Discrimination circuit and motor drive device

Abstract

Provided is a discrimination circuit comprising: a connector provided with shared pins each allocated so as to receive either of an analog encoder output and a serial encoder output, and dedicated pins each allocated so as to receive only an analog encoder output; and a determination unit that determines whether an encoder connected to the connector is an analog encoder or a serial encoder on the basis of the result of comparison between the voltage level of each of the dedicated pins and a predetermined threshold.

Description

Discrimination Circuit and Motor Drive Device

[0001] The present disclosure relates to a discrimination circuit and a motor drive device.

[0002] An encoder for detecting the rotational displacement or linear displacement of a moving body is attached to a motor drive device that is a drive source of a robot or a machine tool. The encoder is electrically connected to a connector of a control device of the motor drive device. The control device controls the motor drive device using the detection data of the encoder received via the connector.

[0003] As types of encoders, there are an analog encoder that outputs detection data in an analog signal format, and a serial encoder that outputs detection data in a digital signal format via serial communication. In a control device that uses the detection data of the encoder, the detection data of the analog encoder needs to be received by a processing circuit for the analog encoder, and the detection data of the serial encoder needs to be received by a processing circuit for the serial encoder. By providing both a processing circuit for the analog encoder and a processing circuit for the serial encoder in the control device, the control device can handle both the detection data of the analog encoder and the detection data of the serial encoder, so the expandability of the motor drive device is improved.

[0004] Japanese Patent Application Laid-Open No. 20-63158 International Publication No. 2014 / 142162

[0005] Since the signal format and communication format are different between the analog encoder and the serial encoder, the signal processing circuit needs to be used properly between the processing circuit for the analog encoder and the processing circuit for the serial encoder. A technology that can automatically discriminate whether the encoder connected to the connector is an analog encoder or a serial encoder is desired.

[0006] According to one aspect of the present disclosure, the discrimination circuit includes a connector provided with a shared pin assigned to accept both analog encoder outputs and serial encoder outputs, and a dedicated pin assigned to accept only analog encoder outputs, and a determination unit that determines whether the encoder connected to the connector is an analog encoder or a serial encoder based on a comparison result between the voltage level of the dedicated pin and a predetermined threshold.

[0007] This figure shows a discrimination circuit according to the first embodiment of the present disclosure. This figure shows a motor drive device equipped with discrimination circuits according to the first to third embodiments of the present disclosure. This figure illustrates the pin assignments of a connector for connecting a serial encoder and a connector for connecting an analog encoder. This figure illustrates the pin assignment of a connector in which pins for receiving signals from a serial encoder and pins for receiving signals from an analog encoder are mixed. This figure illustrates the pin assignments of connectors in the first to third embodiments of the present disclosure. This flowchart shows the operation flow of a discrimination circuit according to the first embodiment of the present disclosure. This figure shows a discrimination circuit according to the second embodiment of the present disclosure. This flowchart shows the operation flow of a discrimination circuit according to the second embodiment of the present disclosure. This figure shows a discrimination circuit according to the third embodiment of the present disclosure. This flowchart shows the operation flow of a discrimination circuit according to the third embodiment of the present disclosure.

[0008] The embodiments of the discrimination circuit and motor drive device will be described below with reference to the drawings. In the following description, components having the same or similar functions will be denoted by the same reference numerals. Duplication of these components may be omitted. The drawings have been scaled appropriately for ease of understanding.

[0009] In the following explanation, "electrically connected" may sometimes be simply written as "connected". "Analog encoder" refers to an encoder that outputs detection data in analog signal format. "Serial encoder" refers to an encoder that outputs detection data in digital signal format via serial communication. However, when simply written as "encoder", it may refer to either an analog encoder or a serial encoder. "Processing circuit for analog encoder" refers to various circuits that process the detection data output by the analog encoder. "Processing circuit for serial encoder" refers to various circuits that process the detection data output by the serial encoder, and this circuit includes a circuit for serial communication with the serial encoder. "Encoder" includes rotary encoders that detect the rotational position information of a rotating moving body, and linear encoders that detect the linear position information of a linear moving body. "Rotational position information" and "linear position information" are collectively referred to as "position information". Position information is sometimes referred to as "displacement information". "Rotating moving body" and "linear moving body" are collectively referred to as "moving body". "Moving object" includes the rotation axis of motor 3, the linear movement axis of motor 3, the rotation axis of the object to which motor 3 is attached, and the movement axis of the object to which motor 3 is attached. "Connector" refers to a type of pin connector used for connecting equipment, in which electrode pins (hereinafter simply referred to as "pins") protrude and are inserted into a socket for connection. Furthermore, the specific numerical examples given below are just examples, and numerical values ​​other than those listed here may be used.

[0010] <Configuration of the First Embodiment> Figure 1 is a diagram showing a discrimination circuit according to the first embodiment of the present disclosure. Figure 2 is a diagram showing a motor drive device equipped with a discrimination circuit according to the first to third embodiments of the present disclosure. The circuit shown in Figure 1 is applicable to the second and third embodiments described later.

[0011] The motor drive device 100 comprises a discrimination circuit 1 according to the first embodiment of this disclosure, a control device 2, an encoder 4, and other circuits (not shown). Here, the other circuits may include, for example, a power converter, a processing unit, a memory device, a display device, an input device, a safety device, a power supply device, various sensors, etc., but other devices may also be included.

[0012] The encoder 4 is attached to the motor 3 and detects the position information of the motor 3. The encoder 4 is connected to a connector 11 provided on the control device 2. The control device 2 controls the motor 3 using the output of the encoder 4 connected to the connector 11. The motor drive device 100, under the control of the control device 2, converts the power supplied from the power source (not shown) into power suitable for driving the motor 3 and supplies it to the motor 3.

[0013] The control device 2 includes a discrimination circuit 1, an analog encoder processing circuit 51, a serial encoder processing circuit 52, and other circuits (not shown). The other circuits may include a command value creation unit, a current control unit, a torque control unit, a position control unit, a memory device, a display device, an input device, a safety device, a power supply device, various sensors, etc., but other devices may also be included. For example, the command value creation unit, the current control unit, the torque control unit, and the position control unit are provided in the arithmetic processing unit.

[0014] The encoder 4 is either an analog encoder or a serial encoder. As will be described later, the connector 11 to which the encoder 4 is connected can accommodate both analog and serial encoder connections. Since the signal format and communication format differ between analog and serial encoders, both an analog encoder processing circuit 51 and a serial encoder processing circuit 52 are provided in the control device 2 to perform processing according to each signal. This improves the expandability of the motor drive device 100. Both the analog encoder processing circuit 51 and the serial encoder processing circuit 52 have the function of calculating position information based on the received detection data (encoder output). If the encoder 4 is an analog encoder, the analog encoder processing circuit 51 operates. If the encoder 4 is a serial encoder, the serial encoder processing circuit 52 operates. In particular, if the encoder 4 is a serial encoder, serial communication is performed between the serial encoder and the serial encoder processing circuit 52. That is, the serial encoder processing circuit 52 sends a request signal to the serial encoder requesting the transmission of detection data, and the serial encoder, upon receiving the request signal, transmits the detection data to the serial encoder processing circuit 52.

[0015] The control device 2 generates drive commands to control the speed, torque, or rotor position of the motor 3 based on the position information of the motor 3 or the moving body to which the motor 3 is connected detected by the encoder 4, the current flowing through the windings of the motor 3 (current feedback), a predetermined torque command, and an operation program. Based on the drive commands created by the control device 2, the power conversion operation of the power converter (not shown) in the motor drive unit 100 is controlled. The motor 3 is driven based on the power supplied from the power converter in the motor drive unit 100.

[0016] Furthermore, the control device 2 is provided with a discrimination circuit 1. The discrimination circuit 1 comprises a connector 11, a determination unit 12, and a switch 13.

[0017] Connector 11 is an analog / serial dual-purpose connector that can be connected whether encoder 4 is an analog encoder or a serial encoder.

[0018] Connector 11 is assigned the following pins: a pin P1 for the 5V control power supply (hereinafter referred to as the "5V pin"), a pin P2 for 0V (hereinafter referred to as the "0V pin"), a pin P3 for ground (hereinafter referred to as the "earth pin"), an analog / serial combined pin (hereinafter referred to as the "combined pin"), and an analog-only pin (hereinafter referred to as the "dedicated pin"). The combined pin is assigned to accept either the analog encoder output or the serial encoder output. The dedicated pin is assigned to accept only the analog encoder output. Since serial encoders generally have two input / output signals, two combined pins are provided to correspond to this. Analog encoders typically have four output signals (A signal, XA signal, B signal, XB signal) or six output signals (A signal, XA signal, B signal, XB signal, Z signal, XZ signal). Since two of these can be handled by the shared pins mentioned above, two or four dedicated pins are provided. In the illustrated example, connector 11 includes two shared pins P4 and P5 and four dedicated pins P6 to P9.

[0019] The 5V pin P1 is connected to the 5V of the control power supply via wire 30-1. The 0V pin P2 is connected to the 0V of the control power supply via wire 30-2. The ground pin P3 is connected to ground via wire 30-3. The multi-purpose pin P4 is connected to switch 13 via wire 30-4. The multi-purpose pin P5 is connected to switch 13 via wire 30-5. Switch 13 switches the destination of wire 30-4, to which multi-purpose pin P4 is connected, to either wire 33A or 33B. Switch 13 also switches the destination of wire 30-5, to which multi-purpose pin P5 is connected, to either wire 34A or 34B. Wires 33A and 34A are connected to the serial encoder processing circuit 52. Wires 33B and 34B are connected to the serial encoder processing circuit 52. Each of the dedicated pins P6 to P9 is connected to the analog encoder processing circuit 51 via wires 30-6 to 30-9, respectively.

[0020] The determination unit 12 determines whether the encoder 4 connected to the connector 11 is an analog encoder or a serial encoder based on the comparison result between the voltage levels of the shared pins P4 and P5 and a predetermined threshold. Details of the determination process by the determination unit 12 will be described later.

[0021] In the first embodiment, the determination unit 12 includes a first pull-down resistor 41A, a second pull-down resistor 41B, a comparison unit 42, and a confirmation unit 43. The comparison unit 42 includes a first comparator 42A and a second comparator 42B.

[0022] One end of the first pull-down resistor 41A is connected to wiring 30-6, and the other end is connected to, for example, 0V. One end of the second pull-down resistor 41B is connected to wiring 30-7, and the other end is connected to, for example, 0V. Here, as an example, 0V is connected to the other end of the first pull-down resistor 41A and the second pull-down resistor 41B, but any voltage value that can be distinguished by comparing it with the threshold value in the comparison unit 42 may be a weak voltage near 0V. The threshold value can be changed according to the voltage value connected to the other end of the first pull-down resistor 41A and the second pull-down resistor 41B. Wiring 30-6 is connected to the inverting input (-) of the first comparator 42A via wiring 31A. Wiring 30-7 is connected to the inverting input (-) of the second comparator 42B via wiring 31B. The threshold value is input to the non-inverting input (+) of the first comparator 42A and the second comparator 42B. The threshold value may be stored in a rewritable memory device (not shown) and rewritable by an external device, and even after the threshold value has been set, it can be changed to an appropriate value as needed. The signals output from the first comparator 42A and the second comparator 42B are input to the confirmation unit 43. The switching operation of the switch 13 is performed according to the signal output from the confirmation unit 43.

[0023] If the determination unit 12 determines that the encoder 4 connected to the connector 11 is an analog encoder, switch 13 sets the connection destination of the shared pins P4 and P5 to the analog encoder processing circuit 51. If the determination unit 12 determines that the encoder 4 connected to the connector 11 is a serial encoder, switch 13 sets the connection destination of the shared pins P4 and P5 to the serial encoder processing circuit 52.

[0024] <Connectors> The output signal of an analog encoder needs to be processed by an analog encoder processing circuit, and the output signal of a serial encoder needs to be processed by a serial encoder processing circuit. Analog encoders generally have four output signals (A signal, XA signal, B signal, XB signal) or six output signals (A signal, XA signal, B signal, XB signal, Z signal, XZ signal), but here we will explain the case where the analog encoder outputs six signals as an example.

[0025] Figure 3A illustrates the pin assignments for connectors for connecting a serial encoder and an analog encoder. One approach is to connect the serial encoder and the analog encoder to separate connectors. For example, connector A is a connector for connecting a serial encoder. Pin QA1 of connector A is the 5V pin, pin QA2 is the 0V pin, and pin QA3 is the ground pin. Pin QA4 is the pin for the first serial input / output of the serial encoder. Pin QA5 is the pin for the second serial input / output of the serial encoder. Pins QA4 and QA5 are connected to the processing circuit for the serial encoder. For example, connector B is a connector for connecting an analog encoder. Pin QB1 of connector B is the 5V pin, pin QB2 is the 0V pin, and pin QB3 is the ground pin. Pin QB4 is the pin that receives the A signal of the analog encoder, and pin QB5 is the pin that receives the XA signal of the analog encoder. Pin QB6 is the pin that receives the B signal of the analog encoder, and pin QB7 is the pin that receives the XB signal of the analog encoder. Pin QB8 is the pin that receives the Z signal of the analog encoder, and pin QB9 is the pin that receives the XZ signal of the analog encoder. Pins QB4 to QB9 are connected to the processing circuit for the analog encoder. If separate connectors A for connecting the serial encoder and connector B for connecting the analog encoder are provided in this way, the number of connectors will be two, which will increase the space required to mount the connectors in the control device, making it unsuitable for miniaturizing the control device.

[0026] Figure 3B illustrates the pin assignment of a connector that contains pins for receiving signals from both a serial encoder and an analog encoder. Connector C contains pins for receiving signals from both serial encoders and analog encoders, but these pins are completely independent. Pin R1 of connector C is the 5V pin, pin R2 is the 0V pin, and pin R3 is the ground pin. Pin R4 is the pin for the first serial input / output of the serial encoder. Pin R5 is the pin for the second serial input / output of the serial encoder. Pin R6 is the pin for receiving the A signal of the analog encoder, and pin R7 is the pin for receiving the XA signal of the analog encoder. Pin R8 is the pin for receiving the B signal of the analog encoder, and pin R9 is the pin for receiving the XB signal of the analog encoder. Pin R10 is the pin for receiving the Z signal of the analog encoder, and pin R11 is the pin for receiving the XZ signal of the analog encoder. Pins R4 and R5 are connected to the processing circuit for the serial encoder. Pins R6 to R11 are connected to the processing circuit for the analog encoder. In this way, connectors that have a mix of pins for connecting serial encoders and pins for connecting analog encoders have an increased number of pins per connector, which makes the connector itself larger and poses a larger mounting space in the control device, making it unsuitable for miniaturizing the control device.

[0027] Figure 3C is a diagram illustrating the pin assignment of a connector in the first to third embodiments of this disclosure.

[0028] In the first to third embodiments of this disclosure, connector D (connector 11 in Figures 1, 2, 5, and 7) is an analog / serial dual-purpose connector having dual-purpose pins P4 and P5 that can be connected whether the encoder 4 is an analog encoder or a serial encoder. Pin P1 of connector D is the 5V pin, pin P2 is the 0V pin, and pin P3 is the ground pin.

[0029] The shared pin P4 serves as both the pin for the first serial input / output of the serial encoder and the pin for receiving the A signal of the analog encoder. The shared pin P5 serves as both the pin for the second serial input / output of the serial encoder and the pin for receiving the XA signal of the analog encoder. The dedicated pin P6 is the pin for receiving the B signal of the analog encoder, and the dedicated pin P7 is the pin for receiving the XB signal of the analog encoder. Alternatively, the shared pins P4 and P5 may be assigned as the pins for receiving the B and XB signals, and the dedicated pins P6 and P7 may be assigned as the pins for receiving the A and XA signals.

[0030] Dedicated pin P8 is a pin that receives the Z signal of the analog encoder, and dedicated pin P9 is a pin that receives the XZ signal of the analog encoder. Shared pins P4 and P5 are connected to the analog encoder processing circuit 51 and the serial encoder processing circuit 52 via switch 13. If the determination unit 12 determines that the encoder 4 connected to the connector 11 is an analog encoder, switch 13 sets the connection destination of shared pins P4 and P5 to the analog encoder processing circuit 51. If the determination unit 12 determines that the encoder 4 connected to the connector 11 is a serial encoder, switch 13 sets the connection destination of shared pins P4 and P5 to the serial encoder processing circuit 52. Dedicated pins P6 to P9 are connected to the analog encoder processing circuit 51. In this way, in the first to third embodiments of this disclosure, the connector D (connector 11) uses shared pins P4 and P5 for both the input / output signals of the serial encoder and the output signals of the analog encoder, so the increase in the number of pins per connector can be suppressed compared to the connector in Figure 3B. Furthermore, the connector D (connector 11) in the first to third embodiments of this disclosure can handle both analog encoder and serial encoder connections with a single connector, making it smaller than the connector in Figure 3A, and thus requiring less space to mount the connector D (connector 11) in the control device 2. Therefore, the connector D (connector 11) in the first to third embodiments of this disclosure contributes to the miniaturization of the control device 2.

[0031] <Decision Processing> As described above, the connector 11 (connector D in Figure 3C) in the first to third embodiments of this disclosure is an analog / serial dual-purpose connector that can connect to both analog encoders and serial encoders. The dual-purpose pin P4 serves as both the pin for the first serial input / output of the serial encoder and the pin for receiving the A signal of the analog encoder. The dual-purpose pin P5 serves as both the pin for the second serial input / output of the serial encoder and the pin for receiving the XA signal of the analog encoder. Serial data can be transmitted bidirectionally between the serial encoder and the serial encoder processing circuit 52. If the encoder 4 connected to the connector 11 is an analog encoder and not a serial encoder, and serial data is transmitted directly from the serial encoder processing circuit 52 to the analog encoder via the connector 11, the analog encoder may be damaged. Therefore, in the first to third embodiments of this disclosure, the determination unit 12 determines whether the encoder 4 connected to the connector 11 is an analog encoder or a serial encoder, and based on the determination result, the switch 13 switches the connection destination of the shared pins P4 and P5 between the analog encoder processing circuit 51 and the serial encoder processing circuit 52. As a result, if the encoder 4 connected to the connector 11 is an analog encoder and not a serial encoder, serial data will not be transmitted from the serial encoder processing circuit 52 to the analog encoder via the connector 11, thus preventing damage to the analog encoder.

[0032] The determination unit 12 determines whether the encoder 4 connected to the connector 11 is an analog encoder or a serial encoder based on the voltage level of the dedicated pin P6 for receiving the B signal of the analog encoder and the voltage level of the dedicated pin P7 for receiving the XB signal of the analog encoder, among a plurality of dedicated pins. If the shared pins P4 and P5 are assigned as pins for receiving the B signal and XB signal, and the dedicated pins P6 and P7 are assigned as pins for receiving the A signal and XA signal, then the determination unit 12 determines whether the encoder 4 connected to the connector 11 is an analog encoder or a serial encoder based on the voltage levels of the A signal and XA signal received by the dedicated pins P6 and P7.

[0033] The reason why the voltage levels of dedicated pin P6 for receiving the B signal of the analog encoder and dedicated pin P7 for receiving the XB signal of the analog encoder are used in the determination process by the determination unit 12 will be explained below.

[0034] Since the voltage levels of the shared pins P4 and P5 may be the same regardless of whether the encoder 4 connected to the connector 11 is an analog encoder or a serial encoder, it is not possible to determine whether it is an analog encoder or a serial encoder using the voltage levels of the shared pins P4 and P5.

[0035] On the other hand, dedicated pins P6 to P9 are open when the encoder 4 connected to connector 11 is a serial encoder, as no signal is received. Therefore, it may be possible to determine whether it is an analog encoder or a serial encoder by using the voltage levels of dedicated pins P6 to P9. Analog encoders generally have four output signals (A signal, XA signal, B signal, XB signal) or six output signals (A signal, XA signal, B signal, XB signal, Z signal, XZ signal). If a four-wire analog encoder that does not output Z and XZ signals is connected to connector 11, dedicated pins P8 and P9 will be open when no Z and XZ signals are received. Therefore, it is not possible to determine whether it is an analog encoder or a serial encoder by using the voltage levels of dedicated pins P8 and P9. On the other hand, there are no analog encoders that do not output B and XB signals. In other words, whether a four-wire or six-wire analog encoder is connected to connector 11, voltage may be generated at dedicated pin P6, which receives the B signal, and dedicated pin P7, which receives the XB signal. Therefore, in the first to third embodiments of this disclosure, it is determined whether the encoder 4 connected to the connector 11 is an analog encoder or a serial encoder based on the voltage level of a dedicated pin P6 for receiving the B signal of the analog encoder and the voltage level of a dedicated pin P7 for receiving the XB signal of the analog encoder. If the shared pins P4 and P5 are assigned as pins for receiving the B signal and the XB signal, and the dedicated pins P6 and P7 are assigned as pins for receiving the A signal and the XA signal, it is determined whether the encoder 4 connected to the connector 11 is an analog encoder or a serial encoder based on the voltage levels of the A signal and the XA signal received by the dedicated pins P6 and P7.

[0036] The voltage levels of the B signal of the analog encoder appearing on dedicated pin P6 and the XB signal appearing on dedicated pin P7 are generally between 1.8V and 3.2V. As described above, if the encoder 4 connected to connector 11 is a serial encoder, dedicated pins P6 and P7 are open and no signal is received, so the voltage levels of dedicated pins P6 and P7 are near 0V. Therefore, by monitoring the voltage levels of dedicated pins P6 and P7, it is possible to determine whether the encoder 4 connected to connector 11 is an analog encoder or a serial encoder. In the first embodiment of this disclosure, a first pull-down resistor 41A is connected to the wiring 30-6 extending from dedicated pin P6, and a second pull-down resistor 41B is connected to the wiring 30-7 extending from dedicated pin P7. This allows the voltage levels of dedicated pins P6 and P7 to be fixed to 0V when the encoder 4 connected to connector 11 is a serial encoder, thus clearly differentiating them from the voltage levels of dedicated pins P6 and P7 (1.8V to 3.2V) when the encoder 4 connected to connector 11 is a serial encoder, and thus enabling accurate determination processing. However, when the encoder 4 connected to connector 11 is an analog encoder, it is preferable to set the resistance values ​​of the first pull-down resistor 41A and the second pull-down resistor 41B to large values, such as several kΩ to several hundred kΩ, in order to reduce the influence of the first pull-down resistor 41A and the second pull-down resistor 41B on the respective voltage levels of dedicated pins P6 and P7. As will be described later, in the second embodiment of this disclosure, the first pull-up resistor 44A is connected to the wiring 30-6 extending from dedicated pin P6, and the second pull-up resistor 44B is connected to the wiring 30-7 extending from dedicated pin P7. As a result, in the second embodiment of this disclosure, the voltage levels of dedicated pins P6 and P7 are fixed to 5V when the encoder 4 connected to the connector 11 is a serial encoder.

[0037] The above explains why the voltage levels of the dedicated pin P6 for receiving the B signal of the analog encoder and the dedicated pin P7 for receiving the XB signal of the analog encoder are used in the determination process by the determination unit 12.

[0038] Next, we will explain why the determination process uses the voltage levels of both dedicated pins P6 and P7, rather than just one of them.

[0039] Generally, the B signal and XB signal of an analog encoder have an inverse relationship, with periods where one is at a high voltage (e.g., 1.5V or higher) and the other at a low voltage (e.g., near 0V, i.e., below 0.5V). The relative voltages of the B signal and XB signal frequently switch depending on the operating state of the analog encoder. For example, there are periods where one of the B signal and XB signal is above 0.5V and the other is below 0.5V. If the voltage level of only one of the dedicated pins P6 (B signal) and P7 (XB signal) is monitored, depending on the monitoring timing, it may be impossible to distinguish whether the voltage level near 0V is due to the open state of dedicated pins P6 and P7 when the serial encoder is connected to the connector 11, or whether it is due to the B signal (or XB signal) when the analog encoder is connected to the connector 11. In contrast, when monitoring the voltage levels of both dedicated pins P6 and P7, when a serial encoder is connected to the connector 11, the voltage levels of both dedicated pins P6 and P7 will be near 0V, and when an analog encoder is connected to the connector 11, the voltage level of at least one of the dedicated pins P6 and P7 should be a voltage value somewhat greater than 0V (for example, 0.5V or more). Therefore, in the first embodiment of this disclosure, it is determined whether the encoder 4 connected to the connector 11 is an analog encoder or a serial encoder based on the voltage levels of both dedicated pins P6 and P7. This is the reason for using the voltage levels of both dedicated pins P6 and P7 in the determination process.

[0040] The determination of whether the voltage level of dedicated pin P6 and dedicated pin P7 and their voltage level are near 0V or somewhat higher than 0V (for example, 0.5V or more) can be done using a threshold value. When the encoder 4 connected to connector 11 is a serial encoder, the voltage levels of dedicated pins P6 and P7 can take on a maximum range of 1.8V to 3.2V, so in the first embodiment, for example, the threshold value is set to about 0.5V. Note that the values ​​given here are just examples, and other values ​​may be used.

[0041] The comparison between the voltage level of dedicated pin P6 and dedicated pin P7 and the threshold is performed by the comparison unit 42 shown in Figure 1. The comparison unit 42 comprises a first comparator 42A and a second comparator 42B. The first comparator 42A compares the voltage level of dedicated pin P6 with the threshold. The second comparator 42B compares the voltage level of dedicated pin P7 with the threshold.

[0042] The first comparator 42A outputs a low (L) signal if the voltage level of the dedicated pin P6 is greater than a threshold, and outputs a high (H) signal if the voltage level of the dedicated pin P6 is less than a threshold. Similarly, the second comparator 42B outputs a low (L) signal if the voltage level of the dedicated pin P7 is greater than a threshold, and outputs a high (H) signal if the voltage level of the dedicated pin P7 is less than a threshold. The signals output from the first comparator 42A and the second comparator 42B are input to the determination unit 43. The determination unit 43 determines that the encoder 4 connected to the connector 11 is an analog encoder if at least one of the signals output from the first comparator 42A and the second comparator 42B is a high (H) signal. Furthermore, the determination unit 43 determines that the encoder 4 connected to the connector 11 is a serial encoder if both the signal output from the first comparator 42A and the signal output from the second comparator 42B are low (L) signals. The signal output from the determination unit 43 is used for the switching operation of the switch 13.

[0043] Thus, in the first embodiment of the present disclosure, when at least one of the voltage levels of the dedicated pin P6 and the dedicated pin P7 is greater than the threshold value as a result of the comparison by the comparison unit 42, the determination unit 12 determines that the encoder 4 connected to the connector 11 is an analog encoder. Further, when both the voltage level of the dedicated pin P6 and the voltage level of the dedicated pin P7 are less than the threshold value as a result of the comparison by the comparison unit 42, the determination unit 12 determines that the encoder 4 connected to the connector 11 is a serial encoder.

[0044] When the determination unit 12 determines that the encoder 4 connected to the connector 11 is an analog encoder, the switch 13 sets the connection destinations of the shared pins P4 and P5 to the analog encoder processing circuit 51. Further, when the determination unit 12 determines that the encoder 4 connected to the connector 11 is a serial encoder, the switch 13 sets the connection destinations of the shared pins P4 and P5 to the serial encoder processing circuit 52.

[0045] In the above example, the comparison process by the comparison unit 42 is performed by the first comparator 42A and the second comparator 42B. However, instead of this, it may be performed using an AD converter.

[0046] As an option, the determination result by the determination unit 12 may be displayed on a display device (not shown). Examples of the display device include displays such as a display, a personal computer, a mobile terminal, and a touch panel. These may be attached to the motor drive device 100 or to the upper control device thereof.

[0047] <Operation Flow of the First Embodiment> FIG. 4 is a flowchart showing the operation flow of the discrimination circuit according to the first embodiment of the present disclosure.

[0048] In step S101, the determination unit 12 detects the voltage level of the dedicated pin P6 (hereinafter referred to as "first voltage level") and the voltage level of the dedicated pin P7 (hereinafter referred to as "second voltage level").

[0049] In step S102, the comparison unit 42 in the determination unit 12 compares the first voltage level of the dedicated pin P6 and the second voltage level of the dedicated pin P7 with a threshold value. If it is determined in step S102 that both the first voltage level of the dedicated pin P6 and the second voltage level of the dedicated pin P7 are smaller than the threshold value, the process proceeds to step S103. If it is not determined in step S102 that both the first voltage level of the dedicated pin P6 and the second voltage level of the dedicated pin P7 are smaller than the threshold value, that is, if at least one of the first voltage level of the dedicated pin P6 and the second voltage level of the dedicated pin P7 is larger than the threshold value, the process proceeds to step S105.

[0050] In step S103, the confirmation unit 43 within the determination unit 12 determines that the encoder 4 connected to the connector 11 is a serial encoder. Next, in step S104, the switch 13 sets the connection destination of the shared pins P4 and P5 to the serial encoder processing circuit 52. After that, the processing of the discrimination circuit 1 is terminated.

[0051] In step S105, the confirmation unit 43 within the determination unit 12 determines that the encoder 4 connected to the connector 11 is an analog encoder. Next, in step S106, the switch 13 sets the connection destination of the shared pins P4 and P5 to the analog encoder processing circuit 51. After that, the processing of the discrimination circuit 1 is terminated.

[0052] The processing of the discrimination circuit 1 described above begins when the power to the control device 2 is turned on and driving power is supplied from the control device 2 to the encoder 4 via the connector 11.

[0053] <Configuration of the second embodiment> Figure 5 is a diagram showing a discrimination circuit according to the second embodiment of the present disclosure.

[0054] In the first embodiment of the present disclosure described above, as shown in Figure 1, a first pull-down resistor 41A is connected to the wiring 30-6 extending from the dedicated pin P6, and a second pull-down resistor 41B is connected to the wiring 30-7 extending from the dedicated pin P7. As an alternative example, in the second embodiment of the present disclosure, as shown in Figure 5, a first pull-up resistor 44A is connected to the wiring 30-6 extending from the dedicated pin P6, and a second pull-up resistor 44B is connected to the wiring 30-7 extending from the dedicated pin P7.

[0055] The configuration of the motor drive device 100 equipped with the discrimination circuit 1 according to the second embodiment of this disclosure has been described with reference to Figure 2.

[0056] As shown in Figure 5, the discrimination circuit 1 according to the second embodiment of the present disclosure comprises a connector 11, a determination unit 12, and a switch 13.

[0057] The connector 11 and switch 13 are as described in the first embodiment with reference to Figures 1 and 3C.

[0058] The determination unit 12 determines whether the encoder 4 connected to the connector 11 is an analog encoder or a serial encoder based on the comparison result between the voltage level of a dedicated pin and a predetermined threshold. In the second embodiment of the present disclosure, the determination unit 12 comprises a first pull-up resistor 44A, a second pull-up resistor 44B, a comparison unit 45, and a confirmation unit 46. The comparison unit 45 comprises a third comparator 45A and a fourth comparator 45B.

[0059] One end of the first pull-up resistor 44A is connected to wire 30-6, and the other end is connected to, for example, 5V. One end of the second pull-up resistor 44B is connected to wire 30-7, and the other end is connected to, for example, 5V. Here, as an example, 5V is connected to the other end of the first pull-up resistor 44A and the second pull-up resistor 44B, but any voltage value that can be distinguished by comparing it with the threshold value in the comparison unit 45 may be a weak voltage near 5V. The threshold value can be changed according to the voltage value connected to the other end of the first pull-up resistor 44A and the second pull-up resistor 44B. Wire 30-6 is connected to the inverting input (-) of the third comparator 45A via wire 31A. Wire 30-7 is connected to the inverting input (-) of the fourth comparator 45B via wire 31B. The threshold value is input to the non-inverting input (+) of the third comparator 45A and the fourth comparator 45B. The threshold value may be stored in a rewritable memory device (not shown) and rewritable by an external device, and even after the threshold value has been set, it can be changed to an appropriate value as needed. The signals output from the third comparator 45A and the fourth comparator 45B are input to the confirmation unit 46. The switching operation of the switch 13 is performed according to the signal output from the confirmation unit 46.

[0060] In the second embodiment of this disclosure, a first pull-up resistor 44A is connected to the wiring 30-6 extending from dedicated pin P6, and a second pull-up resistor 44B is connected to the wiring 30-7 extending from dedicated pin P7. As a result, in the second embodiment of this disclosure, when the encoder 4 connected to the connector 11 is a serial encoder, the voltage levels of dedicated pins P6 and P7 can be fixed to 5V, which can be clearly differentiated from the voltage levels of dedicated pins P6 and P7 (1.8V to 3.2V) when the encoder 4 connected to the connector 11 is a serial encoder, and therefore accurate determination processing can be performed. However, when the encoder 4 connected to the connector 11 is an analog encoder, it is preferable to set the resistance values ​​of the first pull-up resistor 44A and the second pull-up resistor 44B to large values, such as several kΩ to several hundred kΩ, in order to reduce the influence of the first pull-up resistor 44A and the second pull-up resistor 44B on the respective voltage levels of dedicated pins P6 and P7.

[0061] When monitoring the voltage levels of both dedicated pins P6 and P7, if a serial encoder is connected to the connector 11, the voltage levels of both dedicated pins P6 and P7 should be around 5V, and if an analog encoder is connected to the connector 11, the voltage level of at least one of the dedicated pins P6 and P7 should be a voltage value somewhat smaller than 5V (e.g., 4.5V or less). Therefore, in the second embodiment of this disclosure, it is determined whether the encoder 4 connected to the connector 11 is an analog encoder or a serial encoder based on the voltage levels of both dedicated pins P6 and P7.

[0062] The determination of whether the voltage level of dedicated pin P6 and dedicated pin P7 and their voltage level are near 5V or somewhat lower than 5V (for example, 4.5V or less) can be done using a threshold value. When the encoder 4 connected to connector 11 is a serial encoder, the voltage levels of dedicated pins P6 and P7 can take a maximum range of 1.8V to 3.2V, so in the second embodiment, for example, the threshold value is set to about 4.5V. Note that the values ​​given here are just examples, and other values ​​may be used.

[0063] The comparison between the voltage level of dedicated pin P6 and dedicated pin P7 and the threshold is performed by the comparison unit 45 shown in Figure 5. The comparison unit 45 includes a third comparator 45A and a fourth comparator 45B. The third comparator 45A compares the voltage level of dedicated pin P6 with the threshold. The fourth comparator 45B compares the voltage level of dedicated pin P7 with the threshold.

[0064] The third comparator 45A outputs a high (H) signal if the voltage level of the dedicated pin P6 is less than a threshold, and outputs a low (L) signal if the voltage level of the dedicated pin P6 is greater than a threshold. Similarly, the fourth comparator 45B outputs a high (H) signal if the voltage level of the dedicated pin P7 is less than a threshold, and outputs a low (L) signal if the voltage level of the dedicated pin P7 is greater than a threshold. The signals output from the third comparator 45A and the fourth comparator 45B are input to the determination unit 46. The determination unit 46 determines that the encoder 4 connected to the connector 11 is an analog encoder if at least one of the signals output from the third comparator 45A and the fourth comparator 45B is a high (H) signal. Furthermore, the determination unit 43 determines that the encoder 4 connected to the connector 11 is a serial encoder if both the signal output from the third comparator 45A and the signal output from the fourth comparator 45B are low (L) signals. The signal output from the determination unit 46 is used for the switching operation of the switch 13.

[0065] Thus, in the second embodiment of the present disclosure, the determination unit 12 determines that the encoder 4 connected to the connector 11 is an analog encoder if, as a result of the comparison by the comparison unit 45, at least one of the voltage levels of the dedicated pin P6 and the dedicated pin P7 is smaller than a threshold. The determination unit 12 also determines that the encoder 4 connected to the connector 11 is a serial encoder if, as a result of the comparison by the comparison unit 45, both the voltage levels of the dedicated pin P6 and the dedicated pin P7 are larger than a threshold.

[0066] If the determination unit 12 determines that the encoder 4 connected to the connector 11 is an analog encoder, switch 13 sets the connection destination of the shared pins P4 and P5 to the analog encoder processing circuit 51. If the determination unit 12 determines that the encoder 4 connected to the connector 11 is a serial encoder, switch 13 sets the connection destination of the shared pins P4 and P5 to the serial encoder processing circuit 52.

[0067] In the above example, the comparison process by the comparison unit 42 is assumed to be performed by the third comparator 45A and the fourth comparator 45B, but it may be performed using an AD converter instead.

[0068] Optionally, the determination result from the determination unit 12 may be displayed on a display device (not shown). Examples of display devices include displays, personal computers, mobile terminals, and touch panels, but these may be attached to the motor drive unit 100 or to its higher-level control device.

[0069] <Operation Flowchart of the Second Embodiment> Figure 6 is a flowchart showing the operation flowchart of the discrimination circuit according to the second embodiment of the present disclosure.

[0070] In step S201, the determination unit 12 detects the voltage level of the dedicated pin P6 (hereinafter referred to as the "first voltage level") and the voltage level of the dedicated pin P7 (hereinafter referred to as the "second voltage level").

[0071] In step S202, the comparison unit 45 in the determination unit 12 compares the first voltage level of the dedicated pin P6 and the second voltage level of the dedicated pin P7 with a threshold value. If it is determined in step S202 that both the first voltage level of the dedicated pin P6 and the second voltage level of the dedicated pin P7 are greater than the threshold value, the process proceeds to step S203. If it is not determined in step S202 that both the first voltage level of the dedicated pin P6 and the second voltage level of the dedicated pin P7 are greater than the threshold value, that is, if at least one of the first voltage level of the dedicated pin P6 and the second voltage level of the dedicated pin P7 is less than the threshold value, the process proceeds to step S205.

[0072] In step S203, the confirmation unit 46 within the determination unit 12 determines that the encoder 4 connected to the connector 11 is a serial encoder. Next, in step S204, the switch 13 sets the connection destination of the shared pins P4 and P5 to the serial encoder processing circuit 52. After that, the processing of the discrimination circuit 1 is terminated.

[0073] In step S205, the confirmation unit 46 within the determination unit 12 determines that the encoder 4 connected to the connector 11 is an analog encoder. Next, in step S206, the switch 13 sets the connection destination of the shared pins P4 and P5 to the analog encoder processing circuit 51. After that, the processing of the discrimination circuit 1 is terminated.

[0074] The processing of the discrimination circuit 1 described above begins when the power to the control device 2 is turned on and driving power is supplied from the control device 2 to the encoder 4 via the connector 11.

[0075] <Configuration of the Third Embodiment> Figure 7 is a diagram showing a discrimination circuit according to the third embodiment of the present disclosure.

[0076] The configuration of the motor drive device 100 equipped with the discrimination circuit 1 according to the third embodiment of this disclosure has been described with reference to Figure 2.

[0077] As shown in Figure 7, the discrimination circuit 1 according to the third embodiment of the present disclosure comprises a connector 11, a determination unit 12, and a switch 13.

[0078] The connector 11 and switch 13 are as described in the first embodiment with reference to Figures 1 and 3C.

[0079] The determination unit 12 determines whether the encoder 4 connected to the connector 11 is an analog encoder or a serial encoder based on the comparison result between the voltage level of a dedicated pin and a predetermined threshold. In a third embodiment of the present disclosure, the determination unit 12 includes a third pull-down resistor 47A, a third pull-up resistor 47B, a comparison unit 48, and a confirmation unit 49. The comparison unit 48 includes a fifth comparator 48A and a sixth comparator 48B.

[0080] One end of the third pull-down resistor 47A is connected to wiring 30-6, and the other end is connected to, for example, 0V. One end of the third pull-up resistor 47B is connected to wiring 30-7, and the other end is connected to, for example, 5V. Here, as an example, 0V is connected to the other end of the third pull-down resistor 47A, but any weak voltage near 0V may be used as long as it is a voltage value that can be distinguished by comparing it with the threshold in the comparison unit 48. Similarly, although 5V is connected to the other end of the third pull-up resistor 47B, any weak voltage near 5V may be used as long as it is a voltage value that can be distinguished by comparing it with the threshold in the comparison unit 48. The threshold can be changed according to the voltage value connected to the other end of the third pull-down resistor 47A and the third pull-up resistor 47B. Wiring 30-6 is connected to the inverting input (-) of the fifth comparator 48A via wiring 31A. Wiring 30-7 is connected to the inverting input (-) of the sixth comparator 48B via wiring 31B. A first threshold value is input to the non-inverting input (+) of the fifth comparator 48A. A second threshold value is input to the non-inverting input (+) of the sixth comparator 48B. The first and second threshold values ​​may be stored in a rewritable memory device (not shown) and rewritable by an external device, and even after the first and second threshold values ​​have been set, they can be changed to appropriate values ​​as needed. The signals output from the fifth comparator 48A and the sixth comparator 48B are input to the confirmation unit 49. The switching operation of the switch 13 is performed according to the signal output from the confirmation unit 49.

[0081] In the third embodiment of this disclosure, a third pull-down resistor 47A is connected to the wiring 30-6 extending from the dedicated pin P6, and a third pull-up resistor 47B is connected to the wiring 30-7 extending from the dedicated pin P7. In the third embodiment of this disclosure, this makes it possible to fix the voltage level of the dedicated pin P6 to 0V and the voltage level of the dedicated pin P7 to 5V when the encoder 4 connected to the connector 11 is a serial encoder, thereby clearly differentiating the voltage levels of the dedicated pins P6 and P7 (1.8V to 3.2V) when the encoder 4 connected to the connector 11 is a serial encoder, and thus enabling accurate determination processing. However, when the encoder 4 connected to the connector 11 is an analog encoder, it is preferable to set the resistance values ​​of the third pull-down resistor 47A and the third pull-up resistor 47B to large values, such as several kΩ to several hundred kΩ, in order to reduce the influence of the third pull-down resistor 47A and the third pull-up resistor 47B on the respective voltage levels of the dedicated pins P6 and P7.

[0082] When monitoring the voltage levels of both dedicated pins P6 and P7, if a serial encoder is connected to connector 11, the voltage level of dedicated pin P6 will be near 0V and the voltage level of dedicated pin P7 will be near 5V. If an analog encoder is connected to connector 11, the voltage levels of dedicated pins P6 and P7 should be somewhat higher than 0V (e.g., 0.5V or higher) and somewhat lower than 5V (e.g., 4.5V or lower). Therefore, in the third embodiment of this disclosure, it is determined whether the encoder 4 connected to connector 11 is an analog encoder or a serial encoder based on the voltage levels of both dedicated pins P6 and P7.

[0083] The comparison of the voltage levels of dedicated pins P6 and P7 with the first and second thresholds is performed by the comparison unit 48 shown in Figure 7. The comparison unit 48 includes a fifth comparator 48A and a sixth comparator 48B. The fifth comparator 48A compares the voltage level of dedicated pin P6 with the first threshold. The sixth comparator 48B compares the voltage level of dedicated pin P7 with the second threshold.

[0084] The fifth comparator 48A outputs a high (H) signal if the voltage level of the dedicated pin P6 is less than the first threshold, and outputs a low (L) signal if the voltage level of the dedicated pin P6 is greater than the first threshold. Similarly, the sixth comparator 48B outputs a high (H) signal if the voltage level of the dedicated pin P7 is less than the second threshold, and outputs a low (L) signal if the voltage level of the dedicated pin P7 is greater than the second threshold. The signals output from the fifth comparator 48A and the sixth comparator 48B are input to the determination unit 49. The determination unit 49 determines that the encoder 4 connected to the connector 11 is an analog encoder if the signal output from the fifth comparator 48A is a low (L) signal, or if the signal output from the sixth comparator 48B is a high (H) signal. Furthermore, the determination unit 49 determines that the encoder 4 connected to the connector 11 is a serial encoder if the signal output from the fifth comparator 48A is a high (H) signal and both signals output from the sixth comparator 48B are low (L) signals. The signal output from the determination unit 49 is used for the switching operation of the switch 13.

[0085] Thus, in the third embodiment of this disclosure, the determination unit 12 determines, based on the comparison by the comparison unit 48, that the encoder 4 connected to the connector 11 is an analog encoder if the voltage level of the dedicated pin P6 is greater than a first threshold, or if the voltage level of the dedicated pin P7 is less than a second threshold. Furthermore, the determination unit 12 determines, based on the comparison by the comparison unit 48, that the encoder 4 connected to the connector 11 is a serial encoder if the voltage level of the dedicated pin P6 is less than a first threshold and the voltage level of the dedicated pin P7 is greater than a second threshold.

[0086] <Operation Flow of the Third Embodiment> Figure 8 is a flowchart showing the operation flow of the discrimination circuit according to the third embodiment of the present disclosure.

[0087] In step S301, the determination unit 12 detects the voltage level of the dedicated pin P6 (hereinafter referred to as the "first voltage level") and the voltage level of the dedicated pin P7 (hereinafter referred to as the "second voltage level").

[0088] In step S302, the comparison unit 48 in the determination unit 12 compares the first voltage level of the dedicated pin P6 with the first threshold, and compares the second voltage level of the dedicated pin P7 with the second threshold. If it is determined in step S302 that the first voltage level of the dedicated pin P6 is smaller than the first threshold and the second voltage level of the dedicated pin P7 is larger than the second threshold, the process proceeds to step S303. If it is not determined in step S302 that the first voltage level of the dedicated pin P6 is smaller than the first threshold and the second voltage level of the dedicated pin P7 is larger than the second threshold, that is, if the first voltage level of the dedicated pin P6 is larger than the first threshold or the second voltage level of the dedicated pin P7 is smaller than the second threshold, the process proceeds to step S305.

[0089] In step S303, the confirmation unit 46 within the determination unit 12 determines that the encoder 4 connected to the connector 11 is a serial encoder. Next, in step S304, the switch 13 sets the connection destination of the shared pins P4 and P5 to the serial encoder processing circuit 52. After that, the processing of the discrimination circuit 1 is terminated.

[0090] In step S305, the confirmation unit 46 within the determination unit 12 determines that the encoder 4 connected to the connector 11 is an analog encoder. Next, in step S306, the switch 13 sets the connection destination of the shared pins P4 and P5 to the analog encoder processing circuit 51. After that, the processing of the discrimination circuit 1 is terminated.

[0091] The processing of the discrimination circuit 1 described above begins when the power to the control device 2 is turned on and driving power is supplied from the control device 2 to the encoder 4 via the connector 11.

[0092] <Processor and Memory> The motor drive unit 100 is provided with at least one processor, which is an arithmetic processing unit. Examples of arithmetic processing units include ICs, LSIs, CPUs, MPUs, and DSPs. The arithmetic processing unit has a determination unit 43, a determination unit 46, an analog encoder processing circuit 51, a serial encoder processing circuit 52, and other processing units. Each of these parts of the arithmetic processing unit is a functional module realized by a program executed on the processor. For example, if the determination unit 43, the determination unit 46, the analog encoder processing circuit 51, the serial encoder processing circuit 52, and other processing units are constructed in program format, the functions of each part can be realized by operating the arithmetic processing unit according to this program. The programs for executing each process in the determination unit 43, the determination unit 46, the analog encoder processing circuit 51, the serial encoder processing circuit 52, and other processing units may be provided in the form of a program product recorded on a computer-readable recording medium such as a semiconductor memory, a magnetic recording medium, or an optical recording medium. Alternatively, the confirmation unit 43, confirmation unit 46, the processing circuit 51 for the analog encoder, the processing circuit 52 for the serial encoder, and other processing units may be implemented as semiconductor integrated circuits on which programs that realize the functions of each unit are written.

[0093] Furthermore, the motor drive unit 100 is provided with at least one memory, which is a storage device. The memory includes various storage devices within the confirmation unit 43, confirmation unit 46, analog encoder processing circuit 51, serial encoder processing circuit 52, and other processing units. The memory may be an electrically erasable and recordable non-volatile memory such as EEPROM (registered trademark), or a high-speed read / write random access memory such as DRAM or SRAM. The storage device may also have a configuration such as an HDD (hard disk drive) or SSD (solid state drive). The memory stores programs for operating the confirmation unit 43, confirmation unit 46, analog encoder processing circuit 51, serial encoder processing circuit 52, and other processing units. The memory also stores threshold values. The memory stores signals output from the first comparator 42A, the second comparator 42B, the third comparator 45A, and the fourth comparator 45B. The memory stores the signals output from the confirmation unit 43 and the signals output from the confirmation unit 46. The memory stores the processing results of the analog encoder processing circuit 51. The memory stores the processing results of the serial encoder processing circuit 52. The memory stores various programs and data related to the discrimination circuit 1. The memory stores various programs and data related to the control device 2. The memory stores various programs and data related to the motor drive device 100.

[0094] <Advantages of each embodiment of this disclosure> According to each embodiment of this disclosure, it is possible to automatically determine whether the encoder connected to the connector is an analog encoder or a serial encoder.

[0095] Furthermore, according to each embodiment of this disclosure, in a connector to which either an analog encoder or a serial encoder can be connected, a shared pin is provided that is used for both receiving signals from the serial encoder and signals from the analog encoder. This suppresses the increase in the number of pins per connector, and allows for miniaturization of the connector. In a control device to which the connector is attached, the space required for mounting the connector can be reduced, thus allowing for miniaturization of the control device.

[0096] Furthermore, according to each embodiment of this disclosure, if the encoder connected to the connector is an analog encoder, the switch sets the destination of the shared pin to the processing circuit for the analog encoder, and if the encoder connected to the connector is a serial encoder, the switch sets the destination of the shared pin to the processing circuit for the serial encoder. Therefore, when the encoder connected to the connector is an analog encoder, serial data is not transmitted from the processing circuit for the serial encoder to the analog encoder via the connector, thus preventing damage to the analog encoder.

[0097] Although the present disclosure has been described in detail above, it is not limited to the individual embodiments and modifications described above. These embodiments and modifications can be added, replaced, modified, partially deleted, etc., in any way that does not depart from the gist of the present disclosure or from the spirit of the present disclosure derived from the claims and their equivalents. Furthermore, these embodiments and modifications can be implemented in combination. For example, the order of operations and processes in the embodiments and modifications described above are shown as examples only and are not limited thereto. The same applies when numerical values ​​or mathematical formulas are used in the description of the embodiments and modifications described above.

[0098] <Note> The following additional information is disclosed regarding the above embodiments and modifications.

[0099] (Note 1) A discrimination circuit comprising: a connector provided with a shared pin assigned to accept both analog encoder output and serial encoder output, and a dedicated pin assigned to accept only analog encoder output; and a determination unit that determines whether the encoder connected to the connector is an analog encoder or a serial encoder based on a comparison result between the voltage level of the dedicated pin and a predetermined threshold. (Note 2) The discrimination circuit according to Note 1, wherein the determination unit determines whether the encoder connected to the connector is an analog encoder or a serial encoder based on the voltage levels of two of the multiple dedicated pins. (Note 3) The discrimination circuit according to Note 2, wherein the multiple dedicated pins include a first dedicated pin assigned to accept either the A signal or the B signal of the analog encoder output, and a second dedicated pin assigned to accept either the XA signal or the XB signal of the analog encoder output, and the determination unit determines whether the encoder connected to the connector is an analog encoder or a serial encoder based on the voltage level of the first dedicated pin and the voltage level of the second dedicated pin. (Note 4) The determination unit comprises a first pull-down resistor connected to a first wire that electrically connects a first dedicated pin and the determination unit, a second pull-down resistor connected to a second wire that electrically connects a second dedicated pin and the determination unit, and a comparison unit that compares the voltage level of the first dedicated pin with a threshold and compares the voltage level of the second dedicated pin with a threshold, wherein the determination unit determines that the encoder connected to the connector is an analog encoder if, as a result of the comparison by the comparison unit, at least one of the voltage levels of the first dedicated pin and the second dedicated pin is greater than the threshold, and determines that the encoder connected to the connector is a serial encoder if both the voltage level of the first dedicated pin and the voltage level of the second dedicated pin are less than the threshold, as described in Note 3.(Note 5) The determination unit comprises: a first pull-up resistor connected to a first wire that electrically connects a first dedicated pin and the determination unit; a second pull-up resistor connected to a second wire that electrically connects a second dedicated pin and the determination unit; and a comparison unit that compares the voltage level of the first dedicated pin with a threshold and compares the voltage level of the second dedicated pin with a threshold, wherein the determination unit determines that the encoder connected to the connector is an analog encoder if, as a result of the comparison by the comparison unit, at least one of the voltage levels of the first dedicated pin and the second dedicated pin is less than the threshold, and determines that the encoder connected to the connector is a serial encoder if both the voltage level of the first dedicated pin and the voltage level of the second dedicated pin are greater than the threshold, as described in Note 3. (Note 6) The determination unit comprises: a third pull-down resistor connected to a first wire that electrically connects a first dedicated pin and the determination unit; a third pull-up resistor connected to a second wire that electrically connects a second dedicated pin and the determination unit; and a comparison unit that compares the voltage level of the first dedicated pin with a first threshold which is one of the thresholds, and compares the voltage level of the second dedicated pin with a second threshold which is one of the thresholds, wherein the determination unit determines, as a result of the comparison by the comparison unit, that the encoder connected to the connector is an analog encoder if the voltage level of the first dedicated pin is greater than the first threshold, or the voltage level of the second dedicated pin is less than the second threshold, and determines that the encoder connected to the connector is a serial encoder. (Note 7) A determination circuit as described in any one of Notes 1 to 6, comprising a switch that sets the destination of the shared pin to the processing circuit for analog encoders when the determination unit determines that the encoder connected to the connector is an analog encoder, and sets the destination of the shared pin to the processing circuit for serial encoders when the determination unit determines that the encoder connected to the connector is a serial encoder.(Note 8) A motor drive device comprising: a discrimination circuit as described in Note 7; and a control device that controls the motor using the output of an encoder connected to a connector. (Note 9) The determination unit is provided in the control device and is the motor drive device as described in Note 8. (Note 10) The processing circuit for the analog encoder is provided in the control device and is the motor drive device as described in Note 8. (Note 11) The processing circuit for the serial encoder is provided in the control device and is the motor drive device as described in Note 8.

[0100] 1 Discrimination circuit 2 Control device 3 Motor 4 Encoder 11 Connector 12 Judgment unit 13 Switches 30-1 to 30-9, 31A, 31B, 33A, 33B, 34A, 34B Wiring 41A First pull-down resistor 41B Second pull-down resistor 42 Comparison unit 42A First comparator 42B Second comparator 43 Confirmation unit 44A First pull-up resistor 44B Second pull-up resistor 45 Comparison unit 45A Third comparator 45B Fourth comparator 46 Confirmation unit 47A Third pull-down resistor 47B Third pull-up resistor 48 Comparison unit 48A Fifth comparator 48B Sixth comparator 49 Confirmation unit 51 Processing circuit for analog encoder 52 Processing circuit for serial encoder 100 Motor Drive Unit P1 5V Pin P2 0V Pin P3 Ground Pin P4, P5 Combined Pins P6-P9 Dedicated Pins

Claims

1. A connector provided with a shared pin assigned to accept both analog encoder output and serial encoder output, and a dedicated pin assigned to accept only analog encoder output; and a determination unit that determines whether the encoder connected to the connector is an analog encoder or a serial encoder based on a comparison result between the voltage level of the dedicated pin and a predetermined threshold.

2. The determination unit determines whether the encoder connected to the connector is an analog encoder or a serial encoder based on the voltage levels of two of the plurality of dedicated pins, according to claim 1.

3. The determination circuit according to claim 2, wherein the plurality of dedicated pins include a first dedicated pin assigned to receive either the A signal or the B signal of the analog encoder output, and a second dedicated pin assigned to receive either the XA signal or the XB signal of the analog encoder output, and the determination unit determines whether the encoder connected to the connector is an analog encoder or a serial encoder based on the voltage level of the first dedicated pin and the voltage level of the second dedicated pin.

4. The determination unit comprises: a first pull-down resistor connected to a first wiring that electrically connects the first dedicated pin and the determination unit; a second pull-down resistor connected to a second wiring that electrically connects the second dedicated pin and the determination unit; and a comparison unit that compares the voltage level of the first dedicated pin with the threshold and compares the voltage level of the second dedicated pin with the threshold, wherein the determination unit determines, as a result of the comparison by the comparison unit, that if at least one of the voltage level of the first dedicated pin and the voltage level of the second dedicated pin is greater than the threshold, the encoder connected to the connector is an analog encoder, and if both the voltage level of the first dedicated pin and the voltage level of the second dedicated pin are less than the threshold, the encoder connected to the connector is a serial encoder, as described in claim 3.

5. The determination unit comprises: a first pull-up resistor connected to a first wiring that electrically connects the first dedicated pin and the determination unit; a second pull-up resistor connected to a second wiring that electrically connects the second dedicated pin and the determination unit; and a comparison unit that compares the voltage level of the first dedicated pin with the threshold and compares the voltage level of the second dedicated pin with the threshold, wherein the determination unit determines, as a result of the comparison by the comparison unit, that if at least one of the voltage level of the first dedicated pin and the voltage level of the second dedicated pin is smaller than the threshold, the encoder connected to the connector is an analog encoder, and if both the voltage level of the first dedicated pin and the voltage level of the second dedicated pin are larger than the threshold, the encoder connected to the connector is a serial encoder, as described in claim 3.

6. The determination unit comprises: a third pull-down resistor connected to a first wiring that electrically connects the first dedicated pin and the determination unit; a third pull-up resistor connected to a second wiring that electrically connects the second dedicated pin and the determination unit; and a comparison unit that compares the voltage level of the first dedicated pin with a first threshold which is one of the thresholds, and compares the voltage level of the second dedicated pin with a second threshold which is one of the thresholds, wherein the determination unit determines, as a result of the comparison by the comparison unit, that the encoder connected to the connector is an analog encoder if the voltage level of the first dedicated pin is greater than the first threshold, or the voltage level of the second dedicated pin is less than the second threshold, and determines that the encoder connected to the connector is a serial encoder.

7. A determination circuit according to any one of claims 1 to 6, comprising a switch that sets the destination of the shared pin to an analog encoder processing circuit when the determination unit determines that the encoder connected to the connector is an analog encoder, and sets the destination of the shared pin to a serial encoder processing circuit when the determination unit determines that the encoder connected to the connector is a serial encoder.

8. A motor drive device comprising: a discrimination circuit as described in claim 7; and a control device that controls a motor using the output of an encoder connected to the connector.

9. The motor drive device according to claim 8, wherein the determination unit is provided in the control device.

10. The motor drive device according to claim 8, wherein the processing circuit for the analog encoder is provided in the control device.

11. The motor drive device according to claim 8, wherein the processing circuit for the serial encoder is provided in the control device.

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