CPU 221 – standalone S7-200 controller
The Siemens 6ES7211-0AA20-0XB0 is a CPU 221 with DC supply, DC inputs, and DC outputs, holding 2kWords of program memory for standalone control.
Sourcing and fit
This is a current-production item. Siemens continues to manufacture the 6ES7211-0AA20-0XB0 for new builds and spares. For procurement, it is specified directly into the BOM line against this exact order code — no substitute or cross-reference is needed.