Hi all,
Thank you for creating this topic with so much useful information. This is the only detailed explanations for the "Logo_PHsensor v1.1" board I have found in English on the web. Thanks a lot, especially to LeCyb. Now, I know why the red LED turns on and off when I turn the pot by the pins!
That being said, I'm struggling getting my board working. When I apply 5V between V+ and G, the green LED turns on so that's good. Now, when I measure the voltage between Po and the second pin G and change the resistance of the pot by the BNC connector, I always measure 1.85V (+/- 0.04V) no matter what is connected to the BNC connector (a short, open circuit or the black pH probe). The symptom seems to be very similar to the one from rgonzo2, except the difference in voltage.
Does that mean that the board is not working correctly?
Thanks,
John