Resolving Missing HMI Pictures and Navigation Failures in Multi-Client Multi-Project PCS 7 Systems

When process pictures fail to display upon clicking navigation buttons on an OS Client in a multi-project PCS 7 system, the root causes are missing or unassigned OS Server data packages (.pck), Windows network share authentication failures, or desynchronized Picture Tree Manager data. Ensure that server data is generated on all participating OS Servers and loaded into the OS Client project, verify Windows user membership in the 'SIMATIC HMI' group across all machines, configure the Standard Server for Split Screen Manager (SSM), and ensure OS Project Editor is executed on the client.

Executive Summary

In large-scale industrial plants governed by SIMATIC PCS 7 (V8.0 through V9.1), multiple independent multiprojects frequently coexist on a unified plant network (e.g. Project 1 for Utilities and Project 2 for Main Process). In centralized control rooms, multi-client operator stations are tasked with displaying graphics, alarms, and trends from all projects simultaneously. A common post-commissioning failure occurs when client navigation buttons render on screen, but clicking them fails to open process pictures, displaying blank canvases or error dialogs. This article diagnoses the underlying client-server picture loading architecture, network share security requirements, and resolution procedures.

Architecture and Fundamental Mechanics

Picture Navigation Architecture and File Access Mechanics in Multi-Client Systems:

Multi-Client Graphic Retrieval Model:
An OS Client does not store process pictures (.pdl files) on its local hard drive.
When an operator navigates to a process area, the WinCC Split Screen Manager (SSM) queries the loaded Server Data Package (.pck) to identify which server owns that picture.
The client initiates an SMB (Windows File Sharing) request across the Terminal Bus to the target OS Server's shared project directory (\\ServerName\ProjectName.OS\GraCS\PictureName.pdl).
Primary Root Causes of Navigation Failure:
1. Missing or Stale Server Data Package on the Client:
- If Server Data was not generated after adding pictures or if the package was not reloaded on the client, the client Picture Tree contains invalid or unassigned picture pointers.
  2. Windows Share Security and DCOM Permission Denials:
- Because pictures are fetched over Windows SMB shares, the logged-on Windows client account must be authorized on the OS Server.
- If the user account is not a member of the local SIMATIC HMI Windows group on the OS Server, Windows rejects the file read request, and WinCC displays a blank screen.
  3. Unassigned Standard Server for Split Screen Manager (SSM):
- In multi-server environments, the client must know which server manages default layout coordinates and alarms. Under Server Data -> Standard Server..., an explicit server must be assigned for SSM.
  4. Picture Tree Manager Desynchronization:
- If the Picture Tree was edited in WinCC Graphics Designer without running Picture Tree Manager -> Save, the internal picture hierarchy tables become inconsistent.

Step-by-Step Implementation Procedure

Step-by-Step Procedure to Restore Picture Navigation on OS Clients:

Verify Terminal Bus Name Resolution and Network Shares:
- On the OS Client, open Windows File Explorer.
- In the address bar, type the UNC path to the OS Server's shared folder: \\OS_SRV1\<Project_Name>.OS.
- Confirm that the folder opens immediately without prompting for credentials and that you can browse the GraCS folder.
- If credentials are requested, add the client user to the local SIMATIC HMI group on the OS Server and verify matching passwords in workgroup setups.
Regenerate Server Data on All OS Servers:
- In SIMATIC Manager, open each participating OS Server project.
- Open WinCC Explorer on the server; open Picture Tree Manager -> click Save to re-index all graphic hierarchies.
- In SIMATIC Manager Component View, right-click the OS Server object -> select Server Data -> Generate.
Update Server Packages on the OS Client:
- Open the OS Client project in SIMATIC Manager.
- Under the client project tree, navigate to Server Data.
- Right-click each loaded server package -> select Update... (or delete and reload fresh .pck files via Load...).
Configure Standard Server Assignments:
- In the OS Client project, right-click Server Data -> Standard Server....
- Under the SSM (Split Screen Manager) component, assign the designated primary OS Server.
- Under the Alarms component, assign the primary alarm server.
Execute OS Project Editor and Download:
- In the OS Client project, open OS Project Editor -> click OK to re-link all @ navigation pictures.
- Download the updated OS Client project to the physical client workstation.
- Restart WinCC Runtime on the client.

Verification

Verification Procedure:
1. Navigation Hierarchy Test: In WinCC Runtime on the OS Client, click through each top-level area button in the overview area. Verify that the corresponding process pictures load immediately without lag or blank displays.
2. Diagnostic Log Inspection: Open the WinCC diagnostic log file on the client (C:\Program Files (x86)\Siemens\WinCC\Diagnostics\WinCC_Sys_01.log). Confirm zero PDLRT: Picture not found or Access Denied error entries.
3. Cross-Project Faceplate Test: Open a faceplate sourced from Project 1 and a faceplate sourced from Project 2 on the same client screen; verify dynamic values update seamlessly.

Limitations and Operational Precautions

Operational Precautions and Multi-Project Configuration Rules:
- Identical Project Passwords: In workgroup environments without an Active Directory domain, all participating machines must maintain identical usernames and passwords for the SiemensUser service account.
- Picture Name Uniqueness: Never use identical .pdl picture names across different OS Servers in the same multi-client setup; naming collisions cause Split Screen Manager to open the wrong server's picture.
- Avoid Local Picture Copies: Do not copy .pdl files directly to the OS Client GraCS directory; doing so defeats the multi-server architecture and causes client-server graphical version mismatches.

Engineer FAQ

Why does my OS Client display a blank screen when clicking a picture button?

Because the client cannot access the target .pdl file on the OS Server, typically caused by missing Server Data packages, unconfigured Windows share permissions, or missing membership in the 'SIMATIC HMI' group.

Where are process pictures physically stored in a client-server architecture?

Process pictures are stored physically in the GraCS folder of the OS Server; clients load them on-demand across the Terminal Bus.

What does the 'Standard Server' configuration do on an OS Client?

It designates which server handles default split-screen window geometry, alarm operations, and user archive queries when no specific server is targeted.

How do I update picture navigation on the client after adding a new picture on the server?

Save the Picture Tree in WinCC on the server, regenerate Server Data on the server, update the package on the client, and run OS Project Editor on the client.

What Windows user group authorizes access to WinCC network shares?

The local SIMATIC HMI Windows user group authorizes access to WinCC project shares.

Technical References

Related Tags

Multi-Client
Multi-Project
Picture Tree Manager
WinCC Navigation
Server Packages

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Resolving Missing HMI Pictures and Navigation Failures in Multi-Client Multi-Project PCS 7 Systems