Fluke 789 – Combined Loop Calibrator & True-RMS Multimeter Overview The Fluke 789 ProcessMeter combines a precision digital multimeter (DMM) with a loop calibrator in one rugged handheld tool. It can measure, source, and simulate 4-20 mA loops, provide 24 V loop power, and supports true-RMS AC/DC voltage up to 1000 V. Designed for industrial instrumentation, maintenance, and process control, it is especially useful for verifying, troubleshooting, and calibrating current loop devices and transmitters. It includes features like HART mode, dual display, advanced backlight, and durable design. Key Features True-RMS DMM: measures AC/DC voltage and current up to 1000 V / 1 A Loop calibrator: sourcing / simulating 4-20 mA signals Built-in 24 V loop power supply for transmitter testing Selectable 250 Ω resistor for HART communications mode Dual bright display (simultaneous mA and % scale readout) Frequency measurement up to 20 kHz Modes: Min/Max/Average, Hold, Relative, Diode test, Continuity beeper Auto-step / manual coarse / fine / 25% / 100% span adjustments, auto ramp Rugged housing with accessible battery and fuse Safety rating: CAT III 1000 V / CAT IV 600 V Technical Specifications Model: 789 Voltage AC (True-RMS): up to 1000 V Voltage DC: up to 1000 V Current DC (measurement): up to 1 A Current source/simulate: 0-20 mA or 4-20 mA Drive capability: up to 1200 Ω load at 20 mA; 24 V compliance in loop power mode Resolution: down to 0.001 mA in current measure Voltage DC Accuracy: ±0.1 % Resistance: up to 40 MΩ Continuity: beeper threshold
