Calibration White Paper WORLD-CLASS CALIBRATION SOLUTIONS™

BEAMEX Calibration White Paper How to calibra te a 10–50 mA instrument Today, the market consists mostly of 4–20 mA output instruments, but several 10–50 mA instruments still exist. Finding a calibrator that will measure and source the 10–50 mA instruments is a challenge. Beamex has recently introduced a new tool, the Beamex MC6 calibrator and communicator, to help overcome these challenges. urrent loops: 4–20 mA, 10–50 mA, why not 5–25 mA? That is the question that many engineers asked when standardizing on a milliamp output for instrumentation. Believe it or not, several factors were considered...

BEAMEX Calibration White Paper a shock. In the beginning, 0–20 mA was likely considered, but engineers quickly realized the potential danger a 0 mA signal could infer. First, it could mean that the instrument is at the low side, 0%, of its range, but it could also mean that a line to the instrument got cut or removed. It was quickly determined that the low side of the milliamp signal needed to be above 0 mA to recognize a true low side of the instrument range. This is referred to as the “live zero” phenomenon. Four was decided upon because it provides the minimum amperage to power loop-powered...

BEAMEX Calibration White Paper The Beamex MC6 displays a split screen for calibration. The upper window displays the generated or simulated value, while the lower screen displays the measured value. many calibrators were designed to generate 50 mA. When ISA issued standard ISA50 in 1972, plants started replacing their 10-50 mA instruments with the newly standardized 4-20 mA instruments; however, some industries could not adapt to these changes. Forty-one years later, some of these 10-50 mA instruments are still being used, especially in industries such as nuclear power where licensing complicates...