{"id":"plc","model_id":"programmable logic controller","name":"Programmable Logic Controller","summary":"A programmable logic controller is a solid-state control system that contains user-programmable memory for storing instructions. Those stored instructions implement functions such as I/O control, logic, timing, counting, three-mode (PID) control, communication, arithmetic, and data and file processing.","study_notes":["The definition is taken from The Automation, Systems, and Instrumentation Dictionary.","The term appears in NIST SP 800-82r3 and NISTIR 8183, and is carried into NISTIR 8183 Rev. 1.","The term also appears in NISTIR 8183A Vol. 1, Vol. 2 and Vol. 3."],"safety_notes":[],"sources":[{"url":"https://csrc.nist.gov/glossary/term/programmable_logic_controller","title":"programmable logic controller - Glossary | CSRC","accessed":"2026-10-25"}],"verification":{"status":"source_checked","checked_at":"2026-10-25","values":1,"method":"llm_source_check"},"updated_at":"2026-10-25","type":"operational","spec":{"kind":"system","related":[]},"url":"https://machineschema.com/operational/plc","license":"https://creativecommons.org/licenses/by/4.0/"}