Wincc Rest Api Jun 2026

The Definitive Guide to the WinCC Unified REST API As industrial automation shifts toward Industry 4.0, the demand for seamless connectivity between Operational Technology (OT) and Information Technology (IT) has never been higher. Siemens addresses this need within the WinCC Unified environment by providing a powerful, standards-based REST API . This guide covers the architecture, authentication, key functionalities, and a practical example of how to interact with the API.

1. What is the WinCC REST API? Traditionally, accessing SCADA data required proprietary drivers, OPC DA (COM/DCOM), or complex client installations. The WinCC REST API modernizes this by exposing WinCC Unified data and functions via standard HTTP protocols. Key Characteristics:

Protocol: HTTP/HTTPS. Architecture: RESTful (Representational State Transfer). Data Format: JSON (JavaScript Object Notation). Accessibility: Accessible from any modern programming language (Python, C#, JavaScript, Node-RED) without requiring Siemens-specific DLLs on the client side.

2. Use Cases The REST API is typically used for: wincc rest api

Vertical Integration: Sending production data from the SCADA layer to MES/ERP systems (like SAP or custom SQL front-ends). Dashboarding: Creating custom web dashboards (Angular, React, Vue) that display live process data outside the WinCC runtime. Mobile Apps: Developing iOS or Android apps to monitor specific tags or acknowledge alarms remotely. Third-Party Connectivity: bridging WinCC with non-Siemens hardware or cloud platforms (AWS IoT, Azure IoT) via custom middleware.

3. Prerequisites and Configuration Before writing code, the API must be enabled in the WinCC Unified project.

WinCC Unified Project: Open your project in the TIA Portal. Runtime Settings: Navigate to OS Runtime Settings . Enable Web Control Center (WebCC): The REST API is often served alongside the web client capabilities. User Rights: You must assign specific permissions to the user account that will access the API. The user typically needs the "Change variable values" or "Acquisition" rights depending on the operation. The Definitive Guide to the WinCC Unified REST

4. Authentication Security is paramount in OT environments. The WinCC REST API does not allow anonymous access by default.

Basic Authentication: The simplest method where the client sends a Base64 encoded username and password in the header. Token-Based (JWT): For better security and performance, you typically authenticate once to obtain a JSON Web Token (JWT) and use that token for subsequent requests.

5. Core Endpoints and Functionality The API provides access to the three main pillars of SCADA data: A. Variables (Tags) The WinCC REST API modernizes this by exposing

Read Values: Retrieve current values of one or multiple tags. Write Values: Update setpoints or control variables remotely. Browse: List available tags in the tag logging database.

B. Alarms