Study of a Pressure Transmitter Using an Improved Inductance Bridge Network and Bourdon Tube as Transducer
01 Apr 2011-IEEE Transactions on Instrumentation and Measurement (IEEE)-Vol. 60, Iss: 4, pp 1453-1460
TL;DR: An improved inductance bridge-type technique has been developed to convert the Bourdon tube movement into an electrical current signal which can be transmitted to a remote indicator.
Abstract: A Bourdon tube is a mechanical-type pressure sensor. It is generally used in a local pressure indicator and display. Hence, a special technique is needed to transmit to and display the reading of a Bourdon gauge at a remote distance. In this paper, an improved inductance bridge-type technique has been developed to convert the Bourdon tube movement into an electrical current signal which can be transmitted to a remote indicator. A bent ferromagnetic wire attached to the tip of the Bourdon tube acts as a sensing element of pressure. The movement of the wire as a result of pressure variations inside an inductive pickup coil changes the self-inductance of the coil with the changes in pressure. An improved inductance bridge network has been utilized to measure the self-inductance of the coil more accurately when compared with the readings by an LCR meter. It has been observed that the variation of the self-inductance of the pickup coil as well as the variation of the transducer and transmitter outputs with pressure has very good linearity and repeatability. The necessary theoretical equations, along with the experimental results, are reported and compared in this paper.
Citations
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TL;DR: In this article, a microcontroller-based interface circuit for inductive sensors with a variable self-inductance was proposed and analyzed, where the circuit just requires an external resistor and a reference inductor so that two RL circuits are formed.
Abstract: This paper proposes and analyses a microcontroller-based interface circuit for inductive sensors with a variable self-inductance. Besides the microcontroller (μC) and the sensor, the circuit just requires an external resistor and a reference inductor so that two RL circuits are formed. The μC appropriately excites such RL circuits in order to measure the discharging time of the voltage across each inductor (i.e. sensing and reference) and then it uses such discharging times to estimate the sensor inductance. Experimental tests using different commercial μCs at different clock frequencies show the limitations (especially, due to parasitic resistances and quantisation) and the performance of the proposed circuit when measuring inductances in the millihenry range. A non-linearity error lower than 0.3% full-scale span (FSS) and a resolution of 10 bits are achieved, which are remarkable values considering the simplicity of the circuit.
43 citations
Cites background or methods from "Study of a Pressure Transmitter Usi..."
...In the previous applications [3,4,6,7], the sensor inductance is in the range of units or tens of millihenry, but lower values (e....
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...The second type is an AC-excited bridge (such as the Maxwell bridge [6] or the Maxwell-Wien bridge [3]) providing an amplitude-modulated signal that needs to be demodulated and digitized before being read by the digital system....
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...Other physical quantities that indirectly cause a displacement are also measured through these sensors, for instance: inductive pressure sensors based on either a Bourdon tube [6] or a vertical coil embedded into an integrated circuit (IC) package [7]....
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...Furthermore, the sensor is expected to have an inductance of some units or tens of millihenry [3,4,6,7]; lower values of inductance would require a very high speed reference oscillator that is not feasible nowadays in common low-cost 8-bit microcontrollers....
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TL;DR: The design of a noncontact pressure transducer along with a transmitting unit using bellows as the primary sensing element and a Hall sensor as secondary sensing element has been described and theoretical equations describing the operation of the proposed transducers and transmitter have been derived.
Abstract: Bellows is an elastic-type pressure sensor used as a local indicator in industry. Transmission of bellows reading to a remote location in control room is very important in pressure measurement and control system in industry. In this paper, the design of a noncontact pressure transducer along with a transmitting unit using bellows as the primary sensing element and a Hall sensor as secondary sensing element has been described. The theoretical equations describing the operation of the proposed transducer and transmitter have been derived. The function of the transducer and transmitter has been experimentally tested and the experimental results are reported in the paper. Both transducer and transmitter characteristics have been found to be linear with good repeatability. The graphical abstract is shown in Fig. 1 . Fig. 1. Graphical abstract.
17 citations
Cites methods from "Study of a Pressure Transmitter Usi..."
...[5] have proposed an improved inductance bridge-type technique to convert the bourdon tube movement into an electrical current signal which can be transmitted to a remote indicator....
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TL;DR: In this paper, an artificial neural network (ANN)-based improved inductive signal conditioning circuit for pressure transducers with a bellow as a sensor is presented, where the ANN modeling estimates and compensates the nonlinearity of OISCC.
Abstract: This paper presents the development of an artificial neural network (ANN)-based improved inductive signal conditioning circuit for pressure transducer with bellow as sensor. A bellow is an elastic-type mechanical pressure sensor. The deflection of the bellow due to applied pressure must be translated into an efficient electrical signal for continuous monitoring, wireless transmission, and digital readout. A ferromagnetic wire attached to the bellow as a part of an inductive coil arrangement, gets deflected due to applied pressure, thereby changing the self inductance of the coil. An op-amp inductive signal conditioning circuit (OISCC) is designed to produce voltage proportional to changes in self-inductance, but the OISCC voltage versus applied pressure exhibits a considerable nonlinearity error due to stray inductances and component drifts. The ANN modeling estimates and compensates the nonlinearity of OISCC. An embedded unit is used for implementation of ANN learning process. The pressure transducer with significant stability has exhibited high linearity and sensitivity of ±0.35% and 10 mH/psig, respectively, in the measuring range of 0–70 psig. The design and experimental aspects of the technique are reported.
16 citations
Cites methods from "Study of a Pressure Transmitter Usi..."
...The pressure transducer proposed in [11] exhibits a linearity of ±2% in the range 0-45psig, whereas the proposed trans-...
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...An improved inductance circuit with Bourdon tube as pressure sensor is proposed in [11] and the range of pressure is 0 to 45psig with a resolution of 5 psig....
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TL;DR: A novel optical fiber extrinsic Fabry–Perot interferometer (EFPI) for probing pressure changes with subpascal (~0.1 Pa, $\sim 1.45\times 10^{-5}$ psi) resolution" has the potential to find a wide range of applications that require precise instrumentation.
Abstract: This article reports a novel optical fiber extrinsic Fabry–Perot interferometer (EFPI) for probing pressure changes with subpascal (~0.1 Pa, $\sim 1.45\times 10^{-5}$ psi) resolution. The principal idea of the sensor is to employ a traditional C-shaped Bourdon tube as a mechanical transducer that is coupled to a highly sensitive EFPI device. The cavity of the EFPI device is formed between a gold-coated mirror, mounted to a concave section of the Bourdon tube, and the endface of an optical fiber mounted at the base section of the Bourdon tube. Based on this design, the pressure-induced deflections of the Bourdon tube are directly correlated with the changes in cavity length of the EFPI, which can be determined by analyzing the interference signals. An experiment based on probing hydrostatic pressure changes induced by the addition of single water droplets to a test chamber was performed to quantify the measurement resolution of the proposed sensor because an apparatus for producing exceedingly small, stable, and reproducible pressure changes does not exist. Compared with conventional optical fiber pressure sensors, the proposed pressure sensor requires a simple fabrication process and can be used to measure pressure changes with high sensitivity ( $\sim 23.5~\mu \text{m}$ /kPa, cavity length change/pressure change). Moreover, the sensitivity and resolution of the pressure sensor can be flexibly adjusted using Bourdon tubes designed for different dynamic ranges (e.g., 0–70 MPa, 0–10152 psi). It is believed that the proposed novel pressure sensor has the potential to find a wide range of applications that require precise instrumentation.
13 citations
Additional excerpts
...measurements in rugged environments [17]....
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TL;DR: This paper proposes a novel method for demodulating low-frequency amplitude-modulated (AM) signals provided by sensors using a digital timer that carries out the demodulation and digitization simultaneously, without requiring a rectifier, a mixer, a low-pass filter, or an analog-to-digital converter.
Abstract: This paper proposes a novel method for demodulating low-frequency amplitude-modulated (AM) signals provided by sensors. The method relies on a digital timer that carries out the demodulation and digitization simultaneously, without requiring a rectifier, a mixer, a low-pass filter, or an analog-to-digital converter. This timer-based demodulator extracts the amplitude of the AM signal by measuring the period of a reference signal that is altered by the AM signal itself. The period measurement undergoes a deviation that carries information about the amplitude of the AM signal. The feasibility and also the limitations, such as the nonlinearity and aliasing effects, of this novel demodulator are proved theoretically and experimentally. The concept is also applied to measure an inductive displacement sensor in a range of ±30 mm. A nonlinearity error of 0.5% full-scale span and a resolution of 9 bits are achieved for an overall measuring time of 100 ms.
12 citations
Cites background from "Study of a Pressure Transmitter Usi..."
...2711918 demodulator, has a rectifier and a peak detector that can be a simple RC circuit [2], [5], [11] or a more advanced...
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References
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TL;DR: In this article, a continuous gain observer is proposed to estimate the pressure on one side of the cylinder and the other side is estimated, where numerically estimated acceleration is used to observe both pressures, with ultimate bounded stability.
Abstract: Recent research has shown that robust and precise high-speed control of pneumatic actuators is practicable, by application of advanced control techniques such as model-based adaptive and sliding-mode control. However, the resulting need for full state-based feedback and feedforward control-in particular, the measurement of air pressures-increases both the cost and complexity of the overall system. In this paper, we consider the problem of design of observers to estimate the chamber pressure variables in a cylinder actuator. Since the cylinder pressures are not simultaneously observable because of the nature of cylinder dynamics, we first propose a continuous gain observer in which the pressure on one side of the cylinder is measured and the pressure on the other side is estimated. Next, we propose a sliding-mode observer where numerically estimated acceleration is used in order to observe both pressures, with ultimate bounded stability. A sliding-mode controller is proposed, whose sensitivity to errors under the sliding-mode observer is studied. The proposed observers are simple, effective and easy to implement. Results of experimental implementation illustrate the practical effectiveness of the new observers.
90 citations
"Study of a Pressure Transmitter Usi..." refers methods in this paper
...[11] have proposed a continuous gain observer and a sliding mode observer technique to measure the pressure on both sides of a pneumatic cylinder actuator....
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TL;DR: In this article, a simulation method of circular silicon-diaphragm piezoresistive pressure sensors was developed to obtain accurate sensors for very low-pressure measurement, and the simulated results show good agreement with the observed results and indicate that output voltage can be greatly increased while maintaining low nonlinearity even in the low pressure range.
Abstract: A characteristics simulation method of circular silicon-diaphragm piezoresistive pressure sensors was developed to obtain accurate sensors for very-low-pressure measurement. The anisotropic stress-strain relationship of a silicon single-crystal plate and the nonlinear characteristics of silicon piezoresistive gauges were considered. Nonlinear deflection and strain formulas of circular silicon diaphragm sensors with a center boss and sensors with a center boss and ribs were derived by taking the effects of the large deflection and the support stiffness of the diaphragms into account. Based on these considerations, the characteristics of the sensors were simulated. The simulated results show good agreement with the observed results and indicate that output voltage can be greatly increased while maintaining low nonlinearity even in the low-pressure range by narrowing the rib width and thinning the diaphragm thickness of sensors with a center boss and ribs. This is because the rib strain that produces output voltage is increased while maintaining small deflection by using this type of sensor. >
49 citations
"Study of a Pressure Transmitter Usi..." refers background in this paper
...[15] have shown that a circular silicon pressure sensor with a center boss can measure very low pressure....
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TL;DR: In this article, a self-validating pressure sensor is described, including structure design of the transducer, fault detection and diagnosis method and signal transmitter based on double digital signal processors (DSPs) system.
Abstract: A new prototype of self-validating pressure sensor is described, including structure design of the transducer, fault detection and diagnosis method and signal transmitter based on double digital signal processors (DSPs) system. The elastic body of the transducer is based on circular-flat diaphragm structure. Eight groups of strain gauges are distributed on the diaphragm. One group of metal strain gauge with little temperature drift is used as primary pressure sensor, the other seven groups of semiconductor strain gauges with high sensitivity are used as calibration references. Consistency checking of the measured data is used to detect sensor fault. The outputs of self-validating pressure sensor including validated measurement value (VMV) of pressure, validated uncertainty (VU) of pressure, and measurement value status (MVS) of pressure are calculated using the high consistency data. A new fault diagnosis method based on wavelet packet decomposition feature extraction and support vector machine multiclassification is used to identify six sensor fault status. A double DSPs system is implemented using TMS 320 F 2812 and TMS 320 C 6713 to acquire the output signal and complete fault detection, diagnosis, and self-validating parameters calculating. The experiment results show that the designed pressure sensor prototype implements the self-validating function. It can detect fault in real-time and identify sensor status with high accuracy.
47 citations
01 Sep 1988
TL;DR: An absolute barometric pressure sensor which has shown exceptional performance is described in this paper, which consists of a mechanical resonator whose resonant frequency is changed by strain induced by applied pressure, and it has a range from vacuum to a pressure of over 1 bar (105 Pa).
Abstract: An absolute barometric pressure sensor which has shown exceptional performance is described in the paper. It consists of a mechanical resonator whose resonant frequency is changed by strain induced by applied pressure. The active element is formed in one piece, from single-crystal silicon, by microengineering techniques. It has a range from vacuum to a pressure of over 1 bar (105 Pa) and can resolve less than 1 part in 105 of full scale.
37 citations
"Study of a Pressure Transmitter Usi..." refers background in this paper
...Greenwood and Satchell [16] have utilized the effect of the strain produced by the applied pressure on the resonant frequency of a silicon crystal to measure the pressure from vacuum to 1 bar....
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TL;DR: In this article, the design and fabrication of a wireless, passive pressure sensor based on the change in magnetic higher order harmonic fields is described, which is ideal for applications where wire connections are prohibited.
Abstract: The design and fabrication of a wireless, passive pressure sensor based on the change in magnetic higher order harmonic fields is described. The sensor was made of an airtight pressure chamber with two opposite membranes: a rigid membrane attached to a magnetically soft ferromagnetic strip (sensing element) and a flexible membrane attached to a permanent magnetic strip (biasing element). The flexible membrane of the chamber deflected with changing pressure, thus varying the separation distance between the sensing and biasing elements. The change in separation distance in turn altered the biasing field experienced by the sensing element, varying the pattern of its magnetic higher order harmonic fields allowing remote pressure monitoring through a magnetic coil. In this work, different materials were used to fabricate the flexible membranes for sensors of different dynamic ranges. Experimental results showed the shifts in magnetic higher order harmonic fields were linear for all sensors, but with different sensitivity depending on the elasticity of the flexible membrane. The novelty of this sensor is its wireless, passive nature, which is ideal for applications where wire connections are prohibited. In addition, the simple sensor design reduces cost, allowing disposable use. Potential applications of such a sensor technology include long-term structural monitoring (concrete, asphalt) and in vivo pressure monitoring inside the human body.
16 citations
"Study of a Pressure Transmitter Usi..." refers background in this paper
...[7] have observed the effect of the movement of a flexible membrane carrying a permanent magnetic strip on the change in the magnetic higher order harmonic fields of a magnetically soft ferromagnetic strip attached with a rigid membrane and have designed a wireless passive pressure sensor utilizing this effect....
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