As per the expression, you are trying to calculate the total from 6 am in the morning i.e. t+6h. If you are planning to create a calculation for totalizer for today then would suggest using below expression

TagTot("Wet Pump Calculation Calc.", 't', '*')

If you are planning to capture tag total in an interval say 6 am to 6 pm then your expression will be

If Hour('*') >=6 and Hour ('*') <= 18 Then TagTot('InputTag', 't+6h', '*') Else NoOutput()

As per the expression, you are trying to calculate the total from 6 am in the morning i.e. t+6h. If you are planning to create a calculation for totalizer for today then would suggest using below expression

TagTot("Wet Pump Calculation Calc.", 't', '*')

If you are planning to capture tag total in an interval say 6 am to 6 pm then your expression will be

If Hour('*') >=6 and Hour ('*') <= 18 Then

TagTot('InputTag', 't+6h', '*')

Else NoOutput()