JP7268426B2 - Rotation angle detector and servo motor system - Google Patents

Description

The present invention relates to a rotation angle detector and a servomotor system.

A circuit configuration capable of alternatively switching between input and output for a sensor is known.

Japanese Patent No. 6098513

There has been a demand to adopt serial communication in the sensor output.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a rotation angle detector and servo motor system capable of serial communication at the output of the sensor.

A rotation angle detector according to the present invention for achieving the above object comprises an annular magnet with N and S poles alternately arranged in the circumferential direction, and a magnetic sensor disposed facing the magnet in a non-contact state. , a storage circuit provided so as to be able to be referred to by the magnetic sensor and storing correction data of the magnetic sensor; a circuit for outputting serial data based on the output data of the magnetic sensor; and input/output terminals of the circuit. and a substrate on which the magnetic sensor, the storage circuit, the circuit and the interface are provided.

Therefore, since the output of the magnetic sensor becomes serial data by the circuit, it is possible to employ serial communication in the output of the sensor.

In the rotation angle detector of the present invention, the circuit operates in either a first mode or a second mode of operation based on the input from the interface, and the first mode is correction of the magnetic sensor. The second mode is an operation mode in which data is written in the storage circuit, and the second mode is an operation mode in which serial data is output based on the output data of the magnetic sensor.

Therefore, two-way communication including the input of correction data to the sensor and the output of the sensor can be performed from the interface. That is, the connection with the servo amplifier and correction of the sensor can be performed with the same connector.

In the rotation angle detector of the present invention, the circuit makes the impedance of the input/output terminal higher in the first mode than in the second mode.

Therefore, in the case of the first mode, the impedance of the output terminal becomes high, so that the data output can be cut off and the cut off can be recognized from the external configuration connected to the interface.

In the rotation angle detector of the present invention, the circuit determines the operating mode based on the frequency of the signal input from the interface.

Therefore, it becomes possible to switch between the first mode and the second mode based on the frequency of the signal.

The rotation angle detector of the present invention comprises an arithmetic circuit provided on the substrate and interposed between the magnetic sensor and the circuit, wherein the arithmetic circuit determines the operation mode of the circuit based on the input from the interface. to decide.

Therefore, the operation mode can be switched by the arithmetic circuit.

In the rotation angle detector of the present invention, the arithmetic circuit is interposed between the magnetic sensor and the interface, and when the circuit operates in the first mode, correction data of the magnetic sensor is received from the interface. Data is written to the memory circuit via the arithmetic circuit and the magnetic sensor.

Therefore, the protocol adopted for inputting the correction data of the magnetic sensor can be different from the protocol adopted for outputting the serial data through the circuit. Also, the data transmission path used for inputting the correction data of the magnetic sensor and the data transmission path used for outputting the serial data via the circuit can be separate paths.

In the rotation angle detector of the present invention, the arithmetic circuit determines the operation mode of the circuit based on the waiting time until input from the interface is performed after power-on.

Therefore, the operation mode can be switched without providing identification data or the like dedicated to switching the operation mode.

In the rotation angle detector of the present invention, the arithmetic circuit converts the first protocol used for input/output of the magnetic sensor to the second protocol used for input/output of the circuit when the circuit operates in the second mode. protocol conversion process.

Therefore, even if the protocol adopted by the magnetic sensor and the protocol adopted by the circuit are different, the sensor and the circuit can communicate with each other.

The rotation angle detector of the present invention includes a temperature detection circuit provided on the substrate for detecting temperature, and the temperature detection circuit stops the operation of the circuit when detecting a temperature equal to or higher than a predetermined temperature.

Therefore, since the serial data is output when the rotation angle detector is at a temperature at which it can operate more reliably, the accuracy of the output can be maintained at a higher level.

A servo motor system of the present invention for achieving the above object comprises an electric motor provided with the rotation angle detector of the present invention, and a servo amplifier connected to the interface.

Therefore, since the output of the magnetic sensor becomes serial data by the circuit, it is possible to employ serial communication in the output of the sensor.

According to the present invention, it is possible to employ serial communication in the output of the sensor.

FIG. 1 is a diagram showing the main configuration of the servomotor system of the first embodiment. FIG. 2 is a schematic diagram showing a configuration example of a rotation angle detector. FIG. 3 is a schematic configuration diagram showing a configuration example of a substrate. FIG. 4 is a schematic illustration showing an example of protocols used in two signal transmission paths to the magnetic sensor. FIG. 5 is a schematic diagram showing a configuration example of a rotation angle detector. FIG. 6 is a schematic configuration diagram showing a configuration example of a substrate. FIG. 7 is a schematic configuration diagram showing a configuration example of a substrate. FIG. 8 is a schematic configuration diagram showing a configuration example of a substrate.

Embodiments of the present invention will be described below with reference to the drawings, but the present invention is not limited thereto. The requirements of each embodiment described below can be combined as appropriate. Also, some components may not be used.

(First embodiment)
FIG. 1 is a diagram showing the main configuration of a servo motor system 100 of the first embodiment. A servo motor system 100 includes an electric motor M, a rotating member R, and a rotation angle detector 1 . The servo motor system 100 is connected with a servo amplifier 90 .

The electric motor M rotates or rotates the output shaft MS under the operation control of the servo amplifier 90 according to the supply of electric power. The rotating member R is a member that is fixed to the output shaft MS and rotates or rotates according to the rotation or rotation of the output shaft MS. The rotating member R is, for example, a disc-shaped member having a radial center at the rotation center X of the output shaft MS and a plate surface perpendicular to the extending direction of the output shaft MS. The target shape is not limited to this, and can be changed as appropriate.

FIG. 2 is a schematic diagram showing a configuration example of the rotation angle detector 1. As shown in FIG. A rotation angle detector 1 includes a ring magnet 2 and a substrate 3 . The ring magnet 2 is fixed to one surface of the rotating member R. As shown in FIG. The ring magnet 2 is an annular magnetic body centered on the rotation center X. As shown in FIG.

The ring magnet 2 has a first magnetization line C1 and a second magnetization line C2. The first magnetized train C1 and the second magnetized train C2 are magnetized trains whose polarities alternately change in the circumferential direction. The first magnetized array C1 has a larger diameter than the second magnetized array C2. The first magnetized array C1 is positioned outside the second magnetized array C2.

The number of magnetic pole pairs W1 of the first magnetized train C1 and the number of magnetic pole pairs W2 of the second magnetized train C2 are different. FIG. 2 illustrates a case where the number of magnetic pole pairs W1 is greater than the number of magnetic pole pairs W2, but the relationship between the numbers can be changed somewhat. For example, the magnitude relationship between the number of magnetic pole pairs W1 in the first magnetized train C1 and the number of magnetic pole pairs W2 in the second magnetized train C2 may be reversed. Magnetic pole pairs W1 and W2 each include one north pole and one south pole.

A magnetic sensor 11 is provided on the substrate 3 . The substrate 3 supports the magnetic sensor 11 at a position facing the ring of the ring magnet 2 . The magnetic sensor 11 is supported in a non-contact state with the ring of the ring magnet 2, detects a magnetic field corresponding to the rotation angle of the ring magnet 2 that rotates according to the operation of the electric motor M, and detects the detected magnetic flux density (or magnetic field It is an integrated circuit (IC) that outputs a signal corresponding to the intensity of the signal. The output is treated as the sensor output of the magnetic sensor 11 . The magnetic sensor 11 of the first embodiment targets a magnetic field obtained by synthesizing the magnetic flux from the first magnetization train C1 and the magnetic flux from the second magnetization train C2.

In FIG. 1, each component of the rotation angle detector 1 and the rotation member R are covered with a cover member P. As shown in FIG. Since the substrate 3 is supported by the cover member P, the position of the substrate 3 with respect to the ring magnet 2 is held.

FIG. 3 is a schematic configuration diagram showing a configuration example of the substrate 3. As shown in FIG. The substrate 3 includes a magnetic sensor 11, an EEPROM (Electrically Erasable Programmable Read Only Memory) 15, a level shifter LS1, an FPGA (Field Programmable Gate Array) 20, a level shifter LS2, a bus transceiver circuit 30, an interface (I/F) 40, an oscillator 71, It has a temperature monitoring IC 72, an LOD 73, a connector 80, and the like.

The EEPROM 15 stores correction data for the magnetic sensor 11 . The magnetic sensor 11 corrects the output according to the correction data of the EEPROM 15 during operation. The magnetic sensor 11 outputs the corrected signal to the FPGA20. The connection between the magnetic sensor 11 and the EEPROM 15 is, for example, an I2C (Inter Integrated Circuit) serial bus, but this is an example and is not limited to this, and can be changed as appropriate.

In the first embodiment, a level shifter LS1 is provided between the magnetic sensor 11 and FPGA20. The level shifter LS1 performs signal level conversion between the voltage system of the magnetic sensor 11 and the FPGA 20 and the voltage system. In the first embodiment, the magnetic sensor 11 and FPGA 20 operate under different voltage systems. Specifically, the magnetic sensor 11 is a 5V system, and the FPGA 20 is a 3.3V system. Therefore, the level shifter LS1 converts the 5V system signal output from the magnetic sensor 11 into a 3.3V system signal and inputs it to the terminal 21 of the FPGA20. Further, the level shifter LS1 converts the 3.3V system signal output from the terminal 21 into a 5V system signal and inputs it to the magnetic sensor 11 .

The FPGA 20 is an arithmetic circuit that performs protocol conversion between the magnetic sensor 11 and the servo amplifier 90 connected to the substrate 3 . The FPGA 20 allows the use of the magnetic sensor 11 and the servo amplifier 90 without the limitation of direct compatibility between the protocol of the magnetic sensor 11 and the protocol of the servo amplifier 90 .

A terminal 22 of the FPGA 20 is connected to the I/F 40 via a level shifter LS2. The level shifter LS2 performs signal level conversion between the voltage system of the FPGA 20 and the I/F 40 and the voltage system. In the first embodiment, the FPGA 20 and the I/F 40 operate under different voltage systems. Specifically, the FPGA 20 is a 3.3V system, and the I/F 40 is a 5V system. Therefore, the level shifter LS2 converts the 5V system signal input from the I/F 40 to the terminal 22 into a 3.3V system signal. Also, the level shifter LS2 converts the 3.3V system signal output from the terminal 22 into a 5V system signal and transmits the 5V system signal to the I/F40. The level shifter LS2 sets the I/F 40 side output terminal of the level shifter LS2 to high impedance (HighZ) at the OE (output enable) terminal 38 of the level shifter LS2 during normal operation connected to the servo amplifier 90 . As a result, the output of the level shifter LS2 on the side of the I/F 40 is cut off so as not to interfere with the signals entering and exiting the output terminals 33 and 34 of the bus transceiver circuit 30. FIG. A signal to the OE terminal 38 of the level shifter LS2 is output from the terminal 29 of the FPGA 20 in the second mode described later.

Terminal 23 and terminal group 24 of FPGA 20 are connected to bus transceiver circuit 30 . The bus transceiver circuit 30 is a circuit capable of serial communication with the servo amplifier 90 connected to the board 3 . Bus transceiver circuit 30 is interposed between FPGA 20 and I/F 40 . That is, there are two signal transmission paths between the FPGA 20 and the I/F 40 , one via the level shifter LS2 and the other via the bus transceiver circuit 30 .

A connector 51 or a connector 61 is connectably provided to the I/F 40 . The I/F 40 is, for example, a 4-pin female connector, but is not limited to this. A specific aspect of the I/F 40 can be changed as appropriate. The connector 51 and the connector 61 are aspects corresponding to a specific aspect of the I/F 40 (for example, 4-pin male connectors). Two of the lines connected to the four pins are power lines (eg, 5V and GND), and the other two are signal lines for transmitting differential signals.

The FPGA 20 enables correction of the magnetic sensor 11 when an external normalization processing device (not shown) is connected. The normalization processing device is connected to the correction I/F 50 . The correction I/F 50 is a mutual conversion I/F that enables data transmission between the I/F provided in the normalization processing device and the connector 51 . A specific example of the I/F provided in the normalization processing device is, for example, a USB (Universal Serial Bus) I/F, but is not limited to this. The normalization processing device is, for example, a computer provided with a USB I/F and capable of outputting correction data of a magnetic sensor such as the magnetic sensor 11 from the USB I/F, but is not limited to this and can be used as appropriate. Can be changed.

Connector 61 is connected to servo amplifier I/F 60 that is connected to servo amplifier 90 . The sensor output of the magnetic sensor 11 is transmitted to the servo amplifier 90 via the magnetic sensor 11-level shifter LS1-FPGA20-bus transceiver circuit 30-I/F40-connector 61-servo amplifier I/F60. The servo amplifier 90 controls the operation of the electric motor M based on the rotation angle of the ring magnet 2 indicated by the sensor output of the magnetic sensor 11 .

FIG. 4 is a schematic explanatory diagram showing an example of protocols used in two signal transmission paths to the magnetic sensor 11. FIG. In FIG. 4, the serial communication protocol employed in the magnetic sensor 11 is BiSS (Bidirectional Serial Synchronous), particularly Biss C, and the serial communication protocol employed in the bus transceiver circuit 30 and servo amplifier 90 is RS- 485 is illustrated.

Biss C and RS-485 employed in the first embodiment are half-duplex protocols that utilize differential signaling. Therefore, the number of signal lines between the magnetic sensor 11 and the FPGA 20 interposed by the level shifter LS1 is two because the differential signals used in the Biss C are transmitted. In addition, the number of signal lines between the bus transceiver circuit 30 and the correction I/F 50 interposed by the level shifter LS2 is two because the differential signals used in RS-485 are transmitted. In FIG. 2, the arrow connecting the level shifter LS1 and the terminal 21 and the arrow connecting the level shifter LS2 and the terminal 22 are indicated by oblique lines and "2" to indicate the two signal lines.

Also, the sensor output of the magnetic sensor 11 is used as part of the path for transmitting the sensor output of the magnetic sensor 11 to the servo amplifier 90 connected to the I/F 40 via the FPGA 20 and the bus transceiver circuit 30. The number of signal lines is two, including signal lines connected to each of a DE (driver enable) terminal 32a and a D (driver input) terminal 32b. In FIG. 3, reference numeral 32 denotes a terminal group including a DE terminal 32a and a D terminal 32b corresponding to the two signal lines and a TE (termination enable) terminal 32c, which will be described later. The FPGA 20 shown in FIG. 3 also has a terminal 24a for transmitting an output signal to the DE terminal 32a and a terminal 24b for transmitting an output signal to the D terminal 32b. The terminal group 24 includes a terminal 24a, a D terminal 32b, and a terminal 24c, which will be described later. A signal line for connecting the receiver output (R) terminal 31 of the bus transceiver circuit 30 and the input terminal 23 of the FPGA 20 is separately provided as a signal line connecting the signal transmission path for the transmission. Since the number of signal lines (+1) is added to the number of signal lines (2) connected to the DE terminal 32a and the D terminal 32b, the RS-485 communication between the FPGA 20 and the bus transceiver circuit 30 shown in FIG. The number of signal lines in is (2+1).

In addition, between the FPGA 20 and the bus transceiver circuit 30, a signal line is additionally provided for performing input to the TE terminal 32c of the bus transceiver circuit 30 from the terminal 24c of the FPGA 20. Since the signal is not a signal transmitted to the normalization processor and the servo amplifier 90, it is not included in the number of RS-485 signal lines ((2+1) lines) in FIG. The signal carried on this signal line determines whether the bus transceiver circuit 30 operates in the first mode or the second mode. The first mode is an operation mode when correction data for the magnetic sensor 11 input from the normalization input device via the connector 51 is written in the EEPROM 15 . The second mode is an operation mode in which the bus transceiver circuit 30 outputs serial data based on the output data of the magnetic sensor 11 from the plus (+) terminal 33 and the minus (-) terminal 34 .

The bus transceiver circuit 30 switches between the first mode and the second mode depending on whether the connector 51 or the connector 61 is connected to the I/F 40 when the board 3 is powered on. In the first embodiment, the FPGA 20 determines the operation mode of the bus transceiver circuit 30 based on the waiting time until input from the I/F 40 is performed after the board 3 is powered on. This is the time (second time) after power-on until signal input from the servo amplifier 90 starts, rather than the time (first time) after power-on until the FPGA 20 mounted on the substrate 3 operates. It takes a long time. As a specific example, the first time is, for example, 100 [ms]. On the other hand, the second time is several hundred [ms], for example. Therefore, if a signal is input via the I/F 40 before the second time has elapsed after the power is turned on, the signal is not the signal from the servo amplifier 90 but the signal from the normalization processing device. can be determined. It should be noted that when the correction data for the magnetic sensor 11 is input, the normalization processing device is presumed to be in operation when the substrate 3 is powered on.

The FPGA 20 of the first embodiment includes a switching detector 20a that performs processing related to switching of the operation mode of the bus transceiver circuit 30. FIG. A signal input via the I/F 40 after power-on is input to the bus transceiver circuit 30 . The signal is input from the R terminal 31 to the terminal 23 . The FPGA 20 operates after the first time has elapsed. Therefore, the switching detection unit 20a determines that the signal is from the servo amplifier 90 when the signal is input after (second time-first time) has elapsed from the start of operation, and (second time-first time). If the signal is input before the time elapses, it is determined that the signal is from the normalization processor.

If a signal is input before the lapse of (the second time minus the first time) because the normalization processing device is connected when the power is turned on, the switching detection unit 20a outputs a termination enable signal from the terminal 24c. The termination enable signal is input to bus transceiver circuit 30 via TE terminal 32c. The bus transceiver circuit 30 to which the termination enable signal is input operates to set the output impedance of the + terminal 33 and the - terminal 34 to the high impedance (HighZ) at the time of output cutoff, and disconnects the termination resistor. This cuts off the signal transmission path between the FPGA 20 and the I/F 40 via the bus transceiver circuit 30 . Thus, bus transceiver circuit 30 operates in the first mode. Along with this, the level shifter LS2 operates to turn ON the signal transmission path between the FPGA 20 and the I/F 40 via the level shifter LS2. As a result, communication by the BiSS C protocol between the magnetic sensor 11-level shifter LS1-FPGA20-level shifter LS2-I/F40-connector 51-correction I/F50 is established, and correction data is input to the magnetic sensor 11 from the correction I/F50. be done. The correction data input to the magnetic sensor 11 are stored in the EEPROM 15 .

On the other hand, if a signal is input after the lapse of (the second time minus the first time) because the servo amplifier 90 is connected when the power is turned on, the switching detection unit 20a does not output the termination enable signal. This enables signal output from the bus transceiver circuit 30 via the + terminal 33 and the - terminal 34 . Thus, bus transceiver circuit 30 operates in the second mode. Also, in this case, the level shifter LS2 does not operate. As a result, communication including protocol conversion among the magnetic sensor 11--level shifter LS1--FPGA 20--bus transceiver circuit 30--I/F 40--connector 61--servo amplifier I/F 60 is established. is transmitted to When operating in the second mode, the FPGA 20 converts the first protocol (BiSS C) used for the input/output of the magnetic sensor 11 into the second protocol (RS-485) used for the input/output of the bus transceiver circuit 30. process.

Oscillator 71 outputs a clock signal (CLK). The FPGA 20 operates in synchronization with the clock signal input from the terminal 25 .

A temperature monitoring IC 72 is a temperature sensor that monitors the temperature of the substrate 3 . The temperature monitoring IC 72 outputs a signal (circuit cutoff signal) to stop the operation of the FPGA 20 when detecting a temperature equal to or higher than a predetermined operation stop temperature. The FPGA 20 stops operating when the circuit break signal is input from the terminal 26 . In this case, the signal transmission path between the magnetic sensor 11 and the I/F 40 is cut off, and the stop of the operation of the substrate 3 can be detected from the normalization processing device and the servo amplifier 90 . The operation stop temperature can be set to, for example, 100 [° C.], 120 [° C.], or 150 [° C.], but any temperature can be set without being limited to the illustrated temperatures.

LOD73 is the voltage regulator of FPGA20. The FPGA 20 is designed with a voltage rail specification that corresponds to the LOD73. The connector 80 is a connector provided to be directly communicable with the FPGA 20 .

It should be noted that the method of switching between the first mode and the second mode is not limited to the time elapsed after the power is turned on. For example, the communication frame time between the normalization processing device and the FPGA 20 may be set differently from the communication frame time between the servo amplifier 90 and the FPGA 20 . In this case, the switching detector 20a switches whether to output the termination enable signal based on the relationship between the communication performed by the FPGA 20 and the clock signal (CLK) generated during the communication.

As described above, according to the first embodiment, the rotation angle detector 1 includes a ring magnet 2 having N and S poles alternately arranged in the circumferential direction, and a magnetic sensor arranged to face the ring magnet 2 in a non-contact state. 11, an EEPROM 15 which is provided so as to be referenced from the magnetic sensor 11 and stores correction data of the magnetic sensor 11, a bus transceiver circuit 30 which outputs serial data based on the output data of the magnetic sensor 11, and a bus transceiver circuit 30. It comprises an I/F 40 to which the + terminal 33 and the - terminal 34 are connected, and a substrate 3 on which the magnetic sensor 11, the EEPROM 15, the bus transceiver circuit 30 and the I/F 40 are provided. Therefore, since the output of the magnetic sensor 11 becomes serial data by the bus transceiver circuit 30, the output of the magnetic sensor 11 can be serially communicated.

Also, the bus transceiver circuit 30 operates in either the first mode or the second mode based on the input from the I/F 40 . The first mode is an operation mode in which correction data for the magnetic sensor 11 is written to the EEPROM 15 . A second mode is an operation mode for outputting serial data based on the output data of the magnetic sensor 11 . Accordingly, two-way communication including the input of correction data to the magnetic sensor 11 and the output of the magnetic sensor 11 can be performed from the I/F 40 . Therefore, even when the rotation angle detector 1 is housed in the cover member P as shown in FIG. 1, the magnetic sensor 11 can be corrected. That is, there is no need to open the cover member P for correction and write correction data into the EEPROM 15 using a connector dedicated to correction. Thus, connection with the servo amplifier 90 and correction of the magnetic sensor 11 can be performed by the same I/F 40 .

Also, in the first mode, the bus transceiver circuit 30 sets the impedance of the + terminal 33 and the - terminal 34 to high impedance (HighZ), which is higher than in the second mode. Therefore, in the case of the first mode, the impedance of the + terminal 33 and the - terminal 34 becomes high, so that the data output can be blocked and the blocking can be recognized from the external configuration connected to the I/F 40. Become.

Further, an FPGA 20 provided on the substrate 3 and interposed between the magnetic sensor 11 and the bus transceiver circuit 30 is provided. FPGA 20 determines the operation mode of bus transceiver circuit 30 based on the input from I/F 40 . Therefore, the operation mode can be switched by the FPGA 20 .

Moreover, FPGA20 intervenes between the magnetic sensor 11 and I/F40. When the bus transceiver circuit 30 operates in the first mode, the correction data of the magnetic sensor 11 is written from the I/F 40 to the memory circuit via the FPGA 20 and the magnetic sensor 11 . Therefore, the protocol adopted for inputting the correction data of the magnetic sensor 11 and the protocol adopted for outputting the serial data via the bus transceiver circuit 30 can be different protocols. Also, the data transmission path used for inputting the correction data of the magnetic sensor 11 and the data transmission path used for outputting the serial data via the bus transceiver circuit 30 can be different paths.

Also, the FPGA 20 determines the operation mode of the bus transceiver circuit 30 based on the waiting time until the input from the I/F 40 is performed after the power is turned on. Therefore, the operation mode can be switched without providing identification data or the like dedicated to switching the operation mode.

Further, when the bus transceiver circuit 30 operates in the second mode, the FPGA 20 performs processing for converting the first protocol used for input/output of the magnetic sensor 11 into the second protocol used for input/output of the bus transceiver circuit 30. I do. Therefore, even if the protocol adopted by the magnetic sensor 11 and the protocol adopted by the bus transceiver circuit 30 are different, the magnetic sensor 11 and the bus transceiver circuit 30 can communicate with each other.

It also has a temperature monitoring IC 72 that is provided on the substrate 3 and detects the temperature. The temperature monitoring IC 72 stops the operation of the FPGA 20 when detecting a temperature equal to or higher than the operation stop temperature. Therefore, since the serial data is output when the temperature is such that the rotation angle detector 1 can operate more reliably, the accuracy of the output can be maintained at a higher level.

Furthermore, by adopting the level shifter LS1, operation is possible even if the voltage system of the magnetic sensor 11 and the voltage system of the FPGA 20 are different. Furthermore, by adopting the level shifter LS2, it becomes possible to operate even if the voltage system of the FPGA 20 and the voltage system of the I/F 40 are different.

(Second embodiment)
Next, a second embodiment will be described with reference to FIGS. 5 and 6. FIG. Regarding the description of the second embodiment, the same components as those of the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.

FIG. 5 is a schematic diagram showing a configuration example of the rotation angle detector 1A. The second embodiment includes a rotation angle detector 1A instead of the rotation angle detector 1 of the first embodiment. The rotation angle detector 1A has a magnetic ring 2A and a substrate 3A. The magnetic ring 2A is fixed to one surface of the rotating member R, similar to the ring magnet 2. As shown in FIG. The magnetic ring 2A is an annular magnetic body centered on the center of rotation X in the radial direction.

The magnetic ring 2A has, in addition to the first magnetized train C1 and the second magnetized train C2 of the ring magnet 2, a third magnetized train C3. The third magnetized array C3 is a magnetized array whose polarity changes alternately in the circumferential direction. The third magnetized train C3 has a larger diameter than the second magnetized train C2 and a smaller diameter than the first magnetized train C1. The third magnetization train C3 is located between the first magnetization train C1 and the second magnetization train C2.

The number of magnetic pole pairs W3 of the third magnetization train C3 is different from the number of magnetic pole pairs W1 of the first magnetization train C1 and the number of magnetic pole pairs W2 of the second magnetization train C2. For example, if the number of magnetic pole pairs W3 of the third magnetized train C3 is 2 ^m+n (m and n are natural numbers), then the number of magnetic pole pairs W1 of the first magnetized train C1 and the magnetic poles of the second magnetized train C2 One of the numbers of pairs W2 is 2 ^m+n −1 and the other is 2 ^m (2 ⁿ −1). Taking the case of m=2 and n=3 as an example, the number of magnetic pole pairs W3 in the third magnetized train C3 is 2 ⁽³⁺²⁾ =2 ⁵ =32, and the number of magnetic pole pairs W1 in the first magnetized train C1 is 2 ⁽³⁺²⁾ −1=2 ⁵ −1=31, and the number of magnetic pole pairs W2 of the second magnetized train C2 is 2 ² (2 ³ −1)=4×(8−1)=28 is. Here, the case where the number of magnetic pole pairs W3 is larger than the number of magnetic pole pairs W1 and the number of magnetic pole pairs W2 is exemplified, but the relationship between the numbers can be changed somewhat. Magnetic pole pair W3 includes one north pole and one south pole.

A magnetic sensor 11A and a magnetic sensor 12 are provided on the substrate 3A. The substrate 3 supports the magnetic sensors 11A and 12 at positions facing the ring of the magnetic ring 2A. The magnetic sensor 11A targets a magnetic field obtained by synthesizing the magnetic flux from the second magnetization train C2 and the magnetic flux from the third magnetization train C3. The magnetic sensor 12 targets a magnetic field obtained by synthesizing the magnetic flux from the first magnetization sequence C1 and the magnetic flux from the third magnetization sequence C3. The magnetic sensor 11</b>A and the magnetic sensor 11 have the same function as the magnetic sensor 11 except that the target magnetic field is different from that of the magnetic sensor 11 .

FIG. 6 is a schematic configuration diagram showing a configuration example of the substrate 3A. The substrate 3A includes a magnetic sensor 11A instead of the magnetic sensor 11 included in the substrate 3 of the first embodiment. Moreover, the board|substrate 3A is further provided with the magnetic sensor 12 and EEPROM16.

The EEPROM 16 stores correction data for the magnetic sensor 12 . The magnetic sensor 12 corrects the output according to the correction data of the EEPROM 16 during operation. The magnetic sensor 12 is connected to the level shifter LS1 via the magnetic sensor 11A. The number of signal lines between the magnetic sensor 12 and the magnetic sensor 11A corresponds to the serial communication protocol adopted by the magnetic sensor 11A and the magnetic sensor 12. FIG. The protocol is BiSS C, for example, like the serial communication protocol employed in the magnetic sensor 11 of the first embodiment. The magnetic sensor 12 outputs the corrected signal to the FPGA 20 via the magnetic sensor 11A and level shifter LS1.

Input of correction data to the EEPROM 15 via the magnetic sensor 11A is the same as in the case of the magnetic sensor 11 of the first embodiment. Inputting correction data to the EEPROM 16 via the magnetic sensor 12 is the same. However, in the second embodiment, a mechanism is added to identify whether input correction data is data intended for the magnetic sensor 11A or data intended for the magnetic sensor 12 . As an example of the mechanism, there is a method of including information for identification in the header of the correction data, but this is not a limitation, and other methods may be used as long as identification is possible. Except for the points noted above, the second embodiment is the same as the first embodiment.

According to the second embodiment, even the rotation angle detector 1A having the magnetic ring 2A including the three magnetization arrays and the two magnetic sensors 11A and 12 can achieve the same effect as the first embodiment. can.

(Third embodiment)
Next, a third embodiment will be described with reference to FIGS. 1, 2 and 7. FIG. Regarding the description of the third embodiment, the same components as those of the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.

FIG. 7 is a schematic configuration diagram showing a configuration example of the substrate 3B. In 3rd Embodiment, it replaces with the board|substrate 3 of 1st Embodiment, and the board|substrate 3B is provided. The substrate 3B includes a magnetic sensor 11, an EEPROM 15, a bus transceiver circuit 30A, an I/F 40A, a temperature monitoring IC 72, and the like. The magnetic sensor 11, EEPROM 15 and temperature monitoring IC 72 are the same as those of the first embodiment.

In the third embodiment, the bus transceiver circuit 30A communicates with the magnetic sensor 11 using a first protocol (eg, Biss C protocol) and communicates with the servo amplifier 90 using a second protocol (eg, RS-422). The bus transceiver circuit 30A performs input to the magnetic sensor 11 through a signal line connected to the MA (master) terminal 35a, and receives output from the magnetic sensor 11 through a signal line connected to the SL (slave) terminal 35b.

The I/F 40A of the third embodiment is, for example, a 6-pin female connector, but is not limited to this. Specific aspects of the I/F 40A can be changed as appropriate. In the third embodiment, the connector 51A connected to the correction I/F 50 and the connector 61A connected to the servo amplifier I/F 60 are configured in a manner corresponding to the specific manner of the I/F 40 (for example, a 6-pin male connector). be. Two of the lines connected to the six pins are power lines (eg, 5V and GND), and the other four are two terminals (including the MA± (master) terminals 37a of the bus transceiver circuit 30A). MA+ and MA-) and SL± (slave) terminals 37B are signal lines connected to each of two terminals (SL+ and SL-).

In the third embodiment, the bus transceiver circuit 30A determines the operation mode based on the frequency of the signal input from the I/F 40A. That is, in the third embodiment, the frequency of the signal input from the normalization processing device via the correction I/F 50 and the connector 51 and the signal input from the servo amplifier 90 via the servo amplifier I/F 60 and the connector 61 is preset to be different from the frequency of This enables the input of the correction data of the magnetic sensor 11 and the sensor output of the magnetic sensor 11 from the common I/F 40A.

In the third embodiment, the signal from the temperature monitoring IC 72 is input via the receive (/RE) terminal 36 of the bus transceiver circuit 30A. The bus transceiver circuit 30A stops operating when the circuit interruption signal is input from the terminal 26. FIG.

According to the third embodiment, the bus transceiver circuit 30 determines the operation mode based on the frequency of the signal input from the I/F40. Therefore, it becomes possible to switch between the first mode and the second mode based on the frequency of the signal. Also, the rotation angle of the electric motor M can be detected with a simpler configuration.

(Fourth embodiment)
Next, a fourth embodiment will be described with reference to FIGS. 1, 5 and 8. FIG. Regarding the description of the fourth embodiment, the same components as those of the second and third embodiments are denoted by the same reference numerals, and the description thereof is omitted.

FIG. 8 is a schematic configuration diagram showing a configuration example of the substrate 3C. In the fourth embodiment, a substrate 3C is provided in place of the substrate 3A of the second embodiment. The substrate 3C includes a magnetic sensor 11A, a magnetic sensor 12, an EEPROM 15, an EEPROM 16, a bus transceiver circuit 30A, an I/F 40A, a temperature monitoring IC 72, and the like. The magnetic sensor 11A, EEPROM 15, magnetic sensor 12 and EEPROM 16 are the same as those of the second embodiment. The bus transceiver circuit 30A and I/F 40A are the same as those of the third embodiment.

The fourth embodiment is the same as the third embodiment, except that a magnetic sensor 11A is provided instead of the magnetic sensor 11, and a magnetic sensor 12 and an EEPROM 16 are added.

According to the fourth embodiment, the rotation angle of the electric motor M can be detected with a simpler configuration even when the magnetic ring 2A including three magnetization sequences and the two magnetic sensors 11A and 12 are provided. .

In the above-described embodiment, the ring magnet 2 and the magnetic ring 2A are annular and provided with holes inside, but the holes are not essential. The ring magnet 2 and the magnetic ring 2A may have a configuration in which N poles and S poles are alternately magnetized in the circumferential direction, and may be disk-shaped, for example. Further, in the above embodiment, the ring magnet 2 and the magnetic ring 2A are provided with a plurality of magnetized rows, but the number of magnetized rows may be one.

Also, if the FPGA 20 and the magnetic sensor 11 (or the magnetic sensors 11A and 12) have the same voltage system, the level shifter LS1 can be omitted. Moreover, when the voltage systems of the FPGA 20 and the I/F 40 are the same, the level shifter LS2 can be omitted.

For example, the correspondence between the scope of claims and each configuration of the embodiment is as follows.
(Claim 1)
an annular magnet (2, 2A) in which N poles and S poles are alternately arranged in the circumferential direction;
magnetic sensors (11, 11A, 12) arranged opposite to the magnets in a non-contact state;
Storage circuits (EEPROMs 15 and 16) that are provided so as to be able to be referred to from the magnetic sensor and store correction data of the magnetic sensor;
a circuit (bus transceiver circuit 30, 30A) that outputs serial data based on the output data of the magnetic sensor;
an interface (I/F 40, 40A) to which the input/output terminals (plus (+) terminal 33, minus (-) terminal 34) of the circuit are connected;
a substrate (3, 3A, 3B, 3C) on which the magnetic sensor, the memory circuit, the circuit and the interface are provided;
A rotation angle detector (1, 1A) comprising:
(Claim 2)
The circuits (bus transceiver circuits 30, 30A) operate in either a first mode or a second mode based on the input from the interfaces (I/Fs 40, 40A),
The first mode is an operation mode in which the correction data of the magnetic sensors (11, 11A, 12) are written in the storage circuits (EEPROMs 15, 16),
The rotation angle detector (1, 1A) according to claim 1, wherein the second mode is an operation mode for outputting serial data based on the output data of the magnetic sensor.
(Claim 3)
The circuits (bus transceiver circuits 30, 30A) make the impedance of the input/output terminals (plus (+) terminal 33, minus (-) terminal 34) higher in the first mode than in the second mode. 3. A rotation angle detector (1, 1A) according to item 2.
(Claim 4)
4. The rotation angle detector (1) according to claim 2 or 3, wherein said circuit (bus transceiver circuit 30, 30A) determines an operation mode based on the frequency of a signal input from said interface (I/F 40, 40A) , 1A).
(Claim 5)
An arithmetic circuit (FPGA 20) provided on the substrate (3, 3A) and interposed between the magnetic sensor (11, 11A, 12) and the circuit (bus transceiver circuit 30),
The rotation angle detector (1, 1A) according to any one of claims 2 to 4, wherein said arithmetic circuit determines an operation mode of said circuit based on an input from said interface (I/F 40, 40A). ).
(Claim 6)
The arithmetic circuit (FPGA 20) is interposed between the magnetic sensor (11, 11A, 12) and the interface (I/F 40),
When the circuit (bus transceiver circuit 30) operates in the first mode, the correction data of the magnetic sensor is written from the interface to the storage circuits (EEPROMs 15, 16) via the arithmetic circuit and the magnetic sensor. A rotation angle detector (1, 1A) according to claim 5.
(Claim 7)
6. The arithmetic circuit (FPGA 20) determines the operation mode of the circuit (bus transceiver circuit 30) based on the waiting time until the input from the interface (I/F 40) is performed after power-on. 7. Rotational angle detector (1, 1A) according to 6.
(Claim 8)
When the circuit (bus transceiver circuit 30) operates in the second mode, the arithmetic circuit (FPGA 20) converts the first protocol used for the input/output of the magnetic sensors (11, 11A, 12) to the circuit. The rotation angle detector (1, 1A) according to any one of claims 5 to 7, wherein a process of converting into a second protocol used for input/output is performed.
(Claim 9)
A temperature detection circuit (temperature monitoring IC 72) that is provided on the substrate and detects temperature,
The rotation angle detector (1, 1A) according to any one of claims 1 to 8, wherein the temperature detection circuit stops the operation of the circuit (bus transceiver circuit 30A) when detecting a temperature equal to or higher than a predetermined temperature. .
(Claim 10)
an electric motor (M) provided with the rotation angle detector (1, 1A) according to any one of claims 1 to 9;
a servo amplifier (90) connected to the interface (I/F 40, 40A);
A servo motor system (100) comprising:

1, 1A rotation angle detectors 2, 2A ring magnets 3, 3A, 3B, 3C substrates 11, 11A, 12 magnetic sensors 15, 16 EEPROM
20 FPGAs
30, 30A bus transceiver circuit 40, 40A I/F
72 temperature monitoring IC
90 servo amplifier 100 servo motor system

Claims (6)

an annular magnet in which N poles and S poles are alternately arranged in the circumferential direction;
a magnetic sensor arranged opposite to the magnet in a non-contact state;
a storage circuit that is provided so as to be able to be referenced from the magnetic sensor and that stores correction data of the magnetic sensor;
a circuit that outputs serial data based on the output data of the magnetic sensor;
an interface to which input/output terminals of the circuit are connected;
a substrate on which the magnetic sensor, the storage circuit, the circuit and the interface are provided;
an arithmetic circuit provided on the substrate and interposed between the magnetic sensor and the circuit;
with
the circuit operates in either a first mode or a second mode of operation based on inputs from the interface;
the first mode is an operation mode in which correction data of the magnetic sensor is written to the storage circuit;
The second mode is an operation mode for outputting serial data based on the output data of the magnetic sensor,
The arithmetic circuit determines the operation mode of the circuit based on the waiting time from when the power is turned on until the input from the interface is performed.
Rotation angle detector. 2. The rotation angle detector according to claim 1 , wherein the circuit makes the impedance of the input/output terminal higher in the first mode than in the second mode. The arithmetic circuit is interposed between the magnetic sensor and the interface,
3. The rotation angle detection according to claim 1 , wherein when the circuit operates in the first mode, correction data of the magnetic sensor is written from the interface to the storage circuit via the arithmetic circuit and the magnetic sensor. vessel. When the circuit operates in the second mode, the arithmetic circuit converts a first protocol used for input/output of the magnetic sensor into a second protocol used for input/output of the circuit. 4. The rotation angle detector according to any one of items 1 to 3 . A temperature detection circuit provided on the substrate for detecting temperature,
The rotation angle detector according to any one of claims 1 to 4 , wherein the temperature detection circuit stops the operation of the circuit when a temperature equal to or higher than a predetermined temperature is detected. an electric motor provided with the rotation angle detector according to any one of claims 1 to 5 ;
a servo amplifier connected to the interface;
servo motor system.

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