Dead RTD Input

T

TonyD

New member
Giday
Sorry to bother you. I have been testing the RTD card the last week & input 3 has failed & started reporting incorrect temperatures.
The PT100 that was plugged into input 3 that was reporting incorrect temps was moved to another input port & returned correct temperature.
Any suggestions on how to repair the card or is this covered under warranty as returning card to America from the land down under (Australia) takes several weeks to accomplish. Below reading from Card. PT100 Sensors connected to Inputs 1 - 3. Inputs 1 & 2 Good Input 3 returns 690. DegC. PT100 moved to input 4 reads good Order number if you wish to check purchase date Order SH-5161

I await your earliest reply
Regards TonyD

pi@raspberrypi:~ $ rtd 0 read 1
26.780483
pi@raspberrypi:~ $ rtd 0 read 2
26.733181
pi@raspberrypi:~ $ rtd 0 read 3
690.909058
 
alexburcea

alexburcea

Moderator
Staff member
The response is look like from a disconnected sensor. Could you check if is a contact problem? Could you send me a picture with bottom side (SMD components side) from the channel 3 area?
 
T

TonyD

New member
Giday
As requested bottom of RTD card around input 3. Have checked plug in connector & Bootlaces on end of PT100 cable all good
Regards TonyD
 

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  • Botom RTD Input 1 to 4.jpeg
    Botom RTD Input 1 to 4.jpeg
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alexburcea

alexburcea

Moderator
Staff member
I was hopping to see a broken/missing/ bad soldered component but from your picture is impossible. Could you send one with higher resolution?
If the sensor contacts are ok and if you did not, accidentally, connect any voltage on the RTD port we should send you an replacement.
Please try a high resolution picture I might see something fixable..
 
T

TonyD

New member
Giday
Thanks for your rapid reply. Sorry for the shitty photo Hands are not as steady as they used to be. Further to your thoughts of a Contact problem. While i had the card out i found the solder sucker & low melt lead free solder & removed the solder on the pins of the connector 3 & then resoldered the pins. So far all good i will leave on test for a few hours to see if this was the fix. Otherwise thinking possible faulty solder joint on chip or flaky chip directly behind connector. Unfortunately my eyesight & shaky hand prevent me from attempting a repair this fine detail now days. Will let you know how things went.

Regards TonyD
 
T

TonyD

New member
Giday
well its now 1700Hrs Brisbane time & the RTD card input 3 has been functioning perfectly for 4 Hrs. looks like that was the fix dry solder joint.
Thanks for you time & effort in diagnosing this fault. if there is any change will let U know
Regards TonyD
 
T

TonyD

New member
Giday
Sorry to be the bearer of bad news. The RTD card has been running since Wednesday & hadn't missed a beat until today when the same channel Channel 3 Failed returning false temperatures as if the Thermistor was not connected. Looks like it is probably chip related & it was just a fluke that it started working after resoldering the connector.
Where do we go from here

Regards TonyD
 
alexburcea

alexburcea

Moderator
Staff member
If you think is the chip, we can replace your card. Please place an order for a new card on our website and select bank transfer (do not pay).
We will send you an replacement. I think you can still check contact issues.
 
T

TonyD

New member
Giday Alex
Thank you for the reply. I will get a replacement card but in the mean time I will endeavour to try & narrow down the likely cause. It’s a Little difficult at present the only RTD card in the system which is currently live.
Regards TonyD
 
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