What This Module Does in Your S7-300 Rack
The Siemens 6GK7343-1EX11-0XE0 is a CP 343-1 communications processor that slots into an S7-300 rail as a compact double-width module. It brings a single Industrial Ethernet interface running at 10 to 100 Mbit/s via an RJ45 port or AUI connector, so the CPU can talk to higher-level systems, HMIs, or other controllers over TCP/IP without loading the CPU's own backplane bandwidth. Power comes from both the 5 V backplane bus (drawing 0.07 A typical) and an external 24 V DC supply through a 2-pole pluggable terminal block.
This module supports NTP time synchronization, so it can act as a time slave on the plant network and pass that time to the CPU — useful for aligning event logs across multiple controllers. It also supports SICLOCK for higher-accuracy time-stamping if your application needs it. It does NOT support DCP (Discovery and Configuration Protocol), which means you cannot assign the IP address via DCP broadcast from a PG/PC — you will need to set the address through the CPU's configuration or via STEP 7 hardware config. Similarly, LLDP is not supported, so network topology discovery via PROFINET is not available on this module. The module handles up to 32 active connections in multi-protocol mode and supports up to 16 multicast stations. For most line-level applications connecting to one or two HMIs and a SCADA server, that is ample headroom. Operating temperature range is 0 to 60 °C horizontally mounted, or 0 to 40 °C vertically installed.
The module requires STEP 7 V5.1 SP2 or higher for configuration. If your engineering station is running an older version, you will need to update before you can add this module to the hardware catalog.