Scada web hmi system

A SCADA (Supervisory Control And Data Acquisition) web HMI system comprising a plurality of programmable logic controllers (hereinafter, referred to as “PLCs”), a plurality of HMI (Human Machine Interface) client devices, and a SCADA server device that are connected through a computer network, wherein

• each of the PLCs is configured to include a plurality of memory addresses storing signal data relating to field devices configuring an industrial plant, and to periodically transmit block data including a set of the signal data to the computer network,
• each of the HMI client devices is configured to execute a web browser displaying a plurality of screens each including a plurality of arranged parts,
• the SCADA server device includes a communication driver and a client management circuitry connected to the plurality of HMI client devices,
• the communication driver is configured to receive the block data transmitted from the PLCs, to divide the block data into signal data of respective data types, to add a signal identifier to the divided signal data, and to transmit the signal data to the client management circuitry for each data type,
• the client management circuitry is configured to receive the signal data transmitted from the communication driver, and to transmit the received signal data to the HMI client device corresponding to the signal identifier,
• the client management circuitry is configured to acquire in-use screen information indicating the screen currently used in the HMI client devices, and to transmit the acquired screen information to the communication driver, and
• the communication driver is configured to acquire a screen-specific device list in which the parts, and numbers and the memory addresses of the PLCs storing the signal data corresponding to the parts are defined, for each of the screens displayed on the HMI client devices, to select the signal data defined in the screen-specific device list corresponding to the currently-used screen indicated by the in-use screen information, to add a screen identifier to the selected signal data, and to transmit the resultant signal data to the client management circuitry for each data type.