JPS626122A - Rotation detector - Google Patents

Abstract

PURPOSE:To set an abnormal number of revolutions accurately by deciding the abnormal number of revolutions with a signal interval deciding circuit and deciding the duration of the abnormal rotation with a signal duration deciding circuit. CONSTITUTION:A hole element 6 of a rotation detector packaged on the inside of a flowmeter 1 produces two pulses for one rotation of an impeller 4. The number of revolutions is decided from an interval of the continuous pulse train. When the rotation of the impeller 4 becomes slower, since the interval of the pulse train becomes longer and the integration voltage of an integration circuit 14 exceeds the set voltage of a voltage comparison circuit 17, the voltage comparison circuit 17 is made a low level. In other words, it is decided that the number of revolutions, namely, the flow rate is made under a prescribed value with the signal interval deciding circuit 10. Further, when a state that the rotation of the impeller 4 is slow continues, since the integration voltage of an integration circuit 24 is made under the set voltage of a voltage comparison circuit 27, the output of the signal duration deciding circuit 18 is made a high level and a signal 28 is outputted.

Description

[Detailed description of the invention] The present invention relates to a rotation detector fli1 of a rotating device.

A rotary liquid flow meter can be cited as an example of a rotating device.

For cooling equipment in semiconductor manufacturing equipment, etc.

Alternatively, a large amount of cooling water is used to cool the processing liquid. If the cooling water stops flowing, the temperature of the equipment will rise abnormally, making dangerous chemical processing impossible, so it is necessary to check that the cooling water is flowing at a specified flow rate or higher.

The flow rate detection device calculates the flow rate from the rotational speed of the flowmeter, and generates an alarm signal when the flow rate becomes less than a specified flow rate.

With conventional rotation detection devices, an alarm signal is generated even when instantaneous fluctuations in flow rate occur. When opening and closing, even if the flow rate is normal over a long period of time, such as 3 seconds, instantaneous fluctuations in flow rate occur, resulting in a frequent defect that higher-level equipment cannot make correct decisions.

In addition, there are other rotation detection devices that maintain an alarm state once the flow rate drops below a specified level, but these rotation detection devices cannot release the alarm state even if the flow rate returns to normal. There is a flaw.

Further, in the alarm holding type rotation detection device, the alarm is held due to a momentary interruption of the source.

There is a defect that an alarm occurs even though the cooling water continues to flow normally.

The present invention eliminates the above-mentioned defects and is a novel invention, and its purpose is (1) to provide a rotation detection device that allows easy determination by a host device.

(2) To provide a rotation detection device that can accurately set the abnormal rotation speed.

(3) To provide a stable rotation detection device that does not respond to instantaneous rotation speed fluctuations.

(4) To provide a rotation detection device that can automatically release an alarm state when normal rotation continues.

Consisting of a rotation detector that generates a signal in accordance with the rotation of the rotating body, a signal interval determination circuit that determines the interval between the signals, and a signal duration determination circuit that determines the duration of the signal. This is achieved by a rotation detection device tl2 characterized by the following.

Hereinafter, the present invention will be explained in detail with reference to the drawings.

FIG. 1 is a schematic diagram and circuit diagram of an embodiment for explaining a rotation detection device according to the present invention ζ, and FIG. 2 is a signal waveform diagram.

Cooling water flows from input boat 2 of flow meter 1 to output boat 3. The impeller 4, which is a rotating body, generates a flow 11H1 around the shaft 5.
= Rotate accordingly. (Two magnets on the outer circumference of impeller 4)
7a and 7b are fixed. Therefore, the Hall element 6 of the rotation detector mounted inside 42 of the flowmeter 1 is
Two pulses are generated for one rotation of the motor. The number of revolutions is determined from the interval 34 between the consecutive pulse trains 31.

The pulse train 31 detected by the Hall element 6 is compared by the transistor 11 of the signal interval determination circuit 10, and the switch voltage 32 is compared by the voltage comparison circuit 17 with a set voltage 33 by the resistor 15.16.

When the rotation of the impeller 400 becomes slower, the interval 34 between the pulse trains 31 becomes longer, and the integrated voltage 3z exceeds the set voltage 33, so the voltage comparison circuit 17 becomes low level. In other words, the signal interval determination circuit 10 determines that the number of revolutions, that is, the flow rate is below the specified value.
It is composed of a resistor 19 and a capacitor 20.

The pulse width of the negative pulse input to the first integrating circuit 21 is amplified. The signal 35 amplified by the second integrating circuit 24 composed of a resistor 22 and a capacitor 23 is then converted to a longer time constant 1, for example, fPto of the time constant of the first integrating circuit 210.
, IE, are integrated, so the integrated voltage 36 gradually decreases and is compared by the voltage comparison circuit 27 with a set voltage 37 determined by the resistors 25 and 26. The second integration circuit 240 time constant is
By multiplying the time constant of the first integrator circuit 210, the variation of the instantaneous pulse interval m can be made stronger.

If the rotation of the impeller 4 continues to be slow, the integrated voltage 36 becomes lower than the set voltage 37, so the output 28 of the signal duration determination circuit 18 becomes high level and the output 35 becomes high level. Integral voltage 3 of the second integration circuit 24 of the signal duration determination circuit 18
6 gradually rises, and when it exceeds the set voltage 37f, output 2
8 becomes low level and the alarm state is canceled.

In the above explanation, a case has been described in which the pulse width amplification circuit of the signal duration determination circuit 18 is an integrating circuit, but the present invention is not limited to this, and the present invention can also be applied to a single shot multivibrator that amplifies a negative pulse width. It is clear that this can be achieved.

In the above explanation, the case where the rotation detector is a Hall element has been described; however, the present invention is not limited to this, and by using a magnetoresistive element or a pickup coil as the Thor element, there may be a further reflection of the impeller. It is clear that this can also be realized using a reflection mode using light shielding or a transmission type optical sensor.

In addition, in the above explanation, an example was described in which the rotating device is a liquid flow rate needle, but a 71-inch needle for cooling electronic equipment (
: It is exactly the same.

In other words, it is clear that a rotation detection device is necessary to detect the rotation speed of the fan, recognize a decrease in cooling capacity, and prevent accidents to expensive electronic equipment.9 It is clear that the present invention can be applied in exactly the same way. be.

As explained above, the abnormal rotation speed can be accurately set by determining the abnormal rotation speed with the signal interval determination circuit of the rotation detection device of the present invention and determining the duration of abnormal rotation with the signal duration determination circuit. In addition, an alarm signal is generated only when abnormal rotation continues for a long time, ignoring momentary abnormal rotation, and the alarm signal is canceled when normal rotation continues. It becomes possible to send out.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram and circuit diagram of an embodiment for explaining the rotation detection device according to the present invention, and FIG. 2 is a signal waveform diagram. 1 is a flow rate needle, 2 is an input boat, 3 is an output boat, 4 is an impeller, 5 is a shaft, and 6 is a Hall element. 7a, 71) are magnets, and io is a signal interval determination circuit. 11 is a transistor, 12.15.16.19.22
．． 25.26 is a resistor, 13.23 is a capacitor, 14
．． 21.24 is an integration circuit, 17.27 is a voltage comparison circuit!
18, signal duration determination circuit 820 is a capacitor, 28
is the output. 31 is a pulse train, 34 is a pulse train 310 interval, 32°3
6 is an integrated voltage, 33.37 is a set voltage, and 35.38 is a signal. Patent applicant: Sigma Technology Industry Co., Ltd. Representative Kami 1
) Cleaning of Kaoru's drawing (no change in 'a') Procedural amendment (released) September 26, 1985 2, Title of invention Image device

Claims (1)

[Scope of Claims] 1. A rotating body, a rotation detector that generates a signal according to the rotation of the rotating body, a signal interval determination circuit that determines the interval between the signals, and a signal duration determination circuit that determines the duration of the signal. A rotation detection device characterized by consisting of a circuit. 2. The rotation detection device according to claim 1, wherein the rotation detector is an optical sensor. 3. The rotation detection device according to claim 1, wherein the rotation detector is a Hall element. 4. The rotation detection device according to claim 1, wherein the rotation detector is a magnetoresistive element. 5. The rotation detection device according to claim 1, wherein the rotation detector is a pickup coil. 6. The rotation detection device according to claim 1, wherein the signal interval determination circuit is an integrating circuit and a voltage comparison circuit. 7. The rotation detection device according to claim 1, wherein the signal duration determination circuit is a pulse width amplification circuit, an integration circuit, and a voltage comparison circuit. 8. The rotation detection device according to claim 1, wherein the signal duration determination circuit includes at least two integration circuits and a voltage comparison circuit.