PROFINET IRT and security on the S7-300 rail
The Siemens 6GK7343-1GX31-0XE0 is a CP 343-1 Advanced communication processor that snaps onto the S7-300 DIN rail. It brings a managed two-port switch, PROFINET IO controller and device capability, and — the headline feature — support for PROFINET IRT (isochronous real-time), which means it can close the control loop over the network for motion axes or high-speed process sequences without a separate fieldbus. The integrated stateful inspection firewall and IP-based ACLs let you segment the automation network from the IT network at the module level, not at a perimeter gateway. NTP client keeps the CPU clock synchronised across the plant, and DCP enables device discovery and basic configuration without STEP 7 — useful for commissioning a replacement module without the engineering station.
Memory, interfaces, and configuration
The module carries 30 Mibyte of RAM for communication buffers and an additional 28 Mibyte flash file system for web pages or firmware updates. The first Ethernet interface runs at 10/100/1000 Mbit/s; the second is 10/100 Mbit/s. A C-PLUG stores the configuration so a failed module can be swapped without re-downloading the project. Configuration requires STEP 7 V5.5 SP2 HF1 or higher, or STEP 7 Professional V12 (TIA Portal) or higher. For PROFINET CBA (component-based automation), SIMATIC iMap V3.0 SP4 and higher is needed. The module draws 14.7 W from the 24 V supply via the 2-pole pluggable terminal block.