Resolving PCS 7 Faceplate Indication Light Not Showing Red

1. Problem Overview

When an automation engineer builds a custom PCS 7 faceplate with the Faceplate Designer in Siemens PCS 7 V9.x (or V8.x), the indication lamps (LED-style objects) that should turn red when a Boolean (BOOL) data block tag is set (= 1) remain dark, gray, or stay on a default color in runtime. The tag value is being updated correctly in the AS (Automation Station) and is visible in the WinCC tag manager, but the visual color animation on the faceplate never triggers. This article documents the root causes, the correct configuration sequence, and field-proven verification steps for resolving this issue.

2. Symptoms Observed in Runtime

• Indication lights on the custom faceplate stay gray or invisible, regardless of the process tag value.
• Tag value reads 1 in the WinCC Tag Management diagnostic view, but the faceplate element does not change color.
• Color animation is not triggered at all; no flicker, no transition, no event firing.
• The faceplate opens correctly on the standard view, and other (non-color-animated) elements update normally.
• Only the color animation on a specific graphic object (e.g., a circle/ellipse used as a lamp) is broken; text, position, and visibility animations may work.

3. Root Cause Analysis

There are five common root causes for this exact failure mode. They are listed in order of frequency, based on PCS 7 V8.x and V9.x engineering experience.

4. Prerequisites and Environment

Before applying the procedure, verify the engineering station has the correct tool versions installed:

• PCS 7 V9.0 SP2 or higher (or PCS 7 V8.2 SP1 with latest HSPs for legacy systems)
• STEP 7 / SIMATIC Manager with S7-400 or AS 410 firmware compatible with the PCS 7 version
• WinCC Runtime Professional or WinCC Explorer (PCS 7 uses the WinCC Explorer variant, not the TIA Portal variant)
• Faceplate Designer Add-in installed and registered for the active WinCC Explorer project
• OS compilation rights (Engineer-level user on the ES)

Reference: PCS 7 V9.0 Function Manual and the PCS 7 Faceplate Designer manual entry.

5. Step-by-Step Diagnostic Procedure

Step 5.1 — Verify the Source Data Block Element

1. Open the S7 program in SIMATIC Manager or TIA Portal (depending on PCS 7 release).
2. Navigate to the source DB (Data Block) that contains the bit you want to indicate.
3. Confirm the target element is a flat BOOL (1 bit). Example: DB100.DBX2.0 or a symbolic name like "MyMotor".Status.Running.
4. Open a watch table or VAT and force the bit to TRUE to confirm the logic is writing it.

Step 5.2 — Verify the WinCC Tag Subscription

1. Open WinCC Explorer on the engineering station.
2. Expand Tag Management → SIMATIC S7 PROTOCOL SUITE → the connection used (typically S7-400/AS400 or named connection).
3. Locate the tag associated with the faceplate, for example MyMotor_Status_Running or DB100_DBX2_0.
4. Right-click the tag → Properties and confirm the data type is Binary Tag (BOOL).
5. From the runtime, open the diagnostics view (Tools → Status of Connections or WinCC Tag Diagnosis) and verify the tag is updating. If it is not, the connection between AS and OS is the actual fault and the faceplate cannot be fixed without solving that first.

Step 5.3 — Verify the Faceplate Interface Property

1. Open the Faceplate Designer from WinCC Explorer (Tools → Faceplate Designer).
2. Select the relevant faceplate type (e.g., MyMotor_FP or a custom name).
3. In the project tree, navigate to Standard View and select the indication lamp object (typically a circle or polygon graphic).
4. Open Object Properties and switch to the Events tab.
5. Look for the Tag event. The right-hand value column must show the name of the faceplate interface property (e.g., .IndicationBit), and that property must be of type BOOL.

Step 5.4 — Re-attach the Tag to the Event

1. In the Faceplate Designer, on the same Events tab, click the Tag event row to open the dialog.
2. Select Tag in the selection list and click the … button to choose from the WinCC tag list.
3. If the dialog allows you to type a name directly, enter the exact tag name including the leading dot, e.g., .MyBoolTag, then click Apply.
4. If the dialog shows a tag list, pick the BOOL tag corresponding to the indication (often named .RESERVED02 for APL-style blocks).
5. Save the faceplate type.

Step 5.5 — Configure the Color Animation

The Tag event supplies the value, but the color change itself is performed by an animation configured on the graphic object.

1. Still inside Faceplate Designer, right-click the indication lamp object → Properties.
2. Switch to the Animations tab.
3. Double-click the Appearance or Color animation row to open the configuration dialog.
4. Set the trigger to Tag (or, more reliably in PCS 7, to the same faceplate property .IndicationBit).
5. Define the value ranges:
   • Range 0 (default, value = 0): Background color = dark gray or green, depending on the convention.
   • Range 1 (value = 1): Background color = red (RGB 255,0,0).
6. Click OK and save the faceplate type.

Step 5.6 — Re-Compile and Re-Deploy

1. In WinCC Explorer, right-click the OS project and choose OS Project Editor → run it with default settings to regenerate tag linkages.
2. Trigger an Incremental Download to the OS server/runtime.
3. Restart WinCC Runtime on the OS server.
4. Open the picture containing the faceplate instance and force the tag value via a watch table on the AS to verify the lamp changes color.

6. Verification Checklist

7. Common Pitfalls and Field Notes

7.1 — Symbol-Table Flag Missing

When a faceplate instance is placed in a process picture, the Symbol Table (or property dialog of the faceplate instance) must show the tag binding with a flag/checkmark next to the input pin. If the flag is not set, the tag is not propagated to runtime even though the faceplate type is correct. Open the picture in Graphics Designer, double-click the faceplate instance, switch to the Interface tab, and confirm each pin shows a green check, not a red X.

7.2 — Wrong Connection in Tag Management

If the AS-OS connection is configured for a different CPU than the one holding the DB, the tag reads 0 continuously. Confirm the connection name in Tag Management matches the S7 station name. Use Tools → Status of Connections in WinCC Runtime to confirm the connection is "Online/OK" rather than "Offline" or "Error".

7.3 — Reserved Bits Renamed in Newer APL Versions

In APL V9.0, several RESERVED bits have been reassigned or removed. If the source block is from a different PCS 7 version than the faceplate, .RESERVED02 may not exist. Open the block in STEP 7 and verify the bit physically exists in the DB layout before referencing it in the faceplate interface.

7.4 — Color Animation Linked to a Property That Is Not Exposed

A frequent error is configuring the color animation's Tag trigger to point at an external WinCC tag directly, but the faceplate type does not expose that tag as a property. The animation evaluates to uninitialized. Always funnel external values through a faceplate property exposed on the type.

7.5 — Picture Compile Warnings on Tag Resolution

After editing the faceplate type, run a Compile OS (full, not incremental) and inspect the output log for unresolved tags. Warnings are often logged but not surfaced to the engineer because the compile dialog closes automatically. Open the log file from the project directory: <Project>\<OS>\<OS name>.log.

8. Extended Diagnostic Commands

For advanced diagnostics, the following WinCC internal tools help isolate the failure layer:

• WinCC Tag Diagnosis (Tools → Tag Diagnosis) — confirms whether the HMI received the value from the AS.
• Graphics Designer Diagnosis — runtime mode shows evaluated property values on hover; if the Tag event shows 0 when the AS bit is 1, the issue is upstream of the faceplate.
• ApDiag (PCS 7 APL diagnostic) — confirms that the underlying block (e.g., MOT_SPED, MOT_SLOW) is publishing the bit you expect.

9. Standards and Reference Material

• Siemens PCS 7 V9.0 Function Manual (entry ID 109751721)
• PCS 7 Faceplate Designer entry on Siemens Industry Online Support
• PCS 7 V9.0 SP2 release notes and supported APL block versions
• IEC 62443 (industrial communication network security) — relevant when the OS-AS link traverses untrusted networks

10. Field-Proven Quick Reference

1. Confirm tag type is BOOL at the S7 source.
2. Confirm the WinCC tag is created, online, and updating.
3. Confirm the faceplate interface property is a flat BOOL (e.g., .IndicationBit).
4. Confirm the Tag event on the lamp references that property.
5. Confirm the Appearance/Color animation uses the same property and maps value 1 → red.
6. Confirm the faceplate instance in the picture has its tag binding flags set.
7. Re-compile OS, perform incremental download, restart WinCC Runtime.