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temperature sensor problem

Posted by stibo01 
temperature sensor problem
December 20, 2013 03:40PM
Hi all ,

I have completed the assembly of my Ormerod.
The assembly went pretty well.

I do have a problem with both temperature sensors.
When the printer communicates with the arduino IDE :

"RepRapFirmware is up and running" , but nothing about the temperature measurements.
If I disconnect the sensors , everything works well,

The heated bed thermistor must be 10K ( measured : ok )
The hot end thermistor is a 100K ( measured ok )

All wirings doubled checked : everything is ok.

Can anybody help me with this problem.

Re: temperature sensor problem
December 20, 2013 04:32PM
Hi Stibo01

I have had a couple of reports of Duets doing the same thing, but I haven't been able to replicate the problem.

When you say ' If I disconnect the sensors , everything works well,' do you mean it DOES report the temperature (probably -273)?

How is your Duet powered? From USB or ATX PSU? If USB, is it connected to a laptop, or USB hub? Powered or unpowered USB hub?

It's possible that the 5V USB interface isn't supplying enough voltage, particularly if you're working through an unpowered USB hub (there's another thread on this). Plugging all the other connections in may drain enough power to cause the problem, and explain the odd temperature readings.
If your Ormerod is in the first 220 of 500 red machines shipped from RS (see the number on your Certificate), you are due a replacement Duet; see: [forums.reprap.org]
If your board isn't one of the first 220, try running with the 5V supplied from the 12V; connect ATX PSU, put jumper on JP9 (5V_EN)

Check your board over for poorly soldered joints, if you can. We will replace any board under warranty that is defective, though we would like the defective board returned to us for inspection, and to improve our manufacturing reliability.

RepRapPro tech support
Re: temperature sensor problem
December 20, 2013 05:18PM
I got exactly the same thing. I think the commissioning instructions are wrong and you should only get the temperature error messages if the thermistors are not connected. A little later on the commissioning instructions tell you to connect to the Duet using Pronterface, and to expect *correct* temperature readings.
Re: temperature sensor problem
December 21, 2013 01:43AM
@ Ian When I disconnect the sensors , everything works like expected in the building instructions ( -273 )
It'sthe same with the ATX PSU ( with JP9 jumper )
The solder quality is poor , but should work.

Solution : Just like dc42 mentioned : The temperature measurements are not displayed when the sensors are working , only if they are disconnected
I went further in the commissioning instructions and there is no problem.

thanks to all for the quick reply's
Re: temperature sensor problem
December 21, 2013 07:00AM
Thanks, I've updated the commissioning instructions (I think I said I wrote the first draft rather late at night, from memory!), with:

Wait for 1 minute (this is normal when no ethernet is connected and the firmware is searching for the network), and following should show:

RepRapFirmware is up and running.

This indicates that the firmware is working. If your thermistor wires (the heated bed and hot end temperature sensors) are disconnected, or incorrectly wired, you will see:

RepRapFirmware is up and running.
Temperature measurement fault on heater 0, T = -273.1
Temperature measurement fault on heater 1, T = -273.1

If you get no response, close the Serial Monitor window, unplug the USB, check the Arduino settings and try connecting again. Wait for 1 minute after plugging in the USB.

RepRapPro tech support

Edited 1 time(s). Last edit at 12/21/2013 07:01AM by reprappro.
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