I am currently working with WinCC Runtime Professional and would like to build a custom Excel VBA–based OPC client to connect directly to the built-in WinCC OPC servers (DA, HDA, and A&E).

My intended use case is to:

• Connect to the OPC DA server to read live WinCC tag values.
• Connect to the OPC HDA server to retrieve historical tag data for reporting purposes.
• Connect to the OPC A&E server to receive alarms and events.
• Generate custom reports directly in Excel without relying on third-party products.

Current situation / issue:

• I only have a WinCC Runtime Professional license (no Connectivity Pack or other add-ons).
• I do not have the classic OPC Automation wrappers (e.g., OPCDAAuto.dll, OPCHDAAuto.dll) or other SDKs on my system.
• I would like to avoid purchasing third-party OPC client libraries if possible, and instead rely on Siemens-provided documentation or SDKs.
• I am unclear whether access to HDA and A&E interfaces requires additional licensing such as the WinCC Connectivity Pack when working with RT Professional.

My request:

1. Could you please provide me with the official Siemens documentation for WinCC OPC Servers (DA, HDA, A&E), including available ProgIDs, supported interfaces, and programming references?
2. If Siemens provides SDKs, header files, or APIs to develop custom OPC clients in VBA / .NET / C++, can you advise on how to obtain them?
3. Can you confirm whether the WinCC Connectivity Pack license is required in order to access HDA and A&E data with WinCC RT Professional, or if this functionality is included in the base license?

This information will help me implement a custom Excel-based reporting solution that can query both real-time and historical WinCC data without the need for additional third-party software.

Thank you for your guidance and support.