The IR4000 from General Monitors, Lake Forest, CA, is an IR combustible gas detection system that uses an IR4000M multipoint monitor connected up to eight IR400 point IR gas detectors to detect combustible gases. The monitor can also calibrate, gas check, and zero each IR400 sensor with one command. The monitor incorporates a display, relay module, and data concentrator in an explosionproof enclosure with magnetic interface. 8A relays are optional. HART and Modbus communications let the device convey device IDs, concentration readings, and records to the control room. Applications include LNG/LPG processing and storage, electric power generation, oil and gas production platforms, petrochemical refining, compressor stations, aerospace facilities, and wastewater treatment.