Resolving Tag and Event Trigger Failures in SIMATIC Information Server with Process Historian

In SIMATIC Information Server 2014 and PCS 7 v8.1, scheduled report generation works reliably with Time Triggers but fails with Tag / Event Triggers when the target tag is not configured for cyclic/event archiving in WinCC Tag Logging, or when the Process Historian - Information Server Synchronization Service lacks administrative access to the runtime tag database. To resolve this, configure the trigger tag in WinCC Tag Logging with active archiving, verify that Microsoft Message Queuing (MSMQ) permissions permit cross-station event telemetry, and ensure the Information Server Scheduler service runs under a domain account belonging to the SIMATIC Report Services group.

Architecture of Report Triggers in SIMATIC Information Server

SIMATIC Information Server (IS 2014 / IS 2014 SP2) provides web-based reporting for SIMATIC Process Historian (PH 2014), WinCC OS Servers (6ES7652-0XX08-1XB0), and SIMATIC BATCH (6ES7657-0XX08-1YB0). It enables automated generation of shift reports, alarm logs, and batch production protocols via subscription services.

Report subscriptions support two primary trigger mechanisms:
1. Time Trigger: Executed locally by the Information Server Scheduler service based on internal clock schedules (e.g., Daily at 06:00, Weekly on Sunday).
2. Tag / Event Trigger: Initiated dynamically when a designated process tag, message class, or batch status changes state (e.g., Batch_End = 1 or Reactor_Temp > 120).

While Time Triggers operate autonomously within the local Information Server instance, Tag and Event Triggers rely on a multi-tier event pipeline spanning the OS Server runtime tag manager, Process Historian database replication, and Microsoft Reporting Services subscriptions.

Why Time Triggers Succeed While Tag Triggers Fail

When an Information Server report fails to generate under a Tag Trigger, the underlying issue stems from broken event propagation:
* Un-archived Internal Tags: If an engineer selects an online WinCC internal tag that is not configured for continuous or event-driven archiving in WinCC Tag Logging, the value change exists only in OS volatile memory and is never replicated to Process Historian.
* Service Account Rights: The Information Server Scheduler service (IS_Scheduler.exe) queries the Process Historian OLE-DB / OPC UA interface. If the Windows service logon account does not belong to the SIMATIC Report Services and Process Historian Administrators groups, event queries are rejected.
* Message Queuing (MSMQ) Blocking: Process Historian uses MSMQ to capture event notifications from OS Servers. Firewalls or mismatched network security profiles blocking TCP port 1801 prevent event telemetry from reaching the report engine.

Diagnostic Matrix for Information Server Event Subscriptions

The following table details the key subsystems responsible for tag-triggered reporting:

Subsystem / ServiceStation LocationRole in Tag Trigger WorkflowFailure Mode and Diagnostic LocationWinCC Tag LoggingOS ServerArchives tag value changes into SQL database segments.Tag missing from archive; check WinCC Tag Logging editor.PH Ready ServiceOS ServerQueues and forwards tag archive records to Process Historian via MSMQ.PH_Ready.log shows message queue overflow or network disconnect.PH Synchronization ServiceProcess HistorianReplicates real-time tag events into SQL reporting tables.PH_Core.log shows synchronization delay or license missing.IS Scheduler ServiceInformation ServerEvaluates tag trigger thresholds and initiates report generation.IS_Scheduler.log shows failed tag event subscription.Microsoft SQL ReportingInformation ServerRenders and distributes final PDF/Excel report to network shares/email.SSRS execution log shows permission denied or query timeout.

Table 1: Information Server event trigger infrastructure and diagnostic failure points.

Step-by-Step Configuration and Security Validation Workflow

To restore tag-triggered reporting in SIMATIC Information Server:

Verify WinCC Tag Logging Configuration:
* Open the OS project in WinCC Explorer.
* Open Tag Logging, navigate to Process Value Archives, and locate the desired trigger tag (e.g., Batch_State or Unit_Status).
* Ensure the tag archiving type is set to Cyclic, continuous or Event-driven, and verify that the archive segment is actively writing.
Verify Process Historian Data Reception:
* On the Process Historian station, open Process Historian Management Console.
* Confirm that the OS Server status shows Active and synchronized.
* Query the tag in the PH Diagnostic tool to confirm live values are updating in the database.
Configure Information Server Service Credentials:
* Open Windows Services (services.msc) on the Information Server host.
* Locate SIMATIC Information Server Scheduler.
* Open properties and ensure the service logs on under a dedicated domain automation account (e.g., DOMAIN\PH_Admin).
* Verify this account belongs to: SIMATIC HMI, SIMATIC Report Services, and Administrators.
Reconfigure the Tag Subscription in Information Server:
* Open the Information Server web portal.
* Navigate to Subscriptions > Create Subscription.
* Under Trigger, select Tag Trigger.
* Browse through the verified Process Historian archive catalog to pick the tag.
* Specify the condition (e.g., Value == 1 or Value changes) and assign the report output path.
Inspect Log Files:
* Open C:\Program Files (x86)\Siemens\InformationServer\Diagnostics\IS_Scheduler.log.
* Confirm that the scheduler successfully logs: Subscription for Tag [TagName] registered successfully.

Verification

To confirm proper tag-triggered report generation:

In WinCC Runtime or CFC test mode, force the trigger tag to change state (e.g., transition Batch_End from 0 to 1).
Observe Process Historian: verify the value change is recorded in the tag archive table.
Observe Information Server: within 30 to 60 seconds, check the destination file share or email inbox to confirm that the generated report (PDF/Excel) has arrived.
Open the Information Server web interface: navigate to Report History and verify the report status shows Completed Successfully with the matching event timestamp.

Limitations and Operational Precautions

Tag triggers should not be assigned to high-frequency analog tags (e.g., raw pressure changing every 100 ms), as this will overwhelm the SQL reporting server with hundreds of concurrent PDF rendering requests.
Ensure sufficient Process Historian and Information Server client access licenses (6ES7652-0XX08-1XB0, 6AV6372-2DF07-0AX0) are installed via Automation License Manager. Always validate license packages with an authorized Siemens distributor.
If the Information Server and Process Historian reside on separate virtual machines, verify that system clocks are synchronized via NTP to prevent event timestamp validation drops.

Engineer FAQ

Can internal WinCC tags trigger Information Server reports?

Only if the internal tag is explicitly configured as an archive tag in WinCC Tag Logging. Raw internal tags residing solely in WinCC memory are not transmitted to Process Historian.

Why does the tag browser in Information Server appear empty?

This occurs when the Information Server has not completed initial project synchronization with Process Historian, or when DCOM communication between IS and PH is blocked by Windows Firewall.

Does Information Server support SIMATIC BATCH phase triggers?

Yes. If SIMATIC BATCH archiving is enabled, Information Server can trigger reports on batch events such as Batch Start, Unit Allocation, Recipe Phase Completion, and Batch End.