The NSV-10b is a graphical method of describing a system (or system function) response to various events by changing its state.

The explicit time sequencing of system functions in response to external and internal events is not fully expressed in NSV-4. NSV-10b can be used to describe the explicit sequencing of the system functions. Alternatively, NSV-10b can be used to reflect explicit sequencing of the actions internal to a single system function, or the sequencing of system functions in relation to a specific system.

Basically, state chart diagrams can be unambiguously converted to structured textual rules that specify timing aspects of system events and the responses to these events, with no loss of meaning. However, the graphical form of the state diagrams can often allow quick analysis of the completeness of the rule set, and detection of dead ends or missing conditions. These errors, if not detected early during the systems analysis phase, can often lead to serious behavioral errors in fielded systems, or to expensive correction efforts.

The HOPEX NAF can be used to describe specific state machines attached to tasks. A state machine is a specific concept used to describe how a task reacts to different events from the start points to the end points.

The system state machine diagram basically represents the sets of events to which the systems in the architecture will respond (by taking an action to move to a new state) as a function of its current state. Each transition specifies an event and an action.