Relay state prediction device, relay state prediction system, relay state prediction method and recording medium

Abstract

The relay state prediction device (10) of the present invention comprises: a voltage value acquisition unit (22), which measures the detection voltage detected from both ends of the shunt resistor at all times; a voltage value difference calculation unit (28a), which calculates the voltage value difference between a first voltage value when the detection voltage becomes extremely small due to the armature starting to move after the primary side switch is disconnected and a second voltage value when the secondary side contact is disconnected; a slope calculation unit (28b), which calculates the slope of the voltage value difference decreasing as the secondary side contact is repeatedly opened and closed according to the repeated connection and disconnection of the primary side switch; and a state prediction unit (28c), which predicts the number of possible opening and closing times from the current time until the voltage value difference reaches a preset threshold value based on the current voltage value difference and the decreasing slope.

Description

Technical Field

[0001] The present invention relates to a relay state prediction device, a relay state prediction system, a relay state prediction method and a program, for example, to a relay state prediction device, a relay state prediction system, a relay state prediction method and a program, which can predict the number of times a relay can be opened and closed until deterioration occurs by connecting and disconnecting the power to the coil on the primary side to open and close the contacts on the secondary side. Background Art

[0002] In the past, as a relay state prediction device of this type, for example, as disclosed in Japanese Patent Gazette No. 2013-89603, when the relay is disconnected, the maximum value of the current flowing in the operating coil (actuating coil) on the primary side of the relay is measured, and when the maximum value is lower than a predetermined threshold value, it is predicted to be degraded.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2013-89603 Summary of the invention

[0006] Problem that the invention aims to solve

[0007] However, the technology described in Patent Document 1 (Japanese Patent Application Laid-Open No. 2013-89603) does not disclose predicting the number of times a relay can be opened and closed until it deteriorates, that is, the remaining life.

[0008] Therefore, an object of the present invention is to provide a relay state prediction device, a relay state prediction system, a relay state prediction method, and a program capable of predicting the remaining life of a relay.

[0009] Solutions for solving problems

[0010] Therefore, the relay state prediction device disclosed in the present invention predicts the number of times a relay can be opened and closed until it deteriorates. The relay state prediction device is characterized in that the relay includes a primary side switch, an operating coil and a shunt resistor connected in series with a primary side power supply, and the relay includes a diode, which is connected in parallel with the series connection of the operating coil and the shunt resistor and is connected in the following direction: the direction allows the current caused by the back electromotive force of the operating coil to flow to the shunt resistor when the primary side switch is disconnected, and the relay includes an armature, which opens and closes at least one pair of secondary side contacts according to the connection and disconnection of the primary side switch, and when the primary side switch is turned on, the armature uses the electromagnetic force generated by the operating coil to move relative to the operating coil. In response to the displacement, the secondary side contact of one side is brought into contact with the secondary side contact of the other side while being bent by a certain amount of pressing, and the relay state prediction device comprises: a voltage value acquisition unit, which constantly measures the detection voltage detected from both ends of the shunt resistor; a voltage value difference calculation unit, which calculates the voltage value difference between a first voltage value when the detection voltage becomes extremely small due to the start of displacement of the armature after the primary side switch is disconnected and a second voltage value when the secondary side contact is disconnected; a slope calculation unit, which calculates the slope of the voltage value difference as the secondary side contacts are repeatedly opened and closed according to the repeated connection and disconnection of the primary side switch; and a state prediction unit, which predicts the number of possible opening and closing times from the current time until the voltage value difference reaches a preset threshold value based on the current voltage value difference and the decreasing slope.

[0011] In the disclosed relay state prediction device, the voltage value acquisition unit constantly measures the detection voltage detected from both ends of the shunt resistor. The voltage value difference calculation unit calculates the voltage value difference between the first voltage value when the detection voltage becomes extremely small due to the armature starting to displace after the primary side switch is disconnected and the second voltage value when the secondary side contact is disconnected. The slope calculation unit calculates the slope of the voltage value difference as the secondary side contact is repeatedly opened and closed according to the repeated connection and disconnection of the primary side switch. The state prediction unit predicts the number of times that the voltage value difference can be opened and closed from the current time until the voltage value difference reaches a preset threshold value based on the current voltage value difference and the decreasing slope. Here, it is known from experience that as the number of opening and closing increases (i.e., deterioration), the voltage value difference decreases approximately like a linear function. Therefore, it is possible to predict the number of times that the voltage value difference can be opened and closed from the current time until the voltage value difference reaches a preset threshold value, that is, the remaining life of the relay.

[0012] In the relay state prediction device according to one embodiment, the slope calculation unit calculates a slope of a current value decrease obtained by dividing the voltage value difference by a value of the shunt resistor.

[0013] In this specification, "the current value obtained by calculating the voltage difference between the first voltage value when the detection voltage becomes extremely small due to the armature starting to move after the primary switch is disconnected and the second voltage value when the secondary contact is disconnected, and dividing the voltage difference by the value of the shunt resistor" (referred to as "RUS (Reset Undershoot)") refers to the current value flowing in the operating coil during the period from when the pressure pressing the secondary movable contact changes from a certain value to zero. This corresponds to the amount of armature pressed in, and when the amount of pressed in decreases, the armature has deteriorated.

[0014] In the relay state prediction device of this embodiment, the slope calculation unit calculates the slope of the current value decrease obtained by dividing the voltage value difference by the value of the shunt resistor. Therefore, the remaining life of the relay can be predicted based on the current value (ie, RUS).

[0015] In one embodiment, the relay state prediction device further includes a notification unit configured to notify the predicted possible number of switching operations.

[0016] In the relay state prediction device of this embodiment, the user can quantitatively recognize the remaining life of the relay until it deteriorates by receiving the above notification, so that the user can quickly take measures such as replacing the relay.

[0017] On the other hand, the relay state prediction system disclosed in the present invention comprises: a relay, which includes a primary side switch, an operating coil and a shunt resistor connected in series with a primary side power supply, the relay includes a diode, which is connected in parallel with the series connection of the operating coil and the shunt resistor and is connected in the following direction: the direction allows the current caused by the back electromotive force of the operating coil to flow to the shunt resistor when the primary side switch is disconnected, and the relay includes an armature, which opens and closes at least one pair of secondary side contacts according to the connection and disconnection of the primary side switch, and when the primary side switch is connected, the armature is relatively displaced relative to the operating coil by the electromagnetic force generated by the operating coil, thereby bending a certain amount of pressure and bringing one secondary side contact into contact with the other secondary side contact; a first voltmeter, which measures the detection voltage detected from both ends of the shunt resistor; a second A voltmeter for measuring the voltage between the pair of secondary side contacts of the relay; and a relay state prediction device, which is connected to the first voltmeter and the second voltmeter in a communicative manner, the relay state prediction device comprising: a voltage value acquisition unit, which constantly measures the detection voltage detected from both ends of the shunt resistor; a voltage value difference calculation unit, which calculates the voltage value difference between a first voltage value when the detection voltage becomes extremely small due to the armature starting to displace after the primary side switch is disconnected and a second voltage value when the secondary side contacts are disconnected; a slope calculation unit, which calculates the slope of the voltage value difference as the secondary side contacts are repeatedly opened and closed in response to the repeated connection and disconnection of the primary side switch; and a state prediction unit, which predicts the number of possible openings and closings from the current time until the voltage value difference reaches a preset threshold value based on the current voltage value difference and the decreasing slope.

[0018] In the disclosed relay state prediction system, the remaining life of the relay can be predicted.

[0019] On the other hand, the relay state prediction method of the present invention predicts the number of times a relay can be opened and closed before it deteriorates, and the relay state prediction method is characterized in that the relay includes a primary side switch, an operating coil and a shunt resistor connected in series with a primary side power supply, and the relay includes a diode, which is connected in parallel with the series connection of the operating coil and the shunt resistor and is connected in the following direction: the direction allows the current caused by the back electromotive force of the operating coil to flow to the shunt resistor when the primary side switch is disconnected, and the relay includes an armature, which opens and closes at least one pair of secondary side contacts according to the connection and disconnection of the primary side switch, and the armature uses the electromagnetic force generated by the operating coil when the primary side switch is turned on. The relay state prediction method measures the detection voltage detected from both ends of the shunt resistor at all times; calculates the voltage difference between a first voltage value when the detection voltage becomes extremely small due to the displacement of the armature after the primary side switch is disconnected and a second voltage value when the secondary side contact is disconnected; calculates the slope of the voltage difference decreases as the secondary side contact repeatedly opens and closes in response to the repeated connection and disconnection of the primary side switch; and predicts the number of possible openings and closings from the current time until the voltage difference reaches a preset threshold based on the current voltage difference and the decreasing slope.

[0020] In the disclosed relay state prediction method, the remaining life of the relay can be predicted.

[0021] In still another aspect, a program of the present disclosure is a program for causing a computer to execute the relay state prediction method.

[0022] The relay state prediction method can be implemented by causing a computer to execute the program of the present disclosure.

[0023] Effects of the Invention

[0024] As described above, according to the relay state prediction device, relay state prediction system, and relay state prediction method of the present disclosure, the remaining life of the relay can be predicted. In addition, the relay state prediction method can be implemented by causing a computer to execute the program of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 1 is a diagram showing a schematic configuration of a relay state prediction system according to an embodiment.

[0026] Figure 2 Yes means Figure 1 A diagram of a block structure of a relay state prediction device included in a relay state prediction system.

[0027] Figure 3 Yes Description Figure 1 Flowchart of the action of the relay state prediction system.

[0028] Figure 4 (A) is a diagram showing a state where the switch on the secondary side of the relay is "closed". Figure 4 (B) is a diagram showing a state where the switch on the secondary side of the relay is "off".

[0029] Figure 5 It is a diagram illustrating an example voltage waveform.

[0030] Figure 6 This is a diagram showing the relationship between the RUS of the relay and the number of times the relay is opened and closed for each of a plurality of samples. DETAILED DESCRIPTION

[0031] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0032] Schematic structure of relay state prediction system 100

[0033] Figure 1 1 shows the overall structure of the relay state prediction system 100. As an example, the relay state prediction system 100 predicts the remaining life of the relay 4. Here, the "remaining life" of the relay 4 refers to the number of times the relay can be opened and closed from now until the voltage value difference (or RUS) reaches a preset threshold.

[0034] like Figure 1 As shown, the relay state prediction system 100 includes a relay 4, voltmeters 5 and 8, and a relay state prediction device 10. The relay state prediction system 100 also includes a DC power source 1, a switch device 2, a diode 3, a shunt resistor 9, an AC power source 6, and a load 7.

[0035] like Figure 1 As shown, the relay 4 is arranged across the primary side circuit and the secondary side circuit. The relay 4 has an operating coil 4a on the primary side and a switch 4b on the secondary side. In addition, the switch 4b on the secondary side has a pair of contacts (a first contact 4b1 and a second contact 4b2) in this example. The pair of contacts 4b1 and 4b2 are opened and closed by turning on and off the power to the operating coil 4a on the primary side.

[0036] like Figure 1As shown, in the primary side circuit, the positive terminal 1p of the DC power supply 1 is connected to one end 2a of the switching device 2. The other end 2b of the switching device 2 is connected to the cathode terminal 3k of the diode 3. In addition, the other end 2b of the switching device 2 is connected to one end 4a1 of the operating coil 4a. The negative terminal 1m of the DC power supply 1 is connected to the anode terminal 3a of the diode 3. In addition, the negative terminal 1m of the DC power supply 1 is connected to one end 9a of the shunt resistor 9. In addition, the other end 9b of the shunt resistor is connected to the other end 4a2 of the operating coil 4a. In addition, the voltmeter 8 is connected in parallel with the shunt resistor 9. Thus, the voltmeter 8 can measure the voltage value between the two ends 9a and 9b of the shunt resistor 9.

[0037] like Figure 1 As shown, in the secondary side circuit, the first contact 4b1 of the switch 4b is connected to one end 6a of the AC power supply 6 as the load power supply. The other end 6b of the AC power supply 6 is connected to one end 7a of the load 7. The other end 7b of the load 7 is connected to the second contact 4b2 of the switch 4b. In addition, the voltmeter 5 is connected in parallel with the switch 4b. Thus, the voltmeter 5 can measure the voltage value between the pair of contacts 4b1 and 4b2 of the relay 4.

[0038] A relay state prediction device 10 is configured separately from the primary side circuit and the secondary side circuit. Figure 1 As shown, the relay state prediction device 10 is connected to the voltmeters 5 and 8 in a communicative manner. In addition, the connection between the relay state prediction device 10 and the voltmeters 5 and 8 can be either wired or wireless. Through this structure, the relay state prediction device 10 can receive the measurement results of the voltmeters 5 and 8, that is, the voltage values. In addition, the relay state prediction device 10 is connected to the switch device 2 in a communicative manner. In addition, the connection between the relay state prediction device 10 and the switch device 2 can be either wired or wireless. According to this structure, the switch device 2 can notify the relay state prediction device 10 of the timing of the disconnection of the switch device 2.

[0039] The DC power supply 1 supplies a direct current to the operating coil 4a in the relay 4. The switch device 2 is composed of a FET (field effect transistor) in this example, and switches from an on state to an off state, or from an off state to an on state, according to a switch control signal from an external device not shown. The switch device 2 sends a signal indicating the timing of the switching to the relay state prediction device 10. In addition, the switch device 2 can also be composed of a semiconductor switch other than a FET, or can also be composed of a mechanical switch. The diode 3 is provided to protect the circuit from the back electromotive force generated by the operating coil 4a as an inductive load.

[0040] As described above, in the relay 4, the pair of contacts 4b1 and 4b2 on the secondary side are opened and closed by turning on and off the power to the operating coil 4a on the primary side. More specifically, by switching the switch device 2 to on, the power to the operating coil 4a from the DC power supply 1 is turned on. And, by energizing the operating coil 4a, the relay 4 (more specifically, the switch 4b) becomes "closed". On the other hand, by switching the switch device 2 to off, the power to the operating coil 4a from the DC power supply 1 is turned off. And, by de-energizing the operating coil 4a, the relay 4 (more specifically, the switch 4b) becomes "off".

[0041] The switch 4b in the relay 4 has a first contact 4b1 and a second contact 4b2. The voltmeter 5 measures the voltage value between the first contact 4b1 and the second contact 4b2. In addition, the voltmeter 5 sends the measured voltage value as a signal to the relay state prediction device 10. The AC power supply 6 supplies AC power to the load 7. And the load 7 consumes the supplied AC power and performs a predetermined operation.

[0042] Relay Operation

[0043] Figure 4 (A) indicates that the switch device 2 is turned on and the switch 4b of the relay 4 is "closed". In this state, the armature 4A of the switch 4b is relatively displaced relative to the operating coil 4a by the electromagnetic force E1 generated by the operating coil 4a. Specifically, the armature 4A overcomes the tensile force F1 of the coil spring 41 and rotates around the fulcrum SP in the direction indicated by the arrow X1, while bending a certain amount of pressing Bx and making the first contact 4b1 contact the second contact 4b2.

[0044] Figure 4 (B) indicates that the switch device 2 is disconnected and the switch 4b of the relay 4 is in the "off" state. In this state, the electromagnetic force E1 generated by the operating coil 4a becomes smaller, and as a result, the armature 4A of the switch 4b rotates around the fulcrum SP in the direction indicated by the arrow X2 due to the tensile force F2 of the coil spring 41. As a result, the pressure pressing the first contact 4b1 changes from a certain value to zero, causing the first contact 4b1 to separate from the second contact 4b2. In this case, a counter electromotive force is generated in the operating coil 4a, and the current flowing through the operating coil 4a flows back to the diode 3.

[0045] Schematic structure of the relay state prediction device 10

[0046] Next, the structure of the relay state prediction device 10 is described. Figure 2 The schematic structure of the relay state prediction device 10 is shown in FIG. In this embodiment, the relay state prediction device 10 predicts the remaining life of the relay 4. Figure 2As shown, the relay state prediction device 10 includes a signal receiving unit 21 , a voltage value acquiring unit 22 , a display unit 23 , an operation unit 24 , a memory 25 , a threshold value storage unit 26 , a notification unit 27 , and a processor 28 .

[0047] In the relay state prediction device 10, the processor 28 is connected to the signal receiving unit 21, the voltage value acquisition unit 22, the display unit 23, the operation unit 24, the memory 25, the threshold value storage unit 26, and the notification unit 27 in a communicable manner. Thus, the processor 28 controls the signal receiving unit 21, the voltage value acquisition unit 22, the display unit 23, the operation unit 24, the memory 25, the threshold value storage unit 26, and the notification unit 27, and through this control, each unit 21, 22, 23, 24, 25, 26, 27 performs a predetermined action.

[0048] The signal receiving unit 21 transmits and receives signals or data to and from an external terminal. For example, the signal receiving unit 21 of this embodiment is connected to the switch device 2 in a communicable manner. Therefore, the signal receiving unit 21 receives data indicating the timing of the switch device 2 being turned off from the switch device 2.

[0049] The voltage value acquisition unit 22 transmits and receives signals or data with an external terminal. For example, the voltage value acquisition unit 22 of this embodiment is connected to the voltmeters 5 and 8 in a communicable manner. Therefore, the voltage value acquisition unit 22 receives (acquires) a signal indicating the voltage value measured by the voltmeters 5 and 8 from the voltmeters 5 and 8.

[0050] The display unit 23 is a monitor that displays various images. The display unit 23 can display the results of various analyses in the processor 28 in a visual manner. In addition, according to the instructions from the user via the operation unit 24, the display unit 23 can also display the specified information in a visual manner. For example, the display unit 23 can also display the information (data) stored in the memory 25 and the threshold storage unit 26 in a visual manner. In addition, the display unit 23 can also visually display the specified notification, etc. For example, as the display unit 23, a liquid crystal monitor, etc. can be used.

[0051] The operation unit (which can be understood as a threshold input unit) 24 is a part that receives a predetermined operation (instruction) from the user. For example, the operation unit 24 is composed of a mouse and a keyboard. Here, when a touch panel monitor is used as the display unit 23, the display unit 23 has not only a display function but also a function as the operation unit 24.

[0052] The memory 25 stores various data. The memory 25 includes a RAM (Random Access Memory) and a ROM (Read Only Memory). For example, various programs used for the operation of the processor 28 are stored in the memory 25 in a changeable manner. In addition, the memory 25 stores data (data indicating the timing of the switch) from the switch device 2 obtained by the signal receiving unit 21 and voltage value data from the voltmeters 5 and 8 obtained by the voltage value obtaining unit 22. The memory 25 can also delete the various stored data when a predetermined time has passed after the storage.

[0053] The threshold storage unit 26 stores a threshold value Th for predicting whether the relay 4 is degraded. Here, the threshold value Th is determined (set) by the user based on empirical rules or the like. In addition, the threshold value Th stored in the threshold storage unit 26 is changeable. For example, the operation unit 24 functions as a threshold value input unit for variably inputting the threshold value Th. The user inputs a desired threshold value Th to the operation unit 24. Thus, the threshold value Th is stored (set) in the threshold storage unit 26. In addition, in a case where the threshold value Th' is already stored in the threshold storage unit 26, the threshold value Th' is changed to the threshold value Th corresponding to the operation by the user through the operation unit 24. In addition, the threshold storage unit 26 may also have a predetermined threshold value Th as a default value.

[0054] The notification unit 27 notifies the remaining life of the relay 4 based on the analysis result of the processor 28 described later. For example, the notification unit 27 is composed of a liquid crystal display device. In this example, the notification unit 27 digitally or analogically displays the remaining number of times the relay 4 can be opened and closed. In addition, the display unit 23 can have the function of the notification unit 27. In this case, the specified information (information indicating the remaining life of the relay 4) is displayed in a visual manner on the display unit 23.

[0055] In this example, the processor 28 includes a CPU (Central Processing Unit). For example, the processor 28 reads each program and each data stored in the memory 25. In addition, the processor 28 controls each unit 21-27 according to the read program and performs a predetermined action (function). In addition, the processor 28 performs a predetermined calculation, analysis, processing, etc. in the processor 28 (each block 28a, 28c composed of the program) according to the read program. In addition, part or all of the functions executed by the processor 28 can also be configured in hardware by one or more integrated circuits, etc.

[0056] like Figure 2As shown, the processor 28 of this embodiment includes a RUS calculation unit 28a, a slope calculation unit 28b, and a state prediction unit 28c programmed to implement a predetermined operation as functional blocks. In addition, the operation of each block 28a, 28b, 28c is described in detail in the description of the operation described later.

[0057] Operation of the relay state prediction system 100

[0058] Next, use Figure 3 The flowchart shown explains the remaining life prediction operation of the relay 4 in the relay state prediction system 100 .

[0059] Reference Figure 3 , the switch device 2 switches from the on state to the off state (step S1). The switch device 2 notifies the relay state prediction device 10 of the switching. The signal receiving unit 21 of the relay state prediction device 10 receives the notification.

[0060] Next, the voltmeter 8 measures the voltage between the two ends 9a and 9b of the shunt resistor 9 (step S2). Then, the voltmeter 8 sends the voltage value Va as the measurement result to the relay state prediction device 10, and the voltage value acquisition unit 22 of the relay state prediction device 10 receives the voltage value Va. The memory 25 stores the voltage value Va received by the voltage value acquisition unit 22. Here, the voltmeter 8 measures the voltage between the two ends 9a and 9b of the shunt resistor 9 at all times.

[0061] Here, Figure 5 After the disconnection instruction to relay 4 is given ( Figure 3 The time variation of the voltage value Va between the two ends 9a and 9b of the shunt resistor 9 and the voltage value Vb between the first contact 4b1 and the second contact 4b2 of the switch 4b (after step S1). Figure 5 The vertical axis is the voltage value (V), Figure 5 The horizontal axis is time (ms).

[0062] Next, the RUS calculation unit 28a of the relay state prediction device 10 obtains the value of the armature 4A moving in the Figure 4 The voltage value Va decreases and becomes a very small voltage value V1 ( Figure 3 Step S3).

[0063] Next, the voltmeter 5 measures the voltage between the first contact 4b1 and the second contact 4b2 at the switch 4b. Figure 5 When the voltage value Vb drops sharply as shown by the dotted circle D in FIG. 1 ), the RUS calculation unit 28a of the relay state prediction device 10 obtains the voltage value Va measured by the voltmeter 8 as the second voltage value V2 ( Figure 3 Step S4).

[0064] Next, the RUS calculation unit 28a as the voltage value difference calculation unit of the relay state prediction device 10 calculates the voltage value difference VD between the voltage value V1 and the voltage value V2 (step S5).

[0065] Next, the RUS calculation unit 28a of the relay state prediction device 10 calculates RUS by dividing the voltage value difference VD by the resistance value of the shunt resistor 9 (step S6). The memory 25 stores the RUS calculated by the RUS calculation unit 28a.

[0066] Next, the RUS calculation unit 28a sends the RUS to the slope calculation unit 28b.

[0067] Here, Figure 6 The relationship between RUS and the number of times the contacts 4b1 and 4b2 are opened and closed is shown as an example. Figure 6 The vertical axis is RUS (μA), Figure 6 The horizontal axis is the number of times the contacts 4b1 and 4b2 are opened and closed. Figure 6 As shown in the example, it can be seen that as the number of switching times increases, RUS is approximately a linear function (the decreasing slope is S i ) decreases.

[0068] Next, the slope calculation unit 28b receives the value of RUS (assuming it is RUS) at all times during the decrease of RUS. i ). Specifically, in this example, the RUS is received from the RUS calculation unit 28a. i Then, receive the RUS of the previous round (before the specified number of opening and closing times n) i-1 From this, we can find the slope S of the RUS decrease of this round. i =(RUS i -RUS i-1 ) / n( Figure 3 In this way, the slope calculation unit 28b constantly calculates the slope S of the RUS decrease during the decrease of RUS. i In addition, calculate the slope S of RUS decrease i The method is not limited to this. The least square method can also be used to find the reduced slope S i .

[0069] Next, the state prediction unit 28c reads the threshold value Th stored in the threshold value storage unit 26. The state prediction unit 28c calculates the current RUS value based on the current RUS value. i and the slope S of RUS decrease i , predict the number of times M that RUS can be opened and closed until it reaches the threshold Th ( Figure 3 In detail, as in step S8, Figure 6As shown in the example, in this example, the threshold value Th is set to 100 μA. i Based on the slope S of RUS reduction i Extrapolate a function to find the value from the current RUS i The number of times M that can be opened and closed until the threshold value Th is reached is calculated as M = (RUS i -Th) / S i .

[0070] Here, as can be seen from the above, the RUS used in the comparison process of step S7 is the RUS obtained in step S6 . In addition, the threshold used in the comparison process of step S7 is the threshold Th preset in the threshold storage unit 26 of the relay state prediction device 10 .

[0071] In addition, the threshold value Th is set by the user based on empirical rules or the like. Figure 6 The threshold value Th is set based on empirical rules, such as the measurement results of the RUS, the use status of the relay 4, and the expected time point of failure of the relay 4 (the time point when the opening and closing of the relay 4 is expected to no longer operate normally). Figure 6 In the example, the threshold Th is set to 100 μA. Figure 6 In the example of , the user considers the above-mentioned factors, and when RUS of the relay 4 used reaches 100 μA, the user determines that the relay 4 has deteriorated.

[0072] Then, in Figure 3 In step S9, the state prediction unit 28c controls the notification unit 27, and the notification unit 27 notifies the relay 4 of the number of times M ( Figure 3 Step S9). After that, the relay state prediction process ends.

[0073] Effect

[0074] As described in the prior art, there is no disclosed technology for predicting the remaining life of conventional relays. In contrast, in this embodiment, the number of times that can be opened and closed from now until RUS reaches a preset threshold, that is, the remaining life of the relay, can be predicted.

[0075] Figure 6 This is experimental data that illustrates the relationship between the RUS of a relay and the number of times the relay is opened and closed. Figure 6 Samples #1 to #5 shown are relays of the same type (model) and were tested under the same conditions. Figure 6 It can be seen from the experimental example that even for relays of the same type (model), there are large individual differences between samples #1 to #5 regarding RUS, etc.

[0076] In contrast, in the present embodiment, the RUS calculation unit 28a calculates the RUS for the relay 4. Then, the state prediction unit 28c predicts the number of times that the relay 4 can be opened and closed from the current state until the RUS reaches a preset threshold. Here, regarding the RUS when the relay 4 has deteriorated, it is known from experience that the individual differences of the relay 4 are small. Therefore, according to the present embodiment, the remaining life of the relay 4 can be notified with high accuracy.

[0077] In addition, in the present embodiment, the notification unit 27 notifies the user of the number of times the relay 4 can be opened and closed from now until the relay 4 reaches a preset threshold, that is, the remaining life. Therefore, the user can quickly take measures such as replacing the relay 4.

[0078] It is also possible to use a computer to execute the relay state prediction method ( Figure 3 ) is recorded in a recording medium capable of storing data in a non-transitory manner, such as a CD (Compact Disc), a DVD (Digital Versatile Disc), a flash memory, etc. By installing the software recorded in such a recording medium in a physical computer device such as a personal computer, a PDA (Personal Digital Assistant), a smart phone, etc., these computers can execute the relay state prediction method.

[0079] In the above-described embodiment, the processor 28 includes a CPU, but the present invention is not limited thereto and may include a logic circuit (integrated circuit) such as a PLD (Programmable Logic Device) or an FPGA (Field Programmable Gate Array).

[0080] The above embodiments are illustrative and can be variously modified without departing from the scope of the present invention. The multiple embodiments can be established separately, but it is also possible to combine the embodiments with each other. In addition, the various features in different embodiments can also be established separately, but it is also possible to combine the features in different embodiments with each other.

[0081] Description of symbols

[0082] 2: Switching device; 4: Relay; 4a: Operating coil; 4b: Switch; 5: Voltmeter; 8: Voltmeter; 10: Relay state prediction device; 22: Voltage value acquisition unit; 28a: RUS calculation unit; 28b: Slope calculation unit; 28c: State prediction unit; 100: Relay state prediction system.

Claims

1. A relay state prediction device for predicting the number of times a relay can be opened and closed until it deteriorates, the relay state prediction device being characterized in that: The relay includes a primary side switch connected in series with a primary side power supply, an operating coil and a shunt resistor. The relay includes a diode connected in parallel with the operating coil and the shunt resistor connected in series, and the diode is connected in a direction such that a current caused by a back electromotive force of the operating coil flows toward the shunt resistor when the primary side switch is turned off. Furthermore, the relay includes an armature, which opens and closes at least one pair of secondary side contacts according to the on and off of the primary side switch. When the primary side switch is turned on, the armature is relatively displaced relative to the operating coil by the electromagnetic force generated by the operating coil, and is bent by a certain amount of pressure while making the secondary side contact of one of the pair of secondary side contacts contact with the other secondary side contact. The relay state prediction device comprises: a voltage value acquisition unit that constantly measures a detection voltage detected from both ends of the shunt resistor; a voltage value difference calculation unit for calculating a voltage value difference between a first voltage value when the detection voltage becomes extremely small due to the armature starting to displace after the primary side switch is turned off and a second voltage value which is the detection voltage when the secondary side contact is turned off; a slope calculation unit for calculating a slope of a decrease in the voltage difference as the secondary side contact repeatedly opens and closes in response to the repeated on and off of the primary side switch, wherein the slope of a decrease in the voltage difference is an average decrease in the voltage difference per opening and closing; as well as A state prediction unit predicts the number of possible opening and closing times from the present time until the voltage value difference reaches a preset threshold value based on the present voltage value difference and the decreasing slope.

2. The relay state prediction device according to claim 1, characterized in that: The slope calculation unit calculates the slope of the current value reduction obtained by dividing the voltage value difference by the value of the shunt resistor instead of calculating the slope of the voltage value reduction. The slope of the current value reduction is the average reduction in the current value for each opening and closing. In this case, the state prediction unit predicts the number of possible openings and closings from the current to the current value reaching a preset threshold based on the current current value and the slope of the current value reduction.

3. The relay state prediction device according to claim 1, characterized in that: The relay state prediction device further includes a notification unit configured to notify the predicted possible switching number of times.

4. A relay state prediction system, characterized in that: have: A relay, comprising a primary-side switch connected in series with a primary-side power supply, an operating coil and a shunt resistor, the relay comprising a diode connected in parallel with the operating coil and the shunt resistor connected in series, and the diode being connected in a direction such that a current caused by a back electromotive force of the operating coil flows toward the shunt resistor when the primary-side switch is disconnected, and the relay comprising an armature which opens and closes at least one pair of secondary-side contacts in accordance with the on and off of the primary-side switch, and when the primary-side switch is connected, the armature is relatively displaced relative to the operating coil by the electromagnetic force generated by the operating coil, thereby causing the secondary contact of one of the pair of secondary-side contacts to contact the secondary contact of the other while being flexed by a certain amount of pressure; a first voltmeter for measuring a detection voltage detected from both ends of the shunt resistor; a second voltmeter for measuring a voltage between the pair of secondary side contacts of the relay; and a relay state prediction device connected to the first voltmeter and the second voltmeter in a communicable manner, The relay state prediction device comprises: a voltage value acquisition unit that constantly measures a detection voltage detected from both ends of the shunt resistor; a voltage value difference calculation unit for calculating a voltage value difference between a first voltage value when the detection voltage becomes extremely small due to the armature starting to displace after the primary side switch is turned off and a second voltage value which is the detection voltage when the secondary side contact is turned off; a slope calculation unit for calculating a slope of a decrease in the voltage difference as the secondary side contact repeatedly opens and closes in response to the repeated on and off of the primary side switch, wherein the slope of a decrease in the voltage difference is an average decrease in the voltage difference per opening and closing; as well as A state prediction unit predicts the number of possible opening and closing times from the present time until the voltage value difference reaches a preset threshold value based on the present voltage value difference and the decreasing slope.

5. A relay state prediction method, which predicts the number of times a relay can be opened and closed before it deteriorates, wherein the relay state prediction method is characterized in that: The relay includes a primary side switch connected in series with a primary side power supply, an operating coil and a shunt resistor. The relay includes a diode connected in parallel with the operating coil and the shunt resistor connected in series, and the diode is connected in a direction such that a current caused by a back electromotive force of the operating coil flows toward the shunt resistor when the primary side switch is turned off. Furthermore, the relay includes an armature, which opens and closes at least one pair of secondary side contacts according to the on and off of the primary side switch. When the primary side switch is turned on, the armature is relatively displaced relative to the operating coil by the electromagnetic force generated by the operating coil, and is bent by a certain amount of pressure while making the secondary side contact of one of the pair of secondary side contacts contact with the other secondary side contact. In the relay state prediction method, The detection voltage detected from both ends of the shunt resistor is measured at all times. Calculate the voltage difference between a first voltage value when the detection voltage becomes minimum due to the armature starting to displace after the primary side switch is turned off and a second voltage value when the secondary side contact is turned off, The slope of the voltage difference decreases as the secondary side contact repeatedly opens and closes in response to the primary side switch repeatedly turning on and off, and the slope of the voltage difference decreases is calculated, wherein the slope of the voltage difference decreases by an average amount of the voltage difference decreases each time the switch is opened and closed. Based on the current voltage value difference and the decreasing slope, the number of possible opening and closing times from the current time until the voltage value difference reaches a preset threshold is predicted. 6 . A recording medium having a program recorded thereon, the program for causing a computer to execute the relay state prediction method according to claim 5 .

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