# Artisan with Phidgets and RTD Probes



## filthynines (May 2, 2016)

I'm hoping somebody with a clue (unlike me) will be able to help me with my huge difficulties with setting up the Amazon Dalian with RTD probes and Phidgets. I'll try and give as much detail as I can, but I am not a technical person so please ask if there's anything you think I haven't stated.

I have the following:

2 x Duplex 3-wire RTD PT100 sensors from Thermosense. @Hasi kindly supplied me with some specs. They're custom-made and have been calibrated at 160 and 200 degs c.

2 x TMP1200 Phidgets temperature sensors. https://www.phidgets.com/?prodid=968

1 x VINT HUB0000 https://www.phidgets.com/?tier=3&catid=2&pcid=1&prodid=643

I have wired it up as below on each of the TMP1200. There is a short wire (stolen from something else) as required by the user guide. Because my sensors are duplex, I have wired *one sensor* to *both* *TMP1200 **sensors* *simultaneously. *My expectation there is that they should give the same reading. They don't - they are way, way off.

During my test in heating up the Dalian, I can report the following:



Initially Probe 2 lagged both the the Dalian's own control panel reading and Probe 1.


However, at around 100 degrees centrigrade Probe 2 leapfrogged the Dalian's own reading, but continued to lag Probe 1.


The final readings I took were:


*Dalian* - 185 degs c

*Probe 1 *- 247 (193 ohms)

*Probe 2 - *194 (174 ohms)


 Therefore there is a massive 50 degrees celsius difference between the two readings from the sensors. Probably more significantly there is a difference of nearly 20 ohms of resistance.

Also, for those who are familiar with Phidgets: the control panel will not recognise it as anything other than a 2-wire set up. This seems bizarre to me, because it is a 3-wire RTD.

Can anybody make sense of any of the above? Huge thanks in advance.


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