ABB · AC 800M ABB PM861AK02 3BSE018160R1 Redundant Processor Unit — AC 800M Redundant Processor Unit for the AC 800M controller family Article Number 3BSE018160R1 Configuration 2 × PM861AK01 Processor MPC860 · 48 MHz Memory 16 MB RAM Overview AC 800M redundant processor package. PM861AK02 is a redundant processor unit for ABB AC 800M controllers, built around two PM861A processor units. It combines CPU redundancy with the hardware required for the redundant controller