3 CT 16 Step APFC Controller for Contactor switching - etaULTRA 16R. Individual harmonics measurement up to 31st order, Dual PF setting for Mains - DG application, Communication through Inbuilt MODBUS RS-485 Protocol, Cascading (Master - Slave configuration) for APFC panel with more than 16 steps, 2 & 4 Quadrant Operation for sites with / without Solar Plants.