Hi,

I am subtracting the value of two timestamps (today at 7:00 am - first day of the month at 7:00 am) from the same tag, when i do it Excel i get:

This is the correct answer, but when i write the expression in PE i get:

if i do it separately i get the results from the Excel

But when i put them in the equation (just add the symbol "-") the result is not the one that should be.

I don't know what i'm doing wrong, can someone help me?

Thanks,

What are the point types for the source point and the PE tag? Float32 tags are accurate to about 7 digits, while these events have 9-digit values. I suspect you may be running into a loss of significance due to subtracting numbers of similar magnitude (Loss of significance - Wikipedia ).

Try converting the points to Float64 data types, which are accurate to ~15 digits. See 1172OSI8 - PI Server Storage and precision of Float32 and Float64 data for more details.