SIMATIC PCS 7 APL Color Palette Architecture and Color Index Definitions

The standard color palette for the SIMATIC PCS 7 Advanced Process Library (APL) is officially documented in the SIMATIC PCS 7 Advanced Process Library Function Manual under Chapter 2.3 ('Operating and Monitoring Concepts - APL Color Palette'). The APL defines a standardized central color palette in WinCC Graphics Designer where discrete color index numbers (e.g., ID 322 for maintenance/bypass status, ID 100 for high alarms) link directly to specific operational states. Utilizing these centralized color IDs in custom faceplates ensures seamless adherence to the Siemens Style Guide, maintains ergonomic plant consistency, and supports dynamic restyling between Classic and Modern display themes.

APL Central Color Palette Concept

In traditional HMI engineering, developers assigned static RGB color codes directly to graphical shapes. This approach caused visual disharmony, compromised ergonomic clarity, and made plant-wide color updates extremely labor-intensive. Starting with the Advanced Process Library (APL), Siemens introduced a centralized Color Palette system within WinCC.

Each functional state in the plant (Alarm, Warning, Tolerance, Normal, Manual, Simulation, Interlocked, Maintenance) is assigned a specific index number within the WinCC Central Color Palette. When an operator switches the WinCC Design (e.g., from 'Classic' to 'Modern' or 'Dark Mode'), the palette re-maps RGB values globally across all faceplates and block icons without requiring manual edits to individual PDL picture files.

Color Index Reference Table for Operational States

The following table details key APL color palette indices documented in Section 2.3 of the APL Function Manual:

Color Index IDOperational State / FunctionVisual Appearance (Standard / Classic)Ergonomic Meaning & PurposeID 100 / 101Alarm High / Emergency FaultBright RedImmediate operator action required; process parameter beyond critical trip limit.ID 102 / 103Warning High / Warning LowAmber / YellowPre-warning condition; parameter approaching trip limit.ID 104 / 105Tolerance High / Tolerance LowBlue / CyanMinor process deviation; informational boundary.ID 200 seriesOperating Modes (Auto / Manual)Neutral Gray / White / Dark SlateClear distinction between automatic supervisory control and manual operator intervention.ID 300 seriesInterlocks & ProtectionLight Slate Gray / Orange AccentsBlocked by interlock; active bypass; bypass in effect.ID 322Maintenance / Bypass StatusDistinct Orange / Accent YellowIndicates an active bypass, forced state, or maintenance override active on the block.ID 400 seriesQuality Code Bad / SimulatedMagenta / Violet AccentsSignal invalid, wire break detected, or simulation active (SimOn = 1).

Applying Palette Colors to Custom Faceplates

To bind custom faceplate objects to the central APL color palette in WinCC Graphics Designer:

Open the custom faceplate picture (e.g., @PG_CustomBlock_Standard.pdl) in Graphics Designer.
Select the graphic object (e.g., Rectangle, Status Text, or Bar Graph).
In the Object Properties window, navigate to Properties -> Colors.
Right-click the target property (e.g., Background Color or Border Color) and select Central Color Palette (or click the Palette icon).
Enter or select the required Color Index ID (e.g., 322 for maintenance override indication).
Save the picture. In runtime, the object inherits its color dynamically from the active WinCC design scheme.

Verification

To verify that custom faceplates utilize the APL color palette correctly:

In WinCC Explorer, open OS Project Editor and review the selected Layout / Design (e.g., SIMATIC Modern).
Activate WinCC OS Runtime and open the custom faceplate.
Trigger an operational state (such as activating simulation or maintenance bypass on the associated CFC block).
Confirm that the faceplate element reflects the exact color specified by the APL standard (e.g., Orange for ID 322).
Compare the visual appearance of the custom faceplate with standard APL faceplates (MonAnL, MotL) to confirm perfect visual consistency.

Limitations and Operational Precautions

Operational boundaries when utilizing color palettes:

Avoid Hardcoded RGB Values: Assigning static RGB colors via color picker dialogs decouples objects from the central palette, resulting in clashing displays when WinCC designs are switched.
Dynamic Color Scripts: If driving colors via VBScript or C-script, use project functions that reference palette IDs (e.g., GetPaletteColor(index)) rather than hardcoding static hex color constants (RGB(255, 0, 0)).
Version Upgrades: When migrating between PCS 7 releases (e.g., V8.1 to V9.0), review the APL Manual Chapter 2.3 to verify if new color indices were introduced for advanced diagnostics.

Engineer FAQ

Where is the APL color palette officially documented in Siemens manuals?

It is documented in the SIMATIC PCS 7 Advanced Process Library (APL) Function Manual, specifically in Chapter 2.3 under 'Operating and Monitoring Concepts - APL Color Palette'.

What state is represented by Color Index ID 322 in the APL palette?

Color Index ID 322 represents an active Maintenance / Bypass status, typically rendered in distinct orange to indicate that a signal or interlock is bypassed.

Why should engineers avoid hardcoded RGB values in WinCC faceplates?

Hardcoded RGB values do not adapt when the WinCC design theme is changed (e.g., from Classic to Modern or High Contrast), causing visual inconsistencies and poor ergonomics.

Can custom colors be added to the WinCC Central Color Palette?

Yes. In WinCC Explorer, under the Project Properties -> Design Settings, engineers can customize palette slots, but preserving standard APL indices (0-499) is strongly recommended.