JPH0748240B2 - Wireless liquid amount measuring device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a wireless liquid amount measuring device suitable for remotely controlling the liquid level of an underground tank buried in a gas station or the like.

(Prior art) The amount of fuel oil or other liquid stored in an underground tank is usually managed by converting it into an electric signal by a float type level gauge and transmitting it to a monitor device such as an office via a transmission line. Has been done.

However, since the liquid level measuring device of the underground tank and the monitoring device are connected by a transmission line, there is a problem that wiring work considering explosion proof is required and the facility costs.

In order to solve such a problem, the present applicant has previously proposed a wireless liquid amount measuring device that transmits data from the liquid surface measuring means to a monitor device by radio waves. According to this device, wiring work can be eliminated.

(Problems to be Solved by the Invention) However, there was a problem that the data at the stage of supplying fuel oil to the underground tank by Lori was affected by the wave motion of the liquid level and was unstable and unreliable. .

The present invention has been made in view of the above problems, and an object thereof is to provide a wireless liquid amount measuring device capable of managing the liquid amount in an underground tank with higher reliability. To do.

(Means for Solving the Problem) In order to solve such a problem, in the present invention, the liquid level is detected at regular time intervals, while the liquid level is increased, the liquid level is changed every time T1, and the liquid level is increased. When decreasing, the liquid level is set to T2
In the case of transmitting by radio wave every time (T1 <T2), the liquid level is transmitted every time T1 for a certain period from the time when the increase of the liquid level ends.

(Function) The liquid level data is transmitted in a cycle as short as possible immediately after the fuel oil is replenished to the underground tank. The amount can be sent accurately. In addition, the receiving side can accurately know the liquid amount and can eliminate erroneous information when the unreceivable reporting device is provided.

(Example) Therefore, the details of the present invention will be described below based on an illustrated example.

FIG. 1 shows an embodiment of a liquid supply equipment to which the liquid amount measuring device of the present invention is applied. In the drawing, reference numeral 1 is a fuel oil replenishment by a lorry via a replenishment source valve 2. In the underground tank that receives the water, a float type liquid level measuring device (not shown) is provided, and a transmitting device 3 that transmits the liquid level from there by radio waves is installed. Reference numeral 4 denotes a receiver installed in the office 5, and is configured to receive a liquid level signal from the transmitter 3 and display the liquid amount and the liquid level.

FIG. 2 shows an embodiment of the above-described transmitter 1, in which reference numeral 10 is a microcomputer constituting a control means, which supplies a voltage from a battery 11 via a voltage regulator 12 to a power supply terminal. 10a, also voltage regulator 12
Is activated, the activation signal from the timer means 13 is constantly supplied to the activation signal terminal 10b to shift to the operating state, while it is in a restartable state when stopped, that is, in a standby state. Reference numeral 13 denotes the above-mentioned timer means, which is configured to intermittently operate the microcomputer 10 by outputting a start signal at a constant cycle T0, for example, at intervals of 15 seconds.

Reference numeral 14 denotes a voltage drop detection means that detects the output voltage of the battery 11 and, when the output voltage of the battery 11 drops below the rated input voltage of the voltage regulator 12, outputs a voltage drop signal to the voltage detection terminal 10c of the microcomputer 10. Is configured to output.

Reference numeral 15 is a data storage means, which is supplied with an operating voltage at all times via a voltage regulator 12, and is provided with a liquid level measuring means 20 to be described later.
The liquid level data from is taken as the liquid level data F0 of the previous measurement, and the stored data is stored as the liquid level data F-1 of the last two times while being updated, and the numerical values N and M described later are stored. To do.

A liquid level measuring means 20 responds to the vertical movement of the float F installed in the tank 1 and also has a voltage regulator 21.
Potentiometer 22 receiving the reference voltage via
And a voltage-frequency conversion means 23 for converting the output voltage from the potentiometer 22 into a frequency, which is supplied with a voltage via the first switch 16 controlled by the microcomputer 10 and has a frequency matching the liquid level. It is configured to output the signal to the microcomputer 10.

Reference numeral 17 denotes a modulation transmission means, which receives power supply from the battery 11 through the voltage regulator 12 through the second switch 18 which is controlled by the microcomputer 10, and the liquid level measurement unit.
The measurement data of 20 is transmitted from the antenna 19 as a radio signal.

FIG. 3 shows an embodiment of the modulation / transmission means. The band setting circuit 26 and the carrier wave oscillating circuit 25 whose frequency is selected by the frequency setting circuit 27, and the liquid level data and the voltage drop signal It is composed of a modulation circuit 24 that modulates the carrier wave from the carrier wave oscillation circuit 25. In the figure, reference numeral 26
a and 26b are switches for setting the band, and reference numeral 27 in the figure
Reference characters a and 27b denote switches for setting the frequency within the band.

Next, the operation of the apparatus configured as described above will be described based on the flowchart shown in FIG.

When the battery 11 is set and power is supplied to the device, the microcomputer 10 stands by in a standby state in which only the function sufficient to accept the activation signal from the timer means 13 remains. The timer means 13 constantly receives the supply of electric power to execute the time counting operation (step a), and when 15 seconds have elapsed from the start of the time counting, the starting signal is output (step b) (I in FIG. 5). As a result, the microcomputer 10 exits the standby state and shifts to the operating state, turns on the first switch 16 and supplies operating power to the liquid level measuring means 20 (step C). The liquid level measuring means 20 converts the voltage output from the potentiometer 22 according to the liquid level into a frequency signal by the voltage-frequency converting means 23 and outputs the frequency signal to the microcomputer 10. The microcomputer 10 counts this frequency signal for a certain period of time to obtain the liquid level data F + 1 (step D), turns off the first switch 16 to cut off the power to the liquid level detection unit 20, and again the liquid level data. F + 1 and data storage means
The previous liquid level data F0 stored in 15 and the liquid level data F-1 of the last two times are compared (step E).

[When not replenishing] (Fig. 5 III) In the present case, the fuel oil in the underground tank 1 is or is not consumed due to the liquid supply to the vehicle. F + 1 is a data storage means
It is smaller than or equal to the previous liquid level data F0 of 15 (to step). Therefore, the microcomputer 10
Compares the previous liquid level data F0 with the two-previous liquid level data F-1, and in this case as well, the previous liquid level data F0 is small (stepped). If the numerical value M to be described later is "0" (step H), and if the numerical value N to be described later is not "0" (step step), the numerical value N is decremented by 1 (step YO), and the microcomputer 10 performs modulation transmission. The liquid level data F0 and F-1 of the previous time and the previous two times of the data storage means 15 are respectively updated without operating the means 17, and the standby state is entered (stepwa). This allows the entire device to
Minimize power consumption by leaving only the minimum functions required for the next startup.

Repeat this kind of operation (Steps I-I, Y-O,
W) When the numerical value N becomes "0", the microcomputer
In step 10, the second step 18 is turned on to supply power to the modulation transmission means 20, and after transmitting the measured liquid level data F + 1, the second step 18 is performed.
The switch 18 is turned off to suspend the transmission modulator 17, and the numerical value N is set to the transmission interval, for example, 10 (step E). At this time, if the output voltage of the battery 11 is below the specified value (step), the microcomputer
10 also transmits voltage data in accordance with the liquid level data F + 1 (steple). Next, the liquid level data of the previous and the previous two times
F0 and F-1 are updated, respectively, and the state shifts to the standby state (step), and the above steps are repeated again.

Thereafter, the microcomputer 10 shifts from the standby state to the operating state every 15 seconds in this manner to activate the liquid level measuring means 20, and transmits the liquid level data every time such operation is repeated 10 times. As a result, it is possible to transmit the liquid level data necessary and sufficient for the liquid amount management when the fuel is not refueled while minimizing the power consumption.

[At the time of replenishment to the underground tank] (Fig. 5 II) At the time when the start signal from the timer means 13 is output (step B), the microcomputer 10 shifts from the standby state to the operating state and turns on the first switch 16. The liquid level data F + 1 from the liquid level detecting means 20 is obtained by turning it on (step c) (step d). Next, the first switch 16 is turned off, and the measured liquid level data F + 1 and the data storage means
The liquid level data F0 and F-1 stored in 15 are compared (step E).

In the present case, the fuel oil flows from the lory to the underground tank 1 via the replenishment source valve 2, and the liquid level is rising,
The liquid level data F + 1 measured this time becomes larger than the previous liquid level data F0 (to step).

Then, the microcomputer 10 turns on the second switch 18.
When turned on, the liquid level data F + 1 measured this time is transmitted, and after the transmission is completed, the second switch 18 is turned off to stop the modulation transmission means 17, set the numerical value N to "10" (step E), and enter the standby state. Return (Stepwa).

Hereinafter, every time the standby state is changed to the operating state, the second switch 18 is turned on to activate the modulation transmitting means 17, and the measured liquid level data F + 1 is transmitted. If the output voltage of the battery 11 falls below the specified value (step), the liquid level data F
A voltage drop signal is transmitted according to +1 (steple).

When the supply of fuel oil to the underground tank is completed and the increase of the liquid amount is stopped and the liquid is supplied to the vehicle, the liquid level measuring means 20
The liquid level data F + 1 from No. 1 is compared with the liquid level data F0 of the liquid level data storage means 15 and the increase in the liquid level disappears (step F), and the liquid level data F-1 of the last two times is compared with the previous liquid level data F0. (Step), the previous liquid level data F0 is larger than the liquid level data F-1 of the last time, so it is determined that the liquid has been replenished until immediately before, and the numerical value of the number of transmissions M is set to "12" ( After the liquid level data is transmitted in step (step), step (l) or step (e), the liquid level data F-1 and F0 in the data storage means 15 are updated and the standby state is set (step w).

Next, when it is activated, the process proceeds to steps (a) to (g), and in step (h) the numerical value M is not "0", so the number of transmissions M is subtracted by "1" (step re),
Move to step (nu). As described above, the microcomputer 10 operates the modulation transmission means 17 every time the standby state shifts to the operating state to transmit the liquid level data, and repeats until the transmission number M becomes “0”, and the transmission number M
Every time the number of measurements N becomes “10” when becomes “0”, the operation mode is entered and the liquid level data is transmitted.

FIG. 6 shows an embodiment of the receiving device 4 (FIG. 1), in which reference numeral 41 is a liquid level data storage means for updating the liquid level data received by the wireless receiving means 40. While configured to remember. 43 is a microcomputer which constitutes a control means, and receives the liquid level data F
+1 is converted into the liquid amount Q + 1 based on the data in the conversion data storage means 44, and a predetermined operation is executed based on the flow chart described later by comparing with the previous liquid amount Q0.
The data is compared with the data stored in the maximum liquid volume storage means 45 and the minimum liquid volume storage means 46, and the result is output to the display device drive means 47.

50 is a display device, which corresponds to each tank
1, 52, 53, maximum liquid volume indicators 54, 55, 56, minimum liquid volume indicators 57, 58, 59, and battery life indicators 60, 61, 62 are arranged and normal for a certain period of time. It is configured by providing an alarm device 63 that operates when various data cannot be received, and a printer 64 that prints the reception result. Incidentally, reference numeral 48 in the figure indicates a transmission means for transferring data to the POS.

Next, the operation of the apparatus thus configured will be described based on the flow chart shown in FIG.

Liquid level data F + 1 from the transmitter 2 (FIGS. 1 and 2)
When the liquid level data is stored in the liquid level data storage means 41 (step a), the microcomputer 43 reads the liquid level data F + 1 stored in the liquid level data storage means 41 (step b), Whether the data is normal or not is judged by a cyclic redundancy check or the like (step C).

If the data is normal, the liquid level data F + 1 is converted into the liquid amount Q + 1, for example, in liter units by the conversion data of the conversion data storage means 44, the previous liquid amount data Q0 is changed, and the liquid amount Q + 1 is further changed. Display on the display 51 (step 2).

When the current liquid amount data Q + 1 is larger than the previous liquid amount data F0, that is, when the underground tank is replenished with fuel oil, the counter is set to a clock time C1 corresponding to a predetermined time, for example, 1 minute ( Step)), and liquid volume data Q +
When 1 is smaller than the previous liquid quantity Q0, that is, when the fuel oil in the underground tank is consumed, a clock number C2 corresponding to a relatively long time, for example, 10 minutes is set (step).

Next, the microcomputer 43 displays the liquid volume data Q + 1.
Is compared with the maximum liquid amount and the minimum liquid amount stored in the maximum liquid amount storage means 45 and the minimum liquid amount storage means 46 (steps, n), and when the liquid amount matches the maximum liquid amount, the maximum The liquid level indicator 54 is operated (stepwise), and when the minimum liquid level is matched, the minimum liquid level indicator 57 is operated (stepwise) to call the operator's attention.

When the voltage drop signal is received (step E), the battery life indicator 60 is activated to prompt the replacement of the battery 11 of the transmitter 1.

Further, when the transfer request is received from the POS (step C), the liquid volume data is transferred to the POS (step YO).

On the other hand, if the received liquid level data is not normal (step C) or the transmitter 1 or the receiver 4 has failed, etc., and liquid level data is not received within the set cycles C1 and C2. , C = 0 (step) and an alarm is issued.

That is, since C1 is set to the time C at the time of refueling the fuel oil, at the time when one minute has passed since the liquid level data could not be received (step), an alarm is issued by the alarm 63 to call attention. , A valve closing signal is sent to the main valve 2 to forcibly stop the supply (step). Since C2 has been set to the time C except when the liquid is being replenished, an alarm is issued (step) when 10 minutes have passed since the liquid level data could not be received (step).

As a result, it is possible to prevent an accident or fuel oil shortage by detecting a delay in the liquid level data due to the failure of the transmitter or the influence of noise.

In addition, even after turning from the increase in the liquid volume to the decrease, M times (12 times)
The reason why it is sent every start (15 seconds) is
At the transmission interval of every 10th (150 seconds), the receiving side sets the time C1 (1 minute) immediately after it starts to increase and then decreases. Therefore, every Nth transmission causes a false alarm. There is a risk. In order to prevent this, the liquid level is displayed more accurately in consideration of the fact that the liquid surface is wavy and the liquid level is moving up and down for a while after the end of the liquid supply.

Of course, since the surrounding radio wave environment is investigated during installation, the reception status usually recovers within a short time even if noise is mixed in. For this reason, it is possible to prevent unnecessary worry from being given to the user without issuing a frequent alarm.

It should be noted that, in this embodiment, an example using a float type liquid level measuring device has been described, but it is clear that the same action can be obtained even if a capacitance type liquid level measuring device is used. .

(Effect of the invention) As described above, in the present invention, while the liquid level is detected at fixed time intervals, the liquid level is increased every time T1 when the liquid level increases, and the liquid level is changed at the time T2 when the liquid level decreases. Every (however,
In the case of transmitting by radio wave at T1 <T2), the liquid level is transmitted every time T1 for a certain period from the time when the increase in the liquid level ends, so the fuel oil supply to the tank is completed. Immediately after that, the liquid level data can be transmitted in a short cycle for a certain period of time, and a highly reliable liquid amount can be transmitted irrespective of the liquid level fluctuation caused by the ripple of the liquid surface. In addition, not only the liquid amount can be accurately known on the receiving side, but erroneous notification of the reception notification means can be eliminated.

[Brief description of drawings]

FIG. 1 is a diagram showing an outline of a gas station to which the present invention is applied, and FIG.
FIG. 3 is a block diagram showing an embodiment of a transmission device, FIG. 3 is a block diagram showing an embodiment of a modulation transmission device, and FIGS. 4 and 5 are flowcharts and timings showing the operation of the device shown in FIG. FIG. 6 is a block diagram showing an embodiment of the receiving apparatus, and FIG. 7 is a flow chart showing the operation of the apparatus shown in FIG. 1 ... Underground tank, 2 ... Main valve for replenishment 3 ... Transmission device, 4 ... Reception device 5 ... Office, 11 ... Battery 17 ... Modulation transmission means, 19 ... Antenna 20 ... Liquid level Measuring means

Claims (1)

[Claims] 1. A liquid level is detected at regular time intervals, while the liquid level is wirelessly increased every time T1 when the liquid level increases, and the liquid level wirelessly every time T2 (where T1 <T2) when the liquid level decreases. A radio type liquid volume measuring device that transmits by radio wave and transmits the liquid level every time T1 for a certain period from the time when the increase in the liquid level ends.