Modifying PCS 7 V7.1 Faceplates Online Without OS Shutdown

Overview

Siemens SIMATIC PCS 7 V7.1 uses WinCC as the OS layer, where operator faceplates are stored as .pdl (Picture Declaration Language) files inside the project GraCS folder. Engineers frequently need to update these faceplates - add a status indicator, change a color, expose an additional tag - while the plant continues running. The challenge is propagating those modifications to OS Server A (master), OS Server B (standby), and all OS clients without stopping the OS Runtime and without producing a mismatch between what PCS 7 thinks is deployed and what is actually on disk.

This procedure covers two distinct change categories:

1. Picture-only changes - cosmetic edits to an existing .pdl with no new tag wiring. Can be hot-patched by file copy.
2. CFC-driven changes - adding blocks, new I/O tags, or new alarm classes in CFC/SFC that the OS must regenerate. Requires a controlled compile + delta download.

The technique below is documented for PCS 7 V7.1 SPx but applies conceptually to V7.0 through V8.2 with minor differences in the OS Project Editor path and the Download dialog.

PCS 7 V7.1 OS Architecture Recap

Before editing, confirm which OS role each node plays. The default PCS 7 V7.1 template installs a redundant OS Server pair plus one or more OS clients:

The redundant OS Server pair uses WinCC Redundancy: Server A and Server B maintain synchronized archives, messages, and user archives. Any .pdl modification must reach both servers identically; otherwise clients see inconsistent faceplates after a failover.

Prerequisites

• PCS 7 V7.1 ES with the matching Service Pack installed on both the ES and the OS Servers (mixed SP levels cause FWL version errors on download).
• Administrator account on OS Server A, OS Server B, and ES. Domain user with the SIMATIC HMI group membership is mandatory for Runtime access.
• WinCC Explorer installed on ES (component of PCS 7 ES).
• Plant in stable operation - no active download, no SFC step transitions in critical loops.
• Backup of the existing GraCS folder from both OS Server A and B before any file copy.
• Document the current @-prefixed tag list (used for online tag renaming) and the current picture tree path of the faceplate being modified.

Locating the Faceplate .pdl File

All WinCC graphics live under <ProjectPath>\GraCS\. The default PCS 7 path on a WinCC Server project is:

Within GraCS, files are organized by purpose:

The faceplate file you modify is typically found in the GraCS root or under Pictures. Open WinCC Explorer on the ES, expand Graphics in the left tree, and locate the picture by name. Right-click -> Open launches the Graphics Designer with the matching file loaded from GraCS.

Scenario A: Picture-Only Modification (No CFC Changes)

Use this procedure when the edit is purely cosmetic - changing a label, color, geometry, or moving a field - and does not add new tags, blocks, or alarm classes.

Step-by-Step Procedure

1. Edit on the ES: In WinCC Explorer (ES), open the target .pdl via Graphics Designer. Make the modification. Do not save through WinCC Explorer Download - that would require a full OS download.
2. Close the file in Graphics Designer so the file handle is released.
3. Locate the modified file in the ES project GraCS folder, e.g. ES_Project\GraCS\MotSped.pdl.
4. Copy the file from the ES GraCS to a temporary staging folder shared between ES and OS Servers (for example \\PLANT\Patches\Faceplate_Update_2024\).
5. Deploy to OS Server A: Log in to OS Server A. Stop the WinCC Runtime only if you cannot rely on WinCC's hot-reload behavior. In V7.1 SP3+, WinCC re-reads .pdl files from disk when a picture is re-opened. Stop the CCEServer process briefly if needed: net stop "S7DOS" is not required for picture swaps, only for tag database changes.
6. Copy the .pdl file to C:\Program Files\Siemens\Automation\WinCC\WinCCProjects\<OSServer_A>\GraCS\MotSped.pdl, overwriting the existing file.
7. Repeat for OS Server B using the same source file. Both servers must have byte-identical copies; otherwise failover will show the old faceplate.
8. Refresh clients: On each OS client, the picture updates the next time an operator opens it. To force an immediate refresh without closing the picture tree, open the modified picture twice - WinCC detects the file timestamp change and reloads.

Why This Works Without OS Shutdown

WinCC loads a .pdl into memory when an operator first opens the picture. The file on disk is not held under an exclusive lock. When WinCC detects that the file's modification timestamp has changed since the last load, it discards the cached picture and re-reads from disk on the next open. This is the mechanism that makes the GraCS copy path viable for cosmetic changes.

Scenario B: CFC Changes That Require an OS Recompile

If you add a new block (e.g. a CTRL_PID, MOT_SPED, VALVE_ANA, or any APL block) in the CFC chart, or add a new tag to an existing block that must be visible on the faceplate, the OS must regenerate the tag list and the picture's block-icon mappings. This requires the full PCS 7 compile-then-download cycle.

Step-by-Step Procedure

1. Modify the CFC chart in the ES (CFC Editor). Add the new block instance, wire the I/O, and download the chart changes to the AS first: chart -> right-click -> Download -> Changes only to the target AS.
2. Compile the OS: In the plant view or component view, right-click the OS server -> Compile OS. Select Scope = Entire OS if multiple charts changed, or Scope = Changes only for surgical updates. This regenerates Project.xml, the tag database, message configuration, and picture scripts.
3. Verify the compile log in C:\Program Files\Siemens\Automation\WinCC\WinCCProjects\<OSProject>\OS_Compile_Log.txt. Search for WARN and ERROR entries. Common entries: "Tag X is not connected" or "Block icon cannot be assigned".
4. Stop WinCC Runtime on OS Server A only. Right-click the WinCC Explorer -> Stop Runtime. Wait for the Runtime stopped tray notification.
5. Trigger the OS download from the ES. In the OS project editor, select the OS Server target -> Download -> Changes only for delta propagation, or Full download if the manual GraCS copy was previously performed (see Troubleshooting).
6. Start Runtime on OS Server A and verify picture refresh.
7. Repeat steps 4-6 on OS Server B. In V7.1, the redundant pair does not auto-sync a delta download - both servers must be updated manually or via the Download to all OS servers group action.
8. Push clients: Clients pick up changes automatically on next picture open. For force-refresh, restart CCClient on each client workstation.

Compile Scope Decision Table

Maintaining Server A/B Consistency

OS Server redundancy in PCS 7 V7.1 is not automatic for picture files. The redundancy monitor (RM) syncs runtime data (tag values, messages, archives) but it does not sync .pdl files unless they arrive through a proper OS download. Therefore:

• After any GraCS copy, manually replicate the file to Server B via the same Robocopy or shared folder method.
• Verify file hashes match: CertUtil -hashfile MotSped.pdl SHA256 on both servers.
• Schedule the modification during a low-load shift when both servers are healthy and no failover is imminent.

Verification Procedure

After deploying, confirm the modification is live without disrupting operators:

1. Open WinCC Explorer on the ES in Reference mode (read-only) and compare the picture hash to the deployed file.
2. Open an OS client that is logged in but idle. Navigate to the modified picture. Visually confirm the change.
3. Check the WinCC diagnostics window: Start -> SIMATIC -> WinCC -> Tools -> WinCC Diagnosis. Look for Picture cache entries confirming the picture was reloaded from disk.
4. On OS Server A and B, check the Windows Event Viewer -> Siemens Automation log for picture-load errors with event IDs in the range 1000-1099.
5. Failover test (optional, during maintenance): force Server A into stop and verify Server B's faceplate matches.

Troubleshooting Matrix

Safety and Operational Considerations

• Never modify a faceplate whose underlying block controls a critical interlock (e.g. ESD, fire & gas) while the plant is in production. Even a cosmetic change can introduce a typo that misleads operators.
• Before any Runtime change, confirm with operations that no SFC is mid-transition. A restart of WinCC Runtime on a server will not interrupt AS execution but will momentarily freeze the operator display.
• Keep a versioned archive of GraCS folder diffs using Robocopy /MIR or a Git repository. PCS 7's own versioning is limited to project-level snapshots.
• If the project uses APL (Advanced Process Library) blocks, do not edit @APL_*.pdl files. They are regenerated by the OS compile from the master APL picture library.

FAQ