Correct a One-Hour Difference Between PCS 7 Alarm and Operation Lists
A one-hour offset between alarm-list and operation-list entries can occur when timestamps use different time bases or time-zone settings. For the reported PCS 7 V8.0 system, the CEMAT Minerals guide states that the AS works with Greenwich Mean Time and that OS stations should use the same time zone. Configure the intended PCS 7 time-synchronization architecture consistently; do not hide the difference by applying a display offset.
Table of Contents
- Identify each event's timestamp source
- Configure one consistent time basis
- Synchronize all relevant stations
- Verification
- Limitations and Operational Precautions
- Technical References
- Related Articles
- Related Tags
- Engineer FAQ
Identify each event's timestamp source
Determine whether the alarm event was generated by the AS or the OS and whether the operation-list entry was generated by WinCC. Record the timestamp and configured time zone on the AS, OS servers, and clients, including daylight-saving settings.
Configure one consistent time basis
The CEMAT Minerals V9.0 SP2 engineering guide describes the AS as working with Greenwich Mean Time (UTC) and recommends configuring OS stations for the same time zone. It also describes an external time master, such as SICLOCK, as an alternative depending on hardware and network design. For PCS 7 V8.0, check the matching version-specific time synchronization guidance before changing settings.
Synchronize all relevant stations
Apply the approved time-master and client/server configuration to the AS, OS servers, and operator stations. Ensure the time source and local-time interpretation are consistent across stations; redundant OS servers should not disagree about time or time-zone rules.
Verification
Compare new AS alarms and WinCC operation-list events after synchronization. Check that event order is sensible across lists and verify behavior across daylight-saving transitions if the system uses local time.
Limitations and Operational Precautions
The ticket does not identify the time-master architecture, Windows time-zone settings, daylight-saving configuration, or exact event source. Changing system time can affect archives, alarm chronology, and time-dependent control logic; use site change control and do not alter historical timestamps in place.
Technical References
- Siemens, Engineering CEMAT Minerals V9.0 SP2, “Time Synchronization”: https://support.industry.siemens.com/cs/attachments/109768060/Cem_V90_Engineering_001_en.pdf
- Siemens, PCS 7 Time Synchronization overview, referenced by CEMAT: https://support.industry.siemens.com/cs/ww/en/view/109754988
Related Articles
Related Tags
Engineer FAQ
Why is the alarm list one hour different from the operation list? The source reports a timezone-sized difference; the CEMAT PCS 7 guidance says the AS works in GMT/UTC while OS stations use a common configured timezone.
Should the AS use UTC or local time? The cited CEMAT guidance describes the AS as using Greenwich Mean Time and recommends aligning OS stations to a common time-zone configuration.
Are alarm messages and operator messages timestamped identically? They may originate at different system components; verify the event source and timestamp basis rather than applying a blanket offset.
Can I just subtract one hour in the display? No. Correct the time-source/configuration mismatch instead of applying a cosmetic offset to event data.
What should be synchronized across the system? Synchronize OS servers, AS controllers, clients and external time master according to the configured PCS 7 architecture.
Could daylight saving cause the difference? Yes, local-time offset can vary with daylight-saving rules; verify the time zone and DST configuration on all stations.
Will changing time settings alter historical data? Existing timestamps are not repaired merely by changing configuration; evaluate archive/event interpretation and change plans.
What source supports UTC on the AS? The CEMAT Minerals V9.0 SP2 engineering guide says the AS works with Greenwich Mean Time and OS stations should use the same time zone.
Can an external master be used? Yes. The CEMAT guide gives SICLOCK as an example of an external time master, depending on hardware/network configuration.
How do I confirm the fix? Compare AS-generated alarm timestamps and OS-generated operation-list timestamps after synchronization, including the active DST setting.