JP4096401B2 - Seismic device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a seismic sensing device that detects vibration and determines whether the level is a dangerous level or whether the vibration is an earthquake.
[0002]
[Prior art]
Conventionally, this type of seismic device has been known as disclosed in JP-A-8-247818. Hereinafter, the method will be described with reference to FIGS.
[0003]
As shown in FIG. 7, the seismic sensor 1, the impedance conversion circuit 2, the amplifier circuit 3, the filter circuit 4, the comparator circuit 5, the interface circuit 6, and the CPU 7 are configured. A sensor, 9 is a gas pipe, and 10 is a shut-off valve.
[0004]
Further, the impedance conversion circuit 2, the amplifier circuit 3, and the filter circuit 4 are each composed of an operational amplifier 11 as shown in FIG. Here, 12 is a resistor, 13 is a capacitor, 14 is a predetermined voltage terminal, 15 is a ground terminal, 16 is a sensor unit, and 17 is an output terminal.
[0005]
[Problems to be solved by the invention]
However, in the above prior art, the output voltage of the operational amplifier is output with the voltage value of the predetermined voltage terminal as an offset voltage. For example, a positive vibration is a voltage of an offset voltage + α and a negative vibration is an offset voltage −β. Output as voltage. However, when this device is mass-produced, there is a problem that it is difficult to set the offset voltage to a predetermined value, and the device must be manufactured while inspecting one by one.
[0006]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, the present invention provides a vibration detection means for detecting vibration, an output means for outputting a detection signal of the vibration detection means, and the output means after the vibration detection means and the output means are turned on. Zero point setting means for setting the output value from zero to a zero level at which vibration is zero, and stability determination means for determining whether or not the output value continuously fluctuates below a predetermined level after a predetermined time after power-on. When the stability determining means determines that the output is stable, the zero point setting means sets the output value to zero level. It is necessary to adjust and inspect the offset voltage one by one even during mass production. Therefore, it is possible to manufacture a seismic sensing device with high vibration detection accuracy.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
The present invention provides a vibration detection means for detecting vibration, an output means for outputting a detection signal of the vibration detection means, and an output value from the output means after the vibration detection means and the output means are turned on. Zero stability setting means for setting to zero level, which is zero, and stability determination means for determining whether or not the output value continuously fluctuates below a predetermined level after a predetermined time after power-on, the stability determination When the means is determined to be stable, the zero point setting means sets the output value to zero level, and the zero point setting means can set the offset voltage of the manufactured circuit. Even at times, it is not necessary to adjust and check the offset voltage one by one, and it is possible to manufacture a seismic sensing device with high vibration detection accuracy and to output below a predetermined level continuously for a predetermined time. By detecting, it is possible to confirm the stabilization of the transient characteristics after power-on, it is possible to set a higher zero level accuracy.
[0008]
In addition, by providing zero point adjustment instruction means for instructing the zero level correction adjustment operation, zero level adjustment can be performed several times even after the zero level is set, and high accuracy is maintained over a long period of time. be able to.
[0009]
Furthermore, when vibration is detected while the zero point setting means is operating, vibration detection is performed using the initial value or the past zero level setting value. Even if vibration occurs during the zero point setting, the initial value or the past zero level setting value can be used to detect the vibration without missing it.
[0010]
【Example】
Hereinafter, embodiments of the seismic sensing device of the present invention will be described with reference to the drawings.
[0011]
Example 1
FIG. 1 is a block diagram of a seismic device according to Embodiment 1 of the present invention. In FIG. 1, 18 is a vibration sensor as vibration detection means for detecting vibration acceleration, 19 is an impedance conversion circuit for the vibration sensor 18, 20 is an amplification circuit for amplifying a signal as output means, and 21 is a digital signal. AD conversion circuit 22 for converting the battery, 22 as a battery as a power supply, 23 a switch unit for turning on / off electricity, 24 an AD input unit for exchanging signals with the AD conversion circuit 21, 25 input as a digital signal Zero point adjustment instruction unit for instructing to correct the voltage value to zero point, 26 is a zero point setting unit for setting the voltage value to zero point, 27 is a vibration level converting unit for converting a digital value into a vibration level, and 28 is these It is a microcomputer part which performs the process of. As shown in FIG. 2, the impedance conversion circuit 19 is composed of an operational amplifier 29 having a high input impedance, and the amplifier circuit 20 is composed of a two-stage operational amplifier 30.
[0012]
Here, 31 is a resistor section, 32 is a capacitor section, 33 is an offset voltage terminal, 34 is a ground terminal, and 35 is an output terminal. Also, power supply connection lines and the like are omitted.
[0013]
Next, operation | movement and an effect | action are demonstrated using FIGS. 3-5. As shown in FIGS. 3 and 4, the seismic device of the present invention supplies power to the vibration sensor 18, the impedance conversion circuit 19, the amplification circuit 20, and the AD conversion circuit 21 with the switch unit 23 turned on.
[0014]
Then, the output voltage from the amplifier circuit 20 changes with time as shown in FIG. 3, and is stabilized at the final offset voltage. In order to avoid this phenomenon, first, after the power is turned on, an initial value of zero level is set, and the first circuit until the circuits such as the vibration sensor 18, the impedance conversion circuit 19, the amplification circuit 20, and the AD conversion circuit 21 are stabilized. For a predetermined time (for example, 3 seconds).
[0015]
Then, when the first predetermined time has elapsed, the timer for the second predetermined time is cleared and initialized, and the timer is started. Then, AD data is input to A (i) from the AD conversion circuit at a predetermined sampling time interval. Here, i is the number of counters incremented by one. If the absolute value of the difference between A (i) and A (i + 1) is less than a predetermined value A (for example, 2 units), the stability determining unit as the stability determining means has a second predetermined time (for example, 5 seconds). ) Is determined, and if the second predetermined time or more has elapsed, the value of A (i) is set to the zero level set value Z as the zero point.
[0016]
If the absolute value of the difference between A (i) and A (i + 1) is greater than or equal to the predetermined value A, the second predetermined time timer is cleared again and the same is repeated, and the second predetermined time has elapsed. If not, the AD conversion value is input at the next sampling time and the same processing is repeated.
[0017]
Therefore, if the signal becomes stable at a predetermined value after 3 seconds have passed since the power is turned on, the voltage value can be set as the zero point.
[0018]
Furthermore, as shown in FIG. 5, there is a change with time or temperature by adjusting the zero point by a signal from the zero point adjustment instruction unit every third predetermined time (for example, one hour). However, since a highly accurate zero point can always be set, the vibration level can be accurately measured and abnormal vibration can be detected accurately.
[0019]
As described above, after the first predetermined time has elapsed after the power is turned on, the stability determination unit 30 that determines whether the output value continuously fluctuates below a predetermined level within the second predetermined time is determined to be stable. By providing a zero point setting means to set the output value to zero level, transient characteristics at power-on can be removed, and stabilization of transient characteristics after power-on can be confirmed, with high accuracy Zero level can be set.
[0020]
Moreover, even after the zero level is set, the zero level can be adjusted several times, and high accuracy can be maintained over a long period of time. Further, by correcting the zero level periodically, it is possible to always maintain a highly accurate zero level.
[0021]
Further, even in a single power supply driving circuit using a battery power supply, the offset voltage is set to zero level, and a highly accurate vibration level can be detected over a long period of time even if the battery voltage fluctuates.
[0022]
The processing after the zero point setting is omitted, but after the zero point is set in flow 1, vibration is measured at a predetermined interval and whether the level is abnormal or whether the vibration waveform is abnormal. When a dangerous vibration is generated by judging whether or not, predetermined safety measures are taken.
[0023]
Further, although the zero point adjustment instruction means has been described with the clock timer, it may be an activation device that issues a zero point adjustment instruction when manually operating when an abnormality occurs.
[0024]
(Example 2)
FIG. 6 is a flowchart showing the seismic sensing apparatus according to Embodiment 2 of the present invention. The difference from the first embodiment is that when vibration is detected during the zero point setting process, vibration detection is performed using an initial value or a past zero level setting value.
[0025]
For example, when an AD conversion value is input at a predetermined time interval and the value is less than the predetermined value B, a zero point setting process is performed as in the first embodiment. In some cases, since the fluctuation range was too large, the zero point set value was initialized and the vibration level was measured.
[0026]
Thus, even if vibration occurs during the zero point setting, the initial value or the past zero level setting value can be used to detect the vibration without missing it.
[0027]
【The invention's effect】
As described above, the seismic sensing device of the present invention includes a vibration detection unit that detects vibration, an output unit that outputs a detection signal of the vibration detection unit, and the vibration detection unit and the output unit after the power is turned on. Zero point setting means for setting the output value from the output means to a zero level at which vibration is zero, and stability determination for determining whether the output value continuously fluctuates below a predetermined level after turning on the power for a predetermined time or more. And when the stability determining means determines that the output is stable, the zero point setting means sets the output value to zero level, and the zero point setting means is set to the offset voltage of the manufactured circuit. Therefore, even during mass production, it is not necessary to adjust and inspect each offset voltage, and it is possible to manufacture a seismic sensing device with high vibration detection accuracy and for a predetermined time. By detecting a predetermined level below the output value continues, and it is possible to confirm the stabilization of the transient characteristics after power-on, it is possible to set a highly accurate zero level.
[0028]
In addition, by providing zero point adjustment instruction means for instructing the zero level correction adjustment operation, zero level adjustment can be performed several times even after the zero level is set, and high accuracy is maintained over a long period of time. be able to.
[0029]
Furthermore, when vibration is detected while the zero point setting means is operating, vibration detection is performed using the initial value or the past zero level setting value. Even if vibration occurs during the zero point setting, the initial value or the past zero level setting value can be used without missing the vibration.
[Brief description of the drawings]
FIG. 1 is a block diagram of a seismic device according to a first embodiment of the present invention. FIG. 2 is a circuit diagram of the seismic device. FIG. 3 is a diagram showing signal waveforms indicating the operation of the seismic device. FIG. 5 is a timing chart showing the operation of the seismic device. FIG. 6 is a flowchart showing the operation of the seismic device showing Embodiment 2 of the invention. FIG. 7 is a block diagram showing a conventional seismic device. [Fig. 8] Circuit diagram showing the seismic device [Explanation of symbols]
18 Vibration sensor (vibration detection means)
19 Impedance conversion circuit 20 Amplification circuit (output means)
21 AD conversion circuit 22 Battery (power supply)
23 Switch unit 25 Zero point adjustment instruction unit (zero point adjustment instruction means)
26 Zero point setting unit (zero point setting means)
30 Stability determination unit

Claims (3)

Vibration detection means for detecting vibration; output means for outputting a detection signal of the vibration detection means; and output value from the output means after power is turned on for the vibration detection means and the output means. Zero point setting means for setting the level, and stability determination means for determining whether the output value continuously fluctuates below a predetermined level after a predetermined time after turning on the power, the stability determination means being stable A seismic sensing device that, when judged, sets the output value to zero level by the zero point setting means . 2. The seismic sensing device according to claim 1, further comprising zero point adjustment instruction means for instructing an operation for correcting and adjusting the zero level . 2. The seismic sensing device according to claim 1 , wherein when vibration is detected while the zero point setting means is operating, vibration detection is performed using an initial value or a past zero level set value .

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