CP 243-1 Replacement: Migrating S7-200 Ethernet to S7-1200

CP 243-1 Replacement: Migrating S7-200 Ethernet to S7-1200

The communication processor CP 243-1 (article number 6GK7243-1EX01-0XE0) is the factory-shipped Ethernet interface module for the SIMATIC S7-200 micro-PLC family. With the S7-200 system already declared end-of-life and the CP 243-1 itself now formally phased out per Siemens Product Support publication 109780712, every installed unit is one fault event away from a forced migration. This reference consolidates the only four realistic continuation paths: like-for-like spare-parts sourcing, refurbished-equipment supply, full migration to a SIMATIC S7-1200 controller, and bridging through an external serial-to-Ethernet gateway.

1. CP 243-1 Module Profile and Phase-Out Status

The CP 243-1 is a slot-mounted communications processor that slides into the right-hand expansion slot of any CPU 22x in the S7-200 family. It converts the S7-200's MPI/PPI backplane bus into a 10/100 Mbps Industrial Ethernet interface, exposing the controller to:

• S7 communication (server role) for PUT/GET data exchange with S7-300/400/1200/1500 controllers and PC applications.
• OPC DA server connectivity through the legacy SIMATIC NET OPC-Scout interface.
• PG/OP communication for STEP 7 Micro/WIN programming and HMI panel access (e.g., SIMATIC OP/TP/MP panels over Ethernet).
• IT functions on the related CP 243-1 IT variant (FTP client/server, e-mail, web pages, SNMP). The -EX01-0XE0 variant does not carry the IT function set.

Per the official Siemens phase-out notice 109780712, the CP 243-1 is removed from the active catalog with immediate effect. Subsequent orders are routed only through the Siemens Spare Parts Services (SVS) channel and are not guaranteed against future depletion.

2. Functional Specification of the CP 243-1 (6GK7243-1EX01-0XE0)

The following specification snapshot defines the function surface that any replacement must preserve or exceed.

3. Replacement Decision Matrix

There is no drop-in functional equivalent of the CP 243-1 because the S7-200 platform is discontinued. The four technically viable paths each carry different risk profiles and lifecycle implications.

4. Option A: Siemens Spare Parts Service (Like-for-Like)

Siemens Industry Online Support operates an Spare Parts Services (SVS) channel that honors requests for discontinued articles for as long as warehouse stock exists.

1. Open the Siemens Industry Online Support page support.industry.siemens.com and select Products & Services → Services → Spare Parts Services.
2. Enter the article number 6GK7243-1EX01-0XE0.
3. Request a quotation. Spare-parts prices are higher than the original list price and lead time is governed by stock depletion; no guaranteed availability date is given.
4. On receipt, verify the module is unused stock in original Siemens packaging and check the SF/BF/LINK LED behavior at power-up before commissioning.

Useful references:

• Phase-out notice: 109780712
• Spare Parts Services entry: Siemens Industry Online Support – Spare Parts Services

5. Option B: Refurbished or Repaired CP 243-1 Modules

Independent industrial repair houses stock tested CP 243-1 units, typically with a 6-to-12 month limited warranty. The risk profile is acceptable when:

• Spare-parts lead time from SVS exceeds the production-loss budget.
• The installation is non-safety, non-pharmaceutical where warranty terms are acceptable.
• The supplier provides a test report confirming firmware version, all four LEDs functional, and successful S7-communication handshake to a reference S7-200 CPU.

Always require the supplier to confirm:

1. Article number matches: 6GK7243-1EX01-0XE0 (no substitute hardware).
2. Firmware is loaded and the Ethernet Wizard configuration is reset to defaults.
3. All front-panel LEDs are functional.
4. Unit is shipped in anti-static packaging with desiccant.

6. Option C: Migration to S7-1200 (Recommended Long-Term)

The S7-1200 family is the official Siemens successor for S7-200 applications. Every S7-1200 CPU ships with an integrated PROFINET interface that absorbs most of the CP 243-1 functional envelope, removing the need for any slot-mounted communications module.

6.1 Functional Equivalence Map

6.2 Recommended S7-1200 CPU Substitutes

Choose the S7-1200 CPU that meets or exceeds the I/O count of the S7-200 station being replaced:

7. S7-1200 Migration Hardware Equivalents

Beyond the CPU, several S7-200 accessories have direct or near-direct S7-1200 replacements.

8. S7-1200 Migration Software Procedure

There is no automatic source-to-source translator for STEP 7 Micro/WIN programs. The realistic workflow is partial conversion plus manual rewrite.

1. Inventory the existing program. Export the S7-200 project and document every subroutine (SBR), interrupt (INT), and data block (DB). Note all V-memory addresses, I/O mappings, and any CP 243-1 Ethernet Wizard configuration (number of S7 connections, partner IP addresses, TSAP).
2. Create the S7-1200 project in TIA Portal. Add the chosen CPU and configure its PROFINET interface IP address, subnet mask, and router if used.
3. Convert the ladder logic. Use the optional S7-200 migration tool bundled in TIA Portal for first-pass conversion, then manually fix address mapping (V-memory → DB), call structure, and unsupported instructions. Confirm any high-speed counters (HSC) and PTO/PWM outputs are re-mapped to the S7-1200 hardware channels.
4. Re-implement the CP 243-1 S7 connection set. For each former CP 243-1 partner, configure a PUT/GET pair or a single PUT or GET block on the S7-1200 with matching partner IP and TSAP. Example PUT block parameter set:

   REQ    := TRUE
   ID     := W#16#0001            // connection ID
   DONE   := "DB_Comm".done
   ERROR  := "DB_Comm".err
   STATUS := "DB_Comm".status
   ADDR_I := P#DB100.DBX0.0 BYTE 100
   ADDR_Q := P#M100.0 BYTE 100
   SD_1   := P#DB200.DBX0.0 BYTE 100  // send area
   RD_1   := P#DB300.DBX0.0 BYTE 100  // receive area

5. Re-link HMI panels and SCADA. Update the panel or SCADA project to point to the S7-1200 CPU IP and rack/slot = 0/1. Re-import the variable table where the data block layout changed.
6. Validate cyclic and acyclic data. Force a small data block on the S7-1200 side and confirm end-to-end visibility from the original partner controller or SCADA node.

9. Option D: Serial-to-Ethernet Gateway Bridge

When the S7-200 station has no spare PPI/MPI port and migration is not yet scheduled, an external serial-to-Ethernet gateway can convert the CP 243-1 role. This option does not require a CP 243-1; the gateway talks to the S7-200 CPU's PPI or MPI port directly.

9.1 Hardware

• Industrial serial-to-Ethernet converter (e.g., a hardened Modbus/PPI/Ethernet gateway) with RS-485 termination set to match the S7-200 PPI/MPI baud rate.
• Configuration cable and vendor utility for parameter assignment.

9.2 Configuration Outline

1. Configure the gateway serial port: RS-485, 9600 / 19200 / 187500 baud (match S7-200 PPI/MPI), even parity, 8 data bits, 1 stop bit (default PPI).
2. Configure the gateway IP address, subnet mask, and TCP/UDP port.
3. Map the S7-200 station address (e.g., station 2) to a virtual slot/connection for the SCADA / HMI partner.
4. Verify with a PG/PC test client that the S7-200 program data blocks are accessible from the Ethernet side.

10. Network Configuration Migration (CP 243-1 to S7-1200 PROFINET)

Map the CP 243-1 Ethernet Wizard configuration onto the S7-1200 PROFINET parameters.

11. Commissioning and Verification

After any of the four options is implemented, perform the verification matrix below before declaring the system production-ready.

12. Frequently Asked Questions