Integrated PROFINET interface and memory sizing
The Siemens 6ES7317-2EJ10-0AB0 is a CPU 317-2 PN/DP for the S7-300 platform with an integrated PROFINET interface, eliminating the need for a separate CP for Ethernet connectivity in most applications. Work memory is 64 kbyte, which sets the upper limit for the user program and data blocks combined — overshoot it and the CPU refuses to download, so size the program before committing the BOM line. The backup time is 6 weeks at 40 °C ambient temperature, meaning the retentive data survives a power loss for about a month and a half in a warm cabinet — adequate for shift-level buffering but not extended outages.
Programming languages and toolchain
This CPU supports LAD, FBD, STL, SCL, GRAPH, HiGraph, and CFC — the full S7-300 language set — so the integrator can use whatever IEC 61131-3 dialect the project standardises on. Engineering requires STEP 7 V5.3 or higher.
Fieldbus and communication
The integrated PROFINET interface supports TCP/IP via loadable function blocks and can act as both client and server — common for distributed I/O and HMI connectivity without a dedicated CP. RS 485 is onboard for point-to-point links, and the CPU supports PROFIBUS DP via external CP modules — up to 4 CPs for DP, 10 for LAN, and 8 for PtP connections. Routing is supported, so a PG/PC on PROFINET can reach nodes on PROFIBUS through the CPU without additional gateways.
I/O and function module capacity
Forcing is supported on inputs, outputs, memory bits, DBs, timers, and counters — a commissioning tool for locking signals during startup without changing the program logic.
The form factor is standard S7-300 single-width: 80 mm wide, 125 mm high, 130 mm deep — fits any S7-300 rack without adapter plates.