CN0288: LVDT Signal Conditioning Circuit
Complete adjustment-free LVDT signal conditioning circuit for precise linear displacement measurement using AD598, AD8615, and AD7992 with 11-bit noise-free resolution.
Overview
This circuit note describes a complete linear variable differential transformer (LVDT) signal conditioning system for accurate displacement measurement. The design centers on the AD598 signal conditioner, which provides excitation for the LVDT and converts the secondary output to a DC voltage. An AD8615 operational amplifier buffers the signal to drive the AD7992 12-bit ADC via an I2C interface. The ratiometric design eliminates sensitivity to phase shifts and excitation amplitude variations. The system offers a 250 Hz bandwidth and 82 dB dynamic range, supporting remote LVDT placement up to 300 feet away.
Use Cases
- Flight control feedback systems
- Position feedback in servomechanisms
- Automated measurement in machine tools
- Industrial position and gauging applications
- Remote displacement sensing
Topics
Referenced Parts
Analog Devices
If dual-supply operation is required, the ADA4638-1 or ADA4627-1 is suggested.
Analog Devices
If dual-supply operation is required, the ADA4638-1 or ADA4627-1 is suggested.
E-100
Measurement Specialties, Inc.
E-100 Economy Series LVDT sensor from Measurement Specialties™, Inc.
| AD598 | Analog Devices | AD598 LVDT Signal Conditioner |
| AD7992 | Analog Devices | AD7992 2-Channel, 12-Bit ADC with I 2 C Compatible Interface |
| AD8615 | Analog Devices | AD8615 Precision, 20 MHz, CMOS, Single RRIO Operational Amplifier |
| AD7321 | Analog Devices | If the AD598 outputs ±10 V bipolar signals, the AD7321 is suggested. |
| AD8565 | Analog Devices | Other suitable single-supply amplifiers are the AD8565 and AD8601. |
| AD8601 | Analog Devices | Other suitable single-supply amplifiers are the AD8565 and AD8601. |
| ADA4627-1 | Analog Devices | If dual-supply operation is required, the ADA4638-1 or ADA4627-1 is suggested. |
| ADA4638-1 | Analog Devices | If dual-supply operation is required, the ADA4638-1 or ADA4627-1 is suggested. |
| ADP1613 | Analog Devices | ADP1613 Data Sheet |
| ADP7104 | Analog Devices | ADP7104 Data Sheet |
| E-100 | Measurement Specialties, Inc. | E-100 Economy Series LVDT sensor from Measurement Specialties™, Inc. |