Deploying a Temporary Secondary OS Single Station for Commissioning Without Multiproject Reconfiguration

In SIMATIC PCS 7, deploying a temporary secondary operator station during plant commissioning without altering multiproject settings or downloading Station Configuration Editor (SCE) Index 125 can be achieved by cloning the compiled WinCC OS project to a temporary PC. On the temporary PC, assign a unique computer name and IP address on the Plant Bus. Open the cloned project directly in WinCC Explorer, update the computer name in Computer Properties to 'Use Local Computer Name', and in WinCC Tag Management, switch the S7 communication connection under 'SIMATIC S7 Protocol Suite' from 'Named Connections' to 'TCP/IP'. Enter the target CPU IP address and slot number (Rack 0, Slot 3 or 4). This establishes direct S7 communication immediately without modifying NetPro or disturbing the production ES.

Executive Summary

During fast-paced commissioning outages or loop-check phases, engineering teams frequently require a secondary, mobile operator interface (e.g., a commissioning laptop) to monitor field instruments while the primary Engineering Station (ES/OS) is occupied with software changes. Formally adding an OS station into a PCS 7 multiproject requires editing HW Config, re-merging subnets, configuring NetPro S7 Named Connections, downloading Station Configuration Editor (SCE) Index 125, and executing full OS compiles—a time-consuming process that risks project integrity. This article details a safe, rapid commissioning procedure to deploy an autonomous WinCC clone station via direct S7 TCP/IP drivers without multiproject alterations.

Architecture and Fundamental Mechanics

SIMATIC PCS 7 production communications use S7 Named Connections managed by SIMATIC NET HARDNET-IE and the Station Configuration Editor (SCE). A Named Connection binds a WinCC Application object at a specific station index (Index 125) to a symbolic connection table compiled by NetPro.

However, the underlying WinCC runtime communication engine (SIMATIC S7 Protocol Suite) contains multiple channel units:
1. 'Named Connections': Uses local Station Manager tables and CP 1623 MAC/IP routing. Highly rigid, requiring NetPro downloads.
2. 'TCP/IP' Channel Unit: Standard RFC 1006 communication. It requires only the IP address of the target automation system, the controller rack number (always Rack 0 for S7-400), and the CPU slot number (Slot 3 for standard S7-400, or Slot 2/3/4 depending on CPU 410-5H rack layout).

By copying the already-compiled WinCC project folder (wincproj) to a temporary commissioning laptop and reassigning the connection logical channel from 'Named Connections' to 'TCP/IP', the temporary station bypasses NetPro entirely. The S7-400 / CPU 410 controller accepts the incoming RFC 1006 connection on TCP port 102 as an additional HMI connection, allowing the commissioning engineer to view live process graphics and operate faceplates concurrently with the primary ES.

Step-by-Step Implementation Procedure

Prepare Temporary Commissioning Laptop:
a. Install matching WinCC Runtime software (e.g., WinCC V7.4 SP1 or matching PCS 7 runtime version).
b. Configure a unique IP address on the commissioning PC's network card within the Plant Bus subnet.
c. Connect the PC physically to the Plant Bus industrial Ethernet switch (or SCALANCE switch).
d. Ping the AS controller IP addresses to confirm network connectivity.
Copy and Adapt Compiled WinCC Project:
a. On the Engineering Station, copy the compiled WinCC OS project folder (<Project_Path>\wincproj\<OS_Name>) to an external drive or network share.
b. Paste the project folder onto the local C: drive of the temporary PC.
c. Open WinCC Explorer standalone on the temporary PC and open the .mcp project file.
Synchronize WinCC Computer Name:
a. In WinCC Explorer, right-click 'Computer' in the navigation pane and select 'Properties'.
b. In the Computer Properties dialog, highlight the old station name, click 'Properties', and click 'Use Local Computer Name'.
c. Click 'OK' and restart WinCC Explorer as prompted.
Re-route Communication Channel to TCP/IP:
a. In WinCC Explorer, expand Tag Management -> SIMATIC S7 Protocol Suite.
b. Locate the active S7 connection under 'Named Connections' and note its connection name.
c. Right-click 'TCP/IP' under SIMATIC S7 Protocol Suite and select 'New Driver Connection' (or move existing connection parameters).
d. In Connection Properties, enter the controller's Plant Bus IP address, set Rack Number = 0, and CPU Slot Number = 3 (or active CPU slot).
e. Move or duplicate the tag group assignments from Named Connections to the TCP/IP connection.
f. In WinCC Explorer, open 'Set PG/PC Interface' and ensure the S7ONLINE access point is set to the laptop's physical network adapter (TCP/IP -> Network Card Name).
Activate Runtime and Verify Operation:
a. Click 'Activate' in WinCC Explorer to launch WinCC Runtime.
b. Navigate to process screens and verify live dynamic updates.

Verification

In WinCC Runtime on the temporary PC, open WinCC Channel Diagnosis: confirm that the TCP/IP connection to the CPU displays a healthy 'OK' state with incrementing telegram counters.
Open process graphics: confirm that block icons for MotL, VlvL, and MonAnL display valid live values without grayed-out or disconnected badges.
Issue a test command from a faceplate: confirm that the AS controller responds immediately.
Confirm that the primary ES/OS station continues operating normally with zero disruption to its active Named Connections.

Limitations and Operational Precautions

This temporary setup is intended strictly for commissioning, testing, and loop-checking; it must never be used as a permanent operational client because it lacks central archiving, does not synchronize alarms with redundant servers, and will be overwritten if a target download is attempted from the ES. Ensure sufficient S7 connection resources (OP/HMI communication instances) remain available on the CPU. Temporary testing should utilize valid Siemens trial or runtime licenses procured via an authorized Siemens distributor or the Siemens Industry Mall.

Engineer FAQ

Will adding a temporary TCP/IP connection disrupt existing Named Connections on the CPU?

No. S7-400 and CPU 410-5H controllers allocate independent communication connection pools; an incoming RFC 1006 TCP/IP connection uses an available standard HMI connection resource without affecting S7 Named Connections.

What CPU slot number should be configured in the TCP/IP connection properties?

In S7-400 and CPU 410-5H systems, the power supply occupies Slot 1, and the CPU typically occupies Slot 3 (or Slot 2/3 for redundant H-systems). Check HW Config for the exact CPU slot.

Do I need to compile the OS on the Engineering Station to use this clone?

No. The procedure uses the already-compiled OS project files, completely eliminating the need for ES compilation or multiproject editing.

What license is required to run WinCC temporarily on a laptop?

A standard WinCC Runtime license. For brief commissioning periods, WinCC can run in trial mode (with periodic demo popups) without restricting communication functionality.

Can the temporary station download changes to the PLC?

No. The temporary station is configured strictly as a monitoring and operator visualization station; all PLC programming and downloads must remain centralized on the master ES.