CPU 416-3 for S7-400 — what this order code delivers
The Siemens 6ES7416-3ES06-0AB0 is a CPU 416-3 for the S7-400 rack, built for mid-to-large process and factory automation. It carries 244 bytes each of process-input and process-output image, so it handles a substantial I/O count without external DP masters for local racks. The integrated PROFINET interface supports isochronous real-time (IRT) communication, which means deterministic cycle times down to sub-millisecond jitter for motion or high-speed logic — critical when coordinating multiple drives or fast sensor arrays on the same wire. Programming is flexible: the CPU runs STEP 7 and accepts LAD, FBD, STL, SCL, CFC, and GRAPH. That covers everything from ladder for electricians to structured text for software engineers and CFC for continuous-process loops. The backplane is isolated, which reduces ground-loop risk in mixed-voltage panels — a real help when the CPU shares a rack with analog modules or remote I/O on a long PROFIBUS segment.
PROFIBUS DP and PROFINET — what's onboard, what's not
This CPU includes a PROFIBUS DP master interface (DPV0,) but does not support DPV1. For most I/O and drive profiles, DPV0 handles cyclic data exchange — the acyclic parameter-channel (DPV1) is absent, so any device that requires DPV1 for startup configuration (some older drives or intelligent slaves) will need a different DP master or a gateway. The PROFINET interface supports IRT and standard TCP/IP and UDP via loadable function blocks, making it suitable for both real-time motion and IT-level data exchange. The CPU also provides an RS 485 interface for point-to-point or multi-drop serial links, and can host up to four communication processors (CPs) in the central controller — though mixed operation of certain CP 443-1 variants is restricted per the evidence. PtP CPs (CP 440, CP 441) are limited by slot count and connection count.
System resources and block limits
The CPU supports 8 instances each of RDREC, WRREC, RDSYSST, and blocks, plus one and one. That's enough for medium-complexity DP diagnostics and parameter handling. Forcing is supported, which is useful during commissioning to override outputs without modifying the logic. The CPU includes 16 counters with a preset of 120 and a total of 96 counters overall.
The module measures 50 mm wide, 290 mm high, and 219 mm deep — a standard S7-400 single-width slot. It mounts directly into the S7-400 rack (UR1/UR2/CR2) and connects to the backplane bus via the two male connectors on the rear. No DIN-rail adapter; the rack provides the mechanical support and bus routing. Plan for the 219 mm depth when sizing the enclosure depth and cable duct clearance behind the rack.