Adding Siemens CP 343-1 V1.3 to STEP 7 V5.4 When Catalog Shows

Overview

The SIMATIC NET CP 343-1 (order number 6GK7343-1EX21-0XE0) is a communications processor for the S7-300 / ET 200M system used to connect an S7-300 station to Industrial Ethernet and PROFINET. When a newer firmware version, for example V1.3, is downloaded into the module, the STEP 7 V5.x hardware catalog (HWC) does not always receive a brand-new catalog entry alongside the original V1.2 entry. This frequently causes a support situation where the engineer can see the physically installed module reporting firmware V1.3 via the online diagnostic buffer or via the module's accessible node points, but the offline HW Config only lists the V1.2 variant.

The objective of this article is to document the correct field procedure to:

1. Install the module in HW Config using the V1.2 catalog entry.
2. Update the hardware catalog to surface the V1.3 (or newer) entry when Siemens publishes one.
3. Confirm that all V1.3 functions are available in the offline project even when only a V1.2 entry is configured.
4. Avoid mismatches between the offline configuration and the online firmware that would cause download rejection or diagnostic buffer entries.

Identifying the Module Variant and Order Number

Before touching the project, verify the exact order number (MLFB / Article No.) of the CP and the firmware that is currently loaded on the module. The CP 343-1 family has many members; the catalog and firmware paths differ between them.

To read the firmware that is currently loaded on the module, open SIMATIC Manager > PLC > Accessible Nodes or use HW Config > Online > Module Information. The diagnostic buffer reports the firmware version in the Identification tab as Firmware version V1.3.x.

STEP 7 Hardware Catalog Architecture

STEP 7 V5.4 (with Service Packs up to SP5 / HSP) ships the hardware catalog in the file s7hkcatalog.nsf and a set of supporting files under STEP7\S7DAT\HwCatalog\. Updates are delivered as HSP files (Hardware Support Packages) which are ZIP archives named HSP_xxxx.zip and installed from HW Config > Options > Install HW Updates.

Siemens does not publish a separate catalog entry for every firmware revision of a CP. A new entry is created only when the catalog type changes, when the slot assignment changes, when a new diagnostic level is introduced, or when a new module variant is added. For the CP 343-1 EX21, the catalog entry has historically been stable at V1.2 because the catalog-relevant features (interface assignment, PROFINET IO device behavior, port properties, SNMP, time-of-day synchronization, S7 routing) did not change between V1.2 and V1.3. The V1.3 firmware is, in Siemens catalog terms, a compatible firmware update.

Prerequisites

To perform the procedure below, ensure the following tools and conditions are in place:

• STEP 7 V5.4 + SP5 (or higher SP / HSP) installed.
• License key for STEP 7 floating or local, valid for the S7-300 toolkit.
• Administrator rights on the engineering station to write to %ProgramFiles%\Siemens\Automation\STEP7\S7DAT\.
• The target project is open or a new S7-300 station has been inserted.
• Access to the Siemens SiePortal / Industry Online Support to download the latest HSP if an online update is required.
• Ethernet connection between the PG/PC and the S7-300 station for online firmware verification.

Step-by-Step Procedure

Step 1 — Try the Online Hardware Update First

Open the project in SIMATIC Manager, expand the S7-300 station, and double-click Hardware to launch HW Config. The catalog opens on the right side.

1. Click Options > Install HW Updates.
2. Choose Download from Internet if the engineering station has outbound HTTPS access to support.industry.siemens.com.
3. Select the latest available HSP for the CP 343-1 EX21 family and confirm with Install.
4. After installation, the catalog path SIMATIC 300 > CP 300 > Industrial Ethernet > CP 343-1 > 6GK7 343-1EX21-0XE0 should still show the same V1.2 entry, but the underlying catalog object has been refreshed.

If your engineering station is air-gapped, click Download from Internet on a connected PC, choose a network drive or USB stick, and then choose Install from file system in HW Config > Options > Install HW Updates. The HSP files are typically named HSP_xxxx.zip and placed in a folder STEP 7 will scan recursively.

Step 2 — Configure the CP with the V1.2 Catalog Entry

If the HSP does not introduce a V1.3 entry (the most likely outcome), insert the CP using the existing V1.2 entry:

1. In HW Config, browse the catalog to SIMATIC 300 > CP 300 > Industrial Ethernet > CP 343-1.
2. Drag the 6GK7 343-1EX21-0XE0 entry (V1.2) into slot 4 of the S7-300 rail.
3. Double-click the module to open its properties.
4. On the General tab, accept the default IP address; change it as required.
5. On the PROFINET / Ethernet tab, enable S7 communication, PROFINET IO Device, or any other required service.
6. Click OK to confirm the configuration and save the project.

Step 3 — Download the Hardware Configuration

Connect the PG/PC to the CP 343-1 via the Ethernet port (X1). Use PLC > Download to Target > Selected Module in HW Config to push the configuration into the PLC. STEP 7 will report any inconsistencies between the configured module and the physical one.

Step 4 — Verify Online That the CP Reports V1.3

1. Right-click the CP in HW Config and choose PLC > Module Information.
2. Open the Identification tab.
3. Confirm the Firmware version field shows V1.3 (or the exact patch level you downloaded, e.g. V1.3.1).
4. Open the Diagnostic Buffer tab and confirm no entries of type Module does not match configured module or Firmware version mismatch.

Step 5 — (Optional) Install the V1.3 HSP If Released by Siemens

Siemens periodically releases an HSP that refreshes the catalog entry to display the actual firmware level. For the EX21 family, this typically happens in the form of a refreshed catalog description rather than a new object. To check whether a new HSP exists:

1. Open Siemens Industry Online Support — CP 343-1 search.
2. Filter the documents by Hardware Support Packages.
3. Read the change log of the HSP. If it lists CP 343-1 6GK7 343-1EX21-0XE0 with FW V1.3, install the HSP from Options > Install HW Updates.

For the CP 343-1 Advanced (6GK7343-1GX30-0XE0), Siemens does ship a dedicated firmware V1.3 download, which is published at the CP 343-1 Advanced firmware V1.3 download entry in the SiePortal. Use this procedure only if your physical module is the GX30 variant.

Why a V1.3 Entry Is Not Required

The catalog entry exposes the following parameters for the CP 343-1 EX21:

• IP address, subnet mask, router address.
• PROFINET device name and IO cycle time.
• Port properties (autonegotiation, monitor, transmission medium).
• S7 connection / ISO-on-TCP / TCP / UDP connection table.
• Time-of-day synchronization mode (NTP, SIMATIC, ISO).
• SNMP community strings and traps.
• Web server activation (where supported by the firmware).

None of these were altered at the catalog level by the V1.2 → V1.3 firmware update. The V1.3 release added, in general, security hardening (certificate handling, TLS behavior on web diagnostics), an extended NTP retry behavior, and minor diagnostic buffer improvements. These features are activated at runtime by the firmware itself and do not require a new catalog object to be available in HW Config.

Verification Matrix

Edge Cases and Field-Proven Caveats

1. The V1.2 Catalog Entry Was Removed After an HSP Uninstall

If an earlier engineer installed a conflicting HSP and then uninstalled it, the original V1.2 entry can disappear from the catalog. To restore it, reinstall the original STEP 7 DVD image, or reinstall the original HSP shipped with the SP level you are running. A clean reinstallation of the catalog s7hkcatalog.nsf is preferable to manual editing.

2. The CP Is in ET 200M with PROFINET IO

If the CP 343-1 is operated as a PROFINET IO device in an ET 200M station, the IO controller configuration can in some cases complain about a "module revision" mismatch. This is benign for the EX21 because the IO device interface (GSD file import) is independent of the CP catalog entry. Clear the diagnostic buffer and re-establish the AR (Application Relationship) to confirm.

3. The CP 343-1 LEAN Variant (6GK7343-1CX00-0XE0)

The LEAN variant has a different catalog path and a lower functional scope. Do not insert a LEAN entry where an EX21 is installed, or vice versa. The order number on the module front label is the authoritative reference.

4. STEP 7 V5.4 Without SP5

Older SP levels (SP1 to SP4) do not always include the EX21 catalog entry. Upgrade to SP5 (or the latest HSP for V5.4) before troubleshooting the catalog.

5. STEP 7 V5.5 and V5.6

The procedure is identical. V5.5 and V5.6 are functionally a superset of V5.4 + SP5 and contain the same catalog entry for the EX21.

6. Migrating to TIA Portal

If you migrate the project to TIA Portal (V15, V16, V17, or V18), the CP 343-1 EX21 is moved to a TIA-compatible device variant. The firmware V1.3 is fully supported as a catalog option. No manual HSP installation is required; the device description is part of the TIA Portal install or of the TIA HSP package.

Firmware Update Procedure (When Needed)

If the module is currently on V1.2 and you need to upgrade to V1.3, use the SIMATIC Manager firmware update tool:

1. Open SIMATIC Manager > PLC > Accessible Nodes and find the CP's IP.
2. Open PLC > Firmware Update from the menu.
3. Browse to the firmware file (.upd) you downloaded from SiePortal.
4. Select the CP and confirm. The update typically takes 2–4 minutes; the module reboots automatically.

Troubleshooting Matrix

Related Documentation

The official Siemens documentation set for the CP 343-1 EX21 includes the device manual "SIMATIC NET CP 343-1 / CP 343-1 Advanced" (entry ID 1137636 on SiePortal), the STEP 7 V5.4 / V5.5 / V5.6 programming and operating manual, and the diagnostic buffer reference. For the Advanced variant, the V1.3 firmware download entry is available at the Siemens SiePortal firmware V1.3 download. The Siemens CP 343-1 product search page lists all current KB articles, FAQs, and HSPs for the family.

FAQ