Motor control device and motor control method

A motor control device includes a first storage configured to store indicated values of control parameters, motor control circuitry configured to control a motor based on the indicated values stored in the first storage, primary setting circuitry configured to set in the first storage at least one indicated value among the indicated values as a primary indicated value which corresponds to specific parameter among the control parameters, secondary setting circuitry configured to replace, based on a change instruction input via a terminal, the primary indicated value stored in the first storage with a secondary indicated value in accordance with the change instruction, and resetting circuitry configured to replace the secondary indicated value stored in the first storage with the primary indicated value when a return requirement is satisfied after the secondary setting circuitry has replaced the primary indicated value with the secondary indicated value.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims priority under 35 U.S.C. § 119 to Japanese Patent Application No. 2019-136422, filed Jul. 24, 2019. The contents of this application are incorporated herein by reference in their entirety.

BACKGROUND OF THE INVENTION

Field of the Invention

The present invention relates to a motor control device and a motor control method.

Discussion of the Background

Japanese Patent Application Publication No. 2012-060710 describes a motor control system configured to execute, after a lapse of a predefined certain time from execution of a threshold value changing process, a process of returning a threshold value to a first threshold value from a second threshold value.

For example, multiple parameters are sometimes prepared for controlling a motor. As to a specific one of the parameters, there may arise a need to temporarily change the value from the initial set value only during an adjustment to the motor before a normal run or a test run, and then return the changed value to the initial set value after the adjustment or the test run. When an operator temporarily changes the value of the specific parameter and returns the changed value to the initial set value, for example, the operator may inadvertently forget to return the changed value to the initial set value.

SUMMARY OF THE INVENTION

According to one aspect of the present invention, a motor control device includes a first storage configured to store indicated values of control parameters, motor control circuitry configured to control a motor based on the indicated values stored in the first storage, primary setting circuitry configured to set in the first storage at least one indicated value among the indicated values as a primary indicated value which corresponds to specific parameter among the control parameters, secondary setting circuitry configured to replace, based on a change instruction input via a terminal, the primary indicated value stored in the first storage with a secondary indicated value in accordance with the change instruction, and resetting circuitry configured to replace the secondary indicated value stored in the first storage with the primary indicated value when a return requirement is satisfied after the secondary setting circuitry has replaced the primary indicated value with the secondary indicated value.

According to another aspect of the present invention, a motor control method includes storing indicated values of control parameters, controlling a motor based on the indicated values stored in the first storage, setting in the first storage at least one indicated value among the indicated values as a primary indicated value which corresponds to specific parameter among the control parameters, replacing, based on a change instruction input via a terminal, the primary indicated value stored in the first storage with a secondary indicated value in accordance with the change instruction, and replacing the secondary indicated value stored in the first storage with the primary indicated value when a return requirement is satisfied after the secondary setting circuitry has replaced the primary indicated value with the secondary indicated value.

DESCRIPTION OF EMBODIMENTS

An embodiment will be described below with reference to the drawings.

Exemplary Configuration of Motor Control System

With reference toFIG. 1, first, a description will be given of an exemplary configuration of a motor control system according to the present embodiment.

FIG. 1is a schematic block diagram of a hardware configuration of the motor control system according to the present embodiment. As illustrated inFIG. 1, the motor control system1includes a motor11, a motor control device12, and an external terminal13.

The motor11is an electric motor that is driven with electric power to be fed from the motor control device12to be described later (hereinafter, the electric power is appropriately referred to as feed power) to convert the energy into a mechanical force or a displacement. The motor11may be of various types, such as a rotary type, a direct-acting type, a synchronous type, and an inductive type, selectable depending on a difference in mechanical configuration or electromagnetic operating method. In this example, the motor11includes a position detector14capable of detecting an output displacement.

The motor control device12receives alternating-current (AC) power from an AC power source15, converts the AC power into appropriate feed power, feeds the appropriate feed power to the motor11, and controls the driven state of the motor11. The motor control device12mainly includes a converter21, an inverter22, and a motor control circuit unit23.

The converter21includes a rectifier circuit and a smoothing circuit (not illustrated). The converter21receives AC power from the AC power source15, and converts the AC power into desired direct-current (DC) power. The inverter22includes a bridge circuit (not illustrated) that includes a plurality of semiconductor switching elements. The inverter22receives DC power from the converter21, converts the DC power into desired feed power, and feeds the desired feed power to the motor11.

The motor control circuit unit23receives a command from a host control device (not illustrated), an output current value from the inverter22, and a detection signal of an output displacement from the position detector14in the motor11. The motor control circuit unit23controls power conversion by the inverter22, based on the received command, output current value, and detection signal. The motor control device12according to the present embodiment has a plurality of control parameters for the control of the motor11, specifically the control of the inverter22. The motor control circuit unit23controls the power conversion by the inverter22, based on an indicated value (to be described later) of each control parameter set by the external terminal13and an input signal from the host control device or an external device (not illustrated).

The external terminal13(an example of a terminal) may be, for example, a general-purpose personal computer or an engineering tool disposed separately from the motor control device12, in addition to a dedicated terminal device for the motor control device12. The external terminal13is externally connected to the motor control device12to exchange various kinds of information with the motor control device12. The external terminal13may alternatively be an information terminal such as a mobile phone or a personal digital assistant. The external terminal13and the motor control device12may exchange information through wired communications or through wireless communications complying with an appropriate standard.

In the case where the external terminal13is a dedicated terminal device, its appearance roughly takes a form illustrated inFIG. 2. In the example illustrated inFIG. 2, the external terminal13includes, for example, a data display unit131that displays a frequency and a parameter number using a combination of numerals from 0 to 9 with alphabets, various input keys132, an LED lamp133that displays statuses such as abnormality detection (ALM), reverse command input (REV), drive mode (DRY), and output frequency display (FOUT), a RUN lamp134that lights up during the running of the motor control device12, an LO/RE lamp135that lights up during a period in which the operator selects a continuous change mode, and a communication connector136that establishes communications with an external device.

Features of the Present Embodiment

According to the present embodiment, as described above, the indicated value of each control parameter for the inverter22is settable and changeable in accordance with the operations by the operator through the external terminal13. In such a case, for example, as to a certain specific parameter, there may arise a need to temporarily change the value from the initial set value only during an adjustment to the motor before a normal run, specifically an adjustment to the motor control device12or a test run, and then return the changed value to the initial set value after the adjustment. When the operator temporarily changes the value of the specific parameter and returns the changed value to the initial set value, for example, the operator may inadvertently forget to return the changed value to the initial set value.

Exemplary Configuration of Motor Control Circuit Unit

With reference toFIGS. 3 and 4, next, a description will be given of an exemplary configuration of the motor control circuit unit23for addressing the foregoing matters.

FIG. 3illustrates an exemplary hardware configuration of the motor control circuit unit23.

As illustrated inFIG. 3, the motor control circuit unit23includes, for example, a central processing unit (CPU)901that includes a storage area for an inverter control program (a program read only memory (ROM)904) and a timer908, a ROM903(an example of a second storage), a random access memory (RAM)905(an example of a first storage), an electrically erasable/programmable read only memory (EEPROM)906, a dedicated integrated circuit907constructed for specific application, such as an application-specific integrated circuit or a field-programmable gate array, an input device913, an output device915, a connection port921, and a communication device923. The motor control circuit unit23also includes an appropriate storage device917and a drive919as necessary. The RAM905has a normal area905A (an example of a first area) and a save area905B (an example of a second area) disposed separately from the normal area905A (the details will be described later). These constituent elements are connected via a bus909and an input-output (I/O) interface911to achieve mutual signal transfer.

The storage device917is an example of a recording device, and is capable of recording, for example, a program to be described later. The program is stored in the program ROM904of the CPU901. Alternatively, the program may be stored in one of the ROM903, the RAM905, and the EEPROM906.

The program may also temporarily or permanently be recorded in a removable storage medium925. Examples of the removable storage medium925may include magnetic disks such as a flexible disk, various optical disks such as a compact disk, a magneto-optical disk, and a digital versatile disk, and semiconductor memories. The removable storage medium925may also be provided in the form of packaged software. In this case, the program recorded in the removable storage medium925may be read by the drive919and recorded in the recording device via the I/O interface911, the bus909, and the like.

Alternatively, the program may be recorded in, for example, a download site, another computer, or another recording device (not illustrated). In this case, the program is transferred through a network NW such as a local area network or the Internet, and the communication device923receives the program. The program received by the communication device923may be recorded in the recording device via the I/O interface911, the bus909, and the like.

Alternatively, the program may be recorded in, for example, appropriate externally-connected equipment927. In this case, the program may be transferred through the appropriate connection port921and recorded in the recording device via the I/O interface911, the bus909, and the like.

Exemplary Configuration of Software Block Executed by Motor Control Circuit Unit

FIG. 4is a schematic software block diagram of the details of processing to be embodied by the motor control circuit unit23in such a manner that the CPU901executes various processes in accordance with the program recorded in, for example, the foregoing recording device. As illustrated inFIG. 4, the motor control circuit unit23includes, as a functional unit, a power conversion control unit31, a display control unit35, and a parameter setting unit37. As described above, these functional units are implemented by the program which the CPU901executes.

The power conversion control unit31(an example of a motor control circuitry) receives, for example, a command such as a speed command from the host control device, a detection signal of an output displacement from the position detector14in the motor11, and an output current value from the inverter22. The power conversion control unit31controls power conversion by predetermined loop control and pulse width modulation control, based on the received command, detection signal, and output current value. The power conversion control unit31outputs, to the inverter22, a switch signal for the semiconductor switching elements in the inverter22, based on the power conversion control. This enables control of feed power from the inverter22to the motor11.

At this time, a control program module32of the motor control circuit unit23executes the process of power conversion control which the power conversion control unit31performs on the inverter22. For the process, the parameter setting unit37sets values (indicated values) of the control parameters, for use in the control program module32. The control program module32executes the power conversion control process by reference to indicated values set in the normal area905A of the RAM905(the details will be described later). The parameter setting unit37receives the parameter change command from the external terminal13, and sets the indicated values of the control parameters, based on the parameter change command. The parameter setting unit37includes a primary setting unit (primary setting circuitry)37A, a secondary setting unit (secondary setting circuitry)37B, and a resetting unit (resetting circuitry)37C. The parameter setting unit37controls input and output of the indicated values of the control parameters to and from the ROM903, the normal area905A and save area905B of the RAM905, and the EEPROM906(the details will be described later).

The display control unit35generates a display control signal that causes the display unit13A of the external terminal13to display information on the indicated values of the control parameters. The display control unit35then outputs the display control signal to the external terminal13. The display unit13A of the external terminal13displays the parameter setting screen, based on the display control signal.

The foregoing processes in the motor control circuit unit23are not limited to the example of the processes shared among the foregoing functional units31,32,35, and37. For example, the foregoing processes may be executed by one functional unit or may be shared among and executed by functional units that are further subdivided.

Settings of Control Parameters Other than Specific Parameter in Motor Control Device

In the motor control device12, all the control parameters and the indicated values thereof are recorded in the ROM903and the EEPROM906. The ROM903stores indicated values of all the control parameters at factory shipment. When a user changes settings of control parameters other than a specific parameter, the EEPROM906stores the changed values.

In changing the indicated values of the control parameters using the external terminal13illustrated inFIG. 2, the operator selects a parameter setting mode (the details will be described later), selects a parameter number, and changes an indicated value of the parameter, through the input keys132, and then presses an ENTER key132A, thereby changing the indicated value of the selected control parameter.

When the operator performs a parameter change instructing operation through the continuous change instruction unit13E after the input of a series of indicated values, the external terminal13transmits, to the motor control device12, a parameter change command for changing the values of the respective control parameters to indicated values desired by the operator, based on the parameter change instructing operation. As to the control parameters other than the specific parameter, the motor control device12rewrites the indicated values of the parameters in the normal area905A of the RAM905and the indicated values of the parameters in the EEPROM906.

At power-on of the motor control device12, the motor control device12reads the indicated values of the control parameters stored in the ROM903, and stores a copy of the indicated values in the normal area905A. The motor control device12then reads the indicated values of the control parameters stored in tin the EEPROM906, and overwrites the indicated values in the normal area905A.

According to this configuration, as to the control parameters other than the specific parameter, the indicated values of the control parameters changed by the user are reflected even after the power is turned on again. Moreover, the indicated values of the control parameters are returned to the initial set values at factory shipment by reading the indicated values of the control parameters stored in the ROM903and storing a copy of the indicated values in the EEPROM906.

Outline of Method According to the Present Embodiment

With reference toFIG. 5, a description will be given of the outline of a method according to the present embodiment, the method being performed by the primary setting unit37A, the secondary setting unit37B, and the resetting unit37C in the parameter setting unit37in order to address the temporary change in the value of the specific parameter, the return of the changed value to the initial set value, and the lack of memory as to returning the changed value to the initial set value.

In the example illustrated inFIG. 5, first, the ROM903stores, for example, an initial value “100” of the specific parameter that is written at factory shipment, in a state prior to power-on (to be described later). It should be noted that this initial value “100” is held in the ROM903without being rewritten. The EEPROM906also previously stores an indicated value “108” of the specific parameter in the state prior to power-on (to be described later). With regard to the indicated value “108”, the operator selects the specific parameter through the parameter selecting unit13B of the external terminal13, inputs the indicated value “108” through the indicated value input unit13C of the external terminal13, and instructs a change in the indicated value “108” through the continuous change instruction unit13E of the external terminal13.

Thereafter, at the power-on of the motor control device12, the primary setting unit37A of the parameter setting unit37reads the initial value “100” from the ROM903, writes the initial value “100” into the normal area905A of the RAM905, and sets the initial value “100” as an indicated value in the normal area905A. Likewise, the primary setting unit37A reads the indicated value “108” from the EEPROM906, and writes the indicated value “108” into the normal area905A. The primary setting unit37A thus overwrites and updates the value stored in the normal area905A, and sets the indicated value “108” as a primary indicated value in the normal area905A.

Thereafter, for example, the operator performs the parameter change instructing operation of selecting the specific parameter through the parameter selecting unit13B, inputting a new indicated value “150” through the indicated value input unit13C, and changing the indicated value “108” to the indicated value “150” through the instruction unit13D. Specifically, in changing the specific parameter using the external terminal13illustrated inFIG. 2, the operator selects a parameter setting mode, selects a parameter number, and changes an indicated value of the parameter through the input keys132, and then presses the ENTER key132A, thereby changing the indicated value of the selected control parameter. When the operator performs the parameter change instructing operation through the instruction unit13D after the input of the series of indicated values, the external terminal13transmits, to the motor control device12, a parameter change command for changing the value of each control parameter to an indicated value desired by the operator, based on the parameter change instructing operation. The parameter setting unit37then receives the relevant parameter change command from the external terminal13. The secondary setting unit37B thus reads the primary indicated value “108” from the normal area905A, and writes the primary indicated value “108” into the save area905B of the RAM905. Likewise, the secondary setting unit37B writes the new indicated value “150” into the normal area905A, thereby overwriting and updating the value stored in the normal area905A, and setting the indicated value “150” as a secondary indicated value in the normal area905A. In other words, the secondary indicated value “150” is set in place of the primary indicated value “108” in the normal area905A. The timer908starts to measure a time elapsed from the setting of the secondary indicated value in the normal area905A.

When the timer908starts the measurement, the resetting unit37C transmits, during a period in which a return requirement is not satisfied, a signal indicating that the return requirement is not satisfied to the external terminal13. The external terminal13may be configured to display information indicating that the return requirement is not satisfied on the data display unit131, based on the signal.

With reference toFIG. 6similar toFIG. 2, a description will be given of exemplary display on the dedicated terminal in the state in which the timer908is operated. The resetting unit37C transmits a signal indicating that the indicated value of the specific parameter is temporarily changed, to the display unit13A such that the display unit13A displays a character string of “TEST”. The display unit13A displays a character string131A corresponding to “TEST” on the data display unit131such that the character string131A is continuously displayed during a period in which the timer908measures the elapsed time.

With this configuration, the user is able to achieve an adjustment and a test run while confirming that the operation based on the indicated value of the specific parameter is performed provisionally.

Referring back toFIG. 5, when the elapsed time measured by the timer908reaches a predetermined time, the resetting unit37C of the parameter setting unit37reads the primary indicated value “108” from the save area905B, and writes the primary indicated value “108” into the normal area905A of the RAM905. The resetting unit37C thus overwrites and updates the value stored in the normal area905A so as to reset the indicated value to “108” in the normal area905A. In other words, the primary indicated value “108” is reset in place of the secondary indicated value “150” in the normal area905A. In the present embodiment, the elapsed time measured by the timer908is used as a requirement for resetting, in the normal area905A, the primary indicated value set in the save area905B, in other words, a return requirement for returning, to the primary indicated value, the indicated value of the specific parameter to be used in the power conversion control process which the control program module32executes. It is determined that the return requirement is satisfied on condition that the elapsed time reaches the predetermined time.

Examples of the control parameters may include, but not limited to, the maximum speed of the motor11, the minimum speed of the motor11, the resolution, speed loop gain, speed loop integration time, load level, torque or current command of the position detector14, and a threshold value for issuing a predetermined alarm as to each of the foregoing items. Examples of the specific parameter may include, but not limited to, the maximum speed of the motor11, and the threshold value of the torque or current command. It should be noted that the number of specific parameters is not limited to one. For example, the number of specific parameters may be two or more.

Continuous Setting Change in Specific Parameter

According to the setting of the specific parameter by the foregoing method, when the predetermined requirement is satisfied, the indicated value of the specific parameter is returned to the initial set value. That is, the indicated value of the specific parameter is not continuously changed.

Hence, the motor control device12additionally has a function of continuously changing the indicated value of the specific parameter.

Specifically, when the external terminal13issues the specific parameter change instruction while selecting a mode of continuously changing the indicated value of the specific parameter (hereinafter, appropriately referred to as a “continuous change mode”), the secondary setting unit37B and the resetting unit37C are not activated, but the primary setting unit37A further rewrites the indicated value of the specific parameter stored in the ROM903, based on the specific parameter change instruction.

For example, the external terminal13additionally has a function of selecting the continuous change mode. For example, in the case of using the external terminal13illustrated inFIG. 2, the operator presses the LO/RE key132B to switch between a normal mode and the continuous change mode. In the continuous change mode, the LO/RE lamp135lights up.

In the continuous change mode, the operator selects the specific parameter by the foregoing method, changes the indicated value of the specific parameter, and then presses the ENTER key132A, thereby continuously changing the indicated value of the selected specific parameter.

When the operator performs the parameter change instructing operation through the continuous change instruction unit13E after the input of the series of indicated values, the external terminal13transmits, to the motor control device12, the parameter change command for changing the value of the specific parameter to an indicated value desired by the operator based on the parameter change instructing operation. The motor control device12thus rewrites the parameter in the normal area905A of the RAM905and the parameter in the EEPROM906.

With this configuration, as to the specific parameter, the indicated value of the control parameter changed by the user is reflected even after the power is turned on again.

Control Procedure

With reference to a flowchart ofFIG. 7, next, a description will be given of an exemplary control procedure to be executed by the parameter setting unit37in order to embody the foregoing method. This flow starts at the power-on of the motor control device12, and is continuously executed until the parameter setting mode is canceled through the input keys132. Although not illustrated inFIG. 7, in a case where the parameter setting mode is selected anew through the input keys132after the power-on of the motor control device12, step S5and step S10(to be described later) are not carried out in the flowchart ofFIG. 7.

As illustrated inFIG. 7, in step S5to be carried out first at the power-on, the primary setting unit37A of the parameter setting unit37reads an initial value of a control parameter from the ROM903, and writes the initial value into the normal area905A of the RAM905. The primary setting unit37A thus sets the written initial value as an indicated value in the normal area905A. In step S10, the primary setting unit37A of the parameter setting unit37reads an indicated value from the EEPROM906, and writes the indicated value into the normal area905A in a manner similar to that described above. The primary setting unit37A thus overwrites and updates the value stored in the normal area905A, and sets the overwritten value as a primary indicated value in the normal area905A. As a result, the control program module32executes the power conversion control process based on the primary indicated value set in the normal area905A.

In step S25, the parameter setting unit37determines whether the parameter change command for the specific parameter received in step S15is a continuous change which is not a temporary change based on the premise that the value of a specific parameter is returned to the initial set value.

In the present embodiment, specifically, the operator selects the specific parameter through the parameter selecting unit13B, inputs the indicated value through the indicated value input unit13C, and performs the parameter change instructing operation through the instruction unit13D. The specific parameter is thus subjected to a specific parameter temporarily changing process capable of saving the primary indicated value in the save area905B and resetting the primary indicated value in the normal area905A after a lapse of a predetermined time. According to the present embodiment, in the case where the operator desires a continuous change in the specific parameter rather than a temporary change in the specific parameter as described above, in addition to the specific parameter temporarily changing process, for example, the operator selects the specific parameter through the parameter selecting unit13B, inputs the indicated value through the indicated value input unit13C, and then operates the continuous change instruction unit13E (e.g., performs a specific parameter setting changing process by pressing the LO/RE key132B) in place of the instruction operation through the instruction unit13D. The specific parameter is thus subjected to a specific parameter continuously changing process.

In step S25, the parameter setting unit37determines whether the parameter change command for the specific parameter received in step S15is the specific parameter continuously changing process based on the parameter change instructing operation through the continuous change instruction unit13E, rather than the specific parameter temporarily changing process based on the parameter change instructing operation through the instruction unit13D. When the parameter change command received in step S15is an instruction for the specific parameter continuously changing process, the determination in step S25is satisfied (S25: YES). The processing then proceeds to step S55.

In step S55, the secondary setting unit37B of the parameter setting unit37writes into the EEPROM906the indicated value contained in the parameter change command received in step S15. The secondary setting unit37B thus overwrites and updates the value stored in the EEPROM906, and sets the overwritten value as a secondary indicated value in the EEPROM906. In step S60, next, the secondary setting unit37B of the parameter setting unit37also writes into the normal area905A the indicated value contained in the parameter change command received in step S15. The secondary setting unit37B thus overwrites and updates the value stored in the normal area905A, and sets the overwritten value as a secondary indicated value in the normal area905A. As a result, the control program module32executes the power conversion control process based on the secondary indicated value set in the normal area905A. After step S60, the processing proceeds to step S65in which the parameter setting unit37determines whether the parameter setting mode is selected.

On the other hand, when the parameter change command received in step S15is an instruction for the specific parameter temporarily changing process in step S25, the determination in step S25is not satisfied (S25: NO). The processing then proceeds to step S30.

In step S30, the secondary setting unit37B of the parameter setting unit37reads the primary indicated value set in the normal area905A of the RAM905in step S10, and writes the primary indicated value into the save area905B. In step S40, next, the secondary setting unit37B of the parameter setting unit37writes into the normal area905A the indicated value contained in the parameter change command received in step S15. The secondary setting unit37B thus overwrites and updates the value stored in the normal area905A, and sets the overwritten value as a secondary indicated value in the normal area905A. As a result, the control program module32executes the power conversion control process based on the secondary indicated value set in the normal area905A.

Upon completion of the write of the secondary indicated value in step S35, the parameter setting unit37starts to count an elapsed time using the timer908in step S40.

In step S45, next, the parameter setting unit37determines whether the elapsed time measured by the timer908reaches the predetermined time. The determination is not satisfied (S45: NO) until the elapsed time reaches the predetermined time, so that the processing is in a loop standby state. When the elapsed time reaches the predetermined time, the determination is satisfied (S45: YES). The processing then proceeds to step S50.

In step S50, the resetting unit37C of the parameter setting unit37reads the primary indicated value written in the save area905B of the RAM905in step S30, and writes the primary indicated value in the normal area905A again. The resetting unit37C thus overwrites and updates the value stored in the normal area905A with the primary indicated value. As a result, the control program module32executes the power conversion control process based on the primary indicated value again. After step S50, the processing proceeds to step S65.

Exemplary Advantageous Effects of the Present Embodiment

As described above, in the present embodiment, first, the primary setting unit37A of the parameter setting unit37sets the primary indicated value of the specific parameter in the RAM905. When the operator performs the parameter change instructing operation through the external terminal13in order to temporarily change the primary indicated value thus set, the secondary setting unit37B sets in the RAM905the secondary indicated value in accordance with the parameter change instructing operation, in place of the stored primary indicated value. The resetting unit37C of the parameter setting unit37resets in the RAM905the initial primary indicated value in place of the stored secondary indicated value when the predetermined return requirement is satisfied after the secondary indicated value is set. As a result, in the case where the operator temporarily changes the value of the specific parameter through the operation by himself or herself, the changed value of the specific value is automatically returned to the initial value even when the operator does not perform the subsequent operation. This results in improvement of convenience for the operator.

A typical example of an advantageous effect of the present embodiment includes an advantageous effect to be produced in a case of using, as the specific parameter, the threshold value for issuing an alarm. At a test run before the motor control device12normally runs, the operator generally makes an adjustment to the motor control device12so as to largely increase or decrease the indicated value of each control parameter. At this time, if the threshold value for issuing an alarm is still set at a value for the normal run, an alarm is issued since the indicated value deviates from the threshold value each time the indicated value increases or decreases, which is troublesome. In many instances, to avoid this, the threshold value is changed by the parameter change instructing operation such that the indicated value does not deviate from the threshold value. It is necessary to remember that the changed threshold value is returned to the initial value after the test run. Applying the method according to the present embodiment enables automatic return of the threshold value to its initial value even when the operator does not perform an operation after the change of the threshold value.

According to the present embodiment, the RAM905has the normal area905A and the save area905B. When the operator performs the parameter change instructing operation to temporarily change the value of the specific parameter, the secondary setting unit37B sets in the save area905B the primary indicated value before being changed. Thereafter, the resetting unit37C reads the primary indicated value from the save area905B at the time of resetting, and sets the primary indicated value again in the normal area905A. When the primary indicated value is saved and stored in the save area905B as described above, the value of the specific parameter is returned to the initial value in the state in which the primary indicated value before being changed is reliably held.

According to the present embodiment, the initial value of the specific parameter is previously stored in the ROM903. At the power-on, the primary setting unit37A of the parameter setting unit37reads the initial value from the ROM903, sets the initial value in the RAM905, and also sets the primary indicated value in the RAM905. The primary setting unit37A thus overwrites and updates the value stored in the RAM905. With this configuration, even when an initial value of a specific parameter held since, for example, factory shipment is used, a primary indicated value on which the intention of an operator is reflected is set in the RAM905later.

According to the present embodiment, the resetting unit37C of the parameter setting unit37resets the primary indicated value in the RAM905on condition that a predetermined time has elapsed from the setting of the secondary indicated value by the secondary setting unit37B, as the return requirement. With this configuration, in the case where the operator performs the parameter change instructing operation to change the value of the specific parameter to the secondary indicated value by himself or herself, even when the operator does not perform the subsequent operation, the changed value of the specific parameter is reliably returned to the initial value after the lapse of the predetermined time from the change to the secondary indicated value.

It should be noted that the embodiment is not limited to the foregoing description, and various modifications may be made within a range departing from the scope and technical idea of the disclosure. Such modifications will be described below in succession. In the respective modifications, portions similar to those in the foregoing embodiment are denoted with the identical reference signs; therefore, the description thereof will be omitted or simplified as appropriate.

Case of Setting Return Requirement Different from Measurement by Timer

In the foregoing embodiment, as described with reference toFIG. 7(e.g., step S40, step S45), the control program module32executes the power conversion control process using the indicated value of the specific parameter, and the return requirement for returning to the primary indicated value the indicated value of the specific parameter is satisfied on condition that the elapsed time measured by the timer908reaches the predetermined time. However, the condition is not limited thereto. For example, the return requirement may be satisfied on condition that, when the power to the motor control device12is turned on again, the resetting unit37C reads the primary indicated value “108” from the save area905B, and writes the primary indicated value “108” into the normal area905A of the RAM905. With this configuration, in the case where the operator performs the parameter change instructing operation to change the value of the specific parameter to the secondary indicated value by himself or herself, even when the operator does not perform the subsequent operation, the changed value of the specific parameter is reliably returned to the initial value on condition that the power to the motor control device12is turned on again.

Modification in which No Save Area is Disposed

The present modification is different from the foregoing embodiment in that the RAM905has no save area905B and normal area905A, and the changed value of the specific parameter is returned to the initial value based on the parameter change instructing operation performed by the user. In the present modification, the control program module32executes the power conversion control process by reference to the indicated value set in the RAM905.

Outline of Method According to the Present Modification

With reference toFIG. 8similar toFIG. 5illustrating the outline of the method according to the foregoing embodiment, a description will be given of the outline of a method according to the present modification, the method being performed by the primary setting unit37A, secondary setting unit37B, and resetting unit37C in the parameter setting unit37.

As illustrated inFIG. 8, the present modification is similar to the foregoing embodiment in that the ROM903stores an initial value “100” of a specific parameter. The EEPROM906also previously stores an indicated value “108” of the specific parameter. With regard to the indicated value “108”, the operator selects the specific parameter through the parameter selecting unit13B of the external terminal13, inputs the indicated value “108” through the indicated value input unit13C of the external terminal13, and instructs a change in the indicated value “108” through the instruction unit13D of the external terminal13.

Thereafter, at the power-on of the motor control device12, the primary setting unit37A of the parameter setting unit37reads the initial value “100” from the ROM903, writes the initial value “100” into the RAM905, and sets the initial value “100” as an indicated value in the RAM905, in a manner similar to that described in the foregoing embodiment. In addition, the primary setting unit37A reads the indicated value “108” from the EEPROM906. At this time, the primary setting unit37A writes, into the RAM905, a value of “108+0” representing a sum of a fixed value portion taking a fixed value “108” (an example of a first value) and a variable value portion taking a variable value with “0” (an example of a second value) defined as an initial value, based on the indicated value “108” thus read. The primary setting unit37A thus overwrites and updates the value stored in the RAM905, and sets the value of “108+0” as a primary indicated value in the RAM905.

Thereafter, for example, the operator performs the parameter change instructing operation of selecting the specific parameter through the parameter selecting unit13B, inputting a new indicated value “150” through the indicated value input unit13C, and changing the indicated value “108” to the indicated value “150” through the instruction unit13D. When the parameter setting unit37receives the relevant parameter change command from the external terminal13, the secondary setting unit37B of the parameter setting unit37changes the value “0” of the variable value portion stored in the RAM905to a value of “42” (an example of a decrease start value) representing a difference between the new indicated value “150” and the value “108” of the fixed value portion stored in the RAM905. As a result, the secondary setting unit37B overwrites and updates the value stored in the RAM905with the value of “108+42”, and sets the value of “108+42” as a secondary indicated value in the RAM905. In other words, the secondary indicated value “150” is substantially set in place of the primary indicated value “108” in the RAM905.

Immediately after the secondary indicated value “108+42” is set in the RAM905, the value “42” of the variable value portion is subjected to a predetermined decrease process. Specifically, the resetting unit37C of the parameter setting unit37sequentially subtracts an appropriate decrease deviation A from the value of “42” every predefined certain cycle. The resetting unit37C thus overwrites and updates the value stored in the RAM905each time this processes ends. Thereafter, when the value of the variable value portion sequentially decreases to reach “0” that is equal to the initial value, the resetting unit37C overwrites and updates the value stored in the RAM905with the primary indicated value “108+0”, thereby resetting the primary indicated value “108+0” in the RAM905. In other words, the primary indicated value “108” is reset in place of the secondary indicated value “150” in the RAM905. In the present modification, the value of the variable value portion is used as a requirement for resetting the primary indicated value “108” in the RAM905, in other words, a return requirement for returning, to the primary indicated value, the indicated value of the specific parameter to be used in the power conversion control process which the control program module32executes. It is determined that the return requirement is satisfied on condition that the variable value portion takes the value of “0” as the initial value.

Control Procedure

With reference to a flowchart ofFIG. 9similar toFIG. 7illustrating the control procedure according to the foregoing embodiment, next, a description will be given of an exemplary control procedure to be executed by the parameter setting unit37in order to embody the foregoing method according to the present modification. The present modification is similar to the foregoing embodiment in that this flow starts at the power-on of the motor control device12, and is continuously executed until the parameter setting mode is canceled through the input keys132. Although not illustrated inFIG. 9, in a case where the parameter setting mode is selected anew through the input keys132after the power-on of the motor control device12, step S5and step S10are not carried out in the flowchart ofFIG. 9.

The flow illustrated inFIG. 9includes step S5A, step S10A, step S30A, and step S60A in place of step S5, step S10, step S30, and step S60in the flow illustrated inFIG. 7. The flow illustrated inFIG. 9also includes step S42, step S47, and step S52after step S30A in place of step S35, step S40, step S45, and step S50after step S30in the flow illustrated inFIG. 7.

Specifically, in step S5A to be carried out first at the power-on, the primary setting unit37A of the parameter setting unit37reads an initial value of a control parameter from the ROM903, writes the initial value into the RAM905, and sets the written initial value as an indicated value in the RAM905. In step S10A, the primary setting unit37A of the parameter setting unit37reads an indicated value from the EEPROM906, and writes into the RAM905a sum of a fixed value portion and a variable value portion based on the indicated value. The primary setting unit37A thus overwrites and updates the value stored in the RAM905, and sets the overwritten value as a primary indicated value in the RAM905. At this time, the variable value portion takes a value set at a predefined initial value. As a result, the control program module32executes the power conversion control process based on the primary indicated value set in the RAM905.

Thereafter, step S13, step S15, step S20, and step S25are carried out in manners similar to those inFIG. 7. When the determination in step S20is not satisfied and when the determination in step S25is satisfied, the processing proceeds to step S60A via step S55similar to that inFIG. 7. In step S60A, the secondary setting unit37B of the parameter setting unit37writes the indicated value contained in the parameter change command received in step S15into the RAM905. The secondary setting unit37B thus overwrites and updates the value stored in the RAM905, and sets the overwritten value as a secondary indicated value in the RAM905. As a result, the control program module32executes the power conversion control process based on the secondary indicated value set in the RAM905. After step S60A, the processing proceeds to step S65in which the parameter setting unit37determines whether the parameter setting mode is selected, in a manner similar to that inFIG. 7.

On the other hand, when the parameter change command received in step S15is an instruction for the specific parameter temporarily changing process in step S25, the determination in step S25is not satisfied (S25: NO). The processing then proceeds to step S30A.

In step S30A, the secondary setting unit37B of the parameter setting unit37changes the value of the variable value portion stored in the RAM905in step S10A to a decrease start value corresponding to a difference between the new indicated value contained in the parameter change command received in step S15and the value of the fixed value portion stored in the RAM905. As a result, the secondary setting unit37B overwrites and updates the value stored in the RAM905with the sum of the fixed value portion and the variable value portion taking the decrease start value, and sets the sum as a secondary indicated value in the RAM905. As a result, the control program module32executes the power conversion control process based on the secondary indicated value set in the RAM905.

Upon completion of the write of the secondary indicated values in step S30A, in step S42, the resetting unit37C of the parameter setting unit37starts the predetermined process of decreasing the variable value portion stored in the RAM905from the decrease start value. As described above, the resetting unit37C sequentially subtracts, for example, the appropriate decrease deviation A from the decrease start value. The resetting unit37C thus overwrites and updates the value stored in the RAM905each time this process ends.

In step S52, the resetting unit37C of the parameter setting unit37writes again into the RAM905the primary indicated value representing the sum of the variable value portion taking the initial value and the fixed value portion. The resetting unit37C thus overwrites and updates the value stored in the RAM905with the primary indicated value. As a result, the control program module32executes the power conversion control process based on the primary indicated value again. After step S52, the processing proceeds to step S65in which the parameter setting unit37determines whether the parameter setting mode is selected, in a manner similar to that inFIG. 7.

The determination in step S65is satisfied (S65: YES) during a period in which the parameter setting mode is selected through the external terminal13in a manner similar to that inFIG. 7. The processing then returns to step S15. On the other hand, when the external terminal13cancels the selection of the parameter setting mode, the determination in step S65is not satisfied (S65: NO). The processing thus ends.

Exemplary Advantageous Effects of the Present Modification

The present modification produces advantageous effects similar to those produced in the foregoing embodiment. Also in the present modification, first, the primary setting unit37A of the parameter setting unit37sets the primary indicated value of the specific parameter in the RAM905. When the operator performs the parameter change instructing operation through the external terminal13in order to temporarily change the primary indicated value thus set, the secondary setting unit37B sets in the RAM905the secondary indicated value in accordance with the parameter change instructing operation, in place of the stored primary indicated value. The resetting unit37C of the parameter setting unit37resets in the RAM905the initial primary indicated value in place of the stored secondary indicated value when the predetermined return requirement is satisfied after the secondary indicated value is set. As a result, in the case where the operator temporarily changes the value of the specific parameter through the operation by himself or herself, the changed value of the specific value is automatically returned to the initial value even when the operator does not perform the subsequent operation. This results in improvement of convenience for the operator. Also in the present modification, a typical example of an advantageous effect includes an advantageous effect to be produced in a case of using, as the specific parameter, the threshold value for issuing an alarm.

According to the present modification, the primary setting unit37A sets the sum of the fixed value portion and the variable value portion taking the initial value, as the primary indicated value in the RAM905. When the operator temporarily changes the value of the specific parameter, the secondary setting unit37B sets a sum of the fixed value portion and the decrease start value substituted into the variable value portion, as the secondary indicated value in the RAM905. The value of the variable value portion sequentially decreases from the decrease start value after the secondary indicated value is set. The return requirement is satisfied on condition that the value of the variable value portion decreases to the initial value. In response to this, when the value of the variable value portion returns to the initial value, the resetting unit37C resets in the RAM905the primary indicated value representing the sum of the fixed value portion and the initial value of the variable value portion. With this method, the value of the specific parameter is returned to the initial value without the necessity of particularly providing in the RAM905the save area905B for saving the primary indicated value, unlike the foregoing embodiment.

Other Modifications

In the foregoing description, the motor control device12includes the converter21and the inverter22. Specifically, the motor control device12includes the inverter circuit that generates a variable-frequency three-phase AC output from the AC power source15. However, the configuration of the motor control device12is not limited thereto. For example, the motor control device12may include a typical voltage inverter, a current inverter or any inverter circuit. The parameter setting and changing method according to the foregoing embodiment is applicable to a motor control device having a function of driving the motor11while optionally controlling the rotation speed of the motor11. Accordingly, the foregoing method may be applied to, for example, at least one specific parameter among a plurality of control parameters for a servo controller or a servo amplifier that controls a driven state of a servo motor. This case also produces advantageous effects similar to those described above.

InFIGS. 1, 3, and 4, arrows each indicate an exemplary flow of a signal and do not intend to limit a direction in which a signal flows.

The flowchart ofFIG. 7and the flowchart ofFIG. 9do not intend to limit the foregoing embodiment and modifications to the procedures inFIGS. 7 and 9. In these procedures, for example, addition or omission of a step or change of step order may be made within a range departing from the scope and technical idea of the disclosure.

In addition to the foregoing description, the methods according to the embodiment and modifications may be used in combination as appropriate.

Although not exemplified in detail, the foregoing embodiment and others may be modified variously within a range departing from the scope of the disclosure.