JP2019113993A - Abnormality detection device and method of cooling fan - Google Patents

Abstract

To detect abnormality or failure of a cooling fan properly according to various factors such as individual difference among CPUs.SOLUTION: An abnormality detection device 1 of a cooling fan 30 comprises: a revolution number detection part 2 for detecting the number of revolution of a cooling fan 30 cooling a CPU20; and a determination part 5 for determining whether or not the cooling fan 30 has abnormality on the basis of the number of revolution of the cooling fan 30 detected by the revolution number detection part 2. The determination part 5 comprises: an evaluation part for evaluating at lease one evaluation item influencing on cooling of the CPU20; a rank decision part for deciding a rank of difficulty of cooling on the basis of the evaluation by the evaluation part; and a table for storing the rank associated with a threshold that becomes larger as the rank becomes higher. The abnormality detection device determines that the cooling fan 30 has abnormality when the number of revolution of the cooling fan 30 detected by the revolution number detection part 2 is less than the threshold stored in the table associated with the rank determined by the rank decision part.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a cooling fan abnormality detection apparatus and method.

  Conventionally, a cooling fan that detects abnormality or failure of the cooling system by storing CPU temperature rise reference data when the cooling fan for cooling the CPU is normal and comparing it with the actually measured temperature rise data. The failure diagnosis method of is known (for example, refer patent document 1).

JP, 2009-187347, A

  However, in the failure diagnosis method of Patent Document 1, although the abnormality or failure of the cooling fan is detected by comparison with the temperature rise reference data, if the difference from the temperature rise reference data is an extent, the abnormality of the cooling fan It is not clear as to whether it is determined to be a failure. Generally, it is considered that when the difference between the temperature rise reference data and the temperature rise data exceeds a predetermined threshold, it is determined that the cooling fan is abnormal or faulty.

  However, the temperature rise of the CPU fluctuates due to various factors such as individual differences of the CPU. Even if the difference between the temperature rise reference data and the temperature rise data is small, if there is a problem or failure in the cooling fan, it is necessary to reliably detect it as a failure or failure, so the threshold can be set large. In addition, there is a disadvantage that the alarm is output even when it is not an abnormality or a failure in practice.

  The present invention has been made in view of the above-described circumstances, and a cooling fan abnormality detection device and method capable of appropriately detecting a cooling fan abnormality or failure according to various factors such as individual differences among CPUs. It is intended to be provided.

In order to achieve the above object, the present invention provides the following means.
One aspect of the present invention is an abnormality in the cooling fan based on a rotation speed detection unit that detects the rotation speed of a cooling fan that cools an electronic device, and the rotation speed of the cooling fan detected by the rotation speed detection unit. And a determination unit that determines whether or not there is an evaluation unit that evaluates at least one evaluation item affecting the cooling of the electronic device by the determination unit; And a table that associates and stores the rank and a threshold that increases as the rank increases, and the number of rotations of the cooling fan detected by the number-of-rotations detection unit is: Abnormality detection device for cooling fan that determines that the cooling fan is abnormal when it is lower than the threshold value stored in the table in association with the rank determined by the rank determination unit To provide.

  According to this aspect, when the cooling fan for cooling the electronic device is operated, the rotational speed detection unit detects the rotational speed of the cooling fan, and the evaluation unit at least one evaluation item that affects the cooling of the electronic device. Is evaluated, and the rank determination unit determines the degree of difficulty of cooling based on the evaluation by the evaluation unit. Then, the determination unit compares the table with the reference and stores the threshold stored in association with the rank with the rotational speed detected by the rotational speed detection unit, and if the rotational speed is below the threshold, the cooling fan It is determined to be abnormal.

  That is, according to the present aspect, when it is determined that the cooling fan is abnormal when the number of rotations of the cooling fan is decreased, the cooling of the electronic device is not performed by comparing the abnormality with a predetermined threshold. The threshold is set according to the difficulty. The threshold margin is set by setting the threshold corresponding to the rank that can be operated under the condition that the electronic device is difficult to cool large and setting the threshold corresponding to the rank that can be operated under the condition that the electronic device can easily cool down. It is not necessary to ensure a larger size than necessary, and it is possible to appropriately detect an abnormality of the cooling fan according to various factors such as individual differences of electronic devices.

In the above aspect, the evaluation item may include at least one of an ambient temperature of the electronic device, an operation state of the electronic device, and a calorific value based on individual differences of the electronic device.
By doing this, the rotation fan of the cooling fan can be set by setting a large threshold corresponding to the rank at which the electronic device can be operated under the condition where the ambient temperature is high, the condition where the processing amount is large or the individual difference easily occurs. Even if the number does not decrease much, it can be detected as abnormal. Conversely, the number of rotations of the cooling fan is greatly reduced by setting the threshold corresponding to the rank at which the electronic device can be operated under conditions where the ambient temperature is low, the situation where the processing amount is small, or the situation where individual differences are difficult to generate heat. If it does not, it can be made not detected as abnormal. As a result, it is not necessary to secure the threshold margin larger than necessary, and it is possible to appropriately detect the abnormality of the cooling fan according to various factors such as individual differences of the electronic devices.

In the above aspect, the evaluation item includes at least two of an ambient temperature of the electronic device, an operation state of the electronic device, and a calorific value based on individual differences of the electronic device, and the rank determination unit performs the evaluation The rank may be determined based on the sum of the ratings for the items.
In this way, the threshold corresponding to the rank at which the electronic device can be operated is set large under circumstances where the ambient temperature is high, the processing amount is large, or cases where the electronic device easily generates heat due to individual differences overlap. The threshold corresponding to the rank at which the electronic device is operated under the situation where the above cases do not overlap is set small. As a result, it is not necessary to secure the threshold margin larger than necessary, and it is possible to appropriately detect the abnormality of the cooling fan according to various factors such as individual differences of the electronic devices.

  In another aspect of the present invention, the cooling is performed based on the number of rotations of the cooling fan detected in the number of rotations detection step of detecting the number of rotations of the cooling fan for cooling the electronic device and the number of rotations detection step. And a determination step of determining whether or not there is an abnormality in the fan, the determination step evaluating at least one evaluation item affecting cooling of the electronic device, and the evaluation by the evaluation step. The above-mentioned rotation speed detection step is detected by referring to a table including a rank determination step of determining a rank of difficulty of cooling, and associating and storing the rank and a threshold that increases as the rank increases. If the number of revolutions of the cooling fan is lower than the threshold stored in association with the rank determined by the rank determination step Cooling fan is a cooling fan abnormality detecting method for determining as abnormal.

  ADVANTAGE OF THE INVENTION According to this invention, it is effective in the ability to detect the abnormality or failure of a cooling fan appropriately according to various factors, such as the individual difference of an electronic device.

It is a block diagram showing a control device provided with an abnormality detection device of a cooling fan concerning one embodiment of the present invention. It is a block diagram which shows the detail of the determination part of the abnormality detection apparatus of the cooling fan based on this embodiment with which the control apparatus of FIG. 1 is equipped. It is a figure which shows an example of the table which matches and memorize | stores the evaluation item and evaluation score which affect cooling of CPU. It is a figure which shows an example of the table which matches and memorize | stores the rank and the threshold value of the difficulty of cooling determined based on the total evaluation of FIG. It is a flowchart explaining the abnormality detection method using the abnormality detection apparatus of the cooling fan of FIG.

An abnormality detection device 1 and method for a cooling fan according to an embodiment of the present invention will be described below with reference to the drawings.
The abnormality detection device 1 according to the present embodiment is, as shown in FIG. 1, provided in a control device (CNC (computer numerical control) device or robot controller) 10 that controls a machine tool or robot. The control device 10 includes a CPU 20 that processes various data inside the housing 11, a cooling fan 30 that is disposed outside the CPU 20, and that cools the CPU 20 by air blowing, and a monitor 40.

  As shown in FIG. 1, the abnormality detection device 1 according to the present embodiment includes an encoder (rotational speed detection unit) 2 that detects the rotational speed of the cooling fan 30, and a temperature sensor 3 that detects the ambient temperature of the CPU 20. Detection by processing amount detection unit (not shown) for detecting the processing amount of CPU 20, memory 4 for storing calorific value based on individual differences of CPU 20 (hereinafter also referred to as basic calorific value) and a table to be described later And a determination unit 5 that determines whether the cooling fan 30 is abnormal based on the calculated number of revolutions.

  As shown in FIG. 2, the determination unit 5 evaluates each evaluation item of the ambient temperature detected by the temperature sensor 3, the processing amount detected by the processing amount detection unit, and the basic calorific value stored in the memory 4. Referring to a table stored in the memory 4 using the evaluation unit 6 to be evaluated, the rank determination unit 7 to determine the rank based on the evaluation by the evaluation unit 6, and the rank determined by the rank determination unit 7; A threshold determination unit 8 that determines a threshold of the rotational speed of the cooling fan 30 and an abnormality determination unit 9 are provided.

  More specifically, as shown in FIG. 3, the evaluation unit 6 evaluates the evaluation items such as the ambient temperature, the processing amount of the CPU 20, and the basic calorific value of the CPU 20 by using a predetermined evaluation score. It has become. These evaluation items are items that can be evaluated that the CPU 20 is more difficult to cool as the ambient temperature is higher, the processing amount of the CPU 20 is larger, and the basic calorific value of the CPU 20 is higher.

For example, when the specification temperature range of the control device 10 is 0 ° C. or more and less than 55 ° C., when the ambient temperature T is 0 ° C. ≦ T <5 ° C., the evaluation score E1 = 0, 5 ° C. ≦ T <10 ° C. In the case of (1), the evaluation score E1 is evaluated in 11 steps of 0 to 10 as in the evaluation score E1 = 1.
With regard to the processing amount of the CPU 20, the amount of operation of the internal processing of the CPU 20 is measured by software, and it is evaluated, for example, in four stages of evaluation scores E2 = 0 to 3 according to the amount of operation measured. There is.

Further, the basic calorific value of the CPU 20 is evaluated in six stages of evaluation score E3 = 0 to 5 according to the calorific value of the CPU 20 detected when the predetermined evaluation program is executed in the shipping test. There is.
Then, the evaluation unit 6 calculates and outputs the total evaluation E of the evaluation scores E1, E2, and E3 set by evaluating the one or more evaluation items.

  The rank determination unit 7 determines the ranks A, B, and C in the descending order of the total evaluation E which is the evaluation output from the evaluation unit 6, that is, in the order of high difficulty of cooling, as shown in FIG. It is supposed to be. For example, rank A may be set to 16 ≦ E ≦ 18, rank B may be set to 12 ≦ E ≦ 15, and rank C may be set to 8 ≦ E ≦ 11.

The table of FIG. 4 stores ranks A, B and C in association with threshold values. The threshold is set to be the largest at the rank A with the highest rank, and to decrease in the order of the rank B and the rank C as the rank becomes lower.
In the table of FIG. 4, the symbol N indicates the rated rotational speed of the cooling fan 30.

  The ambient temperature and the throughput of the CPU 20 are measured in a cycle of several seconds. The evaluation unit 6 performs evaluation each time the ambient temperature and the processing amount of the CPU 20 are measured, and calculates and outputs the sum E of the evaluation points E1, E2, and E3. The threshold determination unit 8 determines the threshold with reference to the table of FIG. 4 each time the evaluation unit 6 outputs the sum E of the evaluation scores E1, E2, and E3.

  The determination unit 5 compares the threshold value determined by the threshold value determination unit 8 with the rotational speed of the cooling fan 30 detected by the encoder 2, and when the rotational speed of the cooling fan 30 falls below the threshold, the cooling fan 30 It is determined to be abnormal.

An abnormality detection method using the abnormality detection device 1 for the cooling fan 30 according to the present embodiment configured as described above will be described below.
In order to implement the abnormality detection method according to the present embodiment, first, a basic evaluation value of the CPU 20 is detected by executing a predetermined evaluation program at the time of shipment, and the evaluation score E3 is obtained and stored in the memory 4 .

  In this state, when the control device 10 is operated, as shown in FIG. 5, the basic calorific value of the CPU 20 is read from the memory 4 (step S1), and the cooling fan 30 is operated. When the cooling fan 30 rotates, the rotational speed of the cooling fan 30 is sequentially detected by the encoder 2 (rotational speed detection step S2), and the ambient temperature is detected by the temperature sensor 3 for each determination cycle (step S3) S4) The processing amount of the CPU 20 is calculated (step S5).

  Then, whenever the detection of the ambient temperature and the calculation of the processing amount of the CPU 20 are performed, the evaluation by the evaluation unit 6 is performed, and evaluation scores E1 and E2 are obtained from the table of FIG. Further, an evaluation score E3 is obtained from the basic calorific value read from the memory 4 in addition to the evaluation scores E1 and E2 obtained (decision step, evaluation step S6). Then, a total evaluation E of the obtained evaluation scores E1, E2, E3 is calculated (determination step S7).

When the total evaluation E is calculated, the table in FIG. 4 is referred to using the total evaluation E, and the ranks A, B, and C corresponding to the total evaluation E are selected (determination step, rank determination step S8). Thresholds corresponding to ranks A, B, and C are determined from the table (decision step S9).
Determination unit 5 determines whether the number of rotations of cooling fan 30 detected by encoder 2 is below the threshold determined by threshold determination unit 8 (determination step S10). If the number of revolutions is less than the threshold value, the determination unit 5 determines that the cooling fan 30 has an abnormality (determination step S11), and that effect is displayed on the monitor 40 (step S12). If the number of rotations is equal to or greater than the threshold value, it is determined that the operation is normal (step S13), and the process from step S2 is repeated.

  As described above, according to the abnormality detection device 1 and the abnormality detection method of the cooling fan 30 according to the present embodiment, the presence or absence of the abnormality of the cooling fan 30 can be determined by comparing the rotational speed detected by the encoder 2 with a single threshold. Since the determination is made not by the determination but by comparison with the threshold set according to the ambient temperature, the processing amount of the CPU 20 and the basic calorific value of the CPU 20, it is not necessary to secure a large margin of the threshold, and normal cooling It is possible to prevent the occurrence of inconvenience that the fan 30 is determined to be abnormal.

  That is, the evaluation score is set higher as the ambient temperature is higher, the processing amount of the CPU 20 is larger, and the basic calorific value of the CPU 20 is larger, that is, the more difficult the CPU 20 is to be cooled, the threshold is increased. If the number of revolutions of the cooling fan 30 is slightly reduced, it can be determined as abnormal. Conversely, the lower the ambient temperature, the smaller the processing amount of the CPU 20, and the smaller the basic heating value of the CPU 20, the lower the evaluation score is. Therefore, the threshold is made smaller and the number of rotations of the cooling fan 30 slightly decreases. However, it can be determined that there is no abnormality. This has the advantage that the frequency of replacement of the cooling fan 30 can be reduced and the cost and labor can be saved.

In addition, in this embodiment, although ambient temperature, the processing amount of CPU20, and the basic calorific value of CPU20 were illustrated as an evaluation item, you may use 1 or more, without using all of these. Moreover, it is not limited to these evaluation items, For example, you may decide to evaluate the cooling performance of the heat sink attached to CPU20.
Further, the evaluation score of each evaluation item is not limited to the above, and any value may be adopted as long as it is set to be a larger evaluation score as the influence on the cooling of the CPU 20 is larger.

Further, in the above embodiment, the determination period for performing the abnormality determination of the cooling fan 30 is set to about several seconds, but instead of this, determination may be performed with a longer determination period. Further, in the initial state in which an abnormality of the cooling fan 30 is less likely to occur, the determination cycle may be extended, and the determination cycle may be shortened as the life of the cooling fan 30 approaches.
Further, in the present embodiment, the table of FIG. 4 stores the rank of the difficulty of cooling as a rank, but may rank in the order of easy cooling.

1 error detection device 2 encoder (rotational speed detection unit)
5 determination unit 6 evaluation unit 7 rank determination unit 20 CPU
30 Cooling fan S2 Rotational speed detection step S6 evaluation step, determination step S8 rank determination step, determination step S7, S9, S10, S11 determination step

Claims (4)

A rotation speed detection unit that detects the rotation speed of a cooling fan that cools the electronic device;
A determination unit that determines whether or not there is an abnormality in the cooling fan based on the rotation speed of the cooling fan detected by the rotation speed detection unit;
An evaluation unit that evaluates at least one evaluation item affecting cooling of the electronic device; a rank determination unit that determines a rank of difficulty of cooling based on the evaluation by the evaluation unit; And a table for storing in association with a threshold that increases as the rank increases, and the rotational speed of the cooling fan detected by the rotational speed detection unit is associated with the rank determined by the rank determination unit. A cooling fan abnormality detection device that determines that the cooling fan is abnormal if the threshold value stored in the table is lower than the threshold.   The cooling fan abnormality detection device according to claim 1, wherein the evaluation item includes at least one of an ambient temperature of the electronic device, an operation state of the electronic device, and a calorific value based on an individual difference of the electronic device. The evaluation item includes at least two of an ambient temperature of the electronic device, an operation state of the electronic device, and a calorific value based on individual differences of the electronic device,
The cooling fan abnormality detection device according to claim 2, wherein the rank determination unit determines the rank based on a total of evaluations on the evaluation items. A rotational speed detection step of detecting the rotational speed of a cooling fan for cooling the electronic device;
Determining whether the cooling fan has an abnormality based on the rotation speed of the cooling fan detected by the rotation speed detecting step;
The determination step includes an evaluation step of evaluating at least one evaluation item affecting cooling of the electronic device, and a rank determination step of determining a rank of difficulty of cooling based on the evaluation by the evaluation step. With reference to a table that associates a rank with a threshold that increases as the rank increases, the number of revolutions of the cooling fan detected by the number of revolutions detection step is determined by the rank determination step. And a cooling fan abnormality detection method that determines that the cooling fan is abnormal if the threshold value stored in association with the threshold value is stored.

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