Basically, you can set the % moisture content to turn a valve on on a specific sensor at a lower or higher percentage.
Regarding your numbers, could you be more clear what your test conditions are (and be specific about what sensor you are using - it's not clear). I'd like to look at the data.
The test condition where first to look at the value of a dry sensor. (0% moisterize should be messured) A little offset of 5% on testing would is not considered as bad.
It looks like 7 sensors are working correct on 2 extenders.
1 of the extenders (MS port 4) gives 40% on dry condition. where it should be around 0% when put in water it is stuck at 80% and not going to almost 100% like the other sensors. All the sensors are allready changed between ports and cabels also. So is there a way to calibrate a MS port? ore is the extender print having issues from his self?