JPH0247794B2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to a plurality of sensors arranged for disaster prevention, crime prevention, etc., such as temperature sensors and door sensors, and sensors provided corresponding to each sensor. The present invention relates to a transmission method for a wireless monitoring device having a plurality of wireless transmitters and a wireless receiver that receives output signals from the wireless transmitters.

BACKGROUND TECHNOLOGY AND PROBLEMS Conventionally, in this type of monitoring device, each sensor S ₁ , S ₂ , S ₃ was connected to an automatic notification device AL by wire, as shown in FIG. In the figure, only three sensors are shown for simplicity, but the number is not limited to this (the same applies hereinafter). The automatic reporting device AL is a device that receives output signals from activated sensors, identifies which sensor is activated, and automatically reports to the central office via a telephone line or the like. This method of connecting each sensor and an automatic notification device by wire has the drawback of being subject to various construction restrictions. As a countermeasure, the second
A wireless system as shown in the figure can be considered. In the figure, T ₁ , T ₂ , T ₃ are wireless transmitters provided corresponding to the respective sensors S ₁ , S ₂ , S ₃ , and R is a wireless receiver. However, simply transmitting signals at the same frequency makes it impossible to identify the sensors, especially when a plurality of sensors operate simultaneously, and malfunctions are likely to occur due to external noise. Furthermore, although it is possible to identify a plurality of sensors by using different carrier frequencies for each transmitter, the device becomes complicated and expensive, and there is still a possibility of malfunction.

OBJECTS OF THE INVENTION In view of the above-mentioned points, the present invention aims to provide a simple and inexpensive transmission method for a wireless monitoring device using a single frequency, which allows simultaneous identification of sensors and is free from the risk of malfunction.

Summary of the Invention The present invention transmits a signal containing sensor operation (on or off) information intermittently from a corresponding transmitter, and makes the intermittent period different between sensors. Simultaneous signals from wireless transmitters can be received with one transmitter,
Moreover, it prevents malfunctions.

EXAMPLE FIG. 3 is a schematic diagram illustrating an example of a sensor operation signal used in the present invention. FIGS. 3A and 3C show the on-times of sensors S ₁ and S ₂ and FIGS. 3B and D show the outputs of transmitters T ₁ and T ₂ . Although the figure shows only two sensors and transmission outputs, the same applies to the case of two or more sensors. Each transmitter generates an on signal when the sensor turns on, and an off signal when the sensor turns off. Each on or off signal sends a signal (data) containing sensor on/off information a certain number of times, for example 8
The signal is intermittent. Then, the intermittent period, that is, the combined time of data and data interval is made different between transmitters, that is, sensors. In this way, even if the ON signals of sensors S ₁ and S ₂ are transmitted at the same time, they can be received. Further, such an on signal is repeatedly transmitted after a certain pause period until the sensor is turned off. And this hiatus period
The values are different for each sensor as shown by P ₁ and P ₂ .
However, only the intermittent period may be changed for each sensor. If the ON signal is being transmitted when the sensor is OFF as shown in FIG. 3B, the OFF signal is transmitted after the ON signal ends. FIG. 3D shows a case where the off time of the sensor and the start time of the on signal coincide.

FIG. 4 is a block diagram showing a preferred embodiment of the present invention. Although the figure illustrates a transmitter T ₁ provided for sensor S ₁ , transmitters for other sensors have similar configurations. In the figure, 1 is an input gate, 2 is a latch circuit that holds the voltage, 3 is a standby control circuit that controls transmission by turning on and off the power supply, and 4 is an oscillation circuit (for example,
307kHz), 5 is the clock signal and two frequencies
A frequency divider circuit that generates _{(1) and (0)} (for example, 1200Hz and 600Hz), 6 a select gate that selects the two frequencies ₍₁₎ and ₍₀₎ , 7 a low-pass filter for waveform shaping, 8 is an FM modulation transmission circuit. 9 is a counter A, CL is its clock terminal, R is its reset terminal, C is its clear terminal, and Q ₁ to _{Q 9} are its output terminals.
Output terminals Q ₁ -Q ₉ produce outputs corresponding to binary codes as described below. 10 is a kind of selection switch. A 16-bit multiplexer
The select gate 6 is controlled by generating a "1" or "0" output according to the outputs from _Q1 to _Q5 . When the frequency ₍₁₎ corresponds to "1" and the frequency ₍₀₎ corresponds to "0", the select gate 6 selects the frequency ₍₁₎ when the output of the multiplexer 10 is "1" and the output of the multiplexer 10. When is "0", frequency ₍₀₎ is passed. The multiplexer 10 has a start signal (1 bit "1") terminal, a 4-bit terminal representing the group number of sensor _S1 , and a sensor
4-bit terminal that represents the individual number of S ₁ , is the same 4-bit terminal, is a 1-bit terminal that represents on/off information of sensor S ₁ , is 1-bit terminal for parity, is a stop signal (1 bit "0") Indicates terminal. 11 is a switch for setting a 4-bit sensor group number and sensor individual number. 12 is a parity circuit that adds a ``1'' or ``0'' signal so that the total number is always odd (for example, if it is 8, add ``1'',
If so, add "0". ). OR1, OR2 and
OR3 is an or gate.

First, the operation of generating the first data signal among the on signals will be described. FIG. 5 is a time chart for explaining its operation. Now the sensor
When _S1 is turned on (Fig. 5A), its output signal passes through the input gate 1 and is held in the latch circuit 2 (Fig. 5B), turning on the standby control circuit 4 (Fig. 5C). ) Put the low-pass filter 7 and the transmitting circuit 8 on standby, and release the reset of the counter A9. Then, the counter A9 starts counting the clock signal. Counter A
Output signals Q ₁ to Q ₅ appearing on output terminals Q ₁ to Q ₅ of 9
is as shown in FIG. 5D. Each output signal Q ₁ ~
The number attached to the rising point of _Q5 indicates the number of counts. These output signals Q ₁ to Q ₅ are applied to the multiplexer 10 to generate an output, and the output signal Q ₅ is used in the multiplexer 10 to output “0” data up to the first 15 counts (the 5D and F), the transmitting circuit 8 also transmits data "0" for the first 15 bits (FIG. 5G).
When the count number reaches 16, a start signal (1 bit "1") is transmitted, and as the count number increases, the group number of sensor S ₁ (4 bits) and sensor S ₁ are transmitted.
number (4 bits), number of sensor S ₁ (repeat),
A total of 16 bits of data including on/off data (1 bit) of sensor _S1 , parity signal (1 bit), and stop signal (1 bit "0") is transmitted one after another. When the transmission of the stop signal is completed, the count becomes 32, so an output is generated at the _Q6 terminal of the counter A9, and the standby control circuit 3 is turned off via the OR gates OR1 and OR2 (Fig. 5E and C), the transmitting circuit 8 stops transmitting data (FIG. 5 C and G). In this way, the first data signal transmission during the ON signal is completed.

Next, the transmission of the second and subsequent data signals and its repetition will be explained. FIG. 6 is a time chart for explaining its operation. In Figure 4,
13 is the sensor S ₁ set in the setting switch 11
This is a comparator that produces an output when the number (4 bits) of the counter A9 matches the output signal appearing at the _Q5 to _Q8 terminals of the counter A9. AND1 and AND2 are AND gates, 14 and 15 are inverting amplifiers, 16 is a set priority flip-flop, 17 is a reset priority flip-flop, and 18 is a 64-base counter B. When sensor _S1 turns on (Fig. 6A),
Set priority flip-flop 16 produces an output (FIG. 6C) that sends ON data to the terminals of multiplexer 10 as previously described. When the count reaches 32, the output of the OR gate OR1 turns off the standby control circuit 3 as described above (FIG. 6, D and G). The count continues to advance
When 256 counts are reached, a pulse with a pulse width equivalent to the next 256 counts appears at the Q9 terminal of count _A9 , so when the comparator 13 produces an output during that pulse width, the AND gate AND1
produces an output pulse (Fig. 6E) and counter B1
A clock signal is supplied to the counter A9.
Clear. Therefore, the output of the OR gate OR1 disappears (Fig. 6D), and the standby control circuit 3 is turned on again, so that the transmitting circuit 8
starts sending data again. In this way,
A data signal including the number of sensor S ₁ and ON information of sensor S ₁ is repeatedly transmitted at data intervals of time corresponding to the number of sensor S ₁ .

When the eighth clock signal (FIG. 6E) is supplied to the counter B18, an output is generated from the terminal of the counter B18 (FIG. 6F), and the reset terminal R of the flip-flop 16 and the reset terminal R of the flip-flop 17 are output. is applied to the set terminal S. At this time, flip-flop 16 has priority on set, so there is no change, and flip-flop 17 has priority on reset, but since there is no input to reset terminal R by inverting amplifier 14, it produces an output (Fig. 6H).
The standby control circuit 3 is turned off (FIG. 6G). Therefore, the transmitting circuit 8 stops transmitting (FIG. 6J). In this way, the data signal is
Transmission of the on-signal, which has been intermittent several times, is completed.

Counter B18, which continues counting further, produces an output when it reaches 64 counts, and the OR gate OR
3 (FIGS. 6F and H). By the way, or gate
The input to OR2 disappears, and the standby control circuit 3 is turned on until turned off by the output of OR gate OR1, and an on signal consisting of 8 data is transmitted again in the aforementioned order (6th Figure J). In this way, the on signal is repeatedly transmitted after a certain pause period P ₁ until the sensor S ₁ is turned off.

Now, assume that the sensor _S1 turns off during the second data transmission of the on signal (FIG. 6A). However, since the latch circuit 2 continues to hold the voltage (FIG. 6B), no change occurs. Here, when the counter B18 counts 8, it applies an output to the reset terminal R of the flip-flop 16.
At this time, since there is no longer any input to the set terminal S, it is reset (E, F, and C in FIG. 6).
The inverting amplifier 15 inverts the output of the flip-flop 16 and applies it to the AND gate AND2.
Due to the intervention of the delay circuit consisting of R and C, the AND gate AND2 does not produce an output yet, and the latch circuit 2
maintains operation. On the other hand, the ON signal of the sensor _S1 is inverted by the inverting amplifier 14 and applied to the OR gate OR3, which inverts the reset priority flip-flop 17.
is held in the off state (FIG. 6H), so that the standby control circuit 3 continues transmission (FIG. 6G). Therefore, among the 16-bit data included in one data signal mentioned above, eight pieces of data in which the on/off data of sensor _S1 has changed from on data to off data are transmitted as off signals. (Figure 6J). Here, when counter B18 counts 8, the AND gate has already been reached.
Since a voltage is applied to one input of AND2 through the RC delay circuit, AND gate AND2 produces an output, turning off latch circuit 2 (FIG. 6B). Therefore, all the operations described above are stopped.

The on-signal and off-signal as described above can be received by one receiver because the data interval and pause period are different for each sensor, and the configuration of the receiver may be of a conventionally known configuration, so a description thereof will be omitted. .

Modified Example In the above embodiment, both the data interval and the rest period are changed for each sensor, but simultaneous reception is possible by simply changing the data interval, and in this case, the circuit configuration is simpler than in the above embodiment. Further, in the above embodiment, both the data interval and the pause period are set to times corresponding to the sensor numbers, but it is not necessarily limited to this. Further, in the above embodiment, the "1" and "0" signals are FM modulated, but AM or other modulation may be used. In addition, various modifications and changes can be made within the scope of the claims.

Effects of the Invention As explained above, according to the present invention, the transmission timing of sensor on/off data is made different for each sensor, so even if multiple sensors are turned on at the same time, it is possible to identify the sensors and prevent malfunctions. It has the advantage that the device is simple and inexpensive because it uses a single frequency, and its power consumption is low because it uses an intermittent signal.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing a conventional wired monitoring device, Fig. 2 is a block diagram showing the basic configuration of a wireless monitoring device, Fig. 3 is a schematic diagram showing an example of a sensor operation signal used in the present invention, and Fig. 4 is a block diagram showing the basic configuration of a wireless monitoring device. A block diagram showing a preferred embodiment of the present invention, and FIGS. 5 and 6 are time charts for explaining its operation. S ₁ , S ₂ , S ₃ ... Sensor, T ₁ , T ₂ , T ₃ ... Radio transmitter, R ... Receiver, 1 to 12, OR1 ... Single frequency intermittently and for each sensor A means of transmitting at different intermittent periods.

Claims (1)

[Claims] 1. A plurality of sensors, a plurality of wireless transmitters provided corresponding to the sensors and having carrier signal frequencies equal to each other, and a common receiver for receiving output signals from the plurality of wireless transmitters. Each of the plurality of transmitters modulates the carrier wave signal with a signal containing operation information of the corresponding sensor, and the modulated signal is modulated intermittently at a different intermittent period for each sensor. A transmission method for a wireless monitoring device characterized by transmitting data. 2. A transmission system for a wireless monitoring device according to claim 1, wherein the intermittent signal is repeatedly transmitted until the operation of the sensor is restored.