I am using a TC-08 for logging both K-type thermocouples and mV inputs. Before I connect any of the thermocouples, there appears to be a ground isolation problem.
When I connect a 32 mV input the reading is unstable and reads about 24.xx mV.
1 - Disconnecting the AC ground wire, from the instrument that is producing the 32 mV, changes the mV reading but does not correct the problem.
2 - However, if I unplug the notebook pc from the AC line (making it run from itâ€™s battery) the reading goes to 32 mV and is stable. This would not be a bad solution if I was not running a 4 day test.
I would be grateful for any help you could provide.