Resolving PCS 7 V9.0 SP3 WinCC V7.4 Runtime Time Display Issues

Resolving PCS 7 V9.0 SP3 WinCC V7.4 Runtime Time Display Issues

This technical reference addresses three correlated symptoms observed on PCS 7 V9.0 SP3 operator stations running WinCC V7.4: (1) the system time in the runtime header remains static and does not update, (2) a horizontal line is drawn through the time field, and (3) unknown symbols such as ??? and a blue-background X appear in the alarm line. Each symptom has a distinct root cause and a separate fix. The procedures below cover CPU UTC configuration, PCS 7 time synchronization, and the @AlarmOneLine.pdl alarm-column configuration.

1. Problem Overview

When the PCS 7 OS runtime is activated on a V9.0 SP3 station paired with WinCC V7.4 SP1, the top header bar of every process picture shows the date and time. In the failure mode reported here, the displayed clock value does not increment: it freezes on the value it had at runtime start. A horizontal line is drawn through the time digits. In the same picture, the message/alarm line at the top or bottom of the screen shows additional characters that the operator does not recognize:

• Strikethrough time — digits remain static for hours, with a horizontal line crossing the field.
• "???" — appears in fields that should display batch, user, or comment text.
• "X" on a blue background — appears at the right end of the alarm line.

None of these are syntax errors. They are WinCC rendering rules for "value not supplied" or "function available". The fix is to populate the underlying tags and to enable the right runtime options.

2. Affected Software Versions and Components

The time-stamping scheme of PCS 7 from V8.x onward is unified: the OS expects time-of-day information from the AS in UTC (Coordinated Universal Time) without any local time-zone offset. WinCC V7.4 applies the operator station's local time-zone offset on top of the UTC stamp before it draws the header clock. If the AS is configured with a local time-zone offset, the calculation produces a stale or out-of-range value and WinCC draws the strikethrough.

3. Symptom Catalog: Static Time, Strikethrough, and Unknown Symbols

3.1 Static header time with strikethrough

The header picture (typically @Screen.pdl with the embedded @Time.pdl) connects to the internal WinCC tag SystemTime which is updated by the time-sync service. When the source value is invalid, the connection is broken, or the master clock is misconfigured, the field displays the last known value and overlays a strikethrough line — the standard WinCC convention for "no current value available".

3.2 "???" in batch / comment / user fields

The alarm line can display columns for batch name, batch ID, operator, area, comment, etc. If a column is configured but the underlying alarm message has not populated that field with a value, WinCC draws "???" as a placeholder. This is expected behaviour and is not an alarm loss.

3.3 Blue-background "X"

The blue-background X at the right end of the alarm line is the WinCC "Loop-in-alarm" button. It is rendered when the operator has the right to use the Loop-in-alarm function on the configured alarm class. Clicking it jumps from the current picture into the picture associated with the alarm source. If the function is not licensed or the operator authorization is missing, the symbol renders as a disabled grey X.

4. Root Cause Analysis: CPU Time Synchronization

The CPU is the time master for the PCS 7 cell. The WinCC OS reads the AS time over S7 time-of-day and converts it. According to the official Siemens PCS 7 Time Synchronization (V9.1) manual, the time at the AS must be:

• Synchronized to UTC.
• Without any local time-zone offset (no DST offset, no operator-station offset).
• Driven by a stratum-1 or NTP-synchronized source where possible (SICLOCK, GPS, or NTP via CP).

If the AS is set with a time-zone offset (e.g., UTC+1, UTC+2 for summer time), the WinCC OS miscalculates the local time. The result is a value that appears frozen or out of range, and WinCC draws the strikethrough. This is the most common cause of the static-time symptom.

5. Root Cause Analysis: Unknown Symbols in the Alarm Line

5.1 "???"

Configured but unpopulated alarm columns render as ???. The fix is to either disable the unused columns or to populate them from the message source (block) by configuring the message text and process-value fields in STEP 7.

5.2 Blue-background "X" — Loop-in-alarm

This is rendered when the AlarmControl column "Loop-in-alarm" is enabled and the operator authorization Operator_Permissions.LoopInAlarm is set. It is functional, not a fault. If you want to remove the symbol, hide the column in the alarm line or revoke the authorization.

6. Preconditions for the Fix

• WinCC Explorer on the engineering station (ES) with the project open.
• PCS 7 V9.0 SP3 ES license active.
• Administrator rights on the OS server/client to restart the WinCC runtime and the time-sync service.
• Access to the AS (S7-400 / AS 410) via STEP 7 V5.6 or SIMATIC Manager, with the offline/online program of the relevant CPU.
• Reference manual available: PCS 7 Time Synchronization (V9.1).

7. Step-by-Step: Configure the CPU as UTC Time Master

1. Open the S7 project in STEP 7 / SIMATIC Manager.
2. Select the CPU in the project tree (HW Config → CPU object).
3. Open Object Properties → Diagnostics/Clock (German: Diagnose/Uhrzeit).
4. Set Synchronization type to "As master with system clock (without time-zone offset)". Do not select "with time-zone offset".
5. Confirm with OK and download the configuration to the AS.
6. In the CPU online view (PLC → Set Time of Day), verify that the value reported by the CPU is the current UTC time. Example: at 14:00 local CET (UTC+1), the CPU should report 13:00:00.

8. Step-by-Step: Configure PCS 7 Time Synchronization

1. On the OS server, open WinCC Explorer.
2. Right-click "Time Synchronization" in the WinCC Explorer tree and select "Wizard…" (German: Assistent).
3. In the wizard, select "Synchronization via System Bus (S7) and Industrial Ethernet / Plant Bus".
4. Select the access points to the AS that act as time masters. For redundant setups, mark both AS pairs as masters.
5. Set the access interval to a value compatible with the AS load: typical values are 10 s for the polling interval, 1 s for the correction interval.
6. Finish the wizard and restart the WinCC runtime.
7. Verify the result: the header time should now tick every second and the strikethrough should be gone.

The wizard writes the configuration to the OS server's registry keys under HKLM\SOFTWARE\Wow6432Node\Siemens\WinCC\TimeSync. For audit purposes, document the selected access points and intervals in the project quality log.

9. Step-by-Step: Configure the Alarm Line (@AlarmOneLine.pdl)

1. In WinCC Explorer, open Graphics Designer.
2. Open the picture @AlarmOneLine.pdl from the project library (\GraCS\).
3. Double-click the AlarmControl object. The configuration dialog opens.
4. Switch to the "Columns" tab.
5. Review every column listed. Common columns to enable/disable:

   Column	Default state	Behavior when empty
   Date	Enabled	Always populated
   Time	Enabled	Always populated
   Number	Enabled	Always populated
   State	Enabled	Always populated
   Message text	Enabled	Always populated
   Optional fields (often left empty)
   Batch name	Often enabled	Shows ??? if no batch active
   Batch ID	Often enabled	Shows ??? if no batch active
   Operator	Disabled	Shows ??? if logged out
   Comment	Disabled	Shows ??? if no comment
   Loop-in-alarm (X)	Enabled	Shows X if operator has rights

6. To hide the ??? placeholders, clear the check-boxes for the optional columns that are not used in the plant.
7. To remove the blue X, either clear the "Loop-in-alarm" column or, if the function is wanted, leave it enabled and verify operator authorization under User Administrator → Authorizations → Loop-in-alarm.
8. Save the picture. WinCC stores the change in @AlarmOneLine.pdl; the file is reloaded by the runtime at the next start.

10. Step-by-Step: Remove the Strikethrough on the Time Field

The strikethrough is rendered by the picture @Time.pdl when its source tag returns an invalid value. Two paths remove it:

1. Root-cause fix (preferred): correct the AS time configuration per Sections 7 and 8 so the tag SystemTime is always valid.
2. Visual workaround (not recommended): open @Time.pdl, select the time I/O field, and uncheck the property "Output if no value" in the Properties dialog under "Output/Input". This suppresses the strikethrough but does not fix the underlying time sync.

Always apply the root-cause fix first. Visual workarounds hide the symptom and let the OS silently run with an invalid clock, which corrupts message time stamps and audit trails.

11. Verification and Acceptance Test

1. Activate WinCC Runtime on the OS server.
2. Observe the header clock for 60 seconds. Confirm it increments every second and that no strikethrough line is drawn.
3. Trigger a process alarm on a controlled tag (for example, a high-level alarm on a tank). Verify that:
   • The alarm line shows Date, Time, Number, State, and Message text correctly.
   • No ??? appears in columns that have been disabled or are populated by the alarm source.
   • The blue-background X appears at the end of the alarm line (if Loop-in-alarm is enabled) and is clickable. Clicking it opens the loop-in picture.
4. Open the alarm log via the OS controls and verify that the time stamp on each historical alarm matches the local time of the OS station (i.e., UTC + offset + DST).
5. Force a time-jump on the AS (PLC → Set Time of Day → +5 minutes). Confirm that the header time follows within one polling interval.

12. Troubleshooting Matrix

13. Field-Proven Tips and Edge Cases

• Redundant OS servers: run the Time Synchronization wizard on both servers; both must target the same AS pair. Mismatch leads to one server showing strikethrough after failover.
• Workstation clients without time sync: configure the client to use the OS server as time source. In WinCC Explorer → Time Synchronization → "Synchronization via terminal bus (TCP/IP)" and select the OS server's computer name.
• DST transitions: WinCC V7.4 handles DST automatically from the local OS settings; verify that the OS regional settings are correct (Time zone, "Automatically adjust clock for daylight saving time" enabled).
• License: Loop-in-alarm requires the "SFC Visualization" or "PCS 7 OS Runtime" license. If the license is missing, the symbol renders grey instead of blue.
• Upgrade safety: after every PCS 7 SP or hotfix, re-check @AlarmOneLine.pdl and @Time.pdl. The installer replaces them with the WinCC-shipped defaults.
• Cross-cell consistency: when multiple OS servers are deployed, run the Time Synchronization wizard on each server individually and verify that the CPU's "Diagnostics/Clock → Synchronization type" matches across the cell. Mixed UTC and offset masters create intermittent strikethrough after client failover.

14. FAQ