Siemens 6GK7342-5DA03-0XE0 — CP 342-5 PROFIBUS-DP Master/Slave Communication Processor for SIMATIC S7-300 | New in Box

The 6GK7342-5DA03-0XE0 is a genuine Siemens CP 342-5 PROFIBUS Communication Processor — a dedicated communications module that plugs into the S7-300 backplane and offloads all PROFIBUS network management from the S7-300 CPU. It is not a generic "PLC module." It serves one specific and well-defined role: connecting a SIMATIC S7-300 system to a PROFIBUS-DP network as either a DP master (DPM1/DPM2) or DP slave, supporting data rates up to 12 Mbit/s and conforming to the DP-V1 acyclic services standard for parameterization and diagnostics of intelligent field devices.

The "-0XE0" suffix designates the standard export/international firmware version. The "03" in "5DA03" indicates this is the third hardware revision of the CP 342-5 product line, which added full DPV1 master support — a meaningful upgrade over earlier versions. If you're replacing an older CP 342-5 and need to confirm compatibility, the hardware revision does matter.

✅ Genuine Siemens. New in original box. Ships worldwide.

Order Number Decoded

6GK7 342 - 5 D A 03 - 0 X E 0
│ │ │ │ │ │ │ │ │ └── 0: standard version
│ │ │ │ │ │ │ │ └───── E: export version (international firmware)
│ │ │ │ │ │ │ └──────── X: no special configuration
│ │ │ │ │ │ └─────────── 0: standard product
│ │ │ │ │ └───────────────── 03: hardware revision 3 (DPV1 master support)
│ │ │ │ └───────────────────── A: first generation design within 5D family
│ │ │ └──────────────────────── D: PROFIBUS-DP protocol
│ │ └─────────────────────────── 5: communications processor (CP) type
│ └─────────────────────────────────── 342: S7-300 CP product family
└────────────────────────────────────────── 6GK7: Siemens Industrial Communication, S7 rack-mounted

The two characters that matter most when ordering a replacement are "03" (hardware revision) and "DA" (PROFIBUS-DP). Earlier revisions like "5DA02" and "5DA01" do not support the full DPV1 acyclic master services that many modern field devices — variable-speed drives, intelligent valve positioners, ET 200 distributed I/O — require for parameterization via STEP 7 or TIA Portal.

What the CP 342-5 Actually Does

The S7-300 CPUs (314, 315, 317, etc.) have a built-in MPI port and some models include an integrated PROFIBUS-DP interface. So why add a CP 342-5?

There are several situations where it becomes necessary — or at least significantly better:

Scenario 1 — Your CPU has no integrated PROFIBUS port. The S7-314 (6ES7314-1AG14) and similar entry-level CPUs have MPI only. Adding a CP 342-5 gives that CPU full PROFIBUS-DP master capability without replacing the CPU itself.

Scenario 2 — You need a second, independent PROFIBUS segment. A CPU with one integrated DP port can only manage one DP master segment. Adding a CP 342-5 creates a second independent DP master on the same S7-300 rack — useful for separating drive networks from distributed I/O networks, or for managing large device counts across two segments.

Scenario 3 — CPU load reduction on large networks. The CP 342-5 has its own processor that handles all PROFIBUS communication independently. The CPU simply reads and writes data in the process image via the SFC14/SFC15 (DPRD_DAT/DPWR_DAT) function calls. This offloading becomes noticeable on CPUs managing 50+ DP slaves with fast cycle times.

Scenario 4 — DP slave mode needed. The CP 342-5 can operate as a DP slave, allowing the S7-300 to be controlled as a peripheral from a higher-level DP master — common in multi-tier automation architectures.

Technical Specifications

Parameter	Specification
Manufacturer	Siemens
Order Number	6GK7342-5DA03-0XE0
Product Name	CP 342-5
Module Type	PROFIBUS-DP Communication Processor
Compatible Systems	SIMATIC S7-300 (all CPU variants)
Backplane Connection	S7-300 bus connector (right side of module)
PROFIBUS Protocol	DP-V0, DP-V1 (acyclic master services), FMS
Operating Mode	DP master (DPM1 / DPM2) or DP slave (selectable)
Max Data Rate	9.6 kbit/s to 12 Mbit/s
Max DP Slaves	125 per segment (as master)
DP-V1 Acyclic Services	Yes — read/write parameterization, alarm handling
FMS Services	Yes (PROFIBUS FMS as server)
Supply Voltage	24V DC via S7-300 backplane bus
Power Consumption	Approx. 1.2W
Slot Position	Any module slot in S7-300 rack (slots 4 onward)
Configuration Tool	STEP 7 v5.x / TIA Portal (with legacy support)
Hardware Revision	03 (DPV1 master support included)
Certifications	CE, UL, cUL, FM (hazardous location)
Operating Temperature	0°C to +60°C
Condition	New in original box

CP 342-5 Revision History — Does the Revision Number Matter?

Short answer: yes, it does — more than most people realize.

Order Number	Revision	DPV1 Master	FMS	Notes
6GK7342-5DA00	00	❌ No	✅ Yes	Early version, DP-V0 only
6GK7342-5DA01	01	❌ Limited	✅ Yes	Partial DPV1 slave only
6GK7342-5DA02	02	⚠️ Partial	✅ Yes	DPV1 slave + limited master
6GK7342-5DA03	03 ← this unit	✅ Full	✅ Yes	Full DPV1 master + slave

If your application uses devices that require DPV1 acyclic read/write for startup parameterization — Siemens SINAMICS drives, ABB ACS880 with PROFIBUS adapter, Festo CPX valve terminals, or any device where STEP 7 writes parameters at startup via SFB52/53 — you need revision 03. An older revision 01 or 02 CP 342-5 will connect to the DP segment and exchange cyclic I/O data, but will fail silently (or with configuration errors) when acyclic parameterization is attempted.

Programming Interface: SFC14 / SFC15 in STEP 7

Unlike integrated CPU PROFIBUS ports where DP slave data maps directly into the process image, the CP 342-5 requires explicit SFC calls in the S7-300 program to transfer data between the CPU and the CP's communications buffer:

Reading data from a DP slave into the CPU:CALL SFC 14 "DPRD_DAT"
LADDR := W#16#100 // Logical start address of DP slave (set in HW Config)
RET_VAL := MW10 // Return/error code
RECORD := P#M20.0 BYTE 8 // Destination memory area

Writing data from CPU to a DP slave:CALL SFC 15 "DPWR_DAT"
LADDR := W#16#100 // Logical start address of DP slave
RECORD := P#M30.0 BYTE 8 // Source data to send
RET_VAL := MW12

For DPV1 acyclic read/write (parameterization of intelligent devices), SFB52 (RDREC) and SFB53 (WRREC) are used instead, with the CP 342-5 handling the acyclic channel management independently from the cyclic DP data exchange.

The CP's logical start address and all DP slave assignments are configured in STEP 7 Hardware Configuration (HW Config) — the CP 342-5 appears as a module in the S7-300 rack, and the attached DP network is configured in the Properties dialog.

Typical Applications

Automotive body-in-white lines — the CP 342-5 manages a PROFIBUS-DP segment connecting welding gun servo controllers, clamp solenoid valve terminals, and part-present sensor blocks to a central S7-317, while the CPU handles the welding sequence logic independently.

Water and wastewater treatment — S7-300 CPU with CP 342-5 controlling a DP segment of pump VFDs (variable frequency drives) and motor protection relays across long cable runs in pump stations, where PROFIBUS's noise immunity advantages over older fieldbus alternatives are valued.

Pharmaceutical batch processing — CP 342-5 managing a PROFIBUS segment of intelligent valve positioners requiring DPV1 parameterization at each batch startup, with position feedback and partial stroke test results returned via acyclic DP-V1 read services.

Second DP segment on an existing S7-315-2 DP CPU — the S7-315-2 has one integrated DP port already managing distributed I/O. A CP 342-5 in the same rack adds a second independent DP master segment for a separate drive network, avoiding segment size limitations and isolating drive EMI from the I/O network.

Legacy system maintenance — replacement of a failed CP 342-5 (any earlier revision) in an existing installation. The "-03" revision is backward compatible with all earlier CP 342-5 configurations in STEP 7 HW Config — a direct swap-in without GSD file changes.

📦 Shipping & Availability

🔒 Genuine Siemens — factory sealed in original Siemens box with matching order number label
✅ New in box — not refurbished, not pulled from service
🌍 Worldwide express shipping via DHL / FedEx / UPS
⚡ In stock — dispatches within 1–2 business days

❓ FAQ — Siemens 6GK7342-5DA03-0XE0 CP 342-5

Q1: What is the CP 342-5 and how is it different from a CPU's integrated PROFIBUS port?

The CP 342-5 is a dedicated PROFIBUS-DP communication processor — a separate module with its own CPU and firmware that handles all PROFIBUS network management independently. The key difference from an integrated CPU DP port is processing offload: the CP 342-5 manages all cyclic DP data exchange, DPV1 acyclic services, and bus diagnostics on its own processor, while the S7-300 CPU focuses on the control program. For applications with large DP networks (40+ slaves), tight CPU cycle time requirements, or a need for a second independent DP master segment, a CP 342-5 is significantly better than relying on the CPU's integrated port. The CPU accesses CP data via SFC14/15 function calls rather than direct process image mapping.

Q2: Is the 6GK7342-5DA03-0XE0 compatible with TIA Portal, or only STEP 7 Classic?

The CP 342-5 was designed for the STEP 7 V5.x (Classic) environment, which remains the primary configuration tool. TIA Portal can work with it in a limited capacity — TIA Portal V13 SP1 and later include a STEP 7 V5.x compatibility layer for S7-300 projects, but full CP 342-5 HW Config and GSD file management is generally easier in STEP 7 Classic. If your project is running entirely in TIA Portal and the S7-300 CPU is managed there, the CP 342-5 still works but may require some configuration steps to be done in the STEP 7 Classic environment. For completely new projects that require PROFIBUS on an S7-300, Siemens has historically recommended keeping S7-300 projects in STEP 7 V5.x for the most stable CP 342-5 experience.

Q3: Can I replace an older 6GK7342-5DA01 or 5DA02 with this 5DA03 without changing the STEP 7 project?

Generally yes — the CP 342-5 revision 03 is backward compatible with STEP 7 HW Config entries for earlier revisions, and in most cases a physical swap-in will work without any project changes. However, there are two things to verify: first, confirm that your STEP 7 version supports the "03" revision entry in the hardware catalog (STEP 7 V5.4 SP4 and later include it); second, if the older module was configured as a DP slave (not master), verify the slave address and configuration are unchanged. After swapping the module, a brief online connection in STEP 7 to verify the CP is recognized correctly and that no configuration error is reported is always recommended before returning the machine to production.

Q4: How many PROFIBUS slaves can the CP 342-5 manage?

The CP 342-5 supports up to 125 DP slaves on its PROFIBUS segment as a DP master — this is the maximum defined by the PROFIBUS DP standard for a single segment. In practice, the actual number of slaves that can be actively polled within a given cycle time depends on the data volume per slave and the configured bus cycle time. For applications with many slaves transmitting large data sets, the effective limit before cycle times become unacceptably long may be lower than 125. Siemens provides a PROFIBUS configurator tool (part of STEP 7 HW Config) that calculates the actual DP cycle time based on the configured slave list and data sizes, which should be reviewed when the slave count or data volumes are high.

Q5: Does the CP 342-5 support PROFIBUS PA (Process Automation), or only DP?

The CP 342-5 supports PROFIBUS-DP and PROFIBUS-FMS, but not PROFIBUS-PA directly. PROFIBUS-PA uses the same protocol as DP (DP-V1) but runs on a different physical layer (IEC 61158-2, intrinsically safe) at 31.25 kbit/s, requiring a DP/PA coupler or DP/PA link device at the segment boundary. The CP 342-5 can act as the DP master managing a DP/PA coupler, which in turn connects to the PA segment — this is the standard architecture for connecting PROFIBUS-PA field instruments (flow meters, pressure transmitters) to an S7-300 system using a CP 342-5.

Q6: What does "DPV1 acyclic master" mean and when do I actually need it?

Standard PROFIBUS-DP (V0) exchanges data cyclically — every bus cycle, the master polls each slave and the slave responds with its current I/O data. This handles normal process data fine. DPV1 adds an acyclic channel alongside the cyclic data exchange, allowing the master to send parameterization commands and read diagnostic data from individual slaves at any time, independent of the cyclic exchange. You need DPV1 when working with intelligent field devices that require parameter download at startup — for example, a SINAMICS G120 drive needs its parameter set written via DPV1 at power-up; a Festo CPX valve terminal needs valve-specific configuration sent before it can operate; a Endress+Hauser Promag flowmeter needs engineering unit configuration via DPV1. Without DPV1 master support (i.e., using an older CP 342-5 revision), these devices either won't start up correctly or will require manual parameterization via a handheld device.

Q7: The CP 342-5 LEDs are showing a fault pattern — how do I interpret them?

The CP 342-5 has three diagnostic LEDs on its front panel: SF (System Fault — red), BF (Bus Fault — red), and ON (Power — green). The ON LED should always be green when the S7-300 rack is powered. SF lit indicates a module-level error — check the STEP 7 diagnostics buffer for the CPU and the CP 342-5 module status in HW Config online view for the specific error code. BF lit indicates a PROFIBUS communication problem — most commonly a disconnected cable, wrong bus termination (PROFIBUS segments require termination at both physical ends only), a slave with a mismatched address, or a data rate mismatch between the CP and the configured slaves. If both SF and BF are lit simultaneously after a firmware update or after swapping in a replacement module, a download of the hardware configuration to the CPU (not just the program) is usually needed to re-initialize the CP's parameters.

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