Electronic motor protection relay device

Abstract

To detect ON / OFF of a plurality of types of AC operation voltages without using a physical switching method.SOLUTION: An MMR 1 includes: an input circuit 2 that converts an AC operation voltage VAC input from the outside into a binary signal and outputs the binary signal; a determination part 12 that determines ON / OFF of an operation voltage VAC based on a length of a HIGH period that is a period in which a determination signal that is a signal output from the input circuit 2 is at a HIGH level; a storage part 4 that stores a voltage setting value that is a setting value of a voltage of a use operation voltage that is an operation voltage to be used; and a threshold setting part 13 that sets a threshold based on the voltage setting value stored in the storage unit 4. The determination part 12 determines that the operation voltage VAC is ON when the length of the HIGH period is larger than a threshold value, and determines that the operation voltage VAC is OFF when the length of the HIGH period is equal to or smaller than the threshold value.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] SUMMARY OF THE INVENTION An embodiment of the present invention relates to an electronic motor protection relay device. [Background technology]

[0002] Conventionally, the operating voltage of the AC input terminal of a multifunction relay for motors, which is an electronic motor protection relay device, is two types: AC100V (50Hz / 60Hz) and AC200V (50Hz / 60Hz), so by using a jumper pin to switch the AC input circuit in the MMR, it has been possible to detect the on / off of the two types of operating voltage.In this specification, the multifunction relay for motors will sometimes be referred to as MMR.

[0003] However, the above-mentioned jumper pins must be connected to the MMR circuit for each AC input terminal, which increases the number of steps and parts required. Given these circumstances, there is a need for a method to detect the on / off status of multiple types of operating voltages without using physical switching methods such as jumper pins. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 1-049978 Summary of the Invention [Problem to be solved by the invention]

[0005] Therefore, an electronic motor protection relay device is provided that can detect the on / off of multiple types of AC operating voltages without using a physical switching method. [Means for solving the problem]

[0006] The electronic motor protection relay device of this embodiment includes an input circuit that converts an AC operating voltage input from outside into a binary signal and outputs the binary signal, a determination unit that determines whether the operating voltage is on or off based on the length of a first period during which a determination signal output from the input circuit is at a first level, a memory unit that stores a voltage setting value that is a setting value of an operating voltage to be used, and a threshold setting unit that sets a threshold based on the voltage setting value stored in the memory unit. The determination unit determines that the operating voltage is on if the length of the first period is greater than the threshold, and determines that the operating voltage is off if the length of the first period is equal to or less than the threshold. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a diagram illustrating a configuration of an MMR according to a first embodiment; [Figure 2] 1 is a timing chart showing waveforms of various parts when the frequency of the operation voltage according to the first embodiment is 50 Hz; [Figure 3] 1 is a timing chart showing waveforms of various parts when the frequency of the operation voltage according to the first embodiment is 60 Hz; [Figure 4] FIG. 10 is a diagram showing an example of the specific contents of main processing according to the first embodiment; [Figure 5] FIG. 10 is a diagram showing an example of specific contents of initialization processing according to the first embodiment; [Figure 6] FIG. 10 is a diagram showing an example of specific content of loop processing according to the first embodiment; [Figure 7] FIG. 10 is a diagram schematically illustrating a first display example of a warning display according to the first embodiment; [Figure 8] FIG. 10 is a diagram schematically illustrating a second display example of a warning display according to the second embodiment; [Figure 9] FIG. 10 is a diagram showing an example of specific contents of initialization processing according to the second embodiment; [Figure 10] FIG. 10 is a diagram showing an example of the specific contents of loop processing according to the second embodiment. [Figure 11] FIG. 10 is a diagram illustrating the configuration of an MMR according to a third embodiment. [Figure 12] FIG. 11 is a diagram showing an example of specific content of loop processing according to the third embodiment. [Figure 13] FIG. 10 is a diagram schematically illustrating a third example of a warning display according to the third embodiment; DETAILED DESCRIPTION OF THE INVENTION

[0008] Hereinafter, several embodiments will be described with reference to the drawings. Note that substantially the same components in the respective embodiments will be denoted by the same reference numerals, and the description thereof will be omitted. (First embodiment) The first embodiment will be described below with reference to FIGS.

[0009] <Configuration of multi-function relay for motor> As shown in Figure 1, the MMR1 of this embodiment corresponds to an electronic motor protection relay device and includes an input circuit 2, a control unit 3, a memory unit 4, a display unit 5, and an operation unit 6. The input circuit 2 converts an externally input AC operating voltage VAC into a binary signal and outputs it. The operating voltage VAC is an AC signal generated by an AC power source 7, and its effective value determines its on / off state. The input circuit 2 includes input terminals Pi1 and Pi2, a capacitor C1, resistors R1 and R2, a photocoupler 8, and an output terminal Po.

[0010] The input terminal Pi1 is connected to one terminal of the AC power supply 7, and the input terminal Pi2 is connected to the other terminal of the AC power supply 7. The capacitor C1, which is a film capacitor for example, is provided primarily for the purpose of removing noise superimposed on the operating voltage VAC. One terminal of the capacitor C1 is connected to the input terminal Pi1, and the other terminal is connected to a node N1 via a resistor R1. The resistor R2 is connected between the node N1 and a node N2. The node N2 is connected to the input terminal Pi2.

[0011] Resistors R1 and R2 form a voltage divider circuit 9 that divides the operating voltage VAC. The voltage divider circuit 9 divides the operating voltage VAC at a predetermined voltage division ratio and outputs the resulting voltage to the photocoupler 8 via nodes N1 and N2. The photocoupler 8 includes two light-emitting diodes D1 and D2 connected in antiparallel and a phototransistor Q1. The anode of the light-emitting diode D1, i.e., the cathode of the light-emitting diode D2, is connected to node N1. The cathode of the light-emitting diode D1, i.e., the anode of the light-emitting diode D2, is connected to node N2.

[0012] A DC voltage VDC, for example +5 V, is applied to the collector of phototransistor Q1. The emitter of phototransistor Q1 is connected to the output terminal Po of input circuit 2. Although not shown in the figure, output terminal Po is pulled down to ground, which is the reference potential (=0 V) of the circuit, via a resistor. The signal output from output terminal Po of input circuit 2 is a binary square wave signal as shown in Figures 2 and 3.

[0013] In this specification, for the binary signals in Figures 2 and 3, a relatively high level is referred to as a HIGH level, and a relatively low level is referred to as a LOW level. The HIGH level corresponds to the first level, e.g., +5 V. The LOW level is, e.g., 0 V. In the following description, the output signal of the input circuit 2 may be referred to as a determination signal. The upper waveforms in Figures 2 and 3 show the waveforms of the operating voltage VAC after it has been rectified via the light-emitting diodes D1 and D2 of the photocoupler 8.

[0014] 2 and 3, with the input circuit 2 configured as described above, during the period when a voltage equal to or greater than the photocoupler ON voltage Von is applied between nodes N1 and N2, a current flows through light-emitting diodes D1 and D2, and regardless of the direction of the current, phototransistor Q1 turns on and the determination signal goes to a HIGH level. The photocoupler ON voltage is determined by the characteristics of each element of photocoupler 8. Furthermore, with the input circuit 2 configured as described above, during the period when a voltage less than the photocoupler ON voltage Von is applied between nodes N1 and N2, no current flows through light-emitting diodes D1 and D2, phototransistor Q1 turns off, and the determination signal goes to a LOW level, as shown in FIGS.

[0015] 2 and 3, the HIGH period during which the determination signal is at a HIGH level varies depending on the voltage value of the operating voltage VAC. The HIGH period corresponds to the first period. Specifically, the length of the HIGH period when the operating voltage VAC is AC 200V is longer than the length of the HIGH period when the operating voltage VAC is AC 100V.

[0016] The control unit 3 includes a receiving unit 10 such as an input port, and a processing unit 11. The processing unit 11 is configured with an arithmetic processing device including a CPU, RAM, ROM, etc. The processing unit 11 includes functional blocks such as a determining unit 12, a threshold setting unit 13, and a determination time setting unit 14. Each of these functional blocks is realized by the CPU of the processing unit 11 executing a computer program stored in the ROM or the like to perform processing corresponding to the computer program, that is, by software. Note that at least a portion of each functional block may be configured to be realized by hardware.

[0017] The receiving unit 10 is an input port or the like, and inputs the determination signal output from the input circuit 2 to the CPU of the processing unit 11. As described above, the determination signal output from the input circuit 2 is a high-level or low-level voltage, and therefore the voltage at the receiving unit 10 is also a similar voltage. The determining unit 12 determines whether the operating voltage VAC is on or off based on the length of the high-level period during which the determination signal is at a high level. In this case, the high-level period corresponds to the first period.

[0018] The storage unit 4 is, for example, a nonvolatile memory, and stores a voltage setting value, which is a setting value of the operating voltage to be used (VAC), and a frequency setting value, which is a setting value of the frequency of the operating voltage to be used. These values ​​are determined in advance according to the specifications of various types of equipment including the MMR1, and the determined values ​​are written to the storage unit 4. Specifically, there are two voltage setting values, AC 100V and AC 200V, and two frequency setting values, 50Hz and 60Hz.

[0019] The threshold setting unit 13 sets a threshold based on the voltage setting value and the frequency setting value stored in the storage unit 4. In this case, the threshold setting unit 13 sets a threshold number of times corresponding to the threshold. The threshold number of times is set corresponding to a combination of two types of voltage setting values ​​and two types of frequency setting values. In other words, four threshold numbers are set: one corresponding to AC 100V / 50Hz, one corresponding to AC 100V / 60Hz, one corresponding to AC 200V / 50Hz, and one corresponding to AC 200V / 60Hz. The threshold setting unit 13 can store the set threshold or threshold number of times in the storage unit 4.

[0020] The judgment time setting unit 14 sets the judgment time Ta based on the frequency setting value stored in the storage unit 4. The judgment time Ta can be set to a time that satisfies the condition of the following equation (1), where f represents the frequency setting value and n represents a natural number. Ta = (n / f) × 0.5 …(1) The judgment time setting unit 14 can store the set judgment time Ta in the storage unit 4.

[0021] In this embodiment, the determination time Ta is set to the reciprocal of the frequency setting value f, that is, the time for one cycle of the expected operating voltage V AC. Specifically, the determination time Ta is set to 20 ms when the frequency setting value is 50 Hz, and to 16.6 ms when the frequency setting value is 60 Hz.

[0022] The determination unit 12 determines that the operating voltage VAC is on if the length of the HIGH period is greater than a threshold, and determines that the operating voltage VAC is off if the length of the HIGH period is equal to or less than the threshold. Note that in this specification, the operating voltage VAC being on means that the operating voltage VAC is input to the MMR1, and the operating voltage VAC being off means that the operating voltage VAC is not input to the MMR1.

[0023] In this case, the determination unit 12 includes a counter that counts the number of times the determination signal becomes HIGH level at regular intervals. The regular interval may be, for example, the period of an operating clock in the control unit 3. Specifically, the counter of the determination unit 12 performs counting operations at timings shown in Figures 2 and 3. If the count number by the counter within the determination time Ta is greater than a threshold number, the determination unit 12 determines that the length of the HIGH period is greater than the threshold and determines that the operation voltage VAC is ON. If the count number is equal to or less than the threshold number, the determination unit 12 determines that the length of the HIGH period is equal to or less than the threshold and determines that the operation voltage VAC is OFF.

[0024] The display unit 5 is, for example, a 7-segment LED, a display, or the like, and performs various displays on the MMR 1 based on a display control signal provided by the control unit 3. If the count number continues for a certain period of time to indicate a number close to a threshold number determined based on a voltage setting value and a frequency setting value of another operation voltage different from the operation voltage in use, the determination unit 12 uses the display unit 5 to display a warning prompting the user to check the operation voltage in use and to change the setting of the operation voltage in use.

[0025] The operation unit 6 is, for example, various operation means such as operation keys, operation buttons, and a touch panel that can be operated by the user, and accepts various operations related to the MMR 1 and outputs operation signals indicating the results to the control unit 3. The MMR 1 of this embodiment is configured so that, when the determination unit 12 has displayed a warning using the display unit 5, the user can change the voltage setting value and frequency setting value of the operating voltage to be used by operating the operation unit 6.

[0026] <Processing related to on / off detection of operating voltage> Next, the specific contents of the process for detecting the on / off of the operating voltage VAC by the MMR1 configured as described above will be described with reference to FIGS. 4 to 8. After the control power is input to the CPU and reset is released, the control unit 3 of the MMR 1 executes the main process as shown in FIG. 4. In the main process, an initialization process is executed in step S101. The initialization process has contents as shown in FIG. 5, for example. When the initialization process starts, step S201 is executed first. In step S201, the voltage setting value and frequency setting value of the operating voltage VAC are read from the memory unit 4.

[0027] After step S201 is executed, the process proceeds to step S202, where a threshold number of times THa is set corresponding to the combination of the voltage setting value and the frequency setting value read out in step S201. If the threshold number of times is stored in the storage unit 4, the corresponding threshold number of times can be read out in step S202. In step S203, a determination time Ta is set based on the frequency setting value read out in step S201. If the determination time Ta is stored in the storage unit 4, the corresponding determination time Ta can be read out in step S203. After step S203 is executed, the initialization process ends.

[0028] After the initialization process is completed, the process proceeds to step S102, where loop processing is executed. In this case, step S102 is executed repeatedly. The loop processing has, for example, the contents as shown in FIG. 6. When the loop processing starts, step S301 is executed first. In step S301, the count number Cnt for the determination time Ta set in the initialization process is acquired. As described above, the count number Cnt is a number that indicates the number of times the determination signal becomes HIGH level.

[0029] After step S301 is executed, the process proceeds to step S302, where it is determined whether the count number Cnt is greater than the threshold number THa set in the initialization process. If the count number Cnt is greater than the threshold number THa, the result in step S302 is "YES," and the process proceeds to step S303. In step S303, it is determined that the operating voltage VAC is on, that is, the on state of the operating voltage VAC is detected. On the other hand, if the count number Cnt is equal to or less than the threshold number THa, the result in step S302 is "NO," and the process proceeds to step S304. In step S304, it is determined that the operating voltage VAC is off, that is, the off state of the operating voltage VAC is detected.

[0030] The processing of steps S301 to S304 described above is processing for detecting whether the operation voltage is on or off. As shown in Figures 2 and 3, the count number Cnt within the determination time Ta differs between an operation voltage value of AC 100V and an operation voltage value of AC 200V, and it is clear that the count number Cnt within the determination time Ta differs between an operation voltage frequency of 50Hz and an operation voltage frequency of 60Hz. Therefore, according to the processing of steps S301 to S304 described above, since the voltage value and frequency of the operation voltage being used are known, it is possible to accurately detect whether the operation voltage is on or off regardless of any combination of voltage value and frequency.

[0031] After executing step S303 or S304, the process proceeds to step S305. The processes of steps S305 to S306 are processes for detecting an incorrect setting for the operating voltage VAC to be used. For example, if the operating voltage to be applied is AC 100V but the operating voltage setting is mistakenly set to AC 200V, the count number Cnt is smaller than the threshold number THa set for AC 200V, and the operating voltage will be detected as OFF even when it is ON. The processes of steps S305 to S306 make it possible to detect such an error and notify the user.

[0032] In step S305, it is determined whether the count number Cnt is in a state where it indicates a number of times close to the threshold number of times that the input of another operating voltage different from the used operating voltage is turned on. If the count number Cnt is not in a state where it indicates a number of times close to the threshold number of times that the input of another operating voltage is turned on, the result in step S305 is "NO," step S306 is skipped, and the loop processing ends.

[0033] On the other hand, if the count number Cnt is close to the threshold number of times for turning on the input of another operating voltage, the result in step S305 becomes "YES" and the process proceeds to step S306. Note that step S305 may be modified so that the result is "YES" when the condition that the above-mentioned state continues for a certain period of time is satisfied. In step S306, a warning is displayed on the display unit 5. After step S306 is executed, the loop process ends.

[0034] Specifically, the warning display may be, for example, a first display example as shown in FIG. 7 or a second display example as shown in FIG. 8. These display examples assume that the operating voltage in use is set to AC200V by mistake, even though an operating voltage of AC100V has been input. In the first display example, the message "The operating voltage entered may be 100V. Please check the operating voltage and operating voltage setting" is displayed to prompt the user to check that the input operating voltage is different from the operating voltage in use.

[0035] In the second display example, in addition to the same message as in the first display example, a message asking whether or not to change the operating voltage is displayed: "Do you want to change the operating voltage?", and touch-operable operation keys [YES] and [NO] are displayed. These operation keys are realized as functions of the operation unit 6. In this case, when the [YES] key is pressed, the screen transitions to a screen for changing the voltage setting value and frequency setting value of the operating voltage in use, and when the [NO] key is pressed, the warning display ends. If the user checks the warning display and realizes that there is an error in the settings, they can change the voltage setting value and frequency setting value of the operating voltage in use by pressing the [YES] key.

[0036] According to the present embodiment described above, it is possible to detect the on / off state of the operating voltage VAC regardless of the combination of the voltage value and frequency of the input operating voltage VAC. Moreover, in this case, there is no need for a physical switching method such as switching the input circuit using a jumper pin or providing multiple input circuits, and the on / off state of the operating voltage VAC can be detected using a single input circuit 2. Therefore, according to this embodiment, it is possible to obtain the excellent effect of being able to detect the on / off states of multiple types of AC operating voltages without using a physical switching method.

[0037] 2 and 3, the count number Cnt within the determination time Ta differs between an AC 100V and an AC 200V operating voltage, and the count number Cnt within the determination time Ta differs between an AC 50Hz and an AC 60Hz operating voltage frequency. In this embodiment, taking these factors into consideration, the determination time Ta is set based on the frequency setting, and the threshold number THa is set based on the voltage setting and the frequency setting. The determination unit 12 then determines whether the count number Cnt, which is the number of times the determination signal becomes HIGH level within the determination time Ta, is greater than the threshold number THa, and determines whether the operating voltage VAC is on or off based on the determination result. This allows for accurate detection of the on / off state of the operating voltage VAC, regardless of the combination of the voltage value and frequency of the operating voltage.

[0038] When the count number Cnt continues for a certain period of time to indicate a number of times close to a threshold number of times determined based on a voltage setting value and a frequency setting value of an operation voltage different from the operation voltage in use, the determination unit 12 displays a warning using the display unit 5 to prompt the user to check the operation voltage in use and change the setting of the operation voltage in use. In this way, the user can easily notice an error in their own setting by checking the warning display.

[0039] Furthermore, in this embodiment, when the warning display is on, the voltage setting value and frequency setting value of the operating voltage to be used can be changed by operating the operation unit 6. With this configuration, if the user checks the warning display and realizes that there is an error in the settings, they can easily and quickly change the voltage setting value and frequency setting value of the operating voltage to be used by operating the operation unit 6.

[0040] (Second embodiment) The second embodiment will be described below with reference to FIGS. In this embodiment, the content of the processing executed by the processing unit 11 of the control unit 3 is different from that in the first embodiment, but the configuration is the same as that of the first embodiment. In the processing unit 11 of this embodiment, the threshold setting unit 13 sets a threshold time THb corresponding to the threshold based on the voltage setting value and the frequency setting value stored in the storage unit 4.

[0041] The threshold time THb is set corresponding to a combination of two types of voltage setting values ​​and two types of frequency setting values. That is, four threshold times THb are set: one corresponding to AC 100V / 50Hz, one corresponding to AC 100V / 60Hz, one corresponding to AC 200V / 50Hz, and one corresponding to AC 200V / 60Hz. The threshold setting unit 13 can store the set threshold times in the storage unit 4.

[0042] In the processing unit 11 of this embodiment, the determination unit 12 has a period detection function that detects the length of the HIGH period of the determination signal. This period detection function can be realized, for example, by detecting the time from the rising edge to the falling edge of the determination signal. If the period Tb corresponding to the length of the HIGH period detected by the period detection function is longer than a threshold time THb, the determination unit 12 determines that the length of the HIGH period is greater than the threshold and determines that the operating voltage VAC is ON. If the period Tb is equal to or shorter than the threshold time THb, the determination unit 12 determines that the length of the HIGH period is equal to or shorter than the threshold and determines that the operating voltage VAC is OFF.

[0043] Next, the specific details of the process for detecting the on / off state of the operating voltage VAC by the MMR1 of this embodiment will be described with reference to FIGS. 9 and 10. In this embodiment, the contents of the initialization process and loop process are different from those of the first embodiment. As shown in FIG. 9, the initialization process of this embodiment differs from the initialization process of the first embodiment shown in FIG. 5 in that step S212 is provided instead of step S202. In step S212, a threshold time THb corresponding to the combination of the voltage setting value and the frequency setting value read in step S201 is set. Note that if the threshold time is stored in the storage unit 4, the corresponding threshold time can be read in step S212.

[0044] As shown in Fig. 10, the loop processing of this embodiment differs from the loop processing of the first embodiment shown in Fig. 6 in that steps S311, S312, and S315 are provided instead of steps S301, S302, and S305. In step S311, the length of period Tb, specifically the total length of period Tb within the determination time Ta set in the initialization process, is confirmed. As described above, period Tb represents the length of the HIGH period during which the determination signal is at a HIGH level.

[0045] After step S311 is executed, the process proceeds to step S312, where it is determined whether the period Tb is longer than the threshold time THb set in the initialization process. If the period Tb is longer than the threshold time THb, the result in step S312 is "YES," and the process proceeds to step S303. On the other hand, if the period Tb is equal to or shorter than the threshold time THb, the result in step S312 is "NO," and the process proceeds to step S304. In this embodiment, the processes in steps S311, S312, S303, and S304 correspond to the process of detecting whether the operating voltage is on or off.

[0046] 2 and 3, it is clear that the length of the HIGH period of the determination signal differs between an operation voltage value of AC 100V and an operation voltage value of AC 200V, and that the length of the HIGH period of the determination signal differs between an operation voltage frequency of 50Hz and an operation voltage frequency of 60Hz. Therefore, even by performing the processes of steps S311, S312, S303, and S304 described above, the voltage value and frequency of the operation voltage being used are known, and therefore it is possible to accurately detect whether the operation voltage is on or off regardless of any combination of voltage value and frequency.

[0047] In this embodiment, the processes of steps S315 and S306 correspond to processes for detecting an incorrect setting for the operating voltage VAC to be used. The processes of steps S315 and S306 also enable the detection of an incorrect setting and the notification to the user. In step S315, it is determined whether the period Tb indicates a time close to the threshold time for turning on the input of an operating voltage different from the operating voltage to be used.

[0048] Here, if the period Tb is not in a state indicating a time close to the threshold time for turning on the input of another operating voltage, the result in step S315 is "NO," step S306 is skipped, and the loop processing ends. On the other hand, if the period Tb is in a state indicating a time close to the threshold time for turning on the input of another operating voltage, the result in step S315 is "YES," and the process proceeds to step S306. Note that step S315 may be modified so that it is determined to be "YES" if the condition that the above-mentioned state has continued for a certain period of time is met.

[0049] According to the present embodiment described above, as in the first embodiment, it is possible to detect the on / off state of the operating voltage VAC regardless of the combination of the voltage value and frequency of the input operating voltage VAC without using a physical switching method. Therefore, as in the first embodiment, this embodiment also provides the excellent effect of being able to detect the on / off states of multiple types of AC operating voltages without using a physical switching method.

[0050] (Third embodiment) Hereinafter, a third embodiment in which the configuration of the processing unit is modified from that of the first embodiment will be described with reference to FIGS. As shown in FIG. 11, the processing unit 23 provided in the control unit 22 of the MMR 21 of this embodiment differs from the processing unit 11 of the first embodiment in that functional blocks, namely a detection unit 24 and an automatic setting unit 25, have been added.

[0051] The detection unit 24 detects the voltage value and frequency value of the operating voltage to be used based on the count number Cnt when the operating voltage to be used is input. The automatic setting unit 25 automatically sets each setting value by writing each value detected by the detection unit 24 into the memory unit 4 as a voltage setting value and a frequency setting value.

[0052] Next, the specific details of the process for detecting the on / off state of the operating voltage VAC by the MMR 21 of this embodiment will be described with reference to Figures 12 and 13. In this embodiment, the contents of the loop process are different from those of the first embodiment. As shown in Figure 12, the loop process of this embodiment differs from the loop process of the first embodiment shown in Figure 6 in that step S326 is provided instead of step S306.

[0053] In this embodiment, the processes of steps S305 and S326 correspond to the process of detecting that the operating voltage VAC to be used is incorrect. The processes of steps S305 and S326 also enable the detection of a setting error and the notification to the user. In step S326, a warning is displayed on the display unit 5. Specifically, as the warning display of this embodiment, for example, a third display example as shown in FIG. 13 can be adopted. The third display example also assumes the same case as the first and second display examples described in the first embodiment.

[0054] In the third display example, in addition to the same message as the first display example shown in FIG. 7, a message asking whether or not to automatically set the operating voltage, "Do you want to automatically set the operating voltage?", and touch-operable operation keys [YES] and [NO] are displayed. These operation keys are realized as functions of the operation unit 6. In this case, when the [YES] key is operated, the voltage setting value and frequency setting value of the operating voltage to be used are automatically set to values ​​corresponding to the voltage value and frequency of the operating voltage currently input, by the functions of the detection unit 24 and the automatic setting unit 25. In addition, in this case, when the [NO] key is operated, the warning display ends.

[0055] According to the present embodiment described above, in addition to the same effects as those of the first embodiment, the following effect can be obtained. That is, in this embodiment, when a warning display is displayed, by operating the operation unit 6, the voltage set value and frequency set value of the operating voltage to be used are automatically set to values ​​corresponding to the voltage value and frequency of the operating voltage currently input. With this configuration, if the user notices an error in the settings after checking the warning display, they can automatically set the voltage set value and frequency set value of the operating voltage to be used by simply operating one operation key on the operation unit 6, thereby obtaining the effect of improving convenience.

[0056] (Other embodiments) The present invention is not limited to the embodiments described above and illustrated in the drawings, but can be arbitrarily modified, combined, or expanded without departing from the spirit of the invention. The numerical values ​​and the like shown in the above embodiments are examples and are not limited to these.

[0057] In the second embodiment, the judgment unit 12 judges whether the operating voltage VAC is on or off based on the total length of the periods Tb within the judgment time Ta, but this can be modified to judge whether the operating voltage VAC is on or off based on the length of at least one period Tb within the judgment time Ta.

[0058] Although several embodiments of the present invention have been described above, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be embodied in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included within the scope and spirit of the invention, and are also included in the scope of the invention and its equivalents as defined in the claims. [Explanation of symbols]

[0059] 1, 21...MMR, 2...input circuit, 4...memory unit, 5...display unit, 6...operation unit, 12...judgment unit, 13...threshold setting unit, 14...judgment time setting unit, 24...detection unit, 25...automatic setting unit.

Claims

1. an input circuit (2) that converts an AC operating voltage input from the outside into a binary signal and outputs the binary signal; a determination unit (12) that determines whether the operating voltage is on or off based on the length of a first period during which a determination signal that is a signal output from the input circuit is at a first level; a memory unit (4) for storing a voltage setting value that is a setting value of the operating voltage to be used; a threshold setting unit (13) that sets a threshold based on the voltage setting value stored in the storage unit; Equipped with The determination unit determines that the operating voltage is on when the length of the first period is greater than the threshold value, and determines that the operating voltage is off when the length of the first period is equal to or less than the threshold value.

2. The storage unit further stores a frequency setting value that is a setting value of the frequency of the operating voltage to be used, Further, a judgment time setting unit (14) is provided which sets a judgment time based on the frequency setting value stored in the storage unit, the threshold setting unit sets a threshold number of times corresponding to the threshold based on the voltage setting value and the frequency setting value stored in the storage unit, The determination unit a counter that counts the number of times the determination signal reaches the first level at regular intervals; If the count number by the counter within the determination time is greater than the threshold number of times, it is determined that the length of the first period is greater than the threshold value and that the operating voltage is turned on; 2. The electronic motor protection relay device according to claim 1, wherein when the count number is equal to or less than the threshold number, it is determined that the length of the first period is equal to or less than the threshold and that the operating voltage is turned off.

3. Further, a display unit (5) is provided, 3. The electronic motor protection relay device according to claim 2, wherein, when the count value indicates a number close to the threshold number determined based on the voltage setting value and the frequency setting value of another operating voltage different from the operating voltage, the determination unit uses the display unit to display a warning to prompt the user to check the operating voltage and change the setting of the operating voltage.

4. Further, an operation unit (6) is provided, 4. An electronic motor protection relay device as described in claim 3, wherein when the judgment unit has displayed the warning using the display unit, the voltage setting value and the frequency setting value of the operating voltage can be changed by operating the operation unit.

5. moreover, a detection unit (24) that detects a voltage value and a frequency value of the operating voltage in use based on the count number when the operating voltage in use is input; an automatic setting unit (25) that automatically sets each set value by writing each value detected by the detection unit into the storage unit as the voltage set value and the frequency set value; 5. An electronic motor protection relay device according to claim 2, further comprising:

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