Loop Calibrators
Loop Calibrators
Loop calibrators are handheld instruments designed to source, simulate, and measure 4–20 mA current signals used in industrial process control and instrumentation. The 4–20 mA current loop is the dominant standard for transmitting process variables — such as pressure, temperature, flow, and level — over long cable runs in industrial plants. Loop calibrators allow field technicians to verify transmitter output, simulate sensor signals, and power two-wire transmitters during calibration and troubleshooting without needing an external power supply.
Modern loop calibrators such as those in the Fluke 700 series also support HART communication, enabling digital interaction with smart transmitters to read diagnostic data, configure device parameters, and perform automated calibration routines. This dual analog/digital capability makes loop calibrators indispensable tools for instrument technicians working in process industries, oil & gas, chemical plants, and power generation facilities.
Typical Applications
- Calibrating 4–20 mA pressure, temperature, and flow transmitters in oil & gas and chemical plants
- Simulating transmitter output signals to test PLC inputs and DCS analog cards
- Powering and testing two-wire transmitters during loop commissioning and maintenance
- HART communication for configuring smart transmitters without a separate HART communicator
- Troubleshooting current loop faults such as broken wires, short circuits, and out-of-range signals
Popular Brands
Fluke is the leading manufacturer in this category, with the 705E, 707E, and 709/709H series covering a range of accuracy classes from basic field calibration to high-precision laboratory use. The Fluke 789 Process Meter combines loop calibration with clamp measurement capabilities. Other manufacturers offering loop calibration functionality include Beamex and Ametek Crystal Engineering, which integrate loop sourcing into their multifunction process calibrators.
