JPH02118465A - Switch diagnostic device - Google Patents

Abstract

PURPOSE:To recognize the conversion time of a switch and to prevent the operation efficiency from being lowered by measuring a state quantity regarding the life of a switch at every number of times of a constant operation and predicting the remaining life. CONSTITUTION:A measurement part 1 measures the specific state quantity regarding the life of the switch, e.g. the contact resistance of the contact part, etc., at every number of times of the constant operation. This measurement part 1 includes a counter which counts the number of times of switch operation. A storage part 4 is stored with measurement data and setting data on a criterion, etc., and 1st and 2nd arithmetic parts 2 and 3 calculate the predicted value of the remaining life of the switch. Then when the measurement part 1 measures the state quantity of the switch at the number of times of the constant operation, the arithmetic parts 2 and 3 calculates the predicted value of the remaining life from current measurement data and last measurement data and a comparison part 5 compares them with the preset criterion to output a diagnostic result indicating whether or not the switch needs to be replaced.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a switch diagnostic device for diagnosing the state of a switch such as a rim switch to determine its remaining life.

<Prior art> For example, a large number of minotosinches are installed in various machines and equipment on factory production lines, etc. Detects movements, etc. This type of switch is often installed in a deep place in a machine or equipment, and maintenance work such as adjustment or replacement is not easy. Moreover, the lifespan of switches varies, and the timing of failure of the switches varies, so each time a switch fails at the end of its lifespan, the operation of equipment and machinery must be stopped and the switch replaced.

<Problems to be Solved by the Invention> However, if the operation of equipment or machinery is stopped every time a switch breaks down, there is a problem in that work efficiency deteriorates significantly and productivity decreases significantly. If it were possible to determine when it is time to replace a switch, it would be possible to carry out the replacement work while machines and equipment are not in operation, thereby preventing a drop in productivity. Therefore, it is extremely difficult to deal with switch failures in advance.

This invention was made by focusing on the above-mentioned situation, and by diagnosing the state of the switch and predicting the remaining life,
The purpose is to replace switches that have reached the end of their service life in advance to prevent a decline in work efficiency and thereby improve productivity.

In order to achieve the above object, the present invention includes a measuring section for measuring a predetermined state quantity that affects the life of the switch at every fixed number of operations, and a measuring section for measuring a predetermined state quantity that affects the life of the switch. A calculation unit that calculates a predicted value of the remaining life of the switch from data and previous measurement data, and a comparison unit that compares the predicted value obtained by the calculation unit with a predetermined judgment reference value and outputs a diagnosis result of the switch. The switch diagnostic device will be configured with the following.

The measurement unit measures a predetermined state quantity related to the life of the switch (
When the contact resistance (for example, the contact resistance of the contacts) is measured every certain number of operations, the calculation section calculates a predicted value of the remaining life from the current measurement data and the previous measurement data. When this predicted value is given to the comparison section, this predicted value is compared with a preset determination reference value, and a diagnosis result is output as to whether or not the switch should be replaced.

Therefore, by setting the judgment reference value appropriately, you can know when it is time to replace the switch before it reaches the stage where it is on the verge of failure, and you can avoid reducing productivity by performing work such as replacement while machinery and equipment are idle. It can be prevented.

<Embodiment> FIG. 1 shows the configuration of a switch diagnostic device according to an embodiment of the present invention. Each second arithmetic unit 2.3, storage unit 4. It includes a comparison section 5 and the like.

d) The running part 1 is a part for measuring a predetermined state quantity related to the life of the limit switch at every fixed number of operations. Contact resistance is measured every time a switch is operated by measuring the voltage between a movable contact and a fixed contact. Note that the object of measurement is of course not limited to contact resistance as long as it is a state quantity related to the life of the limit switch, and the measurement timing does not have to be for every switch operation, but for constant operation. It may be performed every number of times (for example, every 10 times). This measuring section 1 includes a counter for detecting on/off of the limit switch and counting the number of switch operations.
calculates the number of operations and outputs the contact resistance Rゎ.

The storage section 4 is a section in which measurement data by the measurement section 1 and setting data such as a determination reference value N to be described later are stored in advance.

1st. Each second calculation unit 2.73 is a part that calculates the predicted value Lll of the remaining life of the switch using the current measurement data and previous measurement data by the measurement unit 1 for each switch operation, The first arithmetic unit 2 executes the following calculation of the 0 expression, and the second arithmetic unit 3 executes the following 0 expression.

L, -L.

In the above equation 0, R,, is the contact resistance value obtained in the current measurement, R1-1 is the contact resistance value obtained in the previous measurement, L7 is the number of switch operations during the current measurement, L n -1 indicates the number of times the switch was operated during the previous measurement; Since −■−3° is 1, the formula 0 calculates the change in contact resistance lk for each switch operation.

FIG. 2 shows the relationship between the number of operations and the contact resistance of the limit switch. According to the figure, the change in contact resistance is small while the number of operations is small, but as the number of operations increases, it gradually increases and becomes linear. In the figure, Rc indicates the limit value of operation reliability regarding contact resistance, and Lc indicates the number of operations at that time.

Therefore, the above formula (2) is calculated by dividing the number of switch operations until the limit value Y is reached as the predicted value of the remaining life based on the change in contact resistance found in the current measurement. This predicted value R is almost infinite as long as the number of operations is small, but gradually becomes smaller as the life approaches the end.

Then, this predicted value LM of the remaining life is determined as a predetermined judgment reference value N.
(for example, 10,000 times) is determined by the comparison unit 5, and this comparison unit 5 determines whether the predicted value 1. When R is given from the second calculation section 3, the judgment reference value N is read out from the storage section 4, the two are compared, and if I-1≦N, an alarm output is sent out, indicating that it is time to replace the limit switch. It is to inform you.

The above circuit configuration may be realized by hardware, but
1st. The second calculation units 2 and 3, the comparison unit 5, and the storage unit 4 may be realized by the microcomputer 6.

FIG. 3 shows a control procedure by the microcomputer 6, and the operation of the circuit vj of the switch diagnostic device will be explained below based on the same figure.

First, in step l (indicated by rsTIJ in the figure) in the same figure, initialization such as storing predetermined setting data in the storage unit 4 and clearing the work area is performed, and then in the next step 2, switch operation is performed. The presence or absence is determined. If the determination is "YES", in the next step 3, the first calculation unit 2 receives the current measurement data R, regarding the contact resistance from the measurement unit 1, and the 111th measurement data Rn from the storage unit 4. -1 respectively, execute the calculation of the above equation 0 to calculate the change in contact resistance lk, and output the calculation result to the second calculation unit 3 (step 4.5).
.

In the next step 6, the second calculation section 3 obtains the limit value Rc and the number of operations from the storage section 4. Read each data of
Execute the second calculation to calculate the predicted value LR of the remaining life. Next, in step 7, the comparison unit 5 compares the predicted value RI and the judgment reference value N. If the predicted value RI takes a larger value than the judgment reference value N, then in step 8, "LR≦
The determination of "N" becomes "NO" and the process returns to step 2 to wait for the next switch operation.

On the other hand, if the determination in step 8 is "YES",
Proceeding to the next step 9, the comparator 5 sends out an alarm output to notify that the limit switch is nearing the time for replacement.

It goes without saying that malfunctions in the return of movable contacts and malfunctions in case seals in limit switches can also be diagnosed using the same configuration and procedures as above. It is also possible to obtain the predicted value by performing the calculation.

<Effects of the Invention> The present invention is as described above (i.e., a predetermined state quantity related to the life of a switch is measured every certain number of operations, and the remaining life of the switch is determined from this measurement data and the previous measurement data). After calculating the predicted value, this predicted value is compared with a predetermined criterion value.

By setting the judgment reference values described in 1 appropriately, it is possible to understand when a switch should be replaced before the switch reaches the stage where it is on the verge of failure, and to prevent damage to machinery and equipment. It is possible to perform work such as replacement during the downtime, thereby preventing a decrease in productivity, which achieves the remarkable effect of achieving the purpose of the invention.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of a switch diagnostic device according to an embodiment of the present invention, FIG.
The diagram shows switch diagnosis 1ljlJ? This is a flowchart 1 showing the ffO procedure. 1... Measuring section 2, 3... Calculating section 5...
・Comparison section

Claims (1)

[Scope of Claims] A switch diagnostic device for diagnosing the state of a switch and determining its remaining life, comprising a measuring unit for measuring a predetermined state quantity related to the life of the switch at every fixed number of operations. a calculation unit that calculates a predicted value of the remaining life of the switch from the measurement data from the measurement unit and the previous measurement data; and a switch diagnosis by comparing the predicted value obtained by the calculation unit with a predetermined judgment reference value. A switch diagnostic device comprising a comparison section that outputs a result.