Topics: Partial automatic laboratory, Programmable Logic Controller internal architecture, Programmable Logic Controller address bus, Programmable Logic Controller input processing, Programmable Logic Controller output processing, Programmable Logic Controller output channels, Programmable Logic Controller program scan, latching, latched circuits, reed switch, incremental shaft encoder, photoelectric transmissive switch, diaphragm pressure switch, field bus, OSI model, repeater, bridge, router, SCADA system, SCADA architecture, batch mixing system