Wired Flow Meter Location Before or After BFP

Can anyone confirm that a wired flow meter should be installed after the backflow preventer? I’m 99% sure this is the case, just needed confirmation. I’m using a Toro TFS-100 flow meter, I assume this will be wired to the S1 on my Rachio 3 and the 24 VAC + terminal. Or should it be in the - (negative) VAC terminal? Thanks