C135 PCS 7 (PCS7)
6C
6 Cielo Ciencia y Tecnología
·Publicada en C135 PCS 7 (PCS7)

Resolving OS Server Delta Download Aborts and Path Validation Failures in PCS 7 V9.0 SP2

Resolving OS Server Delta Download Aborts and Path Validation Failures in PCS 7 V9.0 SP2

When performing a delta download ('Changes Only') to a SIMATIC PCS 7 OS Server and the operation aborts with 'No path to the target OS has been selected' or 'The path to the target OS is invalid', the error indicates that the target UNC path in the PC station object properties is missing, points to an unshared folder, or fails Windows authentication. To resolve this: 1) In SIMATIC Manager Component View, open the Object Properties of the OS Server; 2) In the 'Target OS and Standby OS computer' tab, browse to the target network computer and select the shared WinCC project folder (e.g., \OS_SRV01\WinCC_Project); 3) Verify that the network share grants 'Full Control' to the 'SIMATIC HMI' user group; and 4) Ensure WinCC Runtime is running on the target server before initiating the delta download.

Table of Contents

Executive Summary

During plant operation, automation engineers routinely apply incremental graphics and tag updates to operating SIMATIC PCS 7 OS Servers using the 'Changes Only' (delta download) feature from the Engineering Station (ES). In PCS 7 V9.0 SP2, commissioning engineers frequently encounter download rejections where the transfer wizard immediately terminates with messages indicating that no target OS path is selected or that the target path is invalid. This failure disrupts online modifications and risks uncoordinated project states. This article analyzes the underlying network path evaluation mechanics of SIMATIC Manager, outlines Windows share and DCOM security prerequisites, and details the step-by-step procedure to validate target path assignments.

Architecture and Fundamental Mechanics

OS Target Path Architecture in PCS 7

Unlike an S7 CPU where downloads occur via ISO on TCP / S7 communication protocols directly into memory, an OS Server download is a file-system and SQL database transfer orchestrated by the PCS 7 Station Management subsystem.

+-------------------------------------------------------------------------+
|                        Engineering Station (ES)                         |
|                                                                         |
|   SIMATIC Manager: OS Object Properties                                 |
|   Target OS Path: \\OS_SRV01\WinCC_Project\OS_SRV01.mcp                 |
+-------------------------------------------------------------------------+
                                    |
                                    | 1. Windows UNC Share Check (SMB)
                                    | 2. Remote SQL Connection Check
                                    v
+-------------------------------------------------------------------------+
|                         OS Server Station (Target)                      |
|                                                                         |
|   Shared Directory: C:\WinCC_Project (Share Name: WinCC_Project)        |
|   Share Permissions: Everyone -> Full Control                           |
|   NTFS Permissions:  SIMATIC HMI Group -> Full Control                  |
|   WinCC Project:     Active in Runtime (CCDeltaDownload.exe listening)  |
+-------------------------------------------------------------------------+

Why Delta Download Fails

  1. Unassigned or Localized Path: If the OS object properties field 'Path to the Target OS Computer' is empty or configured with a local drive letter (e.g., D:\Projects), SIMATIC Manager cannot resolve the remote destination across the network.
  2. Network Share Permissions: WinCC requires that the shared folder on the OS Server grants Full Control at both the Share level and NTFS file permissions level to the SIMATIC HMI group.
  3. Runtime Incongruence: A delta download requires that WinCC Runtime is currently active on the target OS Server. If Runtime is deactivated, SIMATIC Manager will reject delta download and mandate an Entire Download.

Step-by-Step Implementation Procedure

Step 1: Configure the Shared Folder on the OS Server

  1. Log onto the physical or virtual OS Server machine.
  2. In Windows Explorer, locate the project storage folder (e.g., D:\WinCC_Projects).
  3. Right-click the folder and select Properties > Sharing > Advanced Sharing.
  4. Check Share this folder and name the share clearly (e.g., WinCC_Projects).
  5. Click Permissions and ensure the local group SIMATIC HMI has Full Control.
  6. Select the Security (NTFS) tab and ensure SIMATIC HMI also has Full Control.

Step 2: Configure the Target OS Path in SIMATIC Manager

  1. On the Engineering Station, open SIMATIC Manager.
  2. Switch to Component View and expand the PC Station containing the OS Server.
  3. Right-click the WinCC OS object and select Object Properties.
  4. Navigate to the tab Target OS and Standby OS computer.
  5. In the section Path to the Target OS Computer, click Browse....
  6. In the network browser, navigate through Network > [OS_Server_Name] > [Share_Name].
  7. Select the WinCC project file (<ProjectName>.mcp) located in the shared directory.
  8. If configuring a redundant server pair, repeat this step for the Standby Target OS Computer field pointing to the redundant partner's share.
  9. Click OK to save the path.

Step 3: Verify Network Name Resolution and Credentials

  1. On the ES, open Command Prompt and test network connectivity: ping [OS_Server_Name].
  2. Open Windows Explorer on the ES and paste the full UNC path: \[OS_Server_Name]\[Share_Name].
  3. Confirm that the folder opens without prompting for network credentials.
  4. Ensure that identical Windows user credentials (username and password) exist on both ES and OS, and that the account is an administrator in SIMATIC HMI.

Step 4: Execute Delta Download

  1. Ensure that WinCC Runtime is active on the target OS Server.
  2. In SIMATIC Manager, select the OS object, right-click and choose PLC > Download.
  3. In the download dialog, select Scope: Changes.
  4. Click OK. The progress bar will indicate project verification, delta file transfer, and dynamic SQL database updates without interrupting active process supervision.

Verification

  1. Download Completion: Verify that the download finishes with the status message: Download of changes to OS completed successfully.
  2. Runtime Verification: On the OS Server, observe that updated graphics, modified faceplates, and newly added tags display immediately in WinCC Runtime.
  3. Standby Redundancy Verification: If downloading to a redundant server pair, verify that the standby server also receives the delta changes and remains synchronized.

Limitations and Operational Precautions

  1. Structural Changes Require Entire Download: Certain engineering changes—such as modifying archive tag acquisition cycles, renaming the WinCC project, or altering User Administrator core schemas—cannot be loaded via delta download and mandate a complete OS download in STOP.
  2. Network Interruption Risk: Never disrupt network connections or reboot the ES during delta download execution, as partial SQL database injection can corrupt the target project.

Engineer FAQ

Why does SIMATIC Manager say 'No path to the target OS has been selected'?

The Target OS path field in the OS Object Properties dialog is blank or contains an invalid path.

Can I use a mapped network drive letter (e.g. Z:) for the target path?

No. Siemens requires standard UNC network paths (e.g., \\ServerName\ShareName\Project.mcp) for remote OS downloads.

Does delta download interrupt the running process?

No. Delta download transfers changed graphics and tags online while WinCC Runtime continues operating seamlessly.

Why is delta download grayed out?

Delta download is disabled if a complete download was never performed, if Runtime is not active on the target, or if structural project changes mandate a full download.

What if ES and OS are on the same PC (Single Station)?

If ES and OS are on the same machine, the target path is not required and should be left empty or pointing to the local project.

What Windows group permissions are required for the share?

The Windows local group SIMATIC HMI must be granted Full Control on both Share permissions and NTFS Security.

Can I download changes to redundant servers simultaneously?

Yes, SIMATIC Manager coordinates downloading changes to the master server and then automatically triggers redundancy synchronization.

Where can I see delta download error logs?

Check TRANSFER.LOG and CCDeltaDownload.log located inside the WinCC project directory on the target OS Server.

What happens if network connection drops during download?

WinCC rolls back uncommitted changes or marks the project as inconsistent, requiring a full download.

Does changing alarm message texts support delta download?

Yes, modifying alarm texts, analog limits, and block icons can be downloaded online via changes only.

Technical References

Related Articles

Related Tags

  • OS Download
  • Delta Download
  • Target OS Path
  • WinCC V7.5
  • SIMATIC Manager
  • SIMATIC HMI
  • PCS 7 V9.0 SP2
20 respuestas