Lead-Wire-Resistance Compensation Technique Using a Single Zener Diode for Two-Wire Resistance Temperature Detectors (RTDs)

Abstract

In remote measurement systems, the lead wire resistance of the resistance sensor will produce a large measurement error. In order to ensure the accuracy of remote measurement, a novel lead-wire-resistance compensation technique is proposed, which is suitable for a two-wire resistance temperature detector. By connecting a zener diode in parallel with the resistance temperature detector (RTD) and an interface circuit specially designed for it, the lead-wire-resistance value can be accurately measured by virtue of the constant voltage characteristic of the zener diode when reverse breakdown occurs, and compensation can thereby be made when calculating the resistance of RTD. Through simulation verification and practical circuit testing, when the sensor resistance is in 848–2120 Ω scope and the lead wire resistance is less than 50 Ω, the proposed technology can ensure the measuring error of the sensor resistance within ±1 Ω and the temperature measurement error within ±0.3 °C for RTDs performing 1000 Ω at 0 °C. Therefore, this method is able to accurately compensate the measurement error caused by the lead wire resistance in two-wire RTDsand is suitable for most applications.

The Precise Temperature Measurement System with Compensation of Measuring Cable Influence

“…Solving this function, one can receive the relation between temperature value T C and the resistance value R t . The root of the equation has a form (8). In this Formula, one can find a very characteristic term (9).…”

“…Almost every device used in domestic, industrial, or laboratory environments, ranging from computers, cars, power trains, air conditioners, measuring devices, or thermostats, uses temperature sensors. The most common types of temperature sensors include thermistors, thermocouples, resistance temperature detectors (RTDs), digital thermometer integrated circuits, and analog thermometer integrated circuits [1][2][3][4][5][6][7][8][9][10][11][12][13].…”

“…An important problem that occurs during temperature measurement using a resistive temperature sensor is the need to limit the influence of the resistance of the wires, by which such a sensor is connected to the measuring system, and which is the cause of erroneous temperature determination by such a sensor. Basically, three approaches are considered [8], i.e., using two wires [9,10], three wires [11], and the third approach, using four wires [13]. It should be mentioned that the described measurement system uses the compensation of the resistance of the lead wires by the three-wire method [16], which was improved and adapted to the system described below in this paper.…”

Automatic Low-cost Water Level Indicator for Tanks and Hand Washing Water Dispensers in Kitui; Kenya during the Covid 19 Pandemic

“…Hence this research looked into how water wastage would also be avoided from the hand washing water dispensers [11], [27]. This paper looks into the development and implementation of such a simple and cost effective automatic water level indicator which timely monitors the water level in tanks and hand-washing water dispensers [12], [13], [14], [15], [16], [17], [18].…”

Micro-Fabricated RTD Based Sensor for Breathing Analysis and Monitoring

“…Resistance temperature detector (RTD) devices has to be developed and used to detect the breathing frequency and temperature. This is due to its linearity, measurement repeatability and stability [15,16].…”