The Su-27SM uses radar and avionics that are practically identical to the Su-30MK2, recently of the PLANAF and a couple to Venenzuela. Yes, its not the same as the Su-30KN. As far as I know the Su-30KN uses an upgraded N001 based radar that was running along on the same theme as the N001VEP radar used on the Su-30MKK and MK2. The Su-27UBM was supposed to be based on the -30KN, practically the same aircraft that is an upgrade of the Su-27UB. But the RuAF dropped the Su-27UBM upgrade proposal in favor of the Su-27SM, and the Su-30KN lacked any financing to go further.
