Author(s)

Joel Arumun, Emmanuel Eronu

Department of Electrical/Electronics Engineering, University of Abuja, Abuja, Nigeria.

Instrument calibration is vital to a successful control system because signal inputs to the system controllers come from such instruments. This paper presents a method for actualizing a standard low-cost loop calibrator for the famous 4-20 mA electrical signaling scheme. The loop calibrator generates a linear current signal from 4 to 20 mA over a 250 ? typical process instrument load for calibration. The realization of the loop calibrator relies on a voltage-to-current converter to build a constant current source. The voltage controlled constant current source is built from discrete components and an op-amp to keep the cost low. Results from simulations and the prototype demonstrate the performance of the 4-20 mA loop calibrator which utilizes a greatly reduced number of components. The cost of these components is approximately 34% of the least expensive calibrator sampled, though other production costs are not included. This conclusion reinforces the fact that loop calibrators can be cheaper.

Instruments, Calibration, 4-20 mA Standard, Loop Calibrator

Arumun, J. and Eronu, E. (2023) Low-Cost 4-20 mA Loop Calibrator. Journal of Flow Control, Measurement & Visualization, 11, 49-63. doi: 10.4236/jfcmv.2023.113004.