Distinguishing SIMATIC PDM Licenses from Maintenance Station Engineering and Runtime Packages

SIMATIC PDM and SIMATIC Maintenance Station fulfill distinct functional roles and require separate software licenses in PCS 7. SIMATIC PDM licenses field device parameterization, EDD integration, and instrument diagnostics via HART, PROFIBUS, or PROFINET. It does not license the Maintenance Station diagnostic engineering system. To configure, compile, and generate diagnostic screens for an MS Server or Single Station, the Engineering Station requires the 'SIMATIC PCS 7 Maintenance Station Engineering' license. At runtime, the operator or maintenance station requires an MS Runtime license ('MS Basic' for automation hardware or 'MS Standard' with Asset Packages for extended field assets).

Executive Summary

In SIMATIC PCS 7 (V8.0 through V9.1), comprehensive plant asset management is split into two complementary software subsystems: SIMATIC PDM (Process Device Manager) and the SIMATIC Maintenance Station (MS). A frequent licensing and engineering point of confusion arises when an engineering station already has SIMATIC PDM installed and engineers attempt to configure or compile the Maintenance Station diagnostic screens without holding the dedicated Maintenance Station Engineering license. This article provides a comprehensive analysis of the functional boundaries between PDM and Maintenance Station, the specific license keys required on engineering and runtime nodes, and the precise procedure to configure plant asset diagnostics.

Architecture and Fundamental Mechanics

Software Architecture and Licensing Division between PDM and Maintenance Station:

SIMATIC PDM (Process Device Manager):
Purpose: Universal tool for configuration, parameter assignment, commissioning, and servicing of intelligent field devices using Electronic Device Description (EDD) technology.
Licensing: Structured around PDM Basic (standalone or integrated into STEP 7) and additive PDM TAG packages (e.g., 100, 1,000, or 10,000 tags) representing the number of configured field devices, alongside communication options (HART on PROFIBUS/PROFINET, FF, etc.).
Scope Boundary: PDM allows an engineer or technician to open device faceplates, perform sensor calibration, and view NAMUR NE107 device status. However, PDM does not generate system-level diagnostic plant hierarchy screens or manage cyclic status aggregation across controllers and network components.
SIMATIC PCS 7 Maintenance Station (MS):
Purpose: Plant-wide diagnostic visualization and predictive asset maintenance system based on the WinCC operator station platform. Visualizes the health of AS controllers, redundant power supplies, ET 200 distributed I/O, network switches (SCALANCE), IPCs, and field devices.
Engineering License (ES): Requires 'SIMATIC PCS 7 Maintenance Station Engineering'. This key unlocks the diagnostic hierarchy compiler in SIMATIC Manager ('Create/Update Diagnostic Screens') and creates the diagnostic WinCC pictures (@Diagnostic_...). Without this key, diagnostic screen compilation is blocked.
Runtime Licenses (OS / MS Server / Single Station):
- MS Basic: Monitors automation hardware assets (controllers, communication processors, remote I/O stations, network switches, and PC stations).
- MS Standard: Extends monitoring to intelligent field devices, drives, and valve positioners, integrating cyclic status polling and maintenance request generation.
- MS Asset Packages: Additive runtime licenses scaled by the total number of monitored plant assets (e.g., packages of 100, 500, or 1,000 asset tags).
Co-existence and Integration:
PDM can be launched seamlessly from Maintenance Station faceplates on the operator or maintenance client to inspect field instruments. However, having PDM licenses installed on an ES provides zero authorization for the Maintenance Station engineering tools.

Step-by-Step Implementation Procedure

Step-by-Step Configuration and Licensing Procedure for Maintenance Station:

Verify Engineering Licenses in Automation License Manager (ALM):
- Open ALM on the Engineering Station.
- Verify that the license key 'SIMATIC PCS 7 Maintenance Station Engineering' (matching the PCS 7 version) is present and valid.
- Verify that the 'SIMATIC PDM' base license and sufficient 'PDM TAG' licenses are present if field devices are managed via PDM.
Configure the Plant Diagnostic Hierarchy in SIMATIC Manager:
- In the Plant View, create or identify the designated Diagnostics folder.
- In the Component View, open the designated OS Server or dedicated Maintenance Station PC station properties.
- Under the 'Maintenance Station' tab, designate the station type: 'MS Server', 'MS Single Station', or 'Maintenance in OS' (integrated MS).
Configure Field Devices in PDM and HW Config:
- Configure field instruments in STEP 7 HW Config using standard PDM EDDs.
- Ensure each field device is assigned to its respective technological hierarchy folder.
Execute Diagnostic Screen Generation:
- In SIMATIC Manager, select menu Options -> Plant Diagnostics -> Create/Update Diagnostic Screens.
- Select the compilation scope (Entire plant or Delta) and proceed.
- The compiler uses the MS Engineering license to generate the hierarchical diagnostic overview screens, alarm records, and faceplate connections.
Configure and Verify Runtime Licensing on the Target MS Server:
- On the target MS Server or OS Single Station, open ALM.
- Transfer the required runtime licenses: 'SIMATIC PCS 7 Maintenance Station Basic' or 'SIMATIC PCS 7 Maintenance Station Standard', along with the required 'MS Asset' tag expansions.
- Download the compiled WinCC OS/MS project from the ES to the runtime server.

Verification

Verification Procedure:
1. Diagnostic Compilation Verification: In SIMATIC Manager, inspect the Plant Diagnostics compilation log. Verify that the compilation completed with 0 errors and generated all system diagnostic pictures (@PG_..., @Diagnostics.pdl).
2. Engineering License Check: In ALM on the ES, verify that the 'PCS 7 Maintenance Station Engineering' license key indicates status 'In use' during compilation and returns to 'Available' without licensing violation warnings.
3. Runtime Verification: Start WinCC Runtime on the Maintenance Station. Navigate to the top-level Diagnostics overview button. Verify that the system hierarchy, controller status, ET 200 nodes, and field instruments display valid operational states (e.g. green healthy checkmarks) without any 'License Missing' popups.

Limitations and Operational Precautions

Operational Precautions and Licensing Limits:
- Standalone MS vs Integrated MS: In an 'Integrated MS' configuration (where the OS Server acts as both Operator Station and Maintenance Station), ensure sufficient WinCC Process Objects (OS RT PO) and archive licenses are present on the OS Server in addition to the MS Basic/Standard license.
- Asset Counting Differences: PDM TAG licenses count configured devices in the PDM network view, whereas Maintenance Station Asset packages count objects represented in the diagnostic overview screens. They do not share a common license pool.
- Commercial and Procurement Boundaries: License names, package tiers (e.g. MS Basic vs MS Standard), and order numbers vary between PCS 7 versions. Always validate specific catalog numbers (MLFBs) and required asset tag counts against the latest Siemens ST PCS 7 catalog and an authorized Siemens distributor quotation.

Engineer FAQ

Can I compile Maintenance Station screens if I only have a SIMATIC PDM license?

No. The CFC/Plant Hierarchy compiler strictly requires the 'SIMATIC PCS 7 Maintenance Station Engineering' license. PDM licenses authorize device parameterization, not diagnostic screen generation.

What is the primary functional difference between MS Basic and MS Standard?

MS Basic monitors automation hardware assets such as controllers, CP communication processors, remote I/O racks, network switches, and PC stations. MS Standard adds monitoring for intelligent field devices, drives, and valve positioners with cyclic diagnostics and maintenance request workflows.

Can an existing redundant OS Server pair also host Maintenance Station functions?

Yes. This architecture is known as an 'Integrated Maintenance Station' (MS in OS). It requires MS Runtime licenses on the OS Server pair in addition to standard OS Server Redundancy and OS RT PO licenses.

Does the PDM TAG license limit how many diagnostic screens the MS can generate?

No. PDM TAG counts limit field device parameterization inside the PDM tool. Diagnostic screen asset limits are governed separately by MS Asset packages on the runtime station.

Do SIMATIC SCALANCE switches require PDM licenses for diagnostic monitoring?

No. SCALANCE network switches are monitored via SNMP through standard PCS 7 Maintenance Station hardware diagnostic blocks and do not require PDM licenses.