Just to follow up on this; I’ve looked at the data log today and I see that WD is not taking the file content reliably. I get lots of zero (0) readings even if file content is different (it is a floating point value, e.g. 5.6789). I compared WD’s day log with raw plot (with gnuplot) to confirm my raw data is OK.
It’s not urgent but I thought to ask you here. I’ve checked for file permissions and should be OK.