerod burned... January 11, 2014 11:43AM |
Registered: 12 years ago Posts: 1,611 |
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bobc
If the thermistor has shorted to 12V when the heater failed, then the ADC input on the Due may also be damaged. Unless you can reroute to a different ADC pin, it may need a board replacement.
Re: My Ormerod burned... January 11, 2014 11:55AM |
Registered: 10 years ago Posts: 13 |
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droftarts
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bobc
If the thermistor has shorted to 12V when the heater failed, then the ADC input on the Due may also be damaged. Unless you can reroute to a different ADC pin, it may need a board replacement.
Though this is certainly still possible, we've tried very hard to limit the chances of this happening, by using good connectors and insulating things as much as possible. That's why I suggested testing the temperature sensing with known resistors. If that is what has happened, it's the first Ormerod that has managed to do this!
We got very tired replacing Melzis because of shorting the 12V to 5V, due to dodgy soldering, or mis-connecting wires! It's why we went with looms for the wiring, and it's also much easier to build. Though people are always finding new and interesting ways of breaking their repraps...
Ian
RepRapPro tech support
Re: My Ormerod burned... January 11, 2014 12:28PM |
Registered: 12 years ago Posts: 1,611 |