Siemens CP 243-1 Modules – 6GK7243-1EX00-0XE0

Technical Dossier

Product Details And Specifications

Siemens CP 243-1 Series Technical Notes

The Siemens CP 243-1 series is the dedicated Ethernet communications processor family for the S7-200 Micro PLC platform. Deployed across global heavy industry — including petrochemical complexes, refinery distributed control systems, nuclear auxiliary systems, and continuous process manufacturing — the CP 243-1 provided the S7-200 with Industrial Ethernet connectivity at a time when fieldbus-to-Ethernet migration was the dominant infrastructure challenge. Its compact form factor, direct MPI-bus integration, and support for S7 communication protocols made it the standard network interface module for S7-200 installations worldwide. Installed base counts in the hundreds of thousands of units across EMEA, Asia-Pacific, and the Americas, with a significant proportion still in active service within legacy DCS architectures that have not yet undergone full migration to S7-1200 or S7-1500 platforms.

The Evolution of CP 243-1 Architecture

The CP 243-1 was introduced as part of Siemens' strategy to extend the S7-200 platform into networked automation environments. The original hardware revision supported 10/100 Mbit/s auto-sensing Ethernet via an RJ45 interface and communicated with the S7-200 CPU via the internal expansion bus. Configuration was performed through STEP 7 Micro/WIN, using the Ethernet Wizard to define IP parameters, S7 connections, and open communication (TCP/IP, ISO-on-TCP) channels.

The architecture evolved through several firmware and hardware revisions. Early units (hardware revision 01) had limitations on the number of simultaneous S7 connections (maximum 8 connections). Later revisions expanded connection capacity and improved compatibility with STEP 7 Micro/WIN SP9 and above. The IT variant (6GK7243-1GX00-0XE0) added an integrated web server and FTP client/server capability, enabling data logging and remote diagnostics without a dedicated SCADA front-end — a significant architectural differentiation from the base CP 243-1.

With the discontinuation of the S7-200 platform (end-of-sale announced 2013, end-of-repair support 2018), the CP 243-1 series entered its obsolescence phase. Siemens' designated migration path is to the S7-1200 with CM 1241 or PROFINET-native CPU variants. However, the installed base of S7-200 systems in long-lifecycle industries (nuclear, refinery, water treatment) means demand for CP 243-1 spare parts and tested replacements remains active well into the 2020s.

CP 243-1 Full Catalog & Functionalities (SKU List)

The following SKUs represent the verified CP 243-1 and directly associated S7-200 network module range. Each entry reflects a distinct hardware configuration or functional variant within the series.

6GK7243-1EX00-0XE0: CP 243-1 Ethernet module for S7-200; 10/100 Mbit/s RJ45; 8 S7 connections; base variant.

6GK7243-1GX00-0XE0: CP 243-1 IT variant; Ethernet + integrated web server + FTP client/server; extended remote diagnostics capability.

6GK7243-1EX01-0XE0: CP 243-1 hardware revision 01; updated firmware baseline; improved STEP 7 Micro/WIN SP9 compatibility.

6GK7243-1EX30-0XE0: CP 243-1 revision 30; enhanced connection stability for high-cycle polling environments.

6GK7243-2AX00-0XB0: CP 243-2 AS-Interface master module for S7-200; AS-i network integration; distinct from Ethernet CP 243-1 family.

6GK7243-1EX00-0XE0 (Repair Exchange): Factory-refurbished CP 243-1 base unit; Siemens repair exchange program unit; functionally equivalent to new.

6ES7241-1AA22-0XA0: CM 241 RS232 module for S7-200; serial communications companion to CP 243-1 in mixed-protocol installations.

6ES7241-1CH22-0XA0: CM 241 RS485 module for S7-200; Modbus RTU / USS protocol; frequently co-deployed with CP 243-1.

6GK7343-1EX30-0XE0: CP 343-1 Lean for S7-300; functional successor class for migration projects from S7-200 CP 243-1 environments.

6GK7343-1GX31-0XE0: CP 343-1 Advanced for S7-300; full S7 communication + web server; migration target for CP 243-1 IT installations.

6GK7243-1EX00-0XE0/A1: CP 243-1 with factory accessory kit A1; includes DIN rail clip set and connector shield.

6GK1901-1BB10-2AE0: IE FC RJ45 Plug 180 2x2; standard field-assembly RJ45 connector used with CP 243-1 installations.

6GK1901-1BB10-2AB0: IE FC RJ45 Plug 90 2x2; right-angle RJ45 connector for space-constrained CP 243-1 panel installations.

6GK5005-0BA00-1AB2: SCALANCE X005 unmanaged switch; 5-port; standard network infrastructure companion for CP 243-1 Ethernet segments.

6GK5008-0BA00-1AB2: SCALANCE X008 unmanaged switch; 8-port; used in larger S7-200 network topologies with multiple CP 243-1 nodes.

6GK5016-0BA00-1AB2: SCALANCE X016 unmanaged switch; 16-port; rack-level Ethernet aggregation for multi-node CP 243-1 deployments.

Sourcing Hard-to-Find & Obsolete CP 243-1 Parts

The S7-200 platform reached end-of-repair support in 2018. Siemens no longer manufactures or repairs CP 243-1 modules through standard channels. For operators of legacy S7-200 systems in long-lifecycle industries — where a full migration to S7-1200 is not operationally or economically viable within the current maintenance cycle — sourcing tested surplus and refurbished CP 243-1 units is the primary lifecycle extension strategy.

Quality Control for the CP 243-1 Range

The CP 243-1 module integrates directly with the S7-200 CPU expansion bus and communicates via the internal backplane protocol. Testing procedures for this module class require validation at both the hardware interface level and the network protocol level. DriveKNMS applies the following test sequence to all CP 243-1 units prior to dispatch:

Physical inspection covers connector integrity (RJ45 port, expansion bus connector, DIN rail latch), capacitor condition assessment, and PCB visual inspection for corrosion, burn marks, or component damage. Power-on functional test verifies module initialization, LED status sequence (SF, LINK, RX/TX), and absence of fault codes. Protocol validation is performed using a reference S7-200 CPU (CPU 224 or CPU 226) with STEP 7 Micro/WIN: the Ethernet Wizard is used to configure a test IP address and establish a verified S7 connection to a test PG/PC. Open communication (TCP/IP) is validated via a loopback test. IT variant units (6GK7243-1GX00-0XE0) additionally undergo web server accessibility verification and FTP transfer test. All test results are logged and retained for traceability.