One area where the MODBUS, DNP3 protocols, and SCADA methodologies, are used is in electrical system devices. MODBUS is a communications protocol widely used for industrial machines, in which a device exposes its current status as "registers" which can be queried over a MODBUS connection, and its current behavior can be modified by storing values in some of those registers. DNP3, a.k.a. Distributed Network Protocol, a.k.a. IEEE 1858, is a set of communications protocols used between components in process automation systems. SCADA, a.k.a. "Supervisory control and data acquisition", is a control system architecture that uses computers, networked data communications and graphical user interfaces for high-level process supervisory management, along with other peripheral devices such as programmable logic controllers and discrete PID controllers to interface to the process plant or machinery.