How to Configure a PN-PN Coupler for Third-Party Controller Communication in SIMATIC PCS 7

To configure a SIMATIC PN/PN Coupler for data exchange between PCS 7 and a third-party controller (such as Rockwell or Schneider), insert the PN/PN Coupler from the HW Config catalog onto the PCS 7 PROFINET IO system for Subnet 1, and configure mirrored Input/Output virtual submodules. In the third-party engineering tool, import the coupler's GSDML file for Subnet 2 and configure the reverse mapping (Inputs map to PCS 7 Outputs, and Outputs map to PCS 7 Inputs). In PCS 7 CFC, process data and signal status are managed using standard APL channel blocks or the dedicated PN/PN Coupler library.

PN/PN Coupler Operating Principles and Network Isolation

The SIMATIC PN/PN Coupler (e.g., 6ES7158-3AD10-0XA0) provides deterministic, deterministic cyclic I/O data exchange between two independent PROFINET subnets. It features two electrically and logically isolated PROFINET interfaces (Network Side X1 and Network Side X2).

Key operational characteristics include:
* Subnet Independence: Each side maintains its own IP address range, PROFINET device name, subnet mask, update time, and clock domain. There is no IP routing between sides, preventing third-party broadcast storms or network loops from impacting the PCS 7 Plant Bus.
* Mirrored Memory Transfer: The coupler features internal shared dual-port memory. Bytes written as outputs by Controller 1 (PCS 7 on Side X1) appear cyclically as inputs to Controller 2 (Third-party PLC on Side X2), and vice versa.
* Deterministic Transfer Times: Data transfer across the coupler bridge typically executes within 1 to 2 PROFINET bus cycles.

Step-by-Step HW Config Setup in SIMATIC PCS 7 (Subnet 1)

To integrate the PN/PN Coupler into SIMATIC PCS 7 on Network Side X1:

Insert Device in HW Config:
* Open the PCS 7 AS hardware configuration (HW Config) for the CPU 410-5H or CP 443-1.
* From the Hardware Catalog, expand PROFINET IO -> Gateway -> PN/PN Coupler.
* Drag the coupler model onto the PROFINET IO system.
Assign Device Name and IP Address:
* Open object properties. Assign a unique PROFINET device name (e.g., pn-coupler-x1) and an IP address belonging to the PCS 7 PROFINET subnet.
Configure Virtual I/O Submodules:
* Double-click the coupler to open the slot configuration table.
* Add required input and output modules from the catalog based on process needs (e.g., Slot 1: 16 Bytes In / 16 Bytes Out or Slot 2: 8 Words In with Quality Code).
* Note the start addresses (e.g., PIW 512 and PQW 512).
Compile and Download AS:
* Save and compile HW Config. Download the hardware configuration to the automation station.

Third-Party Controller Configuration and Mirror Mapping (Subnet 2)

On the third-party engineering platform (e.g., Rockwell Automation Studio 5000, Schneider Unity Pro, or Beckhoff TwinCAT):

Install Coupler GSDML File:
* Download the official Siemens PN/PN Coupler GSDML file from Siemens Industry Online Support.
* Register the GSDML in the third-party programming tool.
Configure Network Side X2:
* Add the PN/PN Coupler X2 device to the third-party PROFINET IO scanner.
* Assign the device name (e.g., pn-coupler-x2) and the third-party plant subnet IP.
Apply Inverted Mirror Module Layout:
* The slot configuration on Side X2 must be the exact mirror of Side X1:
- If PCS 7 Slot 1 is configured as 16 Bytes In, the third-party PLC Slot 1 must be configured as 16 Bytes Out.
- If PCS 7 Slot 2 is configured as 32 Bytes Out, the third-party PLC Slot 2 must be configured as 32 Bytes In.
CFC Integration in PCS 7:
* In PCS 7 CFC, link the peripheral I/O addresses to standard channel blocks (Pcs7DiIn, Pcs7DiOu, Pcs7AnIn, Pcs7AnOu) or utilize the specialized Siemens PCS 7 PN/PN Coupler Function Library (9LA1110-6CG20-0AA0), which manages data consistency and NAMUR quality codes across the bridge.

Verification

Inspect the diagnostic LEDs on the physical PN/PN Coupler:
SF1 and BF1 (Side X1) must be OFF, and ON1 / LK1 must illuminate steady green.
SF2 and BF2 (Side X2) must be OFF, and ON2 / LK2 must illuminate steady green.
In PCS 7 CFC, open a chart in test mode reading an input address from the coupler.
Have the third-party engineer write a known hexadecimal pattern (e.g., 16#ABCD) to their output word.
Verify that the identical pattern arrives in PCS 7 CFC within the expected PROFINET cycle (< 10 ms).

Limitations and Operational Precautions

If the slot configuration does not match symmetrically between Side X1 and Side X2 (e.g., 16 bytes vs. 32 bytes), the coupler asserts a bus fault (BF) on the mismatched interface and refuses data transmission.
A power cycle or network loss on the third-party controller causes Side X1 to output zero or stale data unless valid data status (IOPS/IOCS) is monitored. Always evaluate channel quality codes.
For safety-critical signals, use a PROFIsafe-compatible safety bridge or F-I/O communication blocks with CRC checksums.

Engineer FAQ

Can a PN/PN Coupler route IP packets between the two networks?
No. The PN/PN Coupler is strictly an I/O data reflector. It does not route IP traffic, preventing unauthorized access across corporate or plant boundaries.
What happens to PCS 7 inputs if the third-party PLC stops running?
The coupler sets the provider status (IOPS) to bad. In PCS 7, channel blocks evaluating the submodule quality code will assert Bad = 1.
Is the ready-made PCS 7 PN/PN Coupler library mandatory?
No. Standard APL channel blocks (Pcs7DiIn/Pcs7AnIn) or direct peripheral addressing can be used. However, the dedicated library (9LA1110-6CG20-0AA0) simplifies diagnostics and data consistency.

Technical References

SIMATIC PN/PN Coupler Hardware and Software Installation Manual (A5E43242036-AA).
Siemens Industry Online Support Entry ID 109801081: Redundant Process Data Transfer with SIMATIC PN/PN Coupler and PCS 7.
PROFINET IO Specification: Module Mapping and Shared Memory Gateways.