This diagram is a simplified representation of an ICS communication network. The process is controlled by an application running inside the field controllers, which communicates with a series of field inputs and outputs devices. The field controllers consolidate the data and transmits it to the HMI stations where it is presented on displays.
The data flow through ICS varies by vendor, topology, and protocols. The network can be wired or wireless, but it links the components of the ICS. The HMI receives information from the field controllers, relaying information through communication protocols and providing the operator with a view of what is happening in the process.
Copyright: Cybersecurity & Infrastructure Security Agency (CISA)