Integrating Third-Party Controllers with SIMATIC PCS 7 Using PCS 7 Open OS and DBA

To integrate third-party PLCs (e.g. Modbus TCP, Rockwell ControlLogix, OPC DA/UA, or S7-300/1200) into a centralized SIMATIC PCS 7 operator station, engineers deploy SIMATIC PCS 7 Open OS. Open OS utilizes the Database Automation (DBA) engineering tool to import external controller tag lists, map them into standardized PCS 7 technological types (analog indicators, motors, valves), and automatically generate WinCC OS tags, Alarm Logging messages, and Plant Hierarchy block icons with native APL look-and-feel.

The Concept and Architectural Purpose of PCS 7 Open OS

Industrial manufacturing facilities frequently feature heterogeneous automation landscapes. Alongside standard SIMATIC PCS 7 process units, plants operate packaged equipment skids, water treatment packages, boiler controls, and legacy subsystems governed by non-PCS 7 controllers:
* Third-party PLCs (Rockwell Allen-Bradley ControlLogix, Schneider Electric Modicon, GE Fanuc)
* Standard Siemens PLCs programmed outside PCS 7 (SIMATIC S7-300, S7-1200, S7-1500 programmed in TIA Portal)
* Substation automation packages communicating over Modbus TCP or OPC DA/UA

Historically, integrating these skids into PCS 7 required manual WinCC graphics creation, individual tag creation in Tag Management, manual alarm message numbering in Alarm Logging, and custom VBS scripting.

To eliminate this manual burden, Siemens introduced SIMATIC PCS 7 Open OS. Open OS treats third-party controllers as first-class citizens within the PCS 7 OS environment, enabling automatic block icon generation, faceplate navigation, and unified alarm management identical to native S7-400 APL controllers.

The Role of the Database Automation (DBA) Engineering Tool

At the heart of PCS 7 Open OS lies the Database Automation (DBA) software package:
* DBA is a standalone engineering configurator that bridges the external controller database and the WinCC OS project.
* It parses exported tag and symbol files from third-party programming tools (e.g. Rockwell .L5K / .CSV files, Schneider .XSY exports, or live OPC server address spaces).
* Engineers configure technological Type Definitions in DBA (e.g. a standard motor type possessing Run, Stop, Fault, Speed, and Current tags).
* When DBA compiles to the OS, it automatically creates:
1. WinCC Structure Tags matching the technological types.
2. Alarm Logging messages with chronological timestamps and alarm priority classes.
3. WinCC Plant Hierarchy folders.
4. APL-style block icons positioned automatically on target process graphics (.pdl).

Communication Channels Supported by PCS 7 Open OS

PCS 7 Open OS communicates with external controllers through standard WinCC communication channel DLLs:
1. OPC Channel (OPC DA and OPC UA):
The universal gateway. The third-party PLC communicates with an industrial OPC Server (e.g. Kepware KEPServerEX, Matrikon, or Rockwell FactoryTalk Gateway). WinCC connects as an OPC client.
2. Modbus TCP Channel:
Direct Ethernet connection to PLCs, energy meters, and remote terminal units (RTUs) supporting standard Modbus TCP protocol without intermediary software.
3. SIMATIC S7 Protocol Suite:
Communicates directly with SIMATIC S7-300, S7-400 (standard), S7-1200, and S7-1500 controllers via Industrial Ethernet TCP/IP.

Native PCS 7 vs. Open OS Integration Comparison Matrix

The following matrix compares standard PCS 7 engineering against Open OS third-party integration:

Feature / AttributeNative PCS 7 (S7-400 / CPU 410)PCS 7 Open OS (Third-Party / S7-300)Controller EngineeringContinuous Function Chart (CFC)Native vendor software (Studio 5000, TIA Portal)OS Tag GenerationAutomated via AS-OS CompileAutomated via Database Automation (DBA)Faceplate ArchitectureNative APL FaceplatesOpen OS APL-Style FaceplatesAlarm GenerationController-based (ALARM_8P / SFB 35)WinCC Tag-Based Bit Alarms or Controller AlarmsTime SynchronizationCentralized SICLOCK / Plant Bus masterNTP or OPC timestamp synchronizationLicense RequirementStandard AS / OS RT PO LicensesPCS 7 Open OS Engineering + Runtime LicensePlant Hierarchy SupportNative in SIMATIC ManagerSynchronized via DBA into WinCC Plant Hierarchy

Step-by-Step Procedure to Integrate Third-Party PLCs via DBA

Follow this standardized workflow to deploy PCS 7 Open OS:
1. Export Tags from the Third-Party Controller:
- In the third-party PLC programming tool (e.g. Rockwell Studio 5000), export controller tags to a CSV or L5K file.
- Alternatively, if using an OPC server, verify the OPC server is online and browsing tags successfully.
2. Configure the Communication Channel in WinCC:
- In WinCC Explorer, add the appropriate channel under Tag Management (e.g. OPC.chn or Modbus TCPIP.chn).
- Define the connection to the PLC or OPC Server and verify communication is healthy.
3. Create and Configure a DBA Project:
- Launch SIMATIC PCS 7 DBA.
- Create a new DBA project linked to your target WinCC OS project.
- Add a new Controller: Choose the controller type (e.g. Rockwell ControlLogix, Modbus Device, or OPC Source).
- Point DBA to the exported tag file or browse the live OPC server.
4. Define Technological Types and Map Objects:
- In DBA, expand Type Definitions. Match external PLC tags to Open OS technological objects (e.g. map PUMP_RUN_FB to Motor.Run, PUMP_CMD to Motor.Start).
- Assign technological objects to specific folders in the Plant View tree within DBA.
5. Compile DBA to WinCC OS:
- Select File -> Compile -> OS.
- Select target options: Generate Structure Tags, Generate Messages, and Create Block Icons.
- Click Start. DBA will automatically populate the WinCC OS project database.
6. Position Block Icons and Verify Faceplates:
- Open Graphics Designer on the OS: Open the process picture generated in the hierarchy.
- Arrange the newly placed block icons.
- Save the graphic and test faceplate callup in WinCC Runtime.

Verification

Verify third-party controller integration and operator controls:
1. Launch WinCC Runtime on the OS Server / Client.
2. Navigate to the graphic containing the generated Open OS block icon.
3. Confirm that live process values, run feedback, and status indicators reflect the actual physical state of the third-party PLC.
4. Click the block icon: Confirm the Open OS faceplate opens, displaying alarm limits, control buttons, and trend curves.
5. Issue an operator command from the faceplate (e.g. Start Motor): Verify that the third-party PLC receives the command tag and energizes the field actuator.
6. Trigger an alarm condition on the third-party PLC: Verify the alarm appears in the WinCC Alarm Logging banner with correct timestamp and description.

Limitations and Operational Precautions

PCS 7 Open OS cannot execute CFC code downloads or hardware configuration downloads to third-party controllers; controller programming remains entirely within the vendor's native software.
Communication update speed depends on the polling cycle of the underlying channel (e.g. Modbus TCP or OPC DA); do not expect sub-100 ms loop execution across slow polling links.
Commercial licensing note: Deploying Open OS requires dedicated PCS 7 Open OS engineering and runtime packages (e.g. 6ES7658-2G...); validate licensing requirements against authorized Siemens distributor quotations.

Engineer FAQ

Can PCS 7 Open OS generate APL-style faceplates for third-party motors and valves?

Yes. PCS 7 Open OS includes a library of WinCC faceplates and block icons designed with the exact look-and-feel, color schemes, and operating ergonomics of the PCS 7 Advanced Process Library (APL).

Does Open OS support sequence and batch integration via SIMATIC BATCH?

Direct integration of third-party PLCs into SIMATIC BATCH requires equipment phase interface blocks. While basic signals can be mapped, full recipe phase execution is significantly more complex than with native S7-400 controllers.

What happens if the OPC Server loses connection to the third-party PLC?

WinCC marks all dynamic tags as disconnected (??? or bad quality), and Open OS block icons display a communication fault badge, alerting operators immediately.