The invention relates to a sensor system with an arrangement of sensors in which each sensor detects an electric or magnetic field and outputs an electric sensor signal to its sensor outputs. The sensor outputs are connected to one another. In addition, the invention relates to a method to operate the sensor system.
A Hall sensor arrangement, in which several Hall sensors are arranged in a stationary manner and in a fixed configuration with one other, is known from the reference DE 199 43 128 A1. This type of sensor arrangement has the disadvantage that it has low flexibility in measuring magnetic fields, for example, because of a fixed connection of the sensors. In particular, the known sensor arrangement is not suitable for the two-dimensional and three-dimensional measurement of magnetic field distributions.
As a result, the objective of the present invention is disclosing a sensor system that has a plurality of applications and that is suitable for analyzing two-dimensional and three-dimensional magnetic field distributions.
A sensor system is disclosed that has an arrangement of sensors. Each of the sensors detects an electric or magnetic field and outputs an electric sensor signal to its outputs. The same types of sensors but also different types of sensors can be used for the sensor system.
Each of the sensors is connected to a signal modulator, wherein the inputs of the signal modulator are connected to the sensor outputs of the related sensor. Each signal modulator has at least two control states. In a first control state, the corresponding basic sensor signal is fed to the signal modulator output as a sensor end signal. In a second control state, the inverted basic sensor signal is fed to the signal modulator output as a sensor end signal.
In addition, the sensor system features a device for the addition of the sensor end signals to a system signal.
The advantage of the sensor system is that a plurality of configurations can be defined for the sensor system because of the different control states of each signal modulator. As a result, the sensor system can be used flexibly and, in particular, to analyze two-dimensional and three-dimensional magnetic fields. In addition, such a sensor system is suitable for detecting linear, magnetic or electrical fields, and for detecting locational displacements of linear or axial, sinusoidally-distributed magnetic fields.
In addition, a method to operate the sensor system that is made possible for the first time with the sensor system in accordance with the invention is disclosed. In this arrangement, all control states of the signal modulators together define the configuration of the sensor system. The operating method features the following steps:
In a first step, the sensor system is put into a first configuration. A suitable device detects and stores the system signal output by the sensor system.
In a second step of the operating method, the sensor system's configuration is modified from the first configuration to the second configuration. In this arrangement, the second configuration differs from the first configuration.
In a third step, the system signal output by the sensor system in the second configuration is in turn read in and stored in a suitable device.
If necessary, yet other configurations can be set and the signals output by the sensor system can be read in and stored.
Finally, in a further method step, an arithmetic operation is performed with the first and second and any additional system signals. This arithmetic operation can be used to draw conclusions about the two-dimensional or spatial distribution of the magnetic or electrical field being detected.
Hall sensors, for example, can be used as the sensors in the sensor system. These types of Hall sensors can be designed as vertical or lateral Hall sensors on the basis of silicon sensors. But magnetic-field-dependent resistors can also be considered as sensors.
An operational transconductance amplifier can amplify the basic sensor signals output by the Hall sensors. This operational transconductance amplifier is then connected between each sensor and the corresponding signal modulator. The use of operational transconductance amplifiers to amplify the basic sensor signals makes it possible to connect, in parallel, individual sensor units comprised of a sensor and the associated signal modulator. This type of parallel connection makes it possible to add up currents of the sensor end signals to a system signal.
The signal modulators can be connected with a control logic circuit, which allows the switchover between two control states of a signal modulator to be realized via digital control words. This allows particularly quick switching between two control states of a signal modulator and therefore between two configurations of the sensor system.
In an exemplary embodiment of the sensor system, the sensors can be arranged in a plane. Within such a plane, the sensors can in turn be arranged in rows and columns, which are orthogonal to one another. As a result, a checkerboard-like grid of sensors is realized.
The invention is described in greater detail in the following on the basis of exemplary embodiments and the associated figures.
Overall, the signal modulator 30 in
According to
The signal modulators 30, 31 each contain a control logic circuit, which is not shown in
Such a magnet 9 is depicted in
GHall=the electric amplification of the Hall sensors the following relations are produced:
The magnetic source field Bsource at the location of each sensor 10, 11, 12, 13 is determined by the rotational angle α in accordance with:
Bsource=B0·sine(α).
In the configuration according to
VK1=B0·GHall·((sine(α+45)−sine(α+135)−sine(α+225)+sine(α+315)))
The following is yielded by transformation:
VK1=2√{square root over (2)}·B0GHall·sine(α).
Another signal is obtained with the configuration of the sensor system according to FIG. 3B:
VK2=B0·GHall·((sine(α+45)−sine(α+135)−sine(α+225)+sine(α+315)))
Transformation yields:
VK2=2√{square root over (2)}·B0·GHall·cosine(α).
The rotational angle of magnet 9 vis-àvis the sensor system can be computed in a simple manner from signals Vk1 and Vk2 using an arithmetic operation. To do so, the following is calculated:
α=ARC TAN(VK2:VK2)
This calculation can be performed, for example, using the method in accordance with the invention by the sensor system measuring at a first point in time in a configuration K1 and the measured value of the system signal (VOP, VON) being stored. Then, as seen in
Because of the possibility of controlling the signal modulators via digital control words, the switchover between different configurations K1, K2 of the sensor system can take place in a very short time, for example at intervals of several μs. As a result, this guarantees that the sensor system has a high level of flexibility and great speed.
Number | Date | Country | Kind |
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102 01 875 | Jan 2002 | DE | national |
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/EP02/14508 | 12/18/2002 | WO | 00 | 7/15/2004 |
Publishing Document | Publishing Date | Country | Kind |
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WO03/060537 | 7/24/2003 | WO | A |
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Number | Date | Country |
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199 43 128 | Apr 2001 | DE |
WO0118556 | Mar 2001 | WO |
Number | Date | Country | |
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20050088170 A1 | Apr 2005 | US |