SIMATIC S7-200 SMART CPU CR20 AC/DC / Relay
$119.75 – $133.06
CPU CR20s, compact CPU (non-expandable) — 12DI/8DO relay, 20KB program/data memory. IMPORTANT: the Compact (CR) line CANNOT be expanded with EM modules or signal boards, unlike the Standard (ST/SR) line. [VERIFIED via Siemens official datasheet]
Technical Specifications
| Product Line | Compact (CR) — non-expandable, single-body unit |
| Digital I/O | 12 DI 24V DC / 8 DO Relay 2A |
| Power Supply | AC 85–264V, 47–63Hz |
| Program/Data Memory | 20 KB |
| Key Difference from ST/SR line | Cannot accept EM expansion modules or signal boards — fixed I/O count for the life of the unit |
| Security Note | Per CISA advisory ICSA-24-165-02, S7-200 SMART CPU firmware versions affected by CVE-2024-35292 (predictable IP ID sequence number, CVSS up to 8.8) should be checked and updated where a network-facing deployment is planned. |
Typical Applications
The Compact (CR) line is designed for simple, fixed-scope control requirements where the I/O count will never need to change — choose the Standard (ST/SR) line instead if any future I/O expansion is anticipated.






