Configuring Combined ES OS Single Stations and Multi-User Access in PCS 7

A single industrial PC can function as a combined SIMATIC PCS 7 Engineering Station (ES) and Operator Station (OS Single Station). In this minimal architecture, the ES hosts the multiproject database while WinCC Runtime executes locally on the same hardware. However, an ES cannot download the OS to itself via the standard Target OS Download mechanism; instead, activate runtime directly from the local project tree or configure OS simulation. To accommodate additional operators with restricted privileges, equip the single station with a WinCC Server license and connect an OS Client over the terminal bus, configuring specific rights in WinCC User Administrator.

PCS 7 Minimal Architecture: Combined ES/OS Single Station Overview

In small-to-medium process plants, pilot plants, and package units, deploying separate physical servers for engineering, OS server redundancy, and operator clients is often economically unfeasible. Siemens officially validates a minimal architecture known as the Combined ES/OS Single Station (ES/OS Single Station).

In this topology, a single industrial PC (such as a SIMATIC IPC547 or IPC647) fulfills dual roles:

Engineering Station (ES): Runs SIMATIC Manager, CFC, SFC, HW Config, and S7-SCL. It communicates with S7-400 controllers over the Plant Bus (Industrial Ethernet via CP 1623 or standard network adapter via Basic Communication).
Operator Station (OS Single Station): Runs WinCC Runtime directly on the same PC, managing plant visualization, alarm logging, trend archives, and operator faceplates.

Local OS Activation vs Target OS Download Limitations

A foundational engineering rule in SIMATIC PCS 7 states:

An Engineering Station cannot execute a target OS download to its own local computer.

In standard client/server architectures, the ES downloads compiled WinCC project files over the terminal bus to a remote OS Server using the WinCC Download Service (CCProjectMgr.exe). However, on a combined ES/OS single station, the project database already resides on the local drive (C:\... or D:\...). Attempting a network target download to the local machine triggers file sharing conflicts and network path errors.

To operate runtime on a combined ES/OS single station:

Open SIMATIC Manager and navigate to the OS component under the PC Station.
Right-click the OS object and select Open Object to open the project in WinCC Explorer.
Activate runtime directly by clicking Activate (Runtime button) in WinCC Explorer.
For testing during engineering, select the OS in SIMATIC Manager and choose PLC -> Start OS Simulation.

Expanding Multi-User Workstations with OS Clients and Access Rights

When a plant requires a secondary operating location with limited operator privileges (e.g., viewing trends and acknowledging alarms without engineering or setpoint modification rights):

Multi-User Licensing: Equip the combined ES/OS station with the WinCC Server for PCS 7 license option. This transforms the single station into an OS Single Station with multi-user client support.
Deploy an OS Client Workstation: Install an industrial PC loaded with PCS 7 OS Client software (6ES7658-2FX58-0YH5) connected via the terminal bus.
Server Data Assignment: Download server data (<ProjectName>.pck) from the ES/OS to the client.
User Security Hierarchy: In WinCC Explorer on the ES/OS station, open User Administrator and define user groups:
- Administrator Group: Authorization level 1000 (Full engineering and OS configuration).
- Chief Operator Group: Authorization level 5 and 6 (Process control and higher-level setpoints).
- Field Operator Group: Authorization level 5 (Basic process control; limited acknowledgment).
- Guest / Monitor Group: Authorization level 1 (View only; all input fields and faceplate buttons disabled).

Licensing and Hardware Matrix for Minimal Configurations

The following table specifies software packages, license keys, and hardware roles for combined PCS 7 architectures:

System RoleSoftware PackageManufacturer MLFBLicense TypePrimary FunctionCombined ES/OS Single StationPCS 7 Engineering Software V9.06ES7658-1EX58-0YA5Floating License (ES)Multiproject engineering, CFC/SFC compilationOS Runtime AuthorizationOS Software Single Station V9.06ES7658-2CX58-0YH5Single License (OS RT PO)WinCC runtime graphics and alarm loggingMulti-Client EnablementWinCC Server Option for PCS 76ES7658-2BA58-0YB5Single License (Server)Allows up to 3 OS Clients to connect to single stationRemote Operator ClientPCS 7 OS Software Client V9.06ES7658-2FX58-0YH5Single License (OS Client)Dedicated operator visual terminal with limited rights

[!NOTE]
Commercial Accuracy Notice: Distinguish ES engineering licenses from OS runtime capacity. Process Objects (POs) are counted > independently on the AS (AS RT PO) and OS (OS RT PO). Connecting OS Clients to an OS Single Station requires the dedicated > WinCC Server option. Always verify exact MLFBs, PO counts, and software entitlements with an authorized Siemens distributor.

Verification

Validate the combined ES/OS single station and remote client setup:

Local Runtime Activation: In WinCC Explorer on the combined station, click Activate. Confirm that graphic pages load, process tags communicate with the AS, and alarm logging initiates without license shortage popups.
OS Client Connectivity: Power on the remote OS Client workstation. Launch WinCC Runtime and verify that server data loads smoothly across the terminal bus.
Access Control Enforcement: Log in with the restricted operator account on the client. Attempt to change an analog setpoint or access engineering dialogues; verify that unauthorized controls are locked or prompt for higher-level credentials.

Limitations and Operational Precautions

Consider these operational boundaries in minimal configurations:

Maximum Client Capacity: A PCS 7 OS Single Station with the server option supports a maximum of 3 OS Clients. If more clients are needed, upgrade to a dedicated client/server architecture with redundant OS Servers.
Workstation Performance Overhead: Because compilation (CFC, HW Config, OS Compile) consumes substantial CPU and RAM, performing large engineering compiles while WinCC Runtime is active can cause temporary screen update lag for operators.
No Redundancy: A single station lacks server redundancy. Hardware failure or operating system restart halts both engineering and operator visualization until the station reboots.

Engineer FAQ

Can I download an OS project to 'localhost' or 127.0.0.1 in PCS 7?

No. PCS 7 Target OS Download cannot target localhost or the local computer name. For a single station, the project already exists locally and is activated directly in WinCC Explorer.

How many Process Object licenses do I need for a combined ES/OS?

You need AS RT PO licenses on the controller memory card (or SEC card) and OS RT PO licenses on the PC. An ES license alone does not include unlimited runtime operation.

Can the remote OS Client have engineering rights?

No. An OS Client only runs WinCC client runtime. Engineering tools (STEP 7, CFC) are installed exclusively on the Engineering Station.

What happens if the ES/OS station restarts while clients are connected?

The clients will lose connection, display disconnected process pictures with grayed-out fields, and reconnect automatically once the ES/OS WinCC Runtime finishes booting.