Diagnostic device

Abstract

To provide a diagnostic device that can appropriately perform an abnormality diagnosis based on vibration. 【Solution means】 The vibration determination reference value calculation means 6 of the diagnostic main device 2 calculates a vibration determination reference value (for example, a vibration level indicating the magnitude of vibration) based on the measurement output of the acceleration sensor. The abnormality determination means 8 determines that it is abnormal when the vibration determination reference value exceeds the set upper limit threshold value for a predetermined time. It also determines that it is abnormal when the base threshold value is exceeded for a predetermined time. Here, the predetermined time for the base threshold value is set longer than the predetermined time for the upper limit threshold value.

Description

Technical Field

[0001] This invention relates to a diagnostic device that measures the vibration of a monitoring object such as equipment and detects abnormalities in the monitoring object.

Background Art

[0002] Vibrations of equipment that generate vibrations during operation, such as belt conveyors and manufacturing equipment, are measured, and based on the measurement results, it is diagnosed whether the equipment is normal or abnormal. When an abnormality occurs in the operation of the equipment, the vibration increases, and thus the presence or absence of an abnormality is diagnosed based on this.

[0003] For example, a threshold value is determined, and when the detected vibration exceeds this threshold value, it is diagnosed as abnormal.

[0004] Also, Patent Document 1 discloses the following diagnostic device. The average value of the vibration of the equipment detected in the first reference period is obtained. Similarly, the average value of the vibration of the equipment detected in the second period to be diagnosed is obtained. As shown in FIG. 12, a diagnosis is made by comparing the average value AV2 in the first period and the average value AV3 in the second period.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] However, the above prior art has the following problems.

[0007] First, there was a problem that the average value could not be calculated and the determination could not be made unless the predetermined period ended. To increase the accuracy of the determination, the predetermined period could be lengthened, but this was in antinomy with the speed of the determination. On the other hand, for example, if a threshold value was determined and an attempt was made to make a determination using the instantaneous value of the vibration, there was a possibility of false determination due to instantaneous disturbances.

[0008] Second, when determining that it is abnormal when the vibration exceeds a threshold value, although it is possible to cope with a large change in vibration, it was difficult to detect the initial stage of an abnormality in which the vibration gradually changes.

[0009] An object of the present invention is to provide a diagnostic apparatus that solves at least any of the above problems and can appropriately perform abnormality diagnosis based on vibration.

Means for Solving the Problems

[0010] Hereinafter, some independent features of the present invention will be listed. These features are not essential to be combined and can be arbitrarily combined.

[0011] (1)-(3) The diagnostic apparatus according to the present invention includes a vibration sensor that measures the vibration of a monitoring object, a vibration determination reference value calculation means that calculates a vibration determination reference value based on the measurement output of the vibration sensor, and when the vibration determination reference value exceeds the upper limit threshold value continuously for a first predetermined time and also when it falls below the lower limit threshold value continuously for a second predetermined time, an abnormality determination means that determines that the monitoring object is abnormal, and a determination result output means that outputs the determination result of the abnormality determination means.

[0012] Since it is determined that it is abnormal when the threshold value is continuously exceeded (fallen below) for a predetermined time, the speed of determination and prevention of false determination due to disturbances and the like are realized. In addition, since it is also determined when the lower limit threshold value is fallen below, it is possible to determine that it is abnormal even in an abnormality in which the vibration decreases (for example, when the monitored device stops).

[0013] (4) The diagnostic apparatus according to the present invention is characterized in that the second predetermined time is equal to the first predetermined time.

[0014] Therefore, whether the vibration increases or decreases, the determination can be made based on the same criterion.

[0015] (5) The diagnostic apparatus according to the present invention is characterized in that the abnormality determination means determines that the monitoring target is abnormal even when the vibration determination reference value continuously exceeds a base threshold value set between the upper limit threshold value and the lower limit threshold value for a third predetermined time.

[0016] Therefore, it is possible to monitor an abnormality that progresses gradually.

[0017] (6) The diagnostic apparatus according to the present invention is characterized in that the abnormality determination means determines that the monitoring target is abnormal even when the vibration determination reference value continuously falls below a base threshold value set between the upper limit threshold value and the lower limit threshold value for a third predetermined time.

[0018] Therefore, it is possible to monitor an abnormality that progresses gradually.

[0019] (7) The diagnostic apparatus according to the present invention is characterized in that the upper limit threshold value and the lower limit threshold value are set by the threshold value setting means based on the vibration determination reference value calculated based on the measurement output of the vibration sensor in the teaching mode.

[0020] Therefore, since the threshold value is set based on the actually measured value, it is possible to set a more appropriate threshold value.

[0021] (8) The diagnostic method according to the present invention is a method for diagnosing a monitoring object by its vibration, comprising acquiring the vibration of the monitoring object, calculating a vibration determination reference value based on the acquired vibration, and determining that the monitoring object is abnormal not only when the vibration determination reference value continuously exceeds the upper threshold value for a first predetermined time but also when the vibration determination reference value continuously falls below the lower threshold value for a second predetermined time.

[0022] Since it is determined that it is abnormal when the threshold value is continuously exceeded (fallen below) for a predetermined time, the rapidity of the determination and the prevention of misjudgment due to disturbances and the like are realized. Also, since it determines even when the value falls below the lower threshold value, it is possible to determine that it is abnormal even in an abnormal situation where the vibration decreases (for example, when the monitoring target device stops).

[0023] (9)-(11) The diagnostic apparatus according to the present invention includes a vibration sensor that measures the vibration of a monitoring object, a vibration determination reference value calculation means that calculates a vibration determination reference value based on the measurement output of the vibration sensor, and an abnormality determination means that determines that the monitoring object is abnormal in any case where the vibration determination reference value exceeds the upper threshold value and in any case where the vibration determination reference value continuously exceeds a base threshold value set between the upper threshold value and the lower threshold value for a predetermined time, and a determination result output means that outputs the determination result of the abnormality determination means.

[0024] Therefore, not only the determination based on the upper threshold value but also the determination that it is abnormal when the base threshold value is continuously exceeded for a predetermined time enables monitoring of abnormalities that progress gradually.

[0025] (12) The diagnostic apparatus according to the present invention is characterized in that the upper threshold value, the lower threshold value, and the base threshold value are set by a threshold value setting means based on a vibration determination reference value calculated based on the measurement output of the vibration sensor in the teaching mode.

[0026] Therefore, since the threshold value is set based on the actually measured value, it is possible to set a more appropriate threshold value.

[0027] (13) The diagnostic apparatus according to the present invention is characterized in that, in the abnormality determination means, when the vibration determination reference value exceeds the upper limit threshold value, or in addition to this, when the vibration determination reference value is below the lower limit threshold value, it is determined that there is an abnormality.

[0028] Therefore, it is possible to determine that there is an abnormality even when the value is below the lower limit threshold value.

[0029] (14) The diagnostic apparatus according to the present invention is characterized in that the abnormality determination means determines that there is an abnormality when the vibration determination reference value continuously exceeds the base threshold value for a predetermined time, or in addition to this, when the vibration determination reference value continuously falls below the base threshold value for a predetermined time.

[0030] Therefore, it is possible to determine that there is an abnormality even when the value continuously falls below the base threshold value for a predetermined time.

[0031] (15) The diagnostic apparatus according to the present invention is characterized in that the abnormality determination means determines that there is an abnormality when the value temporarily exceeds the upper limit threshold value, or when the value continuously exceeds the upper limit threshold value for a predetermined time.

[0032] Therefore, appropriate abnormality determination can be performed.

[0033] (16) The diagnostic method according to the present invention is a method for diagnosing a monitoring object by its vibration, comprising obtaining the vibration of the monitoring object, calculating a vibration determination reference value based on the obtained vibration, and determining that the monitoring object is abnormal in any case where the vibration determination reference value exceeds the upper limit threshold value and where the vibration determination reference value continuously exceeds a base threshold value set between the upper limit threshold value and the lower limit threshold value for a predetermined time.

[0034] Therefore, not only the determination based on the upper limit threshold value but also the case where the base threshold value is continuously exceeded for a predetermined time is determined as abnormal, so that it is possible to monitor an abnormality that progresses gradually.

[0035] In this invention, the "vibration determination criterion calculation means" corresponds to step ST12 in the embodiment.

[0036] The "abnormality determination means" corresponds to steps ST14, ST15, steps ST54, and ST55 in the embodiment.

[0037] The "determination result output means" corresponds to step ST19 in the embodiment.

[0038] The "threshold value setting means" corresponds to steps ST5 to ST7 in the embodiment.

[0039] The "device" is a concept that includes not only what is constituted by a single computer but also what is constituted by a plurality of computers connected via a network or the like. Therefore, when the means (or even a part of the means) of the present invention is distributed among a plurality of computers, these plurality of computers correspond to the device.

[0040] The "program" is a concept that includes not only a program directly executable by a CPU but also a program in source form, a compressed program, an encrypted program, a program that cooperates with an operating system to exhibit its function, etc.

Brief Description of the Drawings

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Embodiments for Carrying Out the Invention

[0042] 1. First Embodiment 1.1 Overall Configuration FIG. 1 shows the functional configuration of a diagnostic apparatus according to an embodiment of the present invention. The acceleration sensor 4, which is a vibration sensor, is attached to the device to be monitored. Therefore, the acceleration sensor 4 can measure and output the vibration of the device.

[0043] The vibration determination reference value calculation means 6 of the diagnostic main device 2 calculates a vibration determination reference value (for example, a vibration level indicating the magnitude of vibration) based on the measurement output of the acceleration sensor. The abnormality determination means 8 determines whether there is an abnormality in the device based on the vibration determination reference value with reference to the set upper limit threshold value and lower limit threshold value.

[0044] For example, when an abnormality occurs in the device, the amplitude of vibration often increases. Therefore, the abnormality determination means 6 determines that the device is abnormal when the vibration determination reference value continuously exceeds the upper limit threshold value for a first predetermined time. Since it is assumed that the upper limit threshold value is exceeded continuously for the first predetermined time, there is no malfunction due to momentary noise, and since statistical values are not used, abnormalities at the initial stage can also be determined. Note that the upper limit threshold value is preferably near the maximum value of the vibration of the device during normal operation.

[0045] Also, when the device is in a state close to operation stop, the amplitude of vibration often decreases. Therefore, the abnormality determination means 8 determines that the device is abnormal when the vibration determination reference value continuously falls below the lower limit threshold value for a second predetermined time. Accordingly, not only abnormalities during operation but also abnormalities such as the device not operating at all can be detected. Note that the lower limit threshold value is preferably near the minimum value of the vibration of the device during normal operation.

[0046] The determination result output means 10 outputs the determination result by the abnormality determination means 8.

[0047] As described above, in this embodiment, since the upper limit threshold value and the lower limit threshold value are provided, not only abnormalities during device operation but also abnormalities such as the device having stopped can be detected. Also, since it is determined that there is an abnormality when it continues for a predetermined time, there is no malfunction due to momentary noise, and since statistical values are not used, abnormalities at the initial stage can also be determined.

[0048] 1.2 Appearance and Hardware Configuration FIG. 2 shows the appearance of the diagnostic main device 2. Although not shown, terminals for inputting the measurement output from the acceleration sensor 4 and terminals for outputting the determination result are provided. On the upper surface, a teaching button 12 for executing a teaching mode, which is a mode for setting a threshold value, is provided. The diagnostic main device 2 is arranged near the device to be monitored and receives the measurement output from a measurement device such as the acceleration sensor 4 attached to the device.

[0049] Figure 3 shows the hardware configuration of the main diagnostic device 2. A teaching button 12, a memory 32, an A / D converter 34, a non-volatile memory 36, and a communication circuit 38 are connected to the CPU 30. The A / D converter 34 converts the measurement outputs from the acceleration sensor 4 and the temperature sensor 5 into digital data. The communication circuit 38 is for transmitting the judgment result to a higher-level device or the like. The higher-level device or the like performs abnormality response processing such as stopping the device or lighting an abnormality lamp upon receiving the abnormality judgment.

[0050] An operating system 40 such as TRON and a diagnostic program 42 are recorded in the non-volatile memory 36. The diagnostic program 42 exhibits its function in cooperation with the operating system 40. Note that a diagnostic program 42 that functions alone without the operating system 40 may be used.

[0051] 1.3 Teaching Process In this embodiment, a teaching mode for setting a threshold value based on the actually measured vibration is provided. When the teaching button 12 is pressed, the teaching mode is entered for a predetermined time (for example, 2 minutes).

[0052] Figure 4 shows a flowchart of the diagnostic program in the teaching mode. The CPU 30 acquires and records the data of the acceleration sensor 4 and the temperature sensor 5 from the A / D converter 34 (step ST1). For the captured acceleration, the RMS value is calculated in units of a predetermined time (for example, 0.5 seconds) (step ST2). Since the sampling rate of the A / D converter 34 is about 1 / 51200 seconds (which may also be a predetermined sampling rate), the RMS for 25600 samples is calculated.

[0053] The CPU 30 repeats the above processing until the teaching period elapses (step ST3). Therefore, when the teaching period elapses, the temperature data, acceleration data, and RMS value within the period are recorded.

[0054] Subsequently, the CPU 30 acquires the maximum temperature value within the period, adds a margin (for example, a 10% increase) to this maximum value, and sets the temperature upper limit threshold (step ST4). Further, the CPU 30 calculates the average value of the acceleration RMS values within the period and sets this average value as the base threshold (step ST5). Fig. 5 schematically shows the set base threshold.

[0055] Also, the CPU 30 calculates the maximum value of the acceleration RMS values within the period, adds a margin (for example, a 10% increase) to this maximum value, and sets the acceleration upper limit threshold (step ST6). Similarly, the CPU 30 calculates the minimum value of the acceleration RMS values within the period, subtracts a margin (for example, a 10% decrease) from this minimum value, and sets the acceleration lower limit threshold (step ST7). These set values are recorded in the non-volatile memory 36. Fig. 5 schematically shows the set upper limit threshold and lower limit threshold.

[0056] As described above, the threshold is set. Since it is set based on the measured value, an appropriate value according to the actual situation is set. Also, the teaching process is preferably performed when a component of the monitored device is replaced, or when the object handled by the monitored device (for example, the component conveyed in a belt conveyor device) changes.

[0057] 1.4 Diagnostic Process Fig. 6 shows the flowchart of the diagnostic program in the diagnostic mode. The CPU 30 acquires and records the data of the acceleration sensor 4 and the temperature sensor 5 from the A / D converter 34 (step ST11). For the captured acceleration, the RMS value is calculated in units of 0.5 seconds (it may also be between 0.1 second and 1 second) (step ST12). Since the sampling rate of the A / D converter 34 is about 1 / 51200 seconds, the RMS for 25600 samples is calculated.

[0058] Next, the CPU 30 determines whether the maximum value among the recorded temperatures exceeds the temperature upper limit threshold (step ST13). If it exceeds, the CPU 30 makes an abnormality determination based on the temperature (step S17). Since the temperature does not change significantly instantaneously due to disturbances or the like, it is reasonable to make a determination based on whether it exceeds the threshold value in this way. Note that it may also be determined based on whether it is below the threshold value.

[0059] Subsequently, the CPU 30 determines whether the calculated RMS value has continuously exceeded the acceleration upper limit threshold for a first predetermined time (for example, 3 seconds or more) (step ST14). In FIG. 7, as shown in B, if the state where the RMS value exceeds the upper limit threshold for 3 seconds or more continues, it is determined to be abnormal (step ST18). Note that, as shown in A, even if the RMS value exceeds the upper limit threshold, if the continuation is less than 3 seconds, it is not determined to be abnormal.

[0060] Similarly, the CPU 30 determines whether the calculated RMS value has continuously fallen below the acceleration lower limit threshold for a second predetermined time (for example, 3 seconds or more) (step ST15). If it has continuously fallen below for 3 seconds or more, it is determined to be abnormal (step ST18).

[0061] Furthermore, the CPU 30 determines whether the calculated RMS value has continuously exceeded the base threshold for a third predetermined time (preferably longer than the first and second predetermined times. For example, 10 seconds or more) (step ST16). In FIG. 8, as shown in C, if the state where the RMS value exceeds the base threshold for 10 seconds or more continues, it is determined to be abnormal (step ST18). That is, even if it does not exceed the upper limit threshold, if it continuously exceeds the base threshold for a long period, there is a high possibility of abnormality.

[0062] The CPU 30 transmits the above determination result to the host device via the communication circuit 38 (step ST19). When the above processing is completed, the CPU 30 repeats the processing below step ST11 again.

[0063] As described above, it is possible to diagnose in real time the abnormality of the device under monitoring to which the acceleration sensor 4 and the temperature sensor 5 are attached.

[0064] 1.5 Others (Modification Example) (1) In the above-described embodiment, the diagnostic device calculates and sets its own threshold value based on the vibration and temperature actually measured in the teaching mode. However, the threshold value calculated by other devices or the like may be recorded and set.

[0065] (2) In the above-described embodiment, the RMS value is used as the vibration determination reference value. However, other representative values such as the peak value and the crest factor may be used.

[0066] (3) In the above-described embodiment, the abnormality determination based on vibration is performed using the upper limit threshold value, the lower limit threshold value, and the base threshold value. However, the determination may be made only using the upper limit threshold value and the lower limit threshold value without using the base threshold value. Alternatively, the determination may be made using only one of the upper limit threshold value and the lower limit threshold value. For example, when an abnormality occurs in a press machine or the like and there is a high possibility that vibration due to the press operation will not occur, only the lower limit threshold value may be used.

[0067] (4) In the above-described embodiment, the average value of the RMS values in the teaching mode is used as the base threshold value. However, a value between the maximum value and the minimum value other than the average value, such as the median of the histogram, may be used.

[0068] (5) In the above-described embodiment, margins are provided for the maximum value and the minimum value to set the upper limit threshold value and the lower limit threshold value. However, the maximum value and the minimum value may be used as the upper limit threshold value and the lower limit threshold value as they are.

[0069] (6) In the above embodiment, it is determined that there is an abnormality when the RMS value continuously exceeds the base threshold for a predetermined time. However, instead of or in addition to this, it may be determined that there is an abnormality when the RMS value continuously falls below the base threshold for a predetermined time.

[0070] (7) In the above embodiment, the abnormality determination is transmitted to the upper device without distinguishing which of the upper limit threshold, lower limit threshold, and base threshold the abnormality is determined by. However, the abnormality determination that distinguishes these may be transmitted to the upper device.

[0071] (8) In the above embodiment, both the abnormality determination based on temperature and the abnormality determination based on vibration are performed. However, only one of them may be implemented.

[0072] (9) In the above embodiment, the determination result is transmitted to the upper device for output. However, it may be output by lighting an LED or displaying a warning by itself.

[0073] (10) In the above embodiment, the acceleration sensor 4 is used as a vibration sensor, but other vibration sensors such as a speed sensor or a displacement sensor may be used.

[0074] (11) In the above embodiment, the determination result is transmitted to the upper device only when an abnormality occurs. However, the determination result may also be transmitted during the normal state. Also, when transmitting the determination result, the vibration RMS value and temperature may also be transmitted together.

[0075] (12) In the above embodiment, the teaching mode is entered by pressing the teaching button 12. However, it may be set to the teaching mode by an external control signal (for example, a control signal from the upper device).

[0076] (13) In the above-described embodiment, the description has been made focusing on one diagnostic main device 2. As shown in FIG. 9, a plurality of diagnostic main devices 2a to 2n may be connected to the host device 50. The acceleration sensors 4 and temperature sensors 5 of the plurality of diagnostic main devices 2a to 2n are attached to different locations of the same diagnostic target device or different diagnostic target devices. The host device 50 receives the diagnostic results from the plurality of diagnostic main devices 2a to 2n, comprehensively judges them, and accurately determines the abnormal state.

[0077] For example, when the acceleration sensors 4 and temperature sensors 5 of the diagnostic main devices 2a to 2n are attached to different locations of the line conveyor, if an abnormality occurs concentrated in a plurality of diagnostic main devices 2d, 2e, and 2f at a specific location, it can be inferred that a device (such as a blower for cooling) that acts in common on the locations of the devices to which these three diagnostic main devices 2d, 2e, and 2f are attached has failed.

[0078] Also, if configured as shown in FIG. 9, not only the diagnostic results but also the vibration RMS values may be transmitted from the diagnostic main devices 2a to 2n, the vibration RMS values from each of the diagnostic main devices 2a to 2n may be compared, and a diagnostic main device with an abnormal value compared to others may be determined to be abnormal. Alternatively, such a determination and the determination based on the above-described threshold may be combined to determine that it is abnormal.

[0079] (14) In the above-described embodiment, one acceleration sensor 4 and one temperature sensor 5 are provided for one diagnostic main device. However, a plurality of acceleration sensors 4 and temperature sensors 5 may be provided for one diagnostic main device. Monitoring of a plurality of locations can be performed by one diagnostic main device.

[0080] (15) The above-described embodiment and modification example can be implemented in combination with other embodiments and their modification examples.

[0081] 2. Second Embodiment 2.1 Overall Configuration Fig. 10 shows the functional configuration of a diagnostic apparatus according to an embodiment of the present invention. The acceleration sensor 4, which is a vibration sensor, is attached to the device to be monitored. Therefore, the acceleration sensor 4 can measure and output the vibration of the device.

[0082] The vibration determination reference value calculation means 6 of the main diagnostic device 2 calculates a vibration determination reference value (for example, a vibration level indicating the magnitude of vibration) based on the measurement output of the acceleration sensor. The abnormality determination means 8 determines whether there is an abnormality in the device based on the vibration determination reference value with reference to the set upper limit threshold value, lower limit threshold value, and base threshold value.

[0083] For example, when an abnormality occurs in the device, the amplitude of the vibration often increases. Therefore, the abnormality determination means 8 determines that the device is abnormal when the vibration determination reference value exceeds the upper limit threshold value. The upper limit threshold value is preferably near the maximum value of the vibration of the device during normal operation.

[0084] Also, when the device is in a state close to the operation stop, the amplitude of the vibration often decreases. Therefore, the abnormality determination means 8 determines that the device is abnormal when the vibration determination reference value is below the lower limit threshold value. Thus, not only abnormalities during operation but also abnormalities such as the device not operating at all can be detected. The lower limit threshold value is preferably near the minimum value of the vibration of the device during normal operation.

[0085] Furthermore, when the vibration continuously exceeds the base threshold value set between the upper limit threshold value and the lower limit threshold value for a predetermined time, the device is also determined to be abnormal. Even if the vibration does not exceed the upper limit threshold value or fall below the lower limit threshold value, if the state where the vibration continues to increase for a predetermined time continues, there is a high possibility of an abnormality. Therefore, it is also possible to detect an abnormality that progresses gradually.

[0086] The determination result output means 10 outputs the determination result by the abnormality determination means 8.

[0087] As described above, in this embodiment, since the upper limit threshold value, the lower limit threshold value, and the base threshold value are provided, it is possible to detect an abnormality that progresses gradually.

[0088] 2.2 Appearance and Hardware Configuration The appearance and hardware configuration are the same as those in FIGS. 2 and 3 of the first embodiment.

[0089] 2.3 Teaching Process The teaching process is the same as that in FIG. 4 of the first embodiment.

[0090] 2.4 Diagnosis Process In the first embodiment, when the upper limit threshold value is continuously exceeded for a predetermined time or the lower limit threshold value is continuously below for a predetermined time, it is determined that there is an abnormality. However, in this embodiment, when the upper limit threshold value is exceeded even temporarily, it is determined that there is an abnormality.

[0091] FIG. 11 shows a flowchart of the diagnostic program in the diagnostic mode. The CPU 30 captures the data of the acceleration sensor 4 and the temperature sensor 5. For the acceleration sensor 4, the process of calculating the RMS value is the same (steps ST11 and ST12).

[0092] Next, the CPU 30 determines whether the maximum value of the recorded temperatures exceeds the temperature upper limit threshold value (step ST13). If it exceeds, the CPU 30 makes an abnormality determination based on the temperature (step S17).

[0093] Subsequently, the CPU 30 determines whether the calculated RMS value exceeds the acceleration upper limit threshold value (step ST54). In FIG. 7, it is determined that not only the entire period shown by B but also the period of A is abnormal (step ST18).

[0094] Similarly, the CPU 30 determines whether the calculated RMS value is below the acceleration lower limit threshold (step ST55). If it is below, it is determined that there is an abnormality (step ST18).

[0095] Furthermore, the CPU 30 determines whether the calculated RMS value has exceeded the base threshold continuously for a predetermined time (for example, 10 seconds or more) (step ST16). In FIG. 8, as shown at C, if the state where the RMS value exceeds the base threshold for 10 seconds or more continues, it is determined that there is an abnormality (step ST18). That is, even if the upper limit threshold is not exceeded, the fact that the base threshold is continuously exceeded for a long period indicates a high possibility of an abnormality.

[0096] The CPU 30 transmits the above determination result to the host device via the communication circuit 38 (step ST19). When the above processing is completed, the CPU 30 repeats the processing below step ST11 again.

[0097] In the above manner, it is possible to diagnose in real time the abnormality of the monitoring target device to which the acceleration sensor 4 and the temperature sensor 5 are attached.

[0098] 2.5 Others (Modification Examples) (1) In the above embodiment, it is determined that there is an abnormality if the RMS value exceeds (falls below) the acceleration upper limit value (lower limit value). However, it may be determined that there is an abnormality when it exceeds (falls below) continuously for a predetermined time.

[0099] (2) The above embodiment and modification example can be implemented in combination with other embodiments and their modification examples.

Claims

1. A vibration sensor for measuring vibrations caused by the operation of a monitored object; a vibration judgment reference value calculation means for calculating a representative value indicating a state of vibration over a plurality of periods as a vibration judgment reference value based on the measurement output of the vibration sensor; an abnormality determination means for determining that the monitored object is abnormal not only when the vibration determination reference value exceeds an upper limit threshold value continuously for a first predetermined time, but also when the vibration determination reference value exceeds a base threshold value set to be smaller than the upper limit threshold value continuously for a third predetermined time longer than the first predetermined time; a determination result output means for outputting a determination result of the abnormality determination means; A diagnostic device comprising: the upper limit threshold value and the base threshold value are set based on a representative value calculated based on a measurement output of the vibration sensor in a teaching mode, the upper limit threshold is set based on a maximum value of a representative value in a normal state during a teaching period in the teaching mode, The base threshold value is calculated based on the average value of representative values ​​in a normal state during a teaching period in the teaching mode. A diagnostic device comprising:

2. a vibration judgment reference value calculation means for calculating a representative value indicating a state of vibration over a plurality of periods as a vibration judgment reference value based on a measurement output of a vibration sensor that measures vibrations caused by the operation of the monitored object; an abnormality determination means for determining that the monitored object is abnormal not only when the vibration determination reference value exceeds an upper limit threshold value continuously for a first predetermined time, but also when the vibration determination reference value exceeds a base threshold value set to be smaller than the upper limit threshold value continuously for a third predetermined time longer than the first predetermined time; a determination result output means for outputting a determination result of the abnormality determination means; A diagnostic master unit comprising: the upper limit threshold value and the base threshold value are set based on a representative value calculated based on a measurement output of the vibration sensor in a teaching mode, the upper limit threshold is set based on a maximum value of a representative value in a normal state during a teaching period in the teaching mode, The base threshold value is calculated based on the average value of representative values ​​in a normal state during a teaching period in the teaching mode. A diagnostic main device characterized by:

3. A diagnostic program for implementing a diagnostic main device by a computer, the program comprising: a vibration judgment reference value calculation means for calculating a representative value indicating a state of vibration over a plurality of periods as a vibration judgment reference value based on a measurement output of a vibration sensor that measures vibrations caused by the operation of the monitored object; an abnormality determination means for determining that the monitored object is abnormal not only when the vibration determination reference value exceeds an upper limit threshold value continuously for a first predetermined time, but also when the vibration determination reference value exceeds a base threshold value set to be smaller than the upper limit threshold value continuously for a third predetermined time longer than the first predetermined time; A diagnostic program for causing the abnormality determination means to function as a determination result output means for outputting a determination result of the abnormality determination means, the upper limit threshold value and the base threshold value are set based on a representative value calculated based on a measurement output of the vibration sensor in a teaching mode, the upper limit threshold is set based on a maximum value of a representative value in a normal state during a teaching period in the teaching mode, The base threshold value is calculated based on the average value of representative values ​​in a normal state during a teaching period in the teaching mode. A diagnostic program comprising:

4. In any one of the devices or programs according to claims 1 to 3, The vibration judgment reference value calculation means calculates the vibration judgment reference value based on the acceleration or velocity of vibration.

5. A plurality of devices according to claim 1 or 2 are provided at different locations of the object to be monitored, A diagnostic system configured to receive the judgment results from each device and make a comprehensive judgment on these judgment results.

6. A method for diagnosing a monitored object based on vibration caused by its operation, comprising: Acquire the vibration of the monitored object, calculating a representative value indicating a state of vibration over a plurality of periods as a vibration judgment reference value based on the acquired vibration; A diagnostic method for determining that an object to be monitored is abnormal not only when the vibration judgment reference value exceeds an upper limit threshold value continuously for a first predetermined time, but also when the vibration judgment reference value exceeds a base threshold value set to be smaller than the upper limit threshold value continuously for a third predetermined time period longer than the first predetermined time period, the upper limit threshold value and the base threshold value are set based on a representative value calculated based on a measurement output of the vibration sensor in a teaching mode, the upper limit threshold is set based on a maximum value of a representative value in a normal state during a teaching period in the teaching mode, The base threshold value is calculated based on the average value of representative values ​​in a normal state during a teaching period in the teaching mode. A diagnostic method comprising:

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