Configuring WinCC Application Reference (WinCC Appl Ref) for PCS 7 Operator Stations

In SIMATIC PCS 7, a WinCC Application Reference ('WinCC Appl. (ref)') is an architectural component used in a PC Station configuration to deploy identical secondary operator stations—such as redundant OS Single Stations or identical OS Clients—based on an existing 'Base OS'. Rather than duplicating independent WinCC projects, the Reference OS inherits the Base OS project database directly. During project compilation, only the Base OS is compiled. When downloading to the Reference PC station, SIMATIC Manager automatically copies the project, renames internal database computer references to match the destination station, and configures runtime communication without manual reconfiguration.

Executive Summary

Standardizing human-machine interface configurations across multi-station control rooms is essential to reduce engineering overhead and eliminate version divergence. When designing architectures with redundant OS Single Stations or pools of identical OS Clients, commissioning engineers frequently duplicate the primary OS project, resulting in redundant compilations and double the engineering maintenance. SIMATIC PCS 7 provides the WinCC Application Reference (WinCC Appl. (ref)) to solve this challenge. By linking multiple PC Stations to a single Base OS, engineers compile once and deploy universally. This article explains the architectural role of Reference OS applications, details the configuration sequence, and outlines operational mechanics.

Architecture and Fundamental Mechanics

Base OS vs Reference OS Architecture, Single-Compilation Mechanics, and Deployment Synchronization:

Architectural Concept of the Reference OS:
In SIMATIC PCS 7, a standard Operator Station contains a WinCC Application (the Base OS) hosting the master project files, graphics (.pdl), scripts, and tag management databases.
A WinCC Application (ref) is a virtual shadow object inserted into a secondary PC Station's hardware configuration.
The Reference OS contains NO independent project databases in the engineering project tree; it points directly to the Base OS.
Single Compilation and Multi-Target Download:
Single Compile: During OS Compilation, SIMATIC Manager compiles S7 connections, alarms, and tags exclusively into the Base OS project.
Automated Parameter Transformation during Download:
1. When the engineer executes PLC > Download targeting the Reference PC Station, the ES copies the compiled project from the Base OS.
2. During the transfer, the deployment engine modifies the internal WinCC database table (CC_Project.mdf), automatically replacing the Base OS computer name with the Reference PC's Windows computer name.
3. Network communication parameters are adjusted to bind to the Reference PC's Station Configuration Editor slots.
Approved Architectural Use Cases:
Redundant OS Single Stations: Station A hosts WinCC Application (Base); Station B hosts WinCC Appl. (ref) (Standby).
Identical OS Clients: Multiple client stations across a control room sharing an identical operator display layout without maintaining distinct client projects.

Step-by-Step Implementation Procedure

Configure the Primary PC Station (Base OS):
* In SIMATIC Manager Component View, insert a PC Station for the primary station (e.g. OS_BASE).
* Open HW Config for OS_BASE; insert WinCC Application in Slot 1 and IE General (or CP 1623) in Slot 2.
* Save and compile HW Config.
Configure the Secondary PC Station (Reference OS):
* Insert a second PC Station in Component View for the secondary station (e.g. OS_REF01).
* Open HW Config for OS_REF01.
* From the hardware catalog (SIMATIC PC Station > HMI), drag and drop WinCC Appl. (ref) into Slot 1.
* Insert the network interface card (e.g. IE General) into Slot 2.
* Save and compile HW Config.
Assign the Base OS to the Reference OS in SIMATIC Manager:
* In SIMATIC Manager Component View, expand OS_REF01 to view its OS object.
* Right-click the OS object and select Object Properties.
* In the Target OS and Standby OS Computer tab, locate Assign Base OS.
* Select OS_BASE from the dropdown list as the base project.
* Under 'Path to the Target OS Computer', configure the network UNC share for the reference machine (e.g. \\OS_REF01\WinCC_Project).
* Click OK.
Compile the Base OS:
* Right-click OS_BASE and select Compile.
* Complete the OS compilation wizard; confirm that compilation succeeds.
Download to Base and Reference Stations:
* Download OS_BASE first (PLC > Download).
* Download OS_REF01 (PLC > Download); verify that SIMATIC Manager copies the project and updates computer names automatically.

Verification

On the Reference PC station, open WinCC Explorer; confirm that the project title bar displays the Reference PC's local computer name.
Start WinCC Runtime on both stations; verify that process graphics and tag values animate identically on both screens.
If configured for single-station redundancy, verify that alarm acknowledgment and archive synchronization operate across both machines.

Limitations and Operational Precautions

You cannot compile a Reference OS independently; attempting to compile WinCC Appl. (ref) directly prompts an error indicating that compilation must be executed on the Base OS. Always download the Base OS successfully before downloading the Reference OS.

Engineer FAQ

What is a WinCC Appl. (ref) used for in PCS 7?

It is used to configure identical secondary operator stations (such as redundant OS Single Stations or identical OS Clients) that share a Base OS project.