The Cassini spacecraft traversed magnetic field lines which connect the planet Saturn to its main ring system during the 22 Grand Finale orbits. The magnetometer (MAG) measurements from these orbits revealed the presence of a highly variable low-latitude field-aligned current (FAC) system, which is predominantly confined to the magnetic field lines mapping to the D-ring of Saturn. There is also evidence of the low-latitude FACs on field lines which map to the B-ring in the southern hemisphere, however the FACs are suppressed along the other field lines mapping to the A-C rings. The orbit-to-orbit variability in the fine structure of the measurements can be understood by considering the spatial and temporal variability of the Pedersen conductivities and/or neutral wind speeds in the day-side ionosphere of Saturn. Implications of interaction between the planet and the ‘ring ionosphere’ from the MAG measurements will be discussed.