Monitoring device, monitoring system and monitoring method for relay output signals

Abstract

Provided is a monitoring device that monitors an abnormality in the number of repetitions of opening and closing of an output signal of a relay, and determines a cause of the abnormality in the number of repetitions of opening and closing of the output signal of the relay when the abnormality is detected. The monitoring device includes an output signal monitoring section that monitors an abnormality in the number of repetitions of opening and closing of an output signal of a relay, and a cause determining section that determines a cause of the abnormality based on periodicity of the repetitions of opening and closing when the output signal monitoring section detects an abnormality in the number of repetitions of opening and closing. The relay can be opened and closed based on a control signal from a numerical control device, and the cause determining section determines that the control signal is abnormal when the repetitions of opening and closing have periodicity.

Description

Technical Field

[0001] This invention relates to a monitoring device, monitoring system, and monitoring method for monitoring relay output signals, and particularly to a monitoring device, monitoring system, and monitoring method for monitoring abnormalities in the number of times a relay output signal is opened and closed, and for determining the cause of the abnormality when an abnormality in the number of times a relay output signal is opened and closed is detected. Background Technology

[0002] In a relay output module that includes a relay, the relay contacts open and close repeatedly in a short period of time. Due to the continuous arc heat, the contact parts may become fused.

[0003] Abnormalities in the number of times the relay output signal (relay output signal) is generated can be caused by factors such as vibration in the relay output module, a decrease in the voltage applied to the coil, and abnormalities in the control signal from a computer numerical control (CNC) device.

[0004] For example, Patent Document 1 describes a device for detecting the repeated opening and closing of a switch over a short period of time.

[0005] In Patent Document 1, a signal inspection device includes: an acquisition unit that acquires the values ​​of two or more signals from a multiplexed signal at a predetermined period; a counting unit that counts the number of changes of each of the two or more signals within a fixed time period; a calculation unit that calculates the difference between the number of changes; and an output unit that outputs an indication of signal inconsistency if the difference between the number of changes exceeds an allowable value. The output unit can output an indication of a signal with a higher number of changes than others, thereby enabling the detection of short-period signal anomalies.

[0006] In addition, for example, Patent Document 2 describes an anomaly detection circuit that automatically performs anomaly detection of the sequence control circuit without visual confirmation.

[0007] Patent document 2 describes the following: The sequence of changes in input and output signals under normal operation of the sequence control circuit is stored in the internal memory of the CPU in the anomaly detection circuit. Whenever the CPU detects a change in the signal content of the input and output signals, it checks whether the changed input and output signals follow the sequence of changes in the input and output signals stored in the internal memory to confirm the operation of the sequence control circuit.

[0008] Existing technical documents

[0009] Patent documents

[0010] Patent Document 1: Japanese Patent Application Publication No. 2017-151677

[0011] Patent Document 2: Japanese Patent Application Publication No. 04-367003 Summary of the Invention

[0012] The problem that the invention aims to solve

[0013] The repeated opening and closing of a relay within a short period of time can be confirmed by obtaining the waveform of the relay's output signal using an oscilloscope. However, in cases of abnormal control signals from CNC or other sources due to noise, or mechanical vibration, the phenomenon is temporary and therefore difficult to measure.

[0014] Therefore, it is required that even if the phenomenon is temporary, it is possible to monitor whether there is an abnormality in the number of times the relay output signal is repeatedly opened and closed. Furthermore, if an abnormality in the number of times the relay output signal is repeatedly opened and closed occurs, it is required that the cause of the abnormality be determined.

[0015] Methods for solving problems

[0016] (1) A first aspect of the present disclosure is a monitoring device comprising: an output signal monitoring unit that monitors for an abnormality in the number of times the output signal of a relay is repeatedly opened and closed; and a cause determination unit that, when the output signal monitoring unit detects an abnormality in the number of times the opening and closing is repeatedly opened and closed, determines the cause of the abnormality based on the periodicity of the repeated opening and closing.

[0017] (2) A second aspect of this disclosure is a monitoring system comprising: the monitoring device described in (1) above; a relay output module connected to the monitoring device and including a relay and outputting the output signal of the relay to the monitoring device; and a load connected to the monitoring device and outputting the output signal of the relay from the monitoring device.

[0018] (3) The third aspect of this disclosure is a monitoring method in which a relay output module including a relay outputs the output signal of the relay, and a monitoring device monitors for abnormalities in the number of times the output signal of the relay is opened and closed. If an abnormality in the number of times the opening and closing is opened and closed is detected, the cause of the abnormality is determined based on the periodicity of the opening and closing.

[0019] Invention Effects

[0020] According to the various methods of this disclosure, it is possible to monitor for abnormalities in the number of times the relay output signal is repeatedly opened and closed, and to determine the cause of the abnormality when an abnormality in the number of times the relay output signal is repeatedly opened and closed occurs. Attached Figure Description

[0021] Figure 1 This is a block diagram illustrating a structural example of a monitoring system according to a first embodiment of the present disclosure.

[0022] Figure 2It is a waveform diagram representing the number of times the level of the relay output signal changes within a fixed time period.

[0023] Figure 3 These are two examples of relay output signals that have generated an abnormal number of opening and closing cycles.

[0024] Figure 4 This is a flowchart illustrating the operation of the monitoring device. Detailed Implementation

[0025] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0026] (First Implementation)

[0027] Figure 1 This is a block diagram illustrating a structural example of a monitoring system according to a first embodiment of the present disclosure.

[0028] like Figure 1 As shown, the monitoring system 10 includes a relay output module 20, a monitoring device 30, a load 40, and a display unit 50. Alternatively, the display unit 50 may not be included.

[0029] The relay output module 20 includes an inverter 21 and a relay 22. A control signal is input to the inverter 21 from a computer numerical control (CNC) device. The input control signal is inverted by the inverter 21 and input to the relay 22. The relay 22 includes a coil 221 and contacts 222. The inverted control signal controls the switching of the current flowing through the coil 221, which in turn activates an electromagnetic force to open and close the contacts 222. The relay 22 outputs a relay output signal generated by controlling the opening and closing of the contacts 222 to the monitoring device 30.

[0030] The monitoring device 30 includes an alarm notification unit 31, an output signal monitoring unit 32, and a cause determination unit 33. The monitoring device 30 is connected between the relay output module 20 and a load 40 such as a light bulb or lamp.

[0031] The output signal monitoring unit 32 monitors the abnormal number of times the output signal (relay output signal) of the relay 22 is switched on and off (connected and disconnected) (high frequency switching on and off within a short period of time).

[0032] For example, such as Figure 2As shown, the output signal monitoring unit 32 monitors whether the number of times the signal level changes from on to off, or from off to on, of the relay output signal within a fixed time T exceeds a threshold. The fixed time T is set taking into account factors such as the type of relay and the update cycle of the CNC control signal. The threshold is also set taking into account factors such as the type of relay. Depending on the type of relay, the number of times the relay contacts open and close repeatedly and the duration of these repeated opening and closing cycles differ within a short period before the relay reaches the melting point; therefore, the fixed time T and the threshold are set taking into account the type of relay.

[0033] The output signal monitoring unit 32 stores the relay output signal for a fixed time T.

[0034] If the number of times the relay output signal level changes within a fixed time T exceeds a threshold, the output signal monitoring unit 32 determines that the number of times the relay 22's output signal repeatedly opens and closes is abnormal, and outputs the stored relay output signal for the fixed time period to the cause determination unit 33. Additionally, the output signal monitoring unit 32 outputs an alarm instruction command to the alarm notification unit 31.

[0035] Upon receiving an alarm instruction, the alarm notification unit 31 outputs an alarm signal to an alarm generating unit such as an LED (not shown), a speaker, or other suitable device. The alarm notification unit 31 may be configured as needed, or it may be omitted. The alarm notification unit 31 may also output an alarm display signal to the display unit 50.

[0036] The monitoring method for the output signal monitoring unit 32 to monitor whether the number of times the output signal (relay output signal) of the relay 22 is open and closed is abnormal is not particularly limited to the method described above, and other monitoring methods may also be used.

[0037] The cause determination unit 33 determines the cause of the abnormal number of times the output signal of relay 22 is switched on and off (connected and disconnected) (high frequency switching within a short period of time).

[0038] Specifically, the cause determination unit 33 observes the period of level change of the relay output signal over a fixed period of time.

[0039] When there is an abnormality in the control signal from the CNC input to the relay output module 20, but the relay output module 20 is not abnormal, the timing of the level change of the relay output signal depends on the update cycle of the control signal from the CNC and is periodic.

[0040] Therefore, when the timing of the change in the relay output signal level is periodic, the cause determination unit 33 determines that there is an anomaly in the control signal from the CNC. For example, Figure 3The relay output signal Vout1 shown is opened and closed in accordance with the CNC update cycle Tc (Tc = 8msec), so it is periodic. The abnormal number of times the opening and closing is repeated is determined to be due to an abnormality in the control signal from the CNC.

[0041] On the other hand, if the timing of the change in the relay output signal level does not depend on the update cycle of the control signal from the CNC, the cause determination unit 33 determines that there is no abnormality in the control signal from the CNC, and the abnormality in the number of opening and closing repetitions is due to other reasons, such as an abnormality caused by the relay output module 20 (e.g., an abnormality caused by voltage applied to the coil or vibration). For example, Figure 3 The relay output signal Vout2 shown does not open and close in accordance with the update cycle Tc (Tc = 8msec) and has no periodicity. Therefore, the cause determination unit 33 determines that there is no abnormality in the control signal from the CNC and that the cause is other than the control signal from the CNC, such as the abnormality caused by the relay output module 20 (e.g., abnormality caused by voltage applied to the coil or vibration).

[0042] If the cause of the abnormal number of times the opening and closing is repeated is determined, the cause will be displayed on the display unit 50 such as the liquid crystal display device.

[0043] For example, if the abnormal number of opening and closing cycles is caused by a control signal from the CNC, the display unit 50 will display "The abnormal number of opening and closing cycles is caused by a control signal from the CNC". If the abnormal number of opening and closing cycles is caused by a relay output module (e.g., voltage applied to the coil or vibration), the display unit 50 will display "The abnormal number of opening and closing cycles is caused by a relay output module (e.g., voltage applied to the coil or vibration)".

[0044] When an alarm display signal is received from the alarm notification unit 31, the display unit 50 displays "An abnormal number of opening and closing cycles has occurred". The display unit 50 may also display this message along with the aforementioned message indicating the cause of the abnormal number of opening and closing cycles.

[0045] The monitoring device according to the embodiment described above can monitor whether an abnormality in the number of opening and closing repetitions occurs in the relay output signal. Furthermore, it can distinguish whether the abnormality in the number of opening and closing repetitions is caused by an abnormality in the CNC control signal. Moreover, if the abnormality in the number of opening and closing repetitions is not caused by an abnormality in the CNC control signal, it can be determined that it is caused by other reasons, such as an abnormality caused by the relay output module 20 (an abnormality caused by applied voltage to the coil or vibration).

[0046] The functional blocks included in the monitoring device 30 have been described above.

[0047] To implement these functional blocks, the monitoring device 30 includes an arithmetic processing unit such as a CPU (Central Processing Unit). In addition, the monitoring device 30 also includes auxiliary storage devices such as HDDs (Hard Disk Drives) that store application software and various control programs such as the OS (Operating System), and main storage devices such as RAMs (Random Access Memory) that store data temporarily required by the arithmetic processing unit when executing programs.

[0048] Furthermore, in the monitoring device 30, the arithmetic processing unit reads application software and operating system from the auxiliary storage device, expands the read application software or operating system in the main storage device, and performs arithmetic processing based on these application software or operating system. Additionally, based on the processing results, it controls various hardware components of each device. Thus, the functional blocks of the monitoring device 30 of this embodiment are implemented. In other words, this embodiment can be implemented through hardware and software cooperation.

[0049] The following uses Figure 4 The operation of the monitoring device 30 will be explained. Figure 4 This is a flowchart illustrating the operation of the monitoring device 30.

[0050] exist Figure 4 In step S11, the output signal monitoring unit 32 observes the number of times the level of the relay output signal changes from on to off or from off to on within a fixed time period.

[0051] In step S12, the output signal monitoring unit 32 determines whether the number of level changes exceeds a threshold. If the number of level changes exceeds the threshold, the process proceeds to step S13. If the number of level changes does not exceed the threshold, the process ends.

[0052] In step S13, the cause determination unit 33 determines the periodicity of the timing of the level change of the relay output signal. If the timing of the level change of the relay output signal is periodic, in step S14, the cause determination unit 33 determines that the abnormality of the number of opening and closing cycles (high-frequency opening and closing within a short period of time) is caused by an abnormality in the control signal from the CNC.

[0053] On the other hand, if the timing of the change in the level of the relay output signal is not periodic, the cause determination unit 33 determines in step S15 that there is no abnormality in the control signal from the CNC, and the abnormality is caused by other reasons besides the control signal from the CNC, such as the abnormality caused by the relay output module 20 (e.g., abnormality caused by voltage applied to the coil or vibration).

[0054] The various embodiments of the present invention have been described above, but the components included in the monitoring device 30 can be implemented by hardware, software, or a combination thereof. Furthermore, the monitoring method that utilizes the cooperation of the structural components included in the monitoring device 30 can also be implemented by hardware, software, or a combination thereof. Here, implementation by software means implementation by loading and executing a program into a computer.

[0055] Programs can be stored and provided to a computer using various types of non-transitory computer-readable recording media. Non-transitory computer-readable recording media include various types of tangible storage media. Examples of non-transitory computer-readable recording media include magnetic recording media (e.g., hard disk drives), optical-magnetic recording media (e.g., optical discs), CD-ROMs (Read Only Memory), CD-Rs, CD-R / Ws, and semiconductor memories (e.g., mask ROMs, PROMs (Programmable ROMs), EPROMs (Erasable PROMs), flash memory ROMs, and RAMs (random access memory)).

[0056] The above-described embodiments are preferred embodiments of the present invention, but the scope of the present invention is not limited to the above-described embodiments. Various modifications can be made without departing from the spirit of the present invention.

[0057] The relay output signal monitoring device, monitoring system, and monitoring method disclosed herein include the embodiments described above and can be implemented in various ways having the following structures.

[0058] (1) A monitoring device (e.g., monitoring device 30) includes: an output signal monitoring unit (e.g., output signal monitoring unit 32) that monitors for abnormalities in the number of times the output signal of a relay (e.g., relay 22) is switched on and off; and a cause determination unit (e.g., cause determination unit 33) that, when the output signal monitoring unit detects an abnormality in the number of times the switching is switched on and off, determines the cause of the abnormality based on the periodicity of the switching.

[0059] According to the monitoring device, it is possible to monitor for abnormalities in the number of times the relay output signal is repeatedly opened and closed, and to determine the cause of the abnormality when such an abnormality occurs.

[0060] (2) According to the monitoring device described in (1) above, the relay is opened and closed based on the control signal from the numerical control device, and when the opening and closing of the output signal is periodically repeated, the cause determination unit determines that the cause of the abnormality is the control signal.

[0061] (3) According to the monitoring device described in (2) above, wherein the relay is included in a relay output module (e.g., relay output module 20) which is connected to the numerical control device, and when the opening and closing of the output signal is repeated without periodicity, the cause determination unit determines that the cause of the abnormality is the relay output module.

[0062] (4) The monitoring device according to any one of (1) to (3) above, wherein if the number of times the relay’s output signal is opened and closed within a fixed time exceeds a threshold, the output signal monitoring unit determines that the number of times of opening and closing is abnormal.

[0063] (5) The monitoring device according to any one of (1) to (4) above, wherein the monitoring device comprises: an alarm notification unit that notifies an alarm when the output signal monitoring unit detects an abnormality in the number of times the output signal is repeatedly opened and closed.

[0064] (6) A monitoring system (e.g., monitoring system 10) comprising: a monitoring device (e.g., monitoring device 30) as described in any one of (1) to (5) above; a relay output module (e.g., relay output module 20) connected to the monitoring device and including a relay for outputting an output signal of the relay to the monitoring device; and a load connected to the monitoring device for outputting the output signal of the relay from the monitoring device.

[0065] According to this monitoring system, it is possible to monitor for abnormalities in the number of times the relay output signal is repeatedly opened and closed, and to determine the cause of the abnormality when such an abnormality occurs.

[0066] (7) The monitoring system according to (6) above, wherein the monitoring system includes: a display unit that displays the cause of the abnormal number of times the output signal of the relay, which is output from the monitoring device, is repeatedly opened and closed.

[0067] (8) A monitoring method wherein a relay output module (e.g., relay output module 20) including a relay outputs an output signal of the relay, and a monitoring device (e.g., monitoring device 30) monitors for an abnormality in the number of times the output signal of the relay is opened and closed, and, if an abnormality in the number of times the opening and closing is opened and closed is detected, determines the cause of the abnormality based on the periodicity of the opening and closing.

[0068] According to this monitoring method, it is possible to monitor for abnormalities in the number of times the relay output signal is repeatedly opened and closed, and to determine the cause of the abnormality when such an abnormality occurs.

[0069] Symbol Explanation

[0070] 10 monitoring systems

[0071] 20 Relay Output Module

[0072] 30 monitoring devices

[0073] 31 Alarm Notification Department

[0074] 32 Output Signal Monitoring Unit

[0075] 33 Cause Determination Department

[0076] 40 load

[0077] 50 Display Units.

Claims

1. A monitoring device, characterized by have: The output signal monitoring unit monitors for abnormalities in the number of times the relay's output signal is repeatedly opened and closed; and The cause determination unit determines the cause of the abnormality based on the periodicity of the opening and closing repetitions when the output signal monitoring unit detects an abnormality in the number of repetitions of the opening and closing.

2. The monitoring device according to claim 1, characterized in that, The relay is opened and closed based on control signals from the numerical control device. When the opening and closing of the output signal is periodically repeated, the cause determination unit determines that the cause of the abnormality lies in the control signal.

3. The monitoring device according to claim 2, characterized in that, The relay is contained in a relay output module, which is connected to the numerical control device. If the opening and closing of the output signal is repeated without periodicity, the cause determination unit determines that the cause of the abnormality lies in the relay output module.

4. The monitoring device according to any one of claims 1 to 3, characterized in that, If the number of times the relay's output signal is switched on and off within a fixed time exceeds a threshold, the output signal monitoring unit determines that the number of repetitions is abnormal.

5. The monitoring device according to any one of claims 1 to 3, characterized in that, The monitoring device includes an alarm notification unit that issues an alarm when the output signal monitoring unit detects an abnormality in the number of times the output signal is repeatedly turned on and off.

6. A monitoring system, characterized in that, have: The monitoring device according to any one of claims 1 to 5; A relay output module, which is connected to the monitoring device, includes a relay and outputs the output signal of the relay to the monitoring device; as well as The load is connected to the monitoring device and outputs the relay's output signal from the monitoring device.

7. The monitoring system according to claim 6, characterized in that, The monitoring system includes a display unit that displays the cause of the abnormal number of times the output signal of the relay, which is output from the monitoring device, is repeatedly opened and closed.

8. A monitoring method, characterized in that, The relay output module, which includes a relay, outputs the relay's output signal. The monitoring device monitors for abnormalities in the number of times the relay's output signal is switched on and off. If an abnormality is detected in the number of switching on and off cycles, the cause of the abnormality is determined based on the periodicity of the switching on and off cycles.

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