JPS62274832A - Power line carrier control system - Google Patents

Abstract

PURPOSE:To improve the reliability of transmission/reception and the transmission efficiency by short-circuiting a tap of the secondary winding of a transformer to a ground level for a prescribed time just after the output of a transmission signal is stopped and superimposing a high frequency signal with nearly same time interval onto a power line. CONSTITUTION:A short-circuit means 10 short-circuiting the secondary winding of the transformer 9 to a ground level attended with the output stop of a transmission signal is connected to the tap T of the secondary winding of the tuning transformer tuning a high frequency signal connected to a power line 2 and outputted in response to a transmission signal. The tap of the secondary winding of the tuning transformer to superimpose a high frequency signal onto the power line is short-circuited to the ground level for a prescribed time just after the output of the transmission signal is stopped to attenuate the high frequency remainingin the transformer 9 rapidly so as to superimpose the high frequency signal having nearly the same time as that of the transmission signal onto the power line 2, the reliability of transmission/reception and the transmission efficiency are improved.

Description

[Detailed Description of the Invention] 3. Detailed Description of the Invention [Object of the Invention] (Field of Industrial Application) The present invention provides a power line carrier control system that performs load control by transmitting and receiving high frequency signals superimposed on a power line between devices. Regarding.

(Prior Art) In general, a power line carrier control system performs load control by using indoor power lines to transmit information from a transmitter to a receiver that controls loads such as lighting fixtures and various electrical appliances such as televisions. A transmitter having a transmitting section, a receiving section, and a data processing section is connected to a power line connected to a commercial AC power source, and a plurality of receivers having transmitting sections, receiving sections, and data processing sections similar to the transmitter are connected to a power line connected to a commercial AC power source. Based on information from the transmitter, a high-frequency signal is superimposed as a carrier wave on the AC power waveform of the power line, and the receiver receives it and interprets the data to control each load.

(Problems to be Solved by the Invention) By the way, when a high-frequency signal is superimposed on a power line, a tuning transformer connected to the power line via a capacitor is tuned to the carrier frequency of an oscillation circuit. When transmitting intermittently for a certain period of time, as shown in Figure 5, the high frequency signal △ applied to the tuning transformer does not disappear instantly after being applied because the transformer has residual characteristics, but gradually disappears. High frequency signal B that disappears while attenuating
superimposed on the power line as Therefore, there is a drawback that the received signal C received by the data processing section of the receiver is a longer signal than the transmitted signal C output from the data processing section of the transmitter. For this reason,
When a signal is given meaning based on the transmission time, there is a problem that the reliability of transmission and reception deteriorates.

In addition, when trying to transmit as much information as possible by reducing the interval between signals, the interval between the signals must be increased by the length of the received signal, which reduces transmission efficiency. There were also problems.

The present invention has been made based on the above-mentioned problem, and it is possible to improve the reliability of transmission and reception as well as the transmission efficiency by superimposing a high frequency signal with approximately the same time interval as the transmission signal on the power line. The object of the present invention is to provide a power line m transmission $ control system.

[Configuration of the Invention (Means for Solving Problems)] In FIG. 1, a tuning lance 1 to a lance 9 connected to a power line 2 and tuning a high frequency signal output in accordance with a transmission signal.
A shorting means 10 is connected to the intermediate terminal T on the secondary side of the transformer 9 for shorting the secondary side of the transformer 9 to the ground level when the output of the transmission signal is stopped.

(Function) Immediately after the output of the transmission signal is stopped, the high frequency waves remaining in the lances 1 to 9 are rapidly extinguished, and a high frequency signal having almost the same time as the transmission signal can be superimposed on the power line 2.

(Example) Hereinafter, one embodiment of the present invention will be described in detail based on the drawings.

In FIG. 1, 1 is a commercial AC power source, to which a power line 2 is connected.

3 is a transmitter or receiver device connected to the power line 2, and includes a control port 14 that performs various controls, and a device that outputs the high frequency applied from the oscillation circuit 5 in response to the transmission signal E output from the control circuit 4. A transmitting circuit 6 that outputs 1 i! tunes this high frequency signal during transmission and superimposes the high frequency signal on the power line 2, while receiving a power of 1 i! a tuning circuit 7 that tunes the high frequency signal carried by the high frequency signal 2 and extracts the high frequency;
A receiving circuit 8 is provided. Incidentally, these control circuits 49 oscillation circuits 5. Since the transmitting circuit 6 and the receiving circuit 8 are well-known ones, their circuit configurations are omitted.

The tuning transformer 9 connected to the tuning circuit 7 is a capacitor C.
It is connected to power line 2 via I and C2, and these 1 to
A capacitor C3 is connected in parallel to the secondary side of the lance 9.
One end of it is grounded. The secondary side of the transformer 9 is tuned to a high frequency, and the lower intermediate tap thereof is connected to the transmitting circuit 6 and the receiving circuit 8. In addition, the bottom of this intermediate tap is connected to the collector of the emitter-grounded transistor 10, and the base of the 1-hylang transistor 10 is connected to the control circuit 4 via the resistor R, and the transistor 10 is turned on by the short circuit signal G of the control circuit 4. , the intermediate tap T can be short-circuited to the ground level for a certain period of time.

The operation of the present invention configured as described above will be explained with reference to the time chart of FIG.

First, when the control circuit 4 outputs the transmission signal E to the transmission circuit 6, the transmission circuit 6 outputs the carrier wave applied from the oscillation circuit 5 in accordance with the pulse width T1 of the transmission signal. This carrier wave F is applied below the center point tap on the secondary side of the tuning lance 9, is tuned, and is superimposed on the AC power waveform of the power line 2 as a high frequency signal.

By the way, after outputting the transmission signal E, the control circuit 4 applies a short circuit signal G having a pulse width T2 to the bases of the transistors 1 to 10 at the falling timing of the transmission signal E. When this short circuit signal G is applied, the transistor 10 is turned on, so that the intermediate tap T connected to the collector of the transistor 10 is substantially grounded. As a result, at the timing when the output of the transmission signal E stops, the transformer 9
The high frequency wave remaining in The state will be the same.Therefore, the pulse width of the received signal (■) received by the receiving device 3 is the pulse width T1 of the transmitted signal gE.
Since it is possible to superimpose on the power line 2 a high frequency signal having almost the same time as the time during which the high frequency signal is to be transmitted, the reliability of transmission and reception is improved. Furthermore, since it becomes possible to transmit as much information as possible by reducing the interval between signals, transmission efficiency is also improved.

Although one embodiment of the present invention has been described in detail above, it can be modified as appropriate within the scope of the gist of the present invention. For example, in the above embodiment, 1
~A short circuit signal G was output to turn on the transistor 10, but as shown in Fig. 3, the monostable multivibrator 1
A transmission signal E can also be applied to the transistor 10 via the transistor 1 .

In this case, the monostable multivibrator 11 outputs a signal J having a pulse width T2 in synchronization with the transmission signal E when it is inputted, as shown in the timing chart l~ in FIG. It can also be used as the short circuit @G. In addition to the transistor 10, switching elements such as FETs, relays, and various switches can be used as short-circuiting means for grounding the intermediate tap T.

[Effects of the Invention] As detailed above, according to the present invention, the intermediate terminal on the secondary side of the tuning transformer for superimposing a high-frequency signal on the power line is kept at the ground level for a certain period of time after the output of the transmission signal is stopped. By short-circuiting, it is possible to rapidly attenuate the high frequency remaining in the tuning transformer and superimpose a high frequency signal on the power line with almost the same time as the transmitted signal, increasing the reliability of transmission and reception as well as the transmission efficiency. It is possible to provide a power line transport control system that can

[Brief explanation of drawings]

FIG. 1 is a circuit diagram showing one embodiment of the present invention, FIG. 2 is a timing chart of the same, and FIG. 3 is a circuit diagram showing another embodiment.
FIG. 4 is a timing chart of the same, and FIG. 5 is a timing chart of a conventional example. 2...Power line 3...Device 4...Control circuit 7...Tuning circuit 9...Tuning transformer 10...1 to transistor (shorting means) -〇-<co (J.

Claims (1)

[Claims] In a power line carrier control system that superimposes a high frequency signal on a power line and transmits and receives signals between devices,
A tuning transformer that tunes the high frequency signal output according to the transmission signal, and a tuning transformer connected to an intermediate terminal on the secondary side of this transformer, and the intermediate terminal being grounded for a certain period of time when the output of the transmission signal is stopped. A power line transport control system comprising: a short-circuit means for short-circuiting.