Low-Cost 4-20 mA Loop Calibrator
Low-Cost 4-20 mA Loop Calibrator作者机构：Department of Electrical/Electronics Engineering University of Abuja Abuja Nigeria
出 版 物：《Journal of Flow Control, Measurement & Visualization》 (流量控制、测量及可视化（英文）)
年 卷 期：2023年第11卷第3期
页 面：49-63页
学科分类：08[工学] 0827[工学-核科学与技术]
主 题：Instruments Calibration 4-20 mA Standard Loop Calibrator
摘 要：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.
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