JP2023026787A - Vibration monitoring device of machine plant - Google Patents

Abstract

To provide a vibration monitoring device of a machine plant which can perform accurate vibration diagnosis at a low cost and control an external device such as an alarm device on the basis of a result of vibration diagnosis.SOLUTION: A vibration monitoring device 1 of a machine plant according to the present invention for determining the presence/absence of an abnormality of vibration on the basis of a vibration waveform acquired from a vibration sensor 3 that detects the vibration of the machine plant and controlling an alarm device 7 that notifies of an alarm on the basis of the determination result comprises: a vibration input unit 5 which performs noise removal by inputting an analog vibration waveform output from the vibration sensor 3; and a PLC 9 which receives input of the analog vibration waveform whose noise is removed by the vibration input unit 5, converts the waveform into a digital vibration waveform, performs noise removal of the converted vibration waveform, determines the presence/absence of an abnormality on the basis of the noise-removed vibration waveform and controls the alarm device 7 on the basis of the determination result.SELECTED DRAWING: Figure 1

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vibration monitoring device for mechanical equipment used in mechanical equipment having rotating parts.

2. Description of the Related Art Conventionally, in mechanical equipment having a rotating part, vibration of the mechanical equipment accompanying driving of the rotating part is often monitored in order to detect an abnormality of the machine. A vibration monitoring device that performs such vibration monitoring determines the presence or absence of abnormal vibration by data processing and analysis of an output signal of a vibration sensor installed near a rotating part. An example of the vibration monitoring device as described above is disclosed in Patent Documents 1 and 2, for example.

Patent No. 5293300 Patent No. 6283591

Conventional vibration monitoring devices such as those disclosed in Patent Documents 1 and 2 are dedicated machines for vibration monitoring, and therefore basically do not have the function of controlling external devices. Therefore, when it is determined that there is an abnormality in the vibration, for example, when trying to operate an external device such as a buzzer, a warning lamp, or a personal computer that informs the abnormality, a control device that controls the external device based on the vibration diagnosis must be created separately, which incurs development costs.

On the other hand, there is a PLC (Programmable Logic Controller) as a general-purpose machine for controlling external devices. For example, if a program for diagnosing vibration is set in the PLC, a vibration sensor is connected as an input device, and an alarm device such as a buzzer or a warning lamp is connected as an output device, the PLC performs vibration diagnosis based on the signal from the vibration sensor. An alarm device or the like can be operated based on the diagnosis result.
However, in vibration diagnosis using only a general-purpose PLC, if the PLC input signal contains a high frequency that is more than half the sampling frequency, aliasing (folding phenomenon) occurs that appears as a signal with a frequency lower than the actual signal. Therefore, there is a problem that a highly accurate diagnosis such as the above-mentioned dedicated machine cannot be performed.

The present invention has been made in order to solve such problems, and is capable of low-cost, highly accurate vibration diagnosis, and control of external devices such as alarm devices based on the results of vibration diagnosis. The purpose is to provide a monitoring device.

The inventor came up with the idea that, in vibration diagnosis using a PLC, if the same level of diagnostic accuracy as that of a dedicated machine could be obtained, it would be possible to utilize the functions of the PLC and link it with other equipment.
The present invention is based on such an idea, and specifically has the following configuration.

(1) A vibration monitoring apparatus for mechanical equipment according to the present invention determines whether there is an abnormality in the vibration based on a vibration waveform obtained from a vibration sensor that detects vibration of the mechanical equipment, and issues an alarm based on the determination result. A vibration input unit that controls an alarm device that notifies and removes noise by inputting an analog vibration waveform output from the vibration sensor, and an analog vibration waveform that is noise-removed by the vibration input unit. Input is converted into a digital vibration waveform, noise is removed from the converted vibration waveform, the presence or absence of abnormality is determined based on the noise-removed vibration waveform, and the alarm device is controlled based on the determination result It is characterized by comprising a PLC that

(2) Further, in the apparatus described in (1) above, the vibration input unit includes an analog circuit for adjusting gain.

In the vibration monitoring apparatus for mechanical equipment according to the present invention, a vibration input unit that inputs an analog vibration waveform output from a vibration sensor to remove noise, and an analog vibration waveform from which noise has been removed by the vibration input unit are input. and convert it into a digital vibration waveform, remove noise from the converted vibration waveform, determine the presence or absence of an abnormality based on the noise-removed vibration waveform, and control the alarm device based on the determination result , the development cost is low, the accuracy of vibration diagnosis is high, and cooperation with external equipment such as an alarm device can be easily realized.

1 is an explanatory diagram of a vibration monitoring device for mechanical equipment according to an embodiment of the present invention; FIG.

A vibration monitoring device 1 for mechanical equipment according to an embodiment of the present invention (hereinafter simply referred to as “vibration monitoring device 1”) detects whether there is an abnormality in vibration based on an analog vibration waveform output from a vibration sensor 3. and controls the alarm device 7 based on the result of the determination. As shown in FIG. and a PLC 9 for inputting an analog vibration waveform from which noise has been removed by the vibration input unit 5, determining the presence or absence of an abnormality, and controlling the alarm device 7 based on the determination result. Denoising as used here means extracting the desired frequency.
Each component of the vibration monitoring device 1 will be described in detail below. In the following description, an example in which an acceleration sensor that outputs an analog waveform of vibration acceleration is used as the vibration sensor 3 will be described.

<Vibration input unit>
The vibration input unit 5 performs analog signal processing such as noise removal on the analog vibration acceleration waveform output from the vibration sensor 3 and inputs the processed vibration acceleration waveform to the PLC 9 . The vibration input unit 5 can also supply power to the vibration sensor 3 .

Analog signal processing for the vibration acceleration waveform is performed by the vibration waveform processing section 11 of the vibration input unit 5 .
The vibration waveform processing unit 11 is composed of an analog circuit, and performs processing such as AC coupling (HPF: high-pass filter) and aliasing filter (LPF: low-pass filter) on the vibration acceleration waveform to remove noise components. .
By removing noise from the vibration acceleration waveform of the analog signal in this way, it is possible to remove noise components that cannot be dealt with by noise removal by digital processing of the PLC 9 .

Further, the vibration waveform processing section 11 includes an analog circuit for gain adjustment (amplification according to the amplitude of the vibration waveform). By performing gain adjustment on the analog vibration acceleration waveform in the vibration input unit 5, the resolution of the A/D conversion by the PLC 9 can be utilized at full scale, which is preferable.

<PLC>
A PLC (programmable logic controller) 9 inputs an analog vibration waveform (vibration acceleration waveform in this example) from which noise has been removed by the vibration input unit 5, converts it into a digital vibration waveform, and converts the converted vibration waveform. noise is removed, the presence or absence of abnormality is determined based on the noise-removed vibration waveform, and the alarm device 7 is controlled based on the determination result. It includes a unit 15 , a digital filter processing unit 17 , an analysis/arithmetic processing unit 19 , a storage unit 21 , a control unit 23 and a communication unit 25 .
Each configuration will be described in detail below.

<<A/D conversion processor>>
The A/D conversion processing section 13 converts an analog vibration acceleration waveform output from the vibration input unit 5 into a digital vibration acceleration waveform. As described above, in the present embodiment, since the vibration acceleration waveform is gain-adjusted (amplified) by the vibration input unit 5, the full-scale resolution of the A/D conversion processing unit 13 can be utilized, and analysis and calculation can be performed. The accuracy of calculation in the processing unit 19 is improved (details will be described later).

≪Integration processing section≫
The integration processing unit 15 performs integration processing on the vibration acceleration waveform generated by the A/D conversion processing unit 13 to generate a vibration velocity waveform.
By generating a vibration velocity waveform from the vibration acceleration waveform, the state of vibration can be analyzed from the viewpoints of both vibration acceleration and vibration velocity. As a result, different behaviors such as impact vibration such as damage to rotating parts and poor lubrication (determined by acceleration waveforms are preferable) and dynamic vibrations such as backlash and unbalance of mechanical equipment (determined by velocity waveforms are preferable). Abnormal vibration can also be determined at the same time, which is preferable.

≪Digital filter processor≫
The digital filter processing unit 17 performs digital filter processing on the vibration acceleration waveform generated by the A/D conversion processing unit 13 and the vibration velocity waveform generated by the integration processing unit 15 to remove noise components. The filter processing time is 0.25 times or less than the vibration measurement time (as a specific example of 0.25 times, the digital filter processing time is 0.25 seconds for the vibration measurement time of 1.0 seconds per point) This function is realized by executing a predetermined program.

≪Analysis/calculation processing section≫
The analysis/calculation processing unit 19 performs calculations necessary for vibration diagnosis on the vibration acceleration waveform and the vibration velocity waveform from which noise has been removed by the digital filter processing unit 17, and determines whether or not there is an abnormality. Note that the vibration acceleration waveform and vibration velocity waveform that are subjected to vibration diagnosis by the analysis/arithmetic processing unit 19 are stored in the storage unit 21 .

Although the method for determining the presence or absence of an abnormality is not limited, for example, the maximum value, the effective value, and the crest factor (hereinafter also referred to as "level value") of the vibration waveforms (vibration acceleration waveform and vibration velocity waveform) during normal times are stored in the storage unit 21 in advance. ) are stored as vibration analysis parameters, and the presence or absence of an abnormality can be determined based on the vibration analysis parameters and the level value of the diagnosis target.

In the present embodiment, since the analog vibration acceleration waveform output from the vibration sensor 3 is subjected to noise removal by an analog circuit before being input to the PLC 9, noise can be detected only by the digital filter processing of the PLC 9 as in the conventional art. Compared to the case where the noise component is removed, the accuracy is improved by the noise component included due to aliasing being removed.
In addition, by gain adjustment (amplification) of the vibration input unit 5, since the resolution of the A / D conversion processing unit 13 is utilized at full scale, for example, the absolute accuracy (not the A / D conversion resolution, but the overall monitoring device error accuracy), vibration acceleration in units of 0.05 [m/s ² ] or less (measurement frequency range: 1000 to 15000 Hz), vibration velocity in units of 0.5 [mm/s] or less (measurement frequency range: 10 to 1000 Hz) can be calculated with high accuracy.
Therefore, vibration diagnosis with higher reliability than conventional vibration diagnosis by PLC is possible.

≪Memory section≫
The storage unit 21 stores various data, including the above-described vibration analysis parameters, each vibration waveform to be monitored (vibration acceleration waveform, vibration velocity waveform), past level values to be monitored, and abnormal vibrations for which an alarm has been issued. history data, etc. are saved.

≪Control section≫
The control section 23 controls the alarm device 7 based on the determination result of the analysis/arithmetic processing section 19 .
Examples of the alarm device 7 include a buzzer and a rotating lamp.
When the analysis/arithmetic processing unit 19 determines that there is an abnormality in the vibration, the control unit 23 operates the alarm device 7 to issue an alarm.
Note that the control by the control unit 23 can also be operated by an operator via an operation screen 27 (such as a touch panel) that is an external device of the PLC 9 .

≪Communication Department≫
The communication unit 25 transmits and receives data to and from another device 29 via a network. Other devices 29 can access data stored in the storage unit 21 of the PLC 9 via the network and the communication unit 25 .
This makes it possible to monitor each vibration waveform in real time from a personal computer on the network. Furthermore, since it is possible to obtain information from a plurality of PLCs with a single personal computer, operational information other than vibration can also be monitored simultaneously, enabling efficient monitoring of facility conditions.
It is also possible for another device 29 (personal computer, other PLC, etc.) to acquire the vibration waveform from the storage unit 21 and perform more detailed vibration analysis (frequency analysis, etc.).

As described above, according to the present embodiment, by inputting the analog vibration waveform output from the vibration sensor 3 to the PLC 9 via the vibration input unit 5, noise components that cannot be handled by the digital signal processing of the PLC 9 are removed. Since it is removed and the full-scale resolution of A/D conversion in the PLC 9 can be utilized, the accuracy of vibration diagnosis by the PLC 9 is improved.

Further, by using the control function and communication function of the external device of the PLC 9, which is a general-purpose machine, the control of the alarm device 7 and cooperation with other devices 29 via the network can be realized at low cost.

As described above, in this embodiment, the case where an acceleration sensor is used as the vibration sensor 3 has been described as an example, but the present invention is not limited to this, and other types of vibration sensors can also be used. For example, as the vibration sensor 3, a speed sensor that outputs an analog waveform of vibration speed may be used. Differential processing may be performed to generate vibration acceleration waveform data.

1 vibration monitoring device 3 vibration sensor 5 vibration input unit 7 alarm device 9 PLC
11 vibration waveform processing unit 13 A/D conversion processing unit 15 integration processing unit 17 digital filter processing unit 19 analysis/arithmetic processing unit 21 storage unit 23 control unit 25 communication unit 27 operation screen 29 other devices

Claims (2)

A vibration monitoring device for mechanical equipment that determines whether there is an abnormality in the vibration based on a vibration waveform obtained from a vibration sensor that detects vibration of the mechanical equipment, and controls an alarm device that issues an alarm based on the determination result. hand,
a vibration input unit for inputting an analog vibration waveform output from the vibration sensor and removing noise;
Input an analog vibration waveform from which noise has been removed by the vibration input unit, convert it to a digital vibration waveform, remove noise from the converted vibration waveform, and determine whether there is an abnormality based on the noise-removed vibration waveform. A vibration monitoring device for mechanical equipment, comprising: a PLC for determining and controlling the alarm device based on the result of the determination. 2. A vibration monitoring apparatus for mechanical equipment according to claim 1, wherein said vibration input unit includes an analog circuit for gain adjustment.

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