CPU 414-3 PN/DP — what this S7-400 processor brings to the rack
The Siemens 6ES7414-3EM05-0AB0 is a CPU 414-3 PN/DP for the S7-400 family, sitting in the mid-to-high range of the line. It gives you a balanced mix of processing power and integrated communication — PROFINET onboard, PROFIBUS DP via DPV0, and support for all five IEC languages plus CFC and GRAPH. The 244-byte input and 244-byte output process-image limit is generous for a mid-frame CPU, letting you map a substantial number of I/O points without reaching for a larger processor.
Programming languages and engineering tools
This CPU runs STEP 7 and supports LAD, FBD, SCL, STL, and GRAPH — that covers ladder, function block, structured text, statement list, and sequential function chart. It also handles CFC (Continuous Function Chart), which is useful for signal-flow-oriented programming in process applications. For a junior programmer or someone cross-training from another platform, the availability of LAD and FBD means you can start with familiar graphical languages and move to SCL or STL as you get comfortable.
Communication interfaces and limits
Integrated PROFINET gives you UDP and TCP/IP connectivity via loadable function blocks — no separate CP needed for basic Ethernet communication. PROFIBUS DP runs DPV0; DPV1 is not supported on this CPU, so if your application requires acyclic data exchange with DP slaves (like parameterization during operation), you'll need to handle that through other means. RS 485 is available for point-to-point links. The CPU supports routing when the interface is active, which helps when you're bridging PROFINET and PROFIBUS segments. Maximum of 4 CP443-1 communication processors in the central controller, and note that mixed operation of CP443-1 EX40 with EX41/EX20/GX20 is not allowed.
Width is 50 mm, height 290 mm, depth 219 mm — a single-wide S7-400 slot. It mounts into the standard S7-400 rack and connects to the backplane via two male DIN connectors. The CPU is isolated.
This CPU is an established S7-400 model.