Hi there,

Here is a link to information that should answer your questions in regard to your Ph sensor

http://www.picotech.com/experiments/ph- ... index.html

Kindest regards
Stuart

Good Morning,

Thankyou for your response. The TC08 cannot be a totally isolated design as there would be no way to power the front end. The power supples are produced via the USB.

Kindest regards
Stuart

This problem is almost certainly caused by the thermocouple being used touching something which is at a different potential to the TC-08/PC earth. If this voltage is greater than about +/-7V the channel is pulled out of he common mode range of the TC-08. This causes all channels to read very incorre...