Siemens S7-300 CP 342-5 Modules

Technical Dossier

Product Details And Specifications

Siemens S7-300 CP 342-5 Series: Comprehensive Module Range and Technical Overview

The Siemens S7-300 CP 342-5 series comprises PROFIBUS DP communications processors designed for integration into the S7-300 programmable logic controller platform. These modules have been deployed across heavy industrial sectors globally, including petrochemical refineries, nuclear power auxiliary systems, offshore platforms, and large-scale chemical processing plants. The CP 342-5 family enables the S7-300 CPU to offload PROFIBUS DP master and slave communication tasks to a dedicated processor, thereby freeing CPU cycle time for process control logic. Installed base figures across IEC 61511-compliant process industries confirm this series as one of the most widely fielded PROFIBUS interface modules in the S7-300 ecosystem. Its compatibility with STEP 7 v5.x and TIA Portal (in legacy mode) has sustained its relevance in brownfield installations where full system migration is not economically viable.

The Evolution of CP 342-5 Architecture

The CP 342-5 series was introduced as part of Siemens' S7-300 expansion in the mid-1990s, targeting the growing demand for deterministic PROFIBUS DP fieldbus communication in distributed I/O architectures. The initial hardware revision (firmware 1.x) supported DP master mode only, with a maximum of 32 DP slaves and a baud rate ceiling of 1.5 Mbit/s. Subsequent firmware iterations extended slave count to 125 nodes and baud rates to 12 Mbit/s, aligning with EN 50170 / IEC 61158 Type 3 specifications.

The 6GK7342-5DA02-0XE0 (hardware revision 2, firmware V5.0+) introduced simultaneous DP master and DP slave operation on a single module — a critical architectural advancement for hierarchical PROFIBUS networks where an S7-300 station must act as both a master to field devices and a slave to a supervisory S7-400 or DCS host. The 6GK7342-5DA03-0XE0 further refined interrupt handling and added support for PROFIBUS PA segment coupling via DP/PA link devices.

By the 2010s, Siemens positioned the CP 343-1 (Industrial Ethernet) and CP 342-5 as complementary rather than competing interfaces, with many installations running both in parallel. The CP 342-5 series entered the Siemens product lifecycle phase "Classic" (limited new development, continued spare parts support) around 2018, with migration paths recommended toward the ET 200SP and S7-1500 platforms using CM PtP or PROFINET/PROFIBUS proxy solutions. For existing S7-300 installations, the CP 342-5 remains the only hardware-compatible PROFIBUS DP master/slave module and cannot be substituted without CPU or backplane replacement.

CP 342-5 Full Catalog & Functionalities (SKU List)

The following SKUs represent the verified production and spare parts catalog for the Siemens S7-300 CP 342-5 PROFIBUS series. Each entry reflects a distinct hardware or firmware revision with specific functional characteristics. SKUs from unrelated Siemens series are excluded.

PROFIBUS DP Master / Slave Communications Processors

• 6GK7342-5DA00-0XE0: CP 342-5, HW Rev. 1 — PROFIBUS DP master only, max 32 slaves, 12 Mbit/s, STEP 7 V5.1+
• 6GK7342-5DA01-0XE0: CP 342-5, HW Rev. 1 updated — DP master/slave, improved diagnostic buffer, firmware V3.x
• 6GK7342-5DA02-0XE0: CP 342-5, HW Rev. 2 — simultaneous DP master + slave, 125 slaves, firmware V5.0, current standard spare
• 6GK7342-5DA03-0XE0: CP 342-5, HW Rev. 3 — enhanced interrupt latency, DP/PA link support, firmware V6.0+
• 6GK7342-5DF00-0XE0: CP 342-5 FO — fiber optic PROFIBUS DP master/slave, plastic optical fiber interface, 12 Mbit/s
• 6GK7342-5DF01-0XE0: CP 342-5 FO, HW Rev. 1 — updated FO transceiver, extended temperature tolerance

Accessories and Configuration Software

• 6GK1716-0HB12-0AA0: STEP 7 NCM S7 for PROFIBUS — network configuration manager, required for CP 342-5 commissioning
• 6GK1971-5DA00-0AA0: PROFIBUS bus connector, 90° cable exit, 12 Mbit/s, for CP 342-5 sub-D port
• 6ES7390-1AE80-0AA0: S7-300 rail 480 mm — standard mounting rail for CP 342-5 installation
• 6ES7390-1AF30-0AA0: S7-300 rail 530 mm — extended rack for multi-module configurations including CP 342-5

Related S7-300 CPU Modules (Commonly Paired with CP 342-5)

• 6ES7315-2AH14-0AB0: CPU 315-2 DP — integrated PROFIBUS DP port, frequently paired with CP 342-5 for dual-master topologies
• 6ES7317-2AK14-0AB0: CPU 317-2 DP — high-memory CPU, used in large PROFIBUS networks with CP 342-5 as secondary master
• 6ES7318-3EL01-0AB0: CPU 319-3 PN/DP — top-tier S7-300 CPU, supports CP 342-5 for legacy PROFIBUS slave connectivity

Power Supply Modules (Required for CP 342-5 Rack)

• 6ES7307-1BA01-0AA0: PS 307 2A — 24 VDC/2A power supply for S7-300 rack hosting CP 342-5
• 6ES7307-1EA01-0AA0: PS 307 5A — 24 VDC/5A power supply for extended S7-300 racks with multiple CP 342-5 modules
• 6ES7307-1KA02-0AA0: PS 307 10A — high-current supply for fully populated S7-300 racks

Sourcing Hard-to-Find & Obsolete CP 342-5 Parts

The CP 342-5 series has entered Siemens' Classic lifecycle phase, meaning new production volumes are reduced and lead times from authorized distributors have extended to 16–26 weeks in many regions. For process industries operating under IEC 61511 functional safety requirements or long-term service agreements (LTSA), unplanned downtime caused by CP 342-5 module failure is not operationally acceptable.

DriveKNMS maintains a dedicated inventory of CP 342-5 modules across all hardware revisions, including the discontinued 6GK7342-5DA00-0XE0 and 6GK7342-5DA01-0XE0 variants that are no longer available through Siemens' standard distribution channels. Our sourcing protocol covers:

• Direct stock of tested, pull-out units from decommissioned S7-300 installations
• Cross-referencing of hardware revision compatibility to ensure firmware alignment with existing STEP 7 project configurations
• Emergency dispatch capability for critical process shutdowns, with same-day shipping from bonded warehouse stock
• Long-term supply agreements for plant operators requiring guaranteed CP 342-5 availability through 2030 and beyond

For obsolete firmware versions (V3.x, V4.x) required by legacy STEP 7 projects that cannot be upgraded, DriveKNMS can supply pre-configured modules with verified firmware loads upon request.

Quality Control for the CP 342-5 Range

The CP 342-5 module integrates a dedicated PROFIBUS ASIC (Siemens SPC3 or equivalent), a local microprocessor, dual-port RAM for CPU-to-CP data exchange, and a 9-pin sub-D PROFIBUS interface. Each of these subsystems requires targeted verification before a module is released as a serviceable spare.

DriveKNMS applies the following test protocol to all CP 342-5 units:

• Backplane interface continuity test: Verification of all S7-300 bus connector pins against Siemens mechanical specification, including P-bus and K-bus signal integrity
• PROFIBUS DP master functional test: Module configured as DP master in a live PROFIBUS network with a minimum of 8 DP slave devices; cyclic data exchange verified at 1.5, 6, and 12 Mbit/s baud rates
• DP slave mode verification: Module configured as DP slave under an S7-400 master; input/output data consistency checked across 100 consecutive scan cycles
• Firmware version confirmation: Hardware revision label cross-checked against internal firmware identifier via STEP 7 NCM diagnostic read
• Thermal stress test: 4-hour burn-in at 55°C ambient to screen for latent component failures consistent with electrolytic capacitor degradation in aged modules
• Isolation and ESD integrity: Sub-D port isolation resistance measured; ESD protection diode continuity verified per IEC 61000-4-2 Level 2 criteria

Modules that fail any single test stage are quarantined, documented, and not released for sale. Test records are retained for a minimum of 5 years and are available to customers upon request.