Implementing FDA 21 CFR Part 11 Audit Trails in SIMATIC PCS 7 - Standard Operation List vs WinCC Audit

In SIMATIC PCS 7 (v8.1 and v8.2), meeting FDA 21 CFR Part 11 and EU GMP Annex 11 electronic records compliance can be achieved using either the built-in PCS 7 Operation List (Operator Input Messages) or the specialized add-on package SIMATIC WinCC/Audit. While standard PCS 7 APL automatically logs operator setpoint adjustments and mode changes into WinCC Alarm Logging with user ID and timestamps, it lacks cryptographically secured change-verification databases and electronic signature prompts. For regulated pharmaceutical environments requiring reason-for-change dialogs and dual-signature authorizations, WinCC/Audit or SIMATIC BATCH must be integrated following official Siemens GMP guidelines.

Regulatory Framework: 21 CFR Part 11 and EU GMP Annex 11 in PCS 7

In life sciences, pharmaceutical manufacturing, and biotechnology facilities governed by FDA 21 CFR Part 11 and EU GMP Annex 11:
* The Compliance Requirements:
Automated systems must generate secure, computer-generated, time-stamped audit trails to independently record the date and time of operator entries and actions that create, modify, or delete electronic records.
* Core Technical Controls:
1. User Authentication and Authorization: Enforced via SIMATIC Logon with Microsoft Active Directory integration.
2. Audit Trail Logging: Recording operator ID, tag name, old value, new value, and timestamp.
3. Electronic Signatures: Requiring operators to enter credentials and a structured 'Reason for Change' before sensitive recipe or setpoint changes are committed.
4. Data Integrity / Tamper Proofing: Storing audit records in protected, read-only or cryptographically sealed database archives.

PCS 7 Standard Operation List vs WinCC/Audit Feature Matrix

The table below outlines technical compliance differences between standard PCS 7 operation tracking and specialized WinCC/Audit features:

Compliance Feature / CapabilityPCS 7 Standard Operation List (APL)SIMATIC WinCC/Audit (6AV6371-1DV07-4AX0)SIMATIC BATCH (6ES7657-0XX08-1YB0)Operator Action LoggingAutomatic via Alarm_8PMonitored tag changes & script triggersAutomated Electronic Batch RecordsLogged AttributesUser, Old Value, New Value, TimestampUser, Old/New Value, Timestamp, ReasonBatch ID, Formula Steps, User, SignaturesElectronic Signature PromptsNot Available nativelySupported (1-sign or 2-sign 4-eyes)Supported (Recipe phase approvals)Reason for Change SelectionNot AvailableSupported (Drop-down or custom text)Supported (Predefined GMP justifications)Engineering Project AuditVia Version Trail (Separate tool)Supported (Audit RC tracks editor edits)Recipe versioning and change controlTamper-Evident StorageStandard SQL Alarm Logging tablesCryptographically signed SQLite / SQL archiveEncrypted batch database archiveLicensing RequirementIncluded with standard PCS 7 licenseSeparate Audit RC/RT license requiredSeparate SIMATIC BATCH license required

Architecture and Licensing of SIMATIC WinCC/Audit

To satisfy rigorous validation mandates:
* SIMATIC WinCC/Audit (6AV6371-1DV07-4AX0):
* Audit RC (Engineering): Tracks engineering design changes in WinCC editors (Tag Management, Graphics Designer, C/VBS scripts).
* Audit RT (Runtime): Monitors active runtime operations, displays electronic signature dialogs, and records events in a cryptographically signed SQLite / SQL Audit Database.
* Audit Viewer:
A dedicated application used by quality assurance auditors to view, query, and verify the cryptographic integrity of exported audit trails (.csv files with attached SHA-256 digital signatures).

Engineering Challenges of WinCC/Audit in PCS 7 Multiprojects

Integrating WinCC/Audit into PCS 7 requires careful consideration:
* The SCADA vs DCS Conflict:
WinCC/Audit was originally developed for standalone WinCC SCADA systems. In PCS 7, screens and faceplates are generated automatically by the AS-OS Compiler and APL templates. If WinCC/Audit's configuration studio modifies project properties, subsequent AS-OS compilations or running the OS Project Editor can overwrite custom audit triggers.
* Siemens Recommendation:
For continuous plants, use standard PCS 7 Operator Messages paired with SIMATIC Logon. For recipe and batch processes, utilize SIMATIC BATCH (6ES7657-0XX08-1YB0), which natively complies with 21 CFR Part 11 with built-in electronic signatures, recipe versioning, and Electronic Batch Records (EBR).

Step-by-Step Procedure to Implement Validated Audit Trails in PCS 7

Deploy SIMATIC Logon:
Install SIMATIC Logon (6ES7658-7BX58-0YB0) on the Engineering Station and all OS Server/Client stations. Bind user groups to Windows Active Directory domains with enforced password expiration and lockout policies.
Enable Operator Input Messages in APL:
In CFC, ensure block inputs have operator message generation enabled (MsgLock = 0 and feature bits configured for audit reporting).
Configure WinCC Alarm Logging for Operator Messages:
* Open WinCC Alarm Logging.
* Verify that Message Class Operator Input Message is configured.
* Add the message blocks: User name, Old value, New value, Date, Time, and Comment.
Deploy WinCC/Audit (If Mandated by Validation Plan):
* Install WinCC/Audit Runtime (6AV6371-1DV07-4AX0) on the OS Servers.
* Open the WinCC Audit Editor. Select target critical tags (e.g., critical process setpoints) and enable audit tracking with Electronic Signature.
Archive to Long-Term Storage:
Route all audit trails and operator messages to SIMATIC Process Historian (6ES7652-8AX58-0YB0) to establish immutable historical records.

Verification

To verify audit trail compliance:
1. Log into WinCC OS Runtime as an authorized operator via SIMATIC Logon.
2. Modify a critical temperature setpoint on a process faceplate.
3. Open the WinCC Alarm Logging Operation List window.
4. Confirm that an entry is generated documenting the exact timestamp, tag identifier, operator username, original value, and new value.
5. If using WinCC/Audit, verify that the Electronic Signature dialog appeared and that the action is recorded in the Audit Viewer with a status of Signature Valid.

Limitations and Operational Precautions

Electronic Signature Operator Fatigue: Do not apply mandatory electronic signatures to every minor operational button. Prompting operators for passwords on routine valve toggles causes severe operator fatigue and operational delays during emergencies.
Tamper-Evident Exporting: Exported audit trails must be stored in write-protected network storage (WORM storage) to ensure legal non-repudiation during regulatory inspections.
Licensing Disclaimer: Procuring WinCC/Audit licenses (6AV6371-1DV07-4AX0) and SIMATIC Logon options requires validation against the applicable Siemens catalog and authorized distributor quotation.