PT100 or PT1000 temperature reading

Universal Controller for CAN Applications
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Ivaher
Posts: 3
Joined: Mon 11. Nov 2019, 11:46

PT100 or PT1000 temperature reading

Post by Ivaher » Mon 23. Mar 2020, 14:59

Hello,

I want to connect one RTD sensor (PT100 or PT1000) to the PCAN-MIO. I suppose that using one Analog Input and function block "CHARACTERISTIC CURVE WITH LIMIT" I could read the temperature and send this temperature by CAN, could you please confirm it?

Thank you very much.

Regards.

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G.Bohlen
Hardware Development
Hardware Development
Posts: 48
Joined: Wed 22. Sep 2010, 21:38

Re: PT100 or PT1000 temperature reading

Post by G.Bohlen » Mon 23. Mar 2020, 17:55

Hello,

the analog input is not prepared for a PT100, because the voltage difference across the PT100 when the temperature changes is very small.
You might use a PT1000. Please connect a "pull Up" resistor of 1kOhm to 5V output (5V output needs to be enabled via configuration) , connect the other side of the resistor to PT1000 and Analog input, connect the other side of PT1000 to AGND.
At 0°C you should see 2.5V , at 25°C you should see 2.61V.
PCAN-MIO has got an internal voltage divider to allow a voltage range of 0-10V. This voltage divider should be disabled (remove resistor marked with a red cross), otherwise internal voltage divider reduces the resolution by 2 and the internal divider has to be added to the calculation.
Internal voltage divider is 2x 6.8kOhm, see attached schematic diagram.

Regards,
Gunnar Bohlen
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