Configuring Shift and Hourly Interval Aggregation Timestamps in SIMATIC Information Server

In SIMATIC Information Server (integrated with Process Historian and WinCC / PCS 7), hourly average and interval reports display the start of the time interval (e.g., labelling data aggregated from 08:00 to 09:00 with timestamp 08:00:00) by default rather than the interval end (09:00:00). This occurs because Process Historian and SQL Server Reporting Services (SSRS) store and aggregate time-series archives using the Interval-Start convention. To present the data with an interval-end timestamp (09:00:00), engineers can configure the report template parameters to utilize TimeIntervalEnd, define a custom shift model within the Information Server shift calendar, or adjust the report's SQL expression to project the aggregation endpoint. Furthermore, ensure uniform UTC-to-local time synchronization across the PCS 7 OS servers and the Process Historian.

Time Aggregation Mechanics in Process Historian and Information Server

In enterprise industrial reporting architectures, SIMATIC Process Historian acts as the central, long-term archive database for SIMATIC PCS 7 and WinCC, while SIMATIC Information Server provides web-based reporting powered by Microsoft SQL Server Reporting Services (SSRS). Operating plants rely on Information Server to generate shift reports, daily energy consumption tallies, and hourly process averages.

A frequent operational conflict arises regarding timestamp representation. Process Historian ingests high-frequency tags and calculates cyclic averages (e.g., 1-minute, 1-hour, or 8-hour shift aggregations). By database convention, the aggregation engine binds the calculated average to the beginning of the evaluation window (IntervalBegin). However, plant production accounting typically expects hourly production tallies to be reported at the end of the measured hour (i.e. production between 08:00 and 09:00 belongs to the 09:00 production hour).

Interval-Start vs Interval-End Timestamping Conventions

Understanding how the underlying reporting engine handles time intervals is essential for proper report design:

DimensionInterval-Start Convention (Default)Interval-End Convention (Production Accounting)Time Window$[08:00:00 - 08:59:59.999)$$[08:00:00 - 08:59:59.999)$Displayed Timestamp08:00:0009:00:00Database ColumnTimeIntervalStart / TimestampTimeIntervalEnd / DateAdd(hour, 1, TimeIntervalStart)Typical ApplicationScientific data logging, raw trend analysisShift production reports, utility billing, environmental loggingTimezone AlignmentConverted from UTC to Local Time at displayConverted from UTC to Local Time with interval offset

When operators review a daily report, an entry marked 08:00 containing data collected up to 09:00 creates confusion unless the report column header explicitly clarifies whether the timestamp denotes the start or close of the interval.

Configuring Report Templates and Shift Calendars for End-Timestamping

To adjust Information Server reports to display the interval-end timestamp, implement one of the following methods:

Method 1: Configuring Custom Report Parameters in SSRS / Report Designer
1. Open the target report template in Microsoft Report Builder or Visual Studio SQL Server Data Tools.
2. Locate the table column displaying the timestamp. In standard templates, the field expression is =Fields!TimeIntervalStart.Value.
3. Change the field expression to =Fields!TimeIntervalEnd.Value or =DateAdd(DateInterval.Hour, 1, Fields!TimeIntervalStart.Value).
4. Update the column header label from Time to Hour Ending or Interval End.
5. Upload the customized .rdl template back into Information Server under Administration -> Report Templates.

Method 2: Leveraging the Information Server Shift Calendar
1. In Information Server web portal, navigate to Shift Management.
2. Create a shift model where each production hour is configured as an explicit production slice.
3. When generating reports using the standard 'Shift Report' template, select the shift definition that groups data by period completion.

Verification

Verify timestamp accuracy and reporting alignment using these testing steps:

Report Generation Test: In Information Server, trigger an on-demand hourly average report for the previous day. Verify that the first reported row displays 09:00:00 (representing data from 08:00 to 09:00).
Data Consistency Audit: Cross-reference the calculated average against the raw data points in WinCC Online Trend Control for that exact one-hour window. Confirm that numerical values match 100%.
Timezone Offset Check: Confirm that daylight saving time transitions (DST) do not create duplicate or missing one-hour reporting buckets.

Limitations and Operational Precautions

When configuring timestamps and aggregation intervals, adhere to these operational principles:

UTC Time Synchronization: Process Historian and WinCC OS servers must synchronize with a central NTP time master (such as a SICLOCK or domain controller). Never allow manual clock adjustments on database servers.
Template Overwrites During Upgrades: Custom .rdl report templates should be saved under custom names; upgrading Information Server replaces default Siemens report templates with factory defaults.
Archive Cycle Latency: Calculated averages in Process Historian are generated upon interval completion. Requesting a report for the current ongoing hour will omit the latest incomplete interval until the hour finishes.

Engineer FAQ

Why does Process Historian store timestamps in UTC?

Process Historian stores all time-series data in Coordinated Universal Time (UTC) to eliminate ambiguities caused by daylight saving time shifts and across multi-server plants located in different time zones.

Can I change the aggregation convention globally in Process Historian?

No. Process Historian internal database views are hardcoded to the Interval-Start convention to maintain relational database integrity. Formatting for interval-end is handled exclusively at the presentation layer in Information Server.

Does modifying the report template require an Information Server license?

Modifying or creating custom report templates using Microsoft Report Builder is supported without additional software licenses, provided Information Server has valid client access licenses.