OpenPCS 7 Licensing Architecture and Operating System Requirements for OPC Server and Client Communications

To connect a SIMATIC PCS 7 system to a third-party non-Siemens server or SCADA host via OPC, licensing requirements depend strictly on whether PCS 7 acts as an OPC Server or an OPC Client. If external third-party clients need to read data, alarms, or historical archives from PCS 7, you must license OpenPCS 7: select either 'OpenPCS 7 Station / OS' to install the software directly on an existing WinCC OS Server or Single Station, or 'OpenPCS 7 Station' for a dedicated standalone gateway PC. Conversely, if WinCC OS acts purely as an OPC Client connecting to an external third-party OPC server, no OpenPCS 7 license is required; the WinCC OPC DA/UA Client channel is included in standard WinCC Runtime licenses.

Executive Summary

In enterprise automation architectures, industrial facilities frequently require bidirectional data exchange between SIMATIC PCS 7 and external non-Siemens supervisory systems, historians, Manufacturing Execution Systems (MES), or Enterprise Resource Planning (ERP) platforms. A persistent procurement and engineering dilemma arises regarding the licensing, software packaging, and role definitions of OpenPCS 7. Engineers often struggle to determine whether adding an OPC link requires procuring expensive OpenPCS 7 licenses when their WinCC OS is merely acting as a client to an external OPC server, or which specific OpenPCS 7 license package must be applied when exposing PCS 7 data to external third-party consumers. This article establishes the functional boundaries and official licensing rules for OpenPCS 7.

Architecture and Fundamental Mechanics

The communication and licensing models of OpenPCS 7 are defined by distinct server/client roles and network deployments:

PCS 7 as an OPC Server (OpenPCS 7 Architecture):
- When external third-party applications (e.g., OSIsoft PI, AspenTech, SAP, third-party SCADA) need to extract real-time data, alarms, or historical trends from PCS 7, PCS 7 must act as an OPC Server.
- Siemens fulfills this via OpenPCS 7, which provides certified OPC interfaces: OPC Data Access (OPC DA), OPC Historical Data Access (OPC HDA), OPC Alarms & Events (OPC A&E), and modern OPC Unified Architecture (OPC UA).
- OpenPCS 7 consolidates data across multiple OS Servers in a plant, presenting a single unified address space to external clients.
OpenPCS 7 Deployment Packages and Licensing:
- OpenPCS 7 Station / OS Package: A software expansion license designed to install OpenPCS 7 services directly on an existing WinCC OS Server or OS Single Station. It eliminates the need for additional PC hardware, ideal for small-to-medium plants.
- OpenPCS 7 Station (Standalone Client Gateway): A software package installed on a dedicated, standalone PC operating as an OS Client. This dedicated gateway isolates external IT/MES network traffic from the critical plant bus and OS servers, complying with IEC 62443 demilitarized zone (DMZ) security guidelines. Requires dedicated OS Client and OpenPCS 7 runtime licenses.
PCS 7 as an OPC Client (Standard WinCC Channel):
- If the engineering goal is the reverse—where an external third-party PLC or server acts as an OPC server, and PCS 7 WinCC OS must read tags from it—PCS 7 operates as an OPC Client.
- In this mode, WinCC utilizes the integrated OPC or OPC UA WinCC Channel in WinCC Tag Management. This functionality is included natively within standard WinCC Runtime and Process Object (PO) licenses; no OpenPCS 7 license is required.
Engineering and Configuration Tool Licensing: OpenPCS 7 does not require proprietary engineering licenses; its address space is populated automatically during standard PCS 7 OS compilation.

Step-by-Step Implementation Procedure

Determine requirements and deploy the appropriate OPC interface following this procedure:

Scenario A: Configuring WinCC OS as an OPC Client (Zero Extra Licenses)

In WinCC Explorer on the OS, open Tag Management.
Right-click Tag Management -> Add new driver -> select OPC.chn (or OPC UA WinCC Channel).
Right-click the OPC driver -> System Parameters -> browse and select the third-party OPC server on the network.
Browse the remote tags and map them into WinCC tag groups. Standard WinCC RT PO licensing applies.

Scenario B: Deploying OpenPCS 7 as an OPC Server (OpenPCS 7 Required)

Select Deployment Architecture:
- For co-located server: Procure OpenPCS 7 Station / OS.
- For DMZ gateway: Procure a dedicated industrial PC, install as an OS Client, and procure OpenPCS 7 Station.
Install OpenPCS 7 Software:
- On the target machine, run the PCS 7 installation wizard and check OpenPCS 7.
- Transfer the OpenPCS 7 license key using Automation License Manager (ALM).
Configure Component View and OS Compilation:
- In SIMATIC Manager Component View, if using a standalone gateway, insert a SIMATIC PC Station with an OpenPCS 7 application.
- In Plant View, assign the OpenPCS 7 station to the target OS server packages.
- Compile OS and download the configuration.
Establish External Client Connection:
- Point the external third-party client (e.g., OPC Scout or MES client) to OPC.SimaticNET or the OpenPCS 7 OPC UA endpoint (opc.tcp://<HostName>:4862). Authenticate via Windows user accounts configured in the SIMATIC HMI group.

Verification

Verify OPC communication and license authorization:

License Validation: Open Automation License Manager (ALM) on the OpenPCS 7 node. Verify that the OpenPCS 7 license indicates status In Use without licensing error popups.
Address Space Browsing: Launch Siemens OPC Scout V10 on an external client PC. Browse the OpenPCS 7 server. Confirm that the full Plant Hierarchy, process tags, and structured APL variables (.Value, .ST) are visible and readable.
Real-Time Data Streaming: Subscribe to live process variables. Confirm that values update dynamically with status Good (16#80).

Limitations and Operational Precautions

OpenPCS 7 must never be exposed directly to untrusted public networks or corporate intranets without an intervening firewall and proper DMZ architecture; unencrypted OPC DA relies on Microsoft DCOM, which is inherently vulnerable and blocked across modern enterprise routers. Use OpenPCS 7 OPC UA with encrypted certificates whenever communicating across network boundaries. All software order numbers (MLFBs) and license counts must be officially validated with an authorized Siemens distributor or the Siemens Industry Mall.

Engineer FAQ

Do I need an OpenPCS 7 license if WinCC is only reading tags from an external OPC server?

No. When WinCC acts as an OPC client reading from an external server, the standard WinCC OPC channel is used, which requires no additional OpenPCS 7 license.

What is the difference between 'OpenPCS 7 Station / OS' and 'OpenPCS 7 Station'?

'OpenPCS 7 Station / OS' is an add-on license to run OpenPCS 7 directly on an existing OS Server. 'OpenPCS 7 Station' is a license for a dedicated standalone PC acting as an OPC gateway.

Does OpenPCS 7 support OPC UA?

Yes. Starting with PCS 7 V8.0+, OpenPCS 7 provides certified OPC UA server capabilities alongside legacy OPC DA, HDA, and A&E.

Does OpenPCS 7 consume Process Object (PO) licenses?

No. OpenPCS 7 is licensed per server station; it does not consume additional AS or OS Runtime Process Object (PO) licenses.

Can external OPC clients write values back into PCS 7 via OpenPCS 7?

Yes. OpenPCS 7 supports read and write access, provided the connecting Windows user account is granted operational authorization in SIMATIC Logon and the tags are not write-protected in CFC.