LINEAR POSITION MEASUREMENT USING A MAGNETORESISTIVE SENSOR
LINEAR POSITION MEASUREMENT USING A MAGNETORESISTIVE SENSOR
Abstract: A smart transducer used to measure the linear displacement of an object in a magnetic field is presented. The application is to be safely used for demonstration purposes in the Playpen laboratory. The system uses an array of five HMC1501 Magnetoresistive (MR) sensors to sense the position of a magnet attached to the moving object. The system also has the ability to monitor the ambient operating temperature and detect if it is exposed to an external disturbing magnetic field. Several other components such as the differential amplifier, a band-pass filter and a temperature compensation circuit are used to process sensors signal and compensate the errors. The system offers a high resolution of 0.00616 mm, a bandwidth of 9 KHz and a measured distance of 60 mm.
Keywords: MR sensors, band pass filter, magnet, smart transducer.
IntroductionLinear position sensors are very useful in applications where precision positioning is required CITATION Tam08 \l 7177 [1]. There are several methods for measuring the position of moving objects and for each method a specific sensor type can be usedCITATION Placeholder1 \l 7177 [2]. In measurement systems where MR sensors are used, the measurement range of each element is limited to a maximum of 25 mm, however some systems uses a combination of multiple sensors to increase the measurement range to a full scale range above 2 m with a non-linearity less than 0.005 % CITATION Nyc04 \l 7177 [3].
This report details the design of a linear displacement measurement system using an array of five MR sensors. The operating principles of displacement measurement using MR sensor is explained. The designed system is based on the Bentley model CITATION Ben05 \l 7177 [4] of a measurement system. The design of each component of the system is illustrated and the system response and error analysis are presented and analysed.
Background
MR sensors are Wheatstone bridges that
Abstract: A smart transducer used to measure the linear displacement of an object in a magnetic field is presented. The application is to be safely used for demonstration purposes in the Playpen laboratory. The system uses an array of five HMC1501 Magnetoresistive (MR) sensors to sense the position of a magnet attached to the moving object. The system also has the ability to monitor the ambient operating temperature and detect if it is exposed to an external disturbing magnetic field. Several other components such as the differential amplifier, a band-pass filter and a temperature compensation circuit are used to process sensors signal and compensate the errors. The system offers a high resolution of 0.00616 mm, a bandwidth of 9 KHz and a measured distance of 60 mm.
Keywords: MR sensors, band pass filter, magnet, smart transducer.
IntroductionLinear position sensors are very useful in applications where precision positioning is required CITATION Tam08 \l 7177 [1]. There are several methods for measuring the position of moving objects and for each method a specific sensor type can be usedCITATION Placeholder1 \l 7177 [2]. In measurement systems where MR sensors are used, the measurement range of each element is limited to a maximum of 25 mm, however some systems uses a combination of multiple sensors to increase the measurement range to a full scale range above 2 m with a non-linearity less than 0.005 % CITATION Nyc04 \l 7177 [3].
This report details the design of a linear displacement measurement system using an array of five MR sensors. The operating principles of displacement measurement using MR sensor is explained. The designed system is based on the Bentley model CITATION Ben05 \l 7177 [4] of a measurement system. The design of each component of the system is illustrated and the system response and error analysis are presented and analysed.
Background
MR sensors are Wheatstone bridges that
References: Bratland Tamara and Hong Dr. Wan, Linear Position Sensing Using Magnetoresistive Sensors, Honeywell Solid State Electronics Center, 2008. Curtis D David S. Nyce, Linear Position Sensors: Theory and Application: John Wiley & Sons, Inc., 2004. John P Microchip, PIC18F2423/2523/4423/4523 Datasheet, 2007. Philips Semiconductors, General Magnetic fields sensor DataSheet, 1998. Philips Semiconductors, KTY82-210 Series Silicon temperature sensors datasheet, 1998 Microchip Thermal Management, TC1046, TC1047/A and MCP9700/1 Voltage Output Temperature Sensor Familly, 2005.