LVDT Signal Conditioning Circuit (CN0288)

The circuit shown in Figure 1 is a complete adjustment-free linear variable differential transformer (LVDT) signal conditioning circuit. This circuit can accurately measure linear displacement (position).


The LVDT is a highly reliable sensor because the magnetic core can move without friction and does not touch the inside of the tube. Therefore, LVDTs are suitable for flight control feedback systems, position feedback in servomechanisms, automated measurement in machine tools, and many other industrial and scientific electromechanical applications where long term reliability is important.


This circuit uses the AD598 LVDT signal conditioner that contains a sine wave oscillator and a power amplifier to generate the excitation signals that drive the primary side of the LVDT. The AD598 also converts the secondary output into a dc voltage. The AD8615 rail-to-rail amplifier buffers the output of the AD598 and drives a low power 12-bit successive approximation analog-to-digital converter (ADC). The system has a dynamic range of 82 dB and a system bandwidth of 250 Hz, making it ideal for precision industrial position and gauging applications.


The signal conditioning circuitry of the system consumes only 15 mA of current from the ±15 V supply and 3 mA from the +5 V supply, making this ideal for remote applications. The circuit can operate a remote LVDT from up to 300 feet away, and the output can drive up to 1000 feet.


This circuit note discusses basic LVDT theory of operation and the design steps used to optimize the circuit shown in Figure 1 for a chosen bandwidth, including noise analysis and component selection considerations.



Figure 1. LVDT Signal Conditioning Circuit (Simplified Schematic: All Connections and Decoupling Not Shown)

Возможности

  • LVDT signal conditioner
  • No adjustments required
  • Low power

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LVDT Signal Conditioning Circuit  CN0288

Используемые компоненты

Производитель: Analog Devices Inc.
Наименование
Производитель
Описание Корпус/
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Цена, руб. Наличие
AD598AD
AD598AD
Analog Devices Inc.
Арт.: 27154 ИНФО PDF RD
Доступно: 1182 шт. от: 4890 руб.
Нормализатор сигнала LVDT, Uвх=0,1,,,3,5V; 0,,,20kHz; Uвых=+/-11V; 6mA,
AD598AD 4890,00 от 2 шт. 4490,00
35 шт.
(на складе)
1147 шт.
(под заказ)
AD598JRZ
AD598JRZ
Analog Devices Inc.
Арт.: 193966 ИНФО PDF RD
Доступно: 544 шт.
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CONDITIONER, LVDT SIGNAL, WSOIC20; Voltage, Supply Min:13V; Voltage, Supply Max:36V; Termination Type:SMD; Case Style:WSOIC; Pins, No, of:20; Temperature, Operating Range:0°C to +70°C; Temp, Op, Max:70°C; Temp, Op, Min:0°C; Base Number:598
AD598JRZ
544 шт.
(под заказ)
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AD7992BRMZ-0
AD7992BRMZ-0
Analog Devices Inc.
Арт.: 559708 PDF RD
Доступно: 10128 шт.
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12BIT ADC, 2CH I2C I/F, SMD, 7992
AD7992BRMZ-0
10128 шт.
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AD7992BRMZ-0REEL
Analog Devices Inc.
Арт.: 607058 RD
Доступно: 12973 шт.
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AD7992BRMZ-0REEL
12973 шт.
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AD7992BRMZ1
AD7992BRMZ1
Analog Devices Inc.
Арт.: 1197845 PDF RD
Доступно: 1758 шт.
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12BIT ADC, 2CH I2C I/F, SMD, 7992
AD7992BRMZ1
1758 шт.
(под заказ)
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