Abstract:
By configuring independently controlled clock signals to a plurality of sensors, preferably an angle sensor and a turn sensor, in communication with one another, a wider variety of sensors and sensor combinations can be used while still being able to synchronize output data of the sensors. Independently controlling clock signals of the sensors to selectively control the timing and portion(s) of data being communicated between the sensors enables data of the sensors to be merged, fused or otherwise combined using different types of sensors whose outputted data ordinarily cannot easily be combined.

Description:
CROSS-REFERENCE 
       [0001]    Pursuant to 35 U.S.C. §119(e), this application claims all benefits to and priority in U.S. Provisional Application Ser. No. 62/217,146, filed on Sep. 11, 2015, the entirety of which is hereby expressly incorporated by reference herein. 
     
    
     FIELD 
       [0002]    The present invention relates generally to position sensors including rotary position sensors, and more particularly, to an inter-sensor communication system in which an angle sensor and a turn sensor are configured to communicate for absolute position sensing. 
       BACKGROUND 
       [0003]    Rotary encoders of optical or magnetic construction are used to measure or sense rotation, typically of a shaft or the like, by providing rotational-related data from which information, such as absolute or relative rotary position can be determined. Rotary encoders are very versatile and used in applications that frequently require controlling the motion of a rotating object, such as a shaft or the like. Other applications include: monitoring motor feedback, cut-to-length applications, filling applications, backstop applications, robotics, etc. 
         [0004]    Optical rotary encoders typically use a circular disk that has sections coded, such as by being blacked out or otherwise marked, that turns with the object whose rotary movement is being measured. A sensor reads light reflected from the disk in determining whether there has been a change in rotary position of the disk. 
         [0005]    While optical rotary encoders have enjoyed a great deal of commercial success, they nonetheless suffer from numerous drawbacks. They are undesirably complicated, sensitive to dust, oil and dirt, mechanically fragile, typically cannot be used in relatively high temperature environments, and are susceptible to shock and vibration. 
         [0006]    Magnetic rotary encoders have a construction that overcomes most, if not nearly all, of these disadvantages. Many magnetic rotary encoders include relatively precise axial and radial positioning of an encoder shaft-mounted magnet used to excite Hall Effect sensors that define a sensor region of a magnetic rotary encoder chip. 
         [0007]    In some applications, to determine an absolute position, a first magnetic rotary encoder chip (angle sensor) can be used to sense a current angle of the rotary system with respect to a first reference line, while a second magnetic rotary encoder chip (turn sensor) can be used to track a count of complete rotations or turns of the rotary system with respect to a second reference line. For example, as a rotary system rotates, the angle sensor can sense this condition accordingly and can determine a current angle of the system with respect to the first reference line. In addition, as the system rotates through a complete rotation in positive/clock-wise direction with respect to the second reference line, the turn sensor can sense this condition and increment a count by one. Conversely, as the system rotates back in a negative/counter-clock-wise direction past the second reference line, the turn sensor can sense this condition and decrement the count by one. The count from the turn sensor and the current angle from the angle sensor together can provide an absolute position when queried. 
         [0008]    While precise alignment between the aforementioned reference lines of the sensors is ideal, in practical implementations, some error between the reference lines typically exists. As a result, it is oftentimes necessary for one of the sensor chips, or a microcontroller in the system, to synchronize the measurements between the sensor chips in order to determine a consistent absolute position. However, for one of the sensor chips to synchronize the measurements, it is often necessary for the other sensor chip to present sensed data in a predetermined way that would be recognized by the synchronizing sensor chip. This limits the possibility of sensor chips to ones that are strictly compatible in this regard, which might not include sensor chips providing the highest accuracy, lowest power consumption and/or lowest cost. Also, for the microcontroller to synchronize the measurements, it is often necessary to implement additional software for the microcontroller to execute. This can result in inefficient processing delays which may not be acceptable in the system. 
         [0009]    What is therefore needed is a system for absolute position sensing which overcomes one or more of the aforementioned drawbacks. 
       SUMMARY 
       [0010]    The present inventor has recognized that by configuring independently controlled clock signals to a plurality of sensors, preferably an angle sensor and a turn sensor, in communication with one another, a wider variety of sensors and sensor combinations can be used while still being able to synchronize output data of the sensors. Independently controlling clock signals of the sensors to selectively control the timing and portion(s) of data being communicated between the sensors enables data of the sensors to be merged, fused or otherwise combined using different types of sensors whose outputted data ordinarily cannot easily be combined. 
         [0011]    An inter-sensor communication system of the invention utilizes a processor to selectively and independently control clock signals of the plurality of different types of sensors to thereby selectively control the timing and portion(s) of sensor output data communicated between the sensors thereby advantageously enabling sensor output data from the plurality of dissimilar types of sensors to be merged, fused or otherwise combined. A preferred inter-sensor communication system utilizes a processor to selectively and independently control clock signals of an angle sensor and a turn sensor to synchronize measurement data outputted by the sensors in merging, fusing or otherwise combining the data in a manner that outputs absolute position or enables absolute position to be determined. This can be accomplished by using the independently controlled clock signals to selectively control the timing and portions of data being communicated between the sensors. As a result, higher accuracy, lower power consumption and/or lower cost sensors that might not otherwise be configured to provide sensed data in predetermined ways which can be expected by other sensors can nevertheless be used to achieve optimum performance. 
         [0012]    If desired, the inter-sensor communication system can include an angle sensor in communication with a turn sensor. The angle sensor and the turn sensor can be attached to a rotary system which the angle sensor and the turn sensor are intended to sense to provide an output indicating absolute position. 
         [0013]    The angle sensor can sense an angle of rotation of the rotary system. The angle sensor can be used to determine a current angle of the rotary system with respect to a first reference line. The turn sensor can maintain a count of sensed rotations of the rotary system. The turn sensor can be used to track a count of complete rotations or turns (positive or negative) of the rotary system with respect to a second reference line. 
         [0014]    A first clock signal can causes the angle sensor to communicate a sensed angle of rotation to the turn sensor. A second clock signal causes the turn sensor to communicate an output including the sensed angle of rotation and the count. The angle sensor and the turn sensor can be arranged on one or more circuit boards. 
         [0015]    Optionally, multiple circuit boards can be arranged in a housing to operate as the inter-sensor communication system attached in the rotary system. The angle sensor, the turn sensor and various electronics can be mounted, for example, on opposing sides of a first circuit board and can be in communication with one another. A permanent magnet can be axially aligned with centers of the angle sensor and the turn sensor so as to react with a sensor region of the turn sensor and a sensor region the angle sensor. The aforementioned sensor regions can include Hall Effect sensors on each of the sensor chips. 
         [0016]    If desired, a second circuit board can be disposed over the first circuit board. A microcontroller (which can include a microprocessor, controller or other processing logic) and various electronics can be mounted on the second circuit board and can be in communication with the turn sensor and the angle sensor on the first circuit board. A battery can also be mounted on the second circuit board so as to retain sensor measurements and data held by the angle sensor, the turn sensor and the microcontroller. The microcontroller can be configured to independently control first and second clock signals to the angle sensor and the turn sensor, respectively, so as to selectively control the timing and portions of data being communicated between the sensors. Accordingly, the first clock signal can be controlled to cause the angle sensor to communicate a sensed angle of rotation to the turn sensor, and the second clock signal can be controlled to cause the turn sensor to communicate an absolute position including the sensed angle of rotation and the count. 
         [0017]    If desired, a third circuit board can be disposed over the second circuit board. A connector and various electronics can be mounted on the third circuit board and can be in communication with the microcontroller on the second circuit board. The connector can be used to route cable and wiring for reporting the absolute position sensed by the rotary encoder. 
         [0018]    If desired, the inter-sensor communication system can provide a method for position sensing. An angle sensor and a turn sensor can be communicating with one another. The angle sensor and the turn sensor can be attached to a rotary system which the angle sensor and the turn sensor are intended to sense for providing an output indicating absolute position. The angle sensor can sense an angle of rotation of the rotary system. The angle sensor can be used to determine a current angle of the rotary system with respect to a first reference line. The turn sensor can maintain a count of sensed rotations of the rotary system. The turn sensor can be used to track a count of complete rotations or turns (positive or negative) of the rotary system with respect to a second reference line. The first clock signal can causes the angle sensor to communicate a sensed angle of rotation to the turn sensor. The second clock signal causes the turn sensor to communicate an output including the sensed angle of rotation and the count. 
         [0019]    These and other features and advantages of the invention will become apparent to those skilled in the art from the following detailed description and the accompanying drawings. It should be understood, however, that the detailed description and specific examples, while indicating preferred embodiments of the present invention, are given by way of illustration and not of limitation. Many changes and modifications can be made within the scope of the present invention without departing from the spirit thereof, and the invention includes all such modifications. 
     
    
     
       DRAWING DESCRIPTION 
         [0020]    Preferred exemplary embodiments of the invention are illustrated in the accompanying drawings in which like reference numerals represent like parts throughout, and in which: 
           [0021]      FIG. 1  is a cross sectional view of a prior art rotary magnetic encoder assembly illustrating a bearing arrangement used to precisely position an exciter magnet relative to a rotary magnetic encoder integrated circuit chip to ensure it outputs a good signal; 
           [0022]      FIG. 2  is an exploded view of the prior art rotary magnetic encoder assembly of  FIG. 1 ; 
           [0023]      FIG. 3  in an enlarged fragmentary exploded view of an encoder shaft, exciter magnet and rotary magnetic encoder integrated circuit chip of the prior art rotary magnetic encoder assembly of  FIG. 1 ; 
           [0024]      FIG. 4  is an enlarged fragmentary cross sectional view of the encoder shaft and exciter magnet precisely located relative to the rotary magnetic encoder integrated circuit chip of the prior art rotary magnetic encoder assembly of  FIG. 1 ; 
           [0025]      FIG. 5  is a top plan view of the rotary magnetic encoder integrated circuit chip showing its sensor region comprised of an array of Hall Effect sensors or switches; 
           [0026]      FIG. 6  is a rotary magnetic encoder according to an embodiment; 
           [0027]      FIG. 7  is a housing for the rotary magnetic encoder according of  FIG. 6 ; 
           [0028]      FIG. 8  is a diagram of an angle sensor region and a turn sensor region for the rotary magnetic encoder of  FIG. 7 ; 
           [0029]      FIG. 9  is a circuit for a system for position sensing according to a first embodiment; 
           [0030]      FIG. 10  is a timing diagram for the circuit of  FIG. 9 ; 
           [0031]      FIG. 11  is a circuit for a system for position sensing according to a second embodiment; and 
           [0032]      FIG. 12  is a timing diagram for the circuit of  FIG. 11 . 
       
    
    
     DETAILED DESCRIPTION 
       [0033]    An example of a prior art rotary magnetic encoder  30  is shown in  FIGS. 1-5 . With specific reference to  FIGS. 1-3 , the encoder  30  has a substantially rigid housing  32  in which is fixed a bearing arrangement  34  that cooperates with a rotary encoder shaft  36  having a sensor exciter magnet  38  fixed in its free end that overlies a magnetic field sensor region  40  of a magnetic rotary encoder integrated circuit chip  42  attached to a circuit board  44  that is fixed to the housing  32 . The circuit board  44  has onboard electronics  46  used to process data from the encoder chip  42  and output data or a signal that is representative of or which relates to rotary movement of the shaft  36  via a connector  47 . Shaft  36  can be directly connected to that which is being measured or can be connected by a coupling (not shown) or the like to another shaft or other component that is being rotated or otherwise displaced in a manner lending itself to rotary encoder measurement. 
         [0034]    The bearing arrangement  34  is held in place against the encoder housing  32  by a locking ring  48  and includes at least one shaft bearing  50 ,  52  to help ensure the shaft  36  runs axially true for preventing the magnet  38  from wobbling during shaft rotation. The bearing arrangement  34  also includes means to axially lock the shaft  36 , such as by use of a ring  54  or the like that seats in a groove  56  ( FIG. 2 ) formed in the shaft  36 , so that the gap, Z ( FIG. 4 ), between the end of the exciter magnet  38  and the outer surface  58  of the encoder chip  42  is maintained within a desired tolerance. 
         [0035]    The exciter magnet  38  is a bi-polar disk-shaped permanent magnet that is fixed in a pocket  60  in the free end of the encoder shaft  36 . The magnet  38  is bisected with one magnet half defining a North pole  62  and the other magnet half defining a South pole  64 . The magnet  38  is relatively small, typically having a diameter of about 6 millimeters and a height or thickness of no more than about 2.5 millimeters, but is powerful as it is typically a rare earth Alnico (AlNiCo), samarium cobalt (SmCo5), or neodymium (NdFeB) magnet. 
         [0036]    The location of the exciter magnet  38  must be precisely located relative to the sensor region  40  of the encoder chip  42 . The magnet  38  must be centered such that its axial center  61  is substantially coaxial with an axis of rotation  66  of the shaft and a center  68  of the sensor region  40  within an accepted minimal tolerance. This is to ensure that an array of Hall sensors, H 0 -H 7 , arranged generally as depicted in  FIG. 5  in four quadrants, Q 0 -Q 3 , of the sensor region  40  of the encoder chip  42  experience a relatively uniform magnetic field distribution from whichever pole of the magnet  38  is closest. Such an encoder chip  42  can have a greater or lesser number of Hall sensors. For example, such an encoder chip  42  can be equipped with as few as four Hall sensors. 
         [0037]    A couple of preferred examples of a commercially available contactless rotary magnetic encoder chip having such a construction include an AS5040 and AS5046 rotary magnetic angle encoder integrated circuit chip made by Austria Microsystems of Tobelbaderstrasse 30, Schloss Premstaetten, Unterpremstaetten, Austria. The AS5046 is a 16 pin integrated circuit (IC) that includes an onboard array of Hall sensors, H 0 -H 7 , onboard amplifier therefor, onboard digital signal processor, onboard automatic gain control, onboard range pre-select, an onboard OTP (One-Time Programmable) register, an onboard digital to analog converter, and an onboard interface. Other examples of commonly used magnetic encoder chips of similar construction include an AS5040 10-bit programmable magnetic rotary encoder IC chip, an iC-MA Angular Hall Encoder chip made by iC Hause Integrated Circuits of Am Kuemmerling 18, 55294 Bodenheim, Germany, as well as an AM256 rotary magnetic encoder IC chip by Renishaw plc of New Mills, Wotton-under-Edge, Gloucestershire, United Kingdom 
         [0038]    As a result, the distance, Z, of the exciter magnet  38  from the outer surface  58  of the encoder chip  42  (and hence the distance of the magnet  38  from the array of Hall sensors, H 0 -H 7 ), must be within an acceptable distance range depending on the field strength of the magnet  38  and the center of the magnet  38  (and rotational axis  66  of shaft  36 ) must be within an acceptable range of the center point  68  of the sensor region  40  of the encoder chip  42  or errors will undesirably result. For example, such errors can be in the form of increased signal noise in the output signal. Where a pair of offset sine or square waves is outputted by the encoder chip  42 , such errors can be in the form of an erroneous increase or decrease in the offset. Where this offset is determinative of the rotational angle of the exciter magnet  38 , any such error will obviously result in an erroneous rotational angle. 
         [0039]    Referring now to  FIGS. 6 and 7 , in an aspect of the invention, a rotary magnetic encoder  100  (see  FIG. 6 ) can be contained in substantially rigid housing  150  (see  FIG. 7 ) which can operate in cooperation with a rotary encoder shaft similar to that described above with respect to  FIGS. 1-4 . Accordingly, the rotary magnetic encoder  100  can provide absolute position sensing and reporting for a rotary encoder shaft. The rotary magnetic encoder  100  can include one more circuit boards which can be disposed over one another and in communication with one another, such as a first circuit board  102 , a second circuit board  104  and a third circuit board  106 , disposed over one another. In one aspect, a magnetic rotary angle sensor  110  integrated circuit chip and various electronics can be surface mounted on a first side of the first circuit board  102 , and a magnetic rotary turn sensor  112  integrated circuit chip and various electronics can be surface mounted on a second side of the first circuit board  102 , opposing the first side. The angle sensor  110  and the turn sensor  112  can be in communication with one another, such as by circuit board through-hole vias. 
         [0040]    A couple of preferred examples of a commercially available magnetic rotary angle sensors are the iC-TW11 10-Bit Ultra Low Power Magnetic Absolute Rotary Encoder chip made by iC Hause Integrated Circuits of Am Kuemmerling 18, 55294 Bodenheim, Germany, as well as the AM8192B Angular Mgnetic Sensor Chip by Renishaw plc of New Mills, Wotton-under-Edge, Gloucestershire, United Kingdom. A preferred example of a commercially available magnetic rotary turn sensor is the iC-PV Battery-Buffered Hall Multiturn Encoder made by iC Hause Integrated Circuits of Am Kuemmerling 18, 55294 Bodenheim, Germany. 
         [0041]    An exciter magnet  114  (shown in cutaway in  FIG. 6 , contained in a magnet housing  116 ) can be axially aligned with centers of the angle sensor  110  and the turn sensor  112  along a central axis  118  so as to react with an angle sensor region  120  of the angle sensor  110  and a turn sensor region  122  the turn sensor  112 . The exciter magnet  114  can be a bi-polar disk-shaped permanent magnet that is fixed in a pocket of the magnet housing  116  at an end of an encoder shaft  36  similar to the exciter magnet  38 . The angle sensor region  120  and the turn sensor region  122  can each include Hall Effect sensors (on each of the angle sensor  110  and the turn sensor  112 , respectively) as described above with respect to  FIG. 5 . 
         [0042]    With additional reference to  FIG. 8 , the angle sensor region  120  can allow the angle sensor  110  to determine a current angle of the rotary system (via rotation of the exciter magnet  114 ) through 360° of rotation with respect to a first reference line  130 . The turn sensor region  122  of the turn sensor  112 , disposed along the central axis  118 , can be used to determine complete rotations or turns (positive or negative) of the rotary system (via rotation of the exciter magnet  114 ) through 360° of rotation with respect to a second reference line  132 . Accordingly, the angle sensor  110  can track a current angle of the rotary system while the turn sensor  112  can track a count of complete rotations or turns of the rotary system. 
         [0043]    For example, as the rotary system rotates, the angle sensor  110  can sense this condition accordingly and can determine a current angle of the system with respect to the first reference line  130  (such as 30° .) In addition, as the system rotates through a complete rotation in a positive/clock-wise direction with respect to the second reference line  132 , the turn sensor  112  can sense this condition and increment the count by one. Conversely, as the system rotates back in a negative/counter-clock-wise direction past the second reference line  132 , the turn sensor  112  can sense this condition and decrement the count by one. The count from the turn sensor  112  and the current angle from the angle sensor  110  together can provide an absolute position for the rotary system when queried. 
         [0044]    While precise alignment between the first and second references lines  130  and  132 , respectively, is ideal, in practical implementations, some error (shown as an angle θ) between the reference lines typically exists. As a result, it can be necessary for a sensor chip, such as the turn sensor  112 , to synchronize the measurements between the angle sensor  110  and the turn sensor  112  in order to determine a consistent absolute position. Accordingly, in an aspect of the invention, independently controlled clock signals can be provided to the angle sensor  110  and the turn sensor  112  to selectively control the timing and portions of data being communicated between the sensors. This can allow higher accuracy, lower power consumption and/or lower cost sensors that might not otherwise be configured to provide sensed data in predetermined ways which can be expected by other sensors to nevertheless be used to achieve optimum performance. 
         [0045]    Referring again to  FIG. 6 , a microcontroller  140  and various electronics can be mounted on the second circuit board  104  and can be in communication with the angle sensor  110  and the turn sensor  112 . A battery  142  can also be mounted on the second circuit board  104  or elsewhere so as to retain sensor measurements and data held by the angle sensor  110 , the turn sensor  112  and the microcontroller  140  in the event of a power signal loss. 
         [0046]    A connector  144  and various electronics can be mounted on the third circuit board  106 . The connector can be used to route cable and wiring  146  for the angle sensor  110 , the turn sensor  112 , the microcontroller  140  and/or various electronics, including for providing a power signal to the aforementioned components, configuring the aforementioned components, and reporting the absolute position sensed by the rotary magnetic encoder  100 . 
         [0047]    Referring now to  FIG. 9 , in a first aspect of the invention, the microcontroller  140  can be configured to independently control a first clock signal  160  (“Angle Sensor Clock signal”) to the angle sensor  110  and a second clock signal  162  (“Turn Sensor Clock signal”) to the turn sensor  112 , so as to selectively control the timing and portions of data being communicated between the angle sensor  110  and the turn sensor  112 . Accordingly, the first clock signal  160  can be controlled to first cause the angle sensor  110  to communicate a sensed angle of rotation  164  to the turn sensor  112 . Then, the second clock signal  162  can be controlled to cause the turn sensor  112  to receive the sensed angle data and communicate an output  166  indicating an absolute position for the rotary system, including the sensed angle of rotation from the angle sensor  110  and the count from the turn sensor  112 , to the microcontroller  140 . 
         [0048]    With additional reference to the timing diagram of  FIG. 10 , the microcontroller  140  can control the first clock signal  160  to activate at a time period A in order to provide a “Setup” pulse for the angle sensor  110  as may be required according to the characteristics of the angle sensor  110 . Accordingly, the setup pulse for the angle sensor  110  can trigger the angle sensor  110  to sample, store and transmit a currently sensed angle. In one example, the setup pulse can comprise asserting the first clock signal  160  low through an entire clock signal cycle. During the time period A, the second clock signal  162  is not yet activated, and therefore the turn sensor  112  does not yet receive data from the angle sensor  110 . 
         [0049]    Next, in time period B, the microcontroller  140  can control the first clock signal  160  to toggle to allow the angle sensor  110  to communicate data bits on clock signal cycles. However, to the extent the angle sensor  110  initially provides extraneous data bits, the microcontroller  140  can keep the second clock signal  162  to the turn sensor  112  deactivated so as to not allow the turn sensor  112  to receive the extraneous data bits (“Ignored Data”). 
         [0050]    Next, in time period C, which can coincide near an end of time period B and/or a beginning of time period D, the microcontroller  140  can control the second clock signal  162  to activate by providing a “Setup” pulse for the turn sensor  112  as may be required according to the characteristics of the turn sensor  112 . Accordingly, the setup pulse for the turn sensor  112  can trigger the turn sensor  112  to prepare to receive sensed angle data from the angle sensor  110 , to synchronize measurements between the angle sensor  110  and the turn sensor  112  for determining an absolute position, and to provide the output  166  indicating an absolute position for the rotary system, including the sensed angle of rotation from the angle sensor  110  and the count from the turn sensor  112 . In one example, the setup pulse can comprise asserting the second clock signal  162  after a period of non-assertion. During the time period A, the second clock signal  162  is not yet activated and therefore does not yet receive data from the angle sensor  110 . 
         [0051]    Next, in overlapping time periods D and E, the microcontroller  140  can control the first clock signal  160  to continue toggling to allow the angle sensor  110  to communicate the sensed angle data, which can begin with a most-significant bit (such as “AD 13 ,” “AD 12 ,” “AD 11 ,” and so forth), and can control the second clock signal  162  to begin toggling to allow the turn sensor  112  to receive the sensed angle data (the “AD 13 ,” “AD 12 ,” “AD 11 ,” and so forth), having skipped the earlier “Ignored Data” from the angle sensor  110 . In addition, the microcontroller  140  controlling the second clock signal  162  to toggle can allow the turn sensor  112  to being communicating the count, which can begin with a most-significant bit (such as “TD 30 ,” “TD 29 ,” “TD 28 ,” and so forth), 
         [0052]    However, when the angle sensor  110  communicates the last sensed angle data bit (such as “AD 0 ”), to the extent the angle sensor  110  can continue to then provide extraneous data bits, the microcontroller  140  can stop the first clock signal  160  from toggling in time period F, so as to not allow the angle sensor  110  to transmit the extraneous data bits (“Ignored Data”). The microcontroller  140  can still continue toggling the second clock signal  162  in time period E, so as to allow the turn sensor  112  to transmit the absolute position to the microcontroller  140  via the output  166 , including the count and the currently sensed angle. 
         [0053]    Finally, in time period G, after having received the absolute position, the microcontroller  140  can control the second clock signal  162  to also stop toggling, which can also prevent the turn sensor  112  from transmitting extraneous data bits. It will be appreciated that the microcontroller  140  can be preconfigured to control a wide variety of angle sensors and turn sensors in various combinations, including with differing requirements for setup pulses and/or various handling of extraneous bits as desired. Such variations are deemed within the scope of the invention. 
         [0054]    Referring now to  FIG. 11 , in a second aspect of the invention, the microcontroller  240  can be configured to independently control a first clock signal  260  (“Angle Sensor Clock signal”) to an angle sensor  210  and a second clock signal  262  (“Turn Sensor Clock signal”) to a turn sensor  212 , so as to selectively control the timing and portions of data being communicated via a Serial Peripheral Interface (SPI) and/or a Synchronous Serial Interface (SSI). Accordingly, the first clock signal  260  can be controlled to first transmit a command to the angle sensor  210 , via serial input  270 , for the angle sensor  210  to communicate a sensed angle of rotation, via serial output  272 . Then, the second clock signal  262  can be controlled to cause the turn sensor  212  to receive the sensed angle data and communicate an output  266  indicating an absolute position for the rotary system, including the sensed angle of rotation from the angle sensor  210  and the count from the turn sensor  212 , to the microcontroller  240 . 
         [0055]    With additional reference to the timing diagram of  FIG. 12 , the microcontroller  240  can control the first clock signal  260  to activate at a time period I for the microcontroller  240  to transmit a first command to the angle sensor  210  via the serial input  270 . The first command can be a message instructing the angle sensor  210  to communicate a sensed angle of rotation. Next, in time period II, a break can be inserted, then in time period III, the microcontroller  240  can optionally transmit a second command to the angle sensor  210  via the serial input  270 . During the time period I and II, the second clock signal  262  is not yet activated, and the turn sensor  212  therefore does not yet receive data from the angle sensor  210 . 
         [0056]    However, in time period III, while the microcontroller  240  optionally transmits a second command to the angle sensor  210 , the angle sensor  210  communicates data bits on clock signal cycles. To the extent the angle sensor  210  initially provides extraneous data bits, the microcontroller  240  can keep the second clock signal  262  to the turn sensor  212  deactivated so as to not allow the turn sensor  212  to receive the extraneous data bits (“Ignored Data”). 
         [0057]    Next, in time period IV, the microcontroller  240  can control the first clock signal  260  to continue toggling to allow the angle sensor  210  to communicate the sensed angle data. In addition, the microcontroller  240  can control the second clock signal  262  to activate toggling to receive sensed angle data from the angle sensor  210 , to synchronize measurements between the angle sensor  210  and the turn sensor  212  for determining an absolute position, and to provide the output  266  indicating an absolute position for the rotary system, including the sensed angle of rotation from the angle sensor  210  and the count from the turn sensor  212 . Initially, the turn sensor  212  can communicate the count to the microcontroller  240 , and then can communicate the sensed angle of rotation to the microcontroller  240 , via the output  266 . 
         [0058]    Next, in time period V, to the extent the angle sensor  210  can continue to then provide extraneous data bits, the microcontroller  240  can stop the first clock signal  260  from toggling, so as to not allow the angle sensor  210  to transmit such extraneous data bits. The microcontroller  240  can still continue toggling the second clock signal  262  in time period V, so as to allow the turn sensor  212  to transmit the absolute position to the microcontroller  240  via the output  266 , including the count and the currently sensed angle. 
         [0059]    Finally, in time period VI, after having received the absolute position, the microcontroller  240  can control the second clock signal  162  to also stop toggling, which can also prevent the turn sensor  212  from transmitting extraneous data bits. It will be appreciated that the microcontroller  240  can be preconfigured to control a wide variety of angle sensors and turn sensors in various combinations via SPI and/or SSI. Such variations are deemed within the scope of the invention. 
         [0060]    It will be appreciated that various aspects of the first embodiment described above with respect to  FIGS. 9 and 10  could be combined in a system with various aspects of the second embodiment described above with respect to  FIGS. 11 and 12  in a hybrid system. Such variations are deemed within the scope of the invention. 
         [0061]    Accordingly, one aspect of the present invention may provide a system for position sensing including: an angle sensor configured to sense an angle of rotation; a turn sensor in communication with the angle sensor, the turn sensor being configured to maintain a count of sensed rotations; and first and second clock signals independently controlled from one another, the first clock signal being provided to the angle sensor, and the second clock signal being provided to the turn sensor. The first clock signal can cause the angle sensor to communicate a sensed angle of rotation to the turn sensor, and the second clock signal can cause the turn sensor to communicate an output including the sensed angle of rotation and the count. 
         [0062]    Another aspect can provide a method for position sensing including: providing a first clock signal to an angle sensor configured to sense an angle of rotation; and providing a second clock signal independently controlled from the first clock signal to a turn sensor in communication with the angle sensor, the turn sensor being configured to maintain a count of sensed rotations. The first clock signal can cause the angle sensor to communicate a sensed angle of rotation to the turn sensor, and the second clock signal can cause the turn sensor to communicate an output including the sensed angle of rotation and the count. 
         [0063]    Another aspect can provide a rotary magnetic encoder for position sensing including: an exciter magnet; first and second circuit boards disposed over one another; an angle sensor mounted on a first side of the first circuit board, the angle sensor being configured to sense an angle of rotation; a turn sensor mounted on a second side of the first circuit board, the turn sensor being in communication with the angle sensor, the turn sensor being configured to maintain a count of sensed rotations; a microcontroller mounted on a first side of the second circuit board, the microcontroller being in communication with the angle sensor and the turn sensor; and a housing containing the exciter magnet and the first and second circuit boards. A center of the angle sensor and a center of the turn sensor can be axially aligned with a center of the exciter magnet. The microcontroller can provide first and second clock signals independently controlled from one another, the first clock signal being provided to the angle sensor, and the second clock signal being provided to the turn sensor. The first clock signal can cause the angle sensor to communicate a sensed angle of rotation to the turn sensor, and the second clock signal can cause the turn sensor to communicate an output including the sensed angle of rotation and the count to the microcontroller. 
         [0064]    Understandably, the present invention has been described above in terms of one or more preferred embodiments and methods. It is recognized that various alternatives and modifications can be made to these embodiments and methods that are within the scope of the present invention. Various alternatives are contemplated as being within the scope of the present invention. It is also to be understood that, although the foregoing description and drawings describe and illustrate in detail one or more preferred embodiments of the present invention, to those skilled in the art to which the present invention relates, the present disclosure will suggest many modifications and constructions, as well as widely differing embodiments and applications without thereby departing from the spirit and scope of the invention.