Migrating a SIMATIC PCS 7 ES-OS Single Station to a Redundant OS Server Pair and Dedicated ES

To migrate an existing SIMATIC PCS 7 V8.1 ES/OS Single Station to a high-availability client-server architecture with a dedicated Engineering Station (ES) and a redundant OS Server pair (Master and Standby), engineers must restructure the PCS 7 Multiproject. This involves adding two SIMATIC PC Stations configured with WinCC Application and WinCC Application (stby), converting the existing Single-User WinCC project into a Multi-User Project, configuring the WinCC Redundancy Editor, updating NetPro named connections, reassigning the Plant Hierarchy OS assignment, generating Server Data, and replicating the project via the Project Duplicator.

Architecture Transformation: Single Station to Redundant Client-Server

An ES/OS Single Station combines engineering software (STEP 7, CFC, SFC, PDM) and operator station runtime (WinCC Explorer, Graphics Runtime, Alarm Logging) on a single physical IPC. While cost-effective for small facilities, a Single Station presents a single point of failure and prohibits concurrent engineering during continuous operation.

Migrating to a redundant OS architecture with a dedicated ES provides 24/7 high availability. The architecture requires:
1. Dedicated ES: Retains engineering licenses and multiproject databases, communicating with AS controllers over the Plant Bus and with OS servers over the Terminal Bus.
2. OS Server Master (OS1): Executes active data acquisition, process alarming, and historical archiving, hosting a multi-user WinCC project.
3. OS Server Standby (OS2): Operates in continuous warm standby, continuously synchronizing process tags, alarm states, and archive segments with OS1 across a dedicated network redundancy connection.
4. OS Clients: Operator consoles loaded with client projects that access the redundant server pair via generated Server Data packages.

Multiproject Reconfiguration and Station Definition

The conversion requires structural adjustments in the SIMATIC Manager Component View and Plant View:

PC Station Definitions: The original single-station PC Station (WinCC Appl. Single) is decommissioned or repurposed as the dedicated ES. Two new SIMATIC PC Stations are created: OS_SRV1 containing WinCC Appl. and CP 1623 (6GK1162-3AA00), and OS_SRV2 containing WinCC Appl. (stby).
NetPro Communication: Named S7 connections (S7-Verbindung) must be routed from the AS controller (e.g. CPU 410-5H, 6ES7410-5HX08-0AB0) to both OS servers individually.
Project Duplicator: The engineering project is authored and compiled on the ES, and the Project Duplicator tool transfers identical runtime databases to both physical server IPCs (e.g., SIMATIC IPC647D, 6AG4112-2KA40-0BX0).

Comparison of Single Station vs Redundant OS Server Configurations

The following table compares the structural, network, and operational differences between the architectures:

Architectural ParameterES/OS Single StationDedicated ES + Redundant OS ServersWinCC Project TypeSingle-User ProjectMulti-User Project with Redundant PartnerSIMATIC PC Station Objects1 PC Station (WinCC Appl. Single)3 PC Stations (1 ES + 1 WinCC Appl. + 1 WinCC Appl. (stby))Plant Bus Connection1 S7 Connection to AS2 Independent S7 Connections to AS (1 per Server)Redundancy SynchronizationNot ApplicableRedundancy Editor over Terminal Bus and Serial/Network HeartbeatClient SupportStandalone or Web Navigator clients onlyFull OS Multi-Clients with server package loadingEngineering ConcurrencyEngineering actions impact runtime process viewCompletely decoupled; ES downloads changes bumplesslyHardware Failover TimeNone (station failure stops monitoring)Bumpless switchover (< 1 second) with archive sync

Step-by-Step Procedure to Convert and Deploy the Redundant OS Pair

Follow this rigorous engineering procedure to execute the migration:

Multiproject Backup and Hardware Station Insertion:
- Create a complete project archive using File -> Archive.
- In SIMATIC Manager Component View, right-click the Multiproject and insert two new SIMATIC PC Stations: OS_SERVER_1 and OS_SERVER_2.
- Open HW Config for OS_SERVER_1. Insert a WinCC Appl. into Slot 1 and a CP 1623 (or IE General) into Slot 2.
- Open HW Config for OS_SERVER_2. Insert a WinCC Appl. (stby) into Slot 1 and the corresponding network card into Slot 2.
- Save and compile HW Config for both stations.
Configure NetPro S7 Connections:
- Open NetPro. Select OS_SERVER_1 / WinCC Appl. and insert a new S7 connection to the AS controller. Repeat for OS_SERVER_2.
- Select Network -> Save and Compile. Download the network configuration to the AS controller during a scheduled window.
Convert WinCC Project Type and Configure Redundancy:
- Open the WinCC project of OS_SERVER_1 in WinCC Explorer.
- Open Project Properties. Change the Project Type from Single-User Project to Multi-User Project.
- Open the Redundancy editor in WinCC Explorer. Check Activate Redundancy.
- Enter the computer name of OS_SERVER_2 in the 'Redundant Partner Server' field.
- Select the network adapter on the Terminal Bus for connection checking, and enable automatic synchronization after partner recovery.
Reassign Plant Hierarchy and Compile AS-OS:
- In SIMATIC Manager Plant View, right-click the root Plant Hierarchy folder, select Properties, and reassign the target OS from the old single station to OS_SERVER_1.
- Right-click the OS object under OS_SERVER_1 and select Compile. Choose 'Entire OS' with 'With memory reset' to map all S7 tags to the new multi-user structure.
- In WinCC Explorer on OS_SERVER_1, right-click Server Data and select Generate.
Deploy Project to OS Server 2 via Project Duplicator:
- Close the WinCC project on the ES.
- In Windows, launch Tools -> Project Duplicator (from Siemens WinCC tool menu).
- Specify the source project path (OS_SERVER_1.mcp) and target project UNC path (\\OS_SERVER_2\WinCC_Project\). Click Duplicate.
- Verify that the duplicator automatically adapts computer names and redundancy parameters for Server 2.

Verification

Verify system migration and redundancy operation through the following steps:
1. Start WinCC Runtime on OS_SERVER_1. Confirm successful AS-OS communication and dynamic tag updates.
2. Start WinCC Runtime on OS_SERVER_2. Confirm internal redundancy tags: @RedundancyServerState must report 1 (Master) on OS1 and 2 (Standby) on OS2.
3. Verify archive synchronization: Generate a test alarm or process tag change on OS1, disconnect OS2 network cable, reconnect, and verify that the Redundancy Control window indicates 'Archive synchronization completed'.
4. Open an OS Client, download server packages, and confirm that process graphics display without connection errors.

Limitations and Operational Precautions

Software Licensing and Process Object Verification: Migrating from Single Station to a Redundant Server pair requires distinct runtime licenses: two WinCC Server runtime licenses, an OS Redundancy package (6AV6371-1CA07-5AX0), and identical AS RT / OS RT PO counts on both servers. Procurement must be verified prior to commissioning.
Terminal Bus Decoupling: Redundant OS servers must have dedicated network interfaces for the Terminal Bus (OS-to-Client and OS-to-OS) and Plant Bus (OS-to-AS). Never bridge these subnets on a single network adapter.
Computer Name Matching: The Windows computer names of the physical IPCs must exactly match the SIMATIC PC Station computer names configured in SIMATIC Manager; otherwise, WinCC Runtime cannot launch.

Engineer FAQ

Do I need to re-engineer all my graphics screens when migrating to redundant servers?

No. The graphic pictures (*.pdl), global scripts, and alarm configurations remain 100% reusable. Reassigning the Plant Hierarchy and compiling AS-OS updates all tag connections to the new Multi-User server structure automatically.

Why does WinCC Project Duplicator fail during migration?

Project Duplicator typically fails if the source project is currently open in WinCC Explorer, if Windows sharing and security permissions (read/write access for user group SIMATIC HMI) are not granted on the target server folder, or if network name resolution via DNS/NetBIOS is failing.

What happens to existing historical trend data during the migration?

Historical archives stored on the old single station reside in Microsoft SQL Server database segments (*.mdf / *.ldf). They can be exported using the WinCC Archive Configuration backup tool and attached to the new OS Server archive directory using the 'Restore' function.