A photovoltaic, PV, module level monitoring, MLM, system (1) comprising a base station, BS, (2) connected by means of power cables (3) to module level devices, MLD, (4) which are provided to monitor and/or to control associated photovoltaic modules, PVMs, (5), wherein the base station, BS, (2) comprises a base station transmitter (2A) adapted to transmit Rapid Shut Down, RSD, control signals, CS, in predefined time slots, TSCS, in a downlink channel, DL-CH, through said power cables (3) to said module level devices, MLDs, (4) and a base station receiver (2B) adapted to receive monitoring signals, MS, generated by said module level devices, MLDs, (4) through said power cables (3) within time slots, TSMS, via an uplink channel, UL-CH, assigned to the module level devices, MLDs, (4).