HMIClients

HMIClients are client applications that render human-machine interface screens and enable operators to monitor and interact with industrial processes. They connect to HMI servers or SCADA backends to retrieve live data, alarms, and historical trends, while sending operator commands back to the control system. HMIClients run on a range of devices including desktop workstations, tablets, smartphones, and embedded panels, and are designed to be platform-agnostic or platform-specific.

In a typical architecture, an HMIClient acts as a client in a client-server model. The server hosts the HMIs, data models, and control logic; the client fetches screens and data, renders interfaces, and submits user actions. Communication often relies on standard industrial and IT protocols such as OPC Unified Architecture (OPC UA), MQTT, REST/HTTPS, or WebSocket, and may utilize secure channels, authentication, and role-based access control. Data models aim to reflect plant objects, equipment states, alarms, and historical trends, enabling consistent visualization across devices.

Key features commonly found in HMIClients include real-time visualization, alarm and event handling, historical data retrieval and trending, scriptable actions or macros, and support for multiple screen layouts or responsive design. Many clients offer offline or degraded modes, local data caching, and API access for integration with third-party systems or custom extensions.

Deployment considerations for HMIClients include latency and bandwidth requirements, scalability to many concurrent users, cross-platform support, and security implications such as encryption, authentication, and access control. They are used in a variety of contexts, including manufacturing, process industries, building automation, and energy management.

See also: Human-machine interface, SCADA, OPC UA, industrial automation, HMI design.