PT-100 temperature constantly at 2000 degrees after failure

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By CoolM8 17 April 2017 22:20

Member · 27 comments

Hi,

I had the issue on the first print after finally fixing the homing config issue, that the temperature reading showed "Failure". I had to turn the printer off and on again in order to get it working again. Sadly after it failed a second time and it went into reading 2000 degrees ever since then. I'm using a PT-100 sensor and the daughter board and i even switched to the second RTD Pin but it's still reading 2000 degrees. I've even replaced the sensor with no luck.

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By dc42 18 April 2017 06:51

Administrator · 2,672 comments

Does it read 2000 even with just usb power? If so then you have a bad connection, either in the wiring between the daughter board and the sensor, or the links you use for 2-wire connection are not working. Use a multimeter to check the wiring. The resistance of the sensor should should be a little over 100 ohms at room temperature.


Duet WiFi hardware designer and firmware engineer
http://www.escher3d.com
https://miscsolutions.wordpress.com

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By gzcwnk 18 April 2017 08:01

Member · 131 comments

The other possibility that happened to me was electrical interference from the extruder stepper.  So every time I fed filamenthe PT100 went to 2000C and tripped out on safety.  To solve it I ran double shielded super flex microphone cable between the duetwifi and the PT100, no issues in 3+months.  PS only earth it at the duetwifi end if you do this.

Last edited by gzcwnk (18 April 2017 08:01)

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By CoolM8 18 April 2017 12:24

Member · 27 comments

The issue still exists if only connect through USB. As this setup has worked before i don't think that there is any interference. I'm using the E3D PT-100 sensor but the strange thing is that i cannot measure any resistance not with the sensor that used to work nor with the new sensors that hasn't been used before.  I have also another PT-100 sensor where i can measure its resistance to be around 100 Ohms, but the issue with the 2000 degrees still exists.

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By T3P3Tony 18 April 2017 13:30

Administrator · 789 comments

When you say you cant measure any resistance, is that with the PT100 connected to the daughterboard? if so then please try with it not connected to the daughterboard. At that point if it is not ~100R then you have a issue in the sensor or the wiring.


Duet Wifi Hardware Designer
www.duet3d.com
www.think3dprint3d.com

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By CoolM8 18 April 2017 20:59

Member · 27 comments

No, i cannot measure it when sensor is not connect to the daughterboard. But it seems still strange, it would mean I have two new E3D PT100 sensors that do not work? But even with the PT100 sensor from the Ultimaker Original where i can measure the resistance I sill have the same issue with the temperature reading. This would mean i have 2 issues at hand and even with the same setup that used to work before it went 2 times into failure. This is utterly strange.

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By ShadowX 19 April 2017 08:53

Member · 51 comments

Did you inspect the PWB board and connectors to make sure that none of the circuit traces are broken or if there is damage on the solder joint or connector?

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By CoolM8 19 April 2017 21:23

Member · 27 comments

I don't see anything that any of the circuit traces are broken nor does anything look damaged. 

With the reprapfirmwar tool i get this config for the E3D thermistor:

M305 P1 T100000 B4725 C7.060000e-8 R4700 X201 ; Set thermistor + ADC parameters for heater 1 and remap it to channel 201

But i also tried everything else even:

M305 P1 X201
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By dc42 19 April 2017 22:00

Administrator · 2,672 comments

Do you have the PT100 connected to the first or second channel on the daughter board? 201 is the second channel, the first is 200.


Duet WiFi hardware designer and firmware engineer
http://www.escher3d.com
https://miscsolutions.wordpress.com

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By CoolM8 20 April 2017 18:48

Member · 27 comments

Right now i have on the second channel. As I've said, it used to work on channel 1 until the failures and since then it doesn't even work on channel 2.

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By dc42 20 April 2017 19:29

Administrator · 2,672 comments

Do you have a resistor of between 100 and 200 ohms that you can connect to the terminal block in place of the PT100?


Duet WiFi hardware designer and firmware engineer
http://www.escher3d.com
https://miscsolutions.wordpress.com

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By CoolM8 23 April 2017 09:32

Member · 27 comments

No i don't have a resistor around but i think this won't make a difference. Since the Ultimaker Original has a measurable resitance of around 100ohms. It measures like in the image below (the green connection has around 110 ohms):
daughter_board-X2.jpg

It seems to me that the issue is with the daughter board or the duet itself.

Last edited by CoolM8 (23 April 2017 09:44)

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By dc42 23 April 2017 09:51

Administrator · 2,672 comments

Do you have anything else connected to the SPI bus, for example a ribbon cable connecting the CONN_SD port on the Duet to the PanelDue for using a second SD card?

If the answer is no, please ask your supplier for a new daughter board.


Duet WiFi hardware designer and firmware engineer
http://www.escher3d.com
https://miscsolutions.wordpress.com