Introduction Human Machine Interface (HMI)
HMI (Human Machine Interface) is a software layer module of the OPIL architecture. It is a web application server with its own local database for storing data needed in this module. HMI serves a web browser user interface for the human agents to monitor and control OPIL data entities. Figure below shows the components and their connections to each other and to OPIL context management server using HTTP protocol.
Web application server is a Node.js application which uses Express.js back end framework. It has its own local MongoDB database to store information needed such as configuration data, user and floorplan information as well as user interface control buttons. HMI server offers a user authenticated access point to web browser clients and a REST API to manage and retrieve the data from the database. It also connects to Orion Context Broker to manage the entities this module has created such as sensor type control buttons.