Siemens 6FC5357-0BB33-0AA0 Numerical Control Unit

The Siemens 6FC5357-0BB33-0AA0 Numerical Control Unit is the SINUMERIK 840D/DE NCU 573.3 CPU module that acts as the central processing brain for SINUMERIK 840D CNC systems. It uses a 650 MHz processor and provides 64 MB of memory, without system software memory; NC program data memory is 2.5 MB and PLC memory is 96 KB, supporting integrated CNC motion and PLC logic. It is prepared for Profibus DP communications, enabling straightforward integration with standard Siemens drives, I/O blocks, and field devices in a machine-tool environment. The NCU 573.3-based module is designed for SINUMERIK 840D/DE configurations that balance high-precision motion control with robust PLC capabilities, delivering synchronized multi-axis motion and real-time control loops essential for complex machining cycles. Common applications include milling and turning centers that rely on SINUMERIK 840D for coordinated axis control, tool management, and cycle execution, making this NCU a core component in older SINUMERIK 840D installations and a candidate for restoration or replacement in compatible machines. The package is identified by 6FC5357-0BB33-0AA0 and belongs to the SINUMERIK 840D/DE hardware family that uses the 573.3 processor core.