The language used in Human-Machine Interfaces (HMIs) for industrial automation systems can vary depending on the specific HMI software or platform being used. Some common languages and technologies used in HMI development include:

1. Graphical Programming Languages: Many HMIs use graphical programming languages that allow users to create applications by arranging graphical elements (such as buttons, gauges, and indicators) on a visual canvas. Examples of graphical programming languages commonly used in HMIs include:

   • Function Block Diagram (FBD): FBDs represent functions and function blocks in the form of interconnected blocks.
   • Sequential Function Chart (SFC): SFCs represent the sequential operation of processes using graphical elements like steps, transitions, and actions.
   • Structured Text (ST): ST is a textual programming language based on Pascal syntax, often used for more complex logic and calculations in HMIs.

2. Scripting Languages: Some HMIs support scripting languages for more advanced customization and automation. Common scripting languages used in HMIs include:

   • JavaScript: JavaScript is often used for web-based HMIs or for custom scripting within HMI applications.
   • VBScript: VBScript, a subset of Visual Basic, is sometimes used for scripting within HMI environments.
   • Lua: Lua is a lightweight scripting language commonly used for embedding scripting capabilities into applications.

3. Vendor-Specific Languages: Many HMI software platforms have their own proprietary languages or scripting environments tailored to their specific features and capabilities.

4. Standardized Communication Protocols: While not programming languages per se, standardized communication protocols such as Modbus, OPC UA, and Ethernet/IP are often used in conjunction with HMIs to facilitate communication with industrial devices, PLCs, and other systems.

5. Configuration Tools: In some cases, HMIs are configured using specialized software tools that abstract away the programming aspect, allowing users to configure the HMI interface, data tags, alarms, and other features through a user-friendly graphical interface.

The choice of language or technology used in an HMI depends on factors such as the specific requirements of the application, the capabilities of the HMI software or platform being used, and the preferences and expertise of the developers and operators involved.