JPH0783302B2 - Power line communication device - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power line communication device that performs communication by superimposing a high frequency signal on a power line.

2. Description of the Related Art In recent years, for the purpose of centrally controlling a plurality of devices and monitoring the status of the devices, there has been a transmission control method in which each device is connected by an electrical transmission communication path and signals are transmitted to each other. Various reports have been made. Among them, the power line communication in which the communication signal voltage (carrier wave) having a sufficiently higher frequency is superimposed on the AC voltage of the indoor power line to communicate between the devices is
Since special wiring for control is unnecessary, it has attracted attention because it has the features of low installation cost and labor. In power line communication, a method of transmitting and receiving a signal in synchronization with a power supply frequency is often used.

FIG. 3 shows an internal configuration diagram of a conventional power line communication device. In FIG. 3, 1 is a power line which is a signal transmission path, and 2 is a communication means for transmitting and receiving signals on the power line 1. 3 is a zero volt pulse generating means for generating a pulse in the vicinity of zero volt of the AC power source on the power line 1, and 4
Is the input of the output of the zero volt pulse generating means 3, detects the end edge of the zero volt pulse, and after a certain time has elapsed from this point, starts communication with the power line 1 or transmission of the signal onto the power line 1. It is a calculation control means for controlling 2.

The operation of the power line communication device configured as described above will be described below with reference to the transmission / reception timing chart of FIG. First, the arithmetic control means 4 monitors the output of the zero volt pulse generation means 3 and detects this end edge,
Confirm that the pulse width of the zero volt pulse is T ₅ in the case of timing (a), T ₆ in the case of (b), and T ₇ in the case of (c). Then, after the lapse of T ₁ hour, the communication means 2 is controlled to transmit the carrier wave on the T ₂ time power line 1 when transmitting the data “0”, and the carrier wave on the T ₂ time power line 1 is received when receiving the data. The communication means 2 is controlled so as to allow it.
Then, when the data “1” is transmitted again after the elapse of T ₃ hours,
Call means 2 to transmit carrier wave on power line 1 for T ₄ hours
When receiving, the communication means 2 is controlled so as to receive the carrier wave on the power line 1 for T ₄ time. The above is power line 1
This is the half cycle operation of the above AC power supply, which enables transmission / reception of one bit of data. Therefore, the AC power frequency 50
Communication is possible at a speed of 100 bps at Hz and 120 bps at 60 Hz.

Problems to be Solved by the Invention However, the above configuration has the following problems. That is, due to variations in the circuit components of the zero volt pulse generating means 3, temperature changes, etc., the zero volt pulse width is T ₅ , T ₆ , T ₇ and each power line as shown in (a), (b) and (c) of FIG. Assuming that the transmitter has a zero volt pulse of (b) and the receiver has a zero volt pulse of (c), the transmitter and the receiver have different communication timings (T ₇ −T ₆ ) / 2 hours. Will be done. This timing shift may impair the reliability of communication.

In view of the above drawbacks, the present invention provides a power line communication device with high communication reliability that can always perform communication at the same timing even if there is a variation in the zero volt pulse width on the transmission side and the reception side.

Means for Solving the Problems In order to achieve this object, a power line communication device of the present invention is a communication means for transmitting and receiving a signal on a power line and a zero volt pulse generation for generating a pulse in the vicinity of zero volt of an AC power source of the power line. Means, the output of the zero volt pulse generating means is input and measures the width of the zero volt pulse, the zero volt pulse width measuring means, the output of the zero volt pulse generating means is input and detects the end edge of the zero volt pulse, and the end edge thereof. After the detection, if the width of the zero volt pulse obtained from the output of the zero volt pulse width measuring means is shorter than the standard time, the reception of the signal on the power line or the transmission of the signal on the power line is started after a long time has passed, and the zero volt is started. If the pulse width is longer than standard time,
The arithmetic and control means controls the communication means so as to start receiving a signal on the power line or transmitting a signal on the power line after a short time has elapsed.

Operation With this configuration, even if there is a variation in the width of the zero volt pulse on the transmitting side and the receiving side, the output of the zero volt pulse width measuring means makes the arithmetic control means slow when the zero volt pulse width is short and quick when the zero volt pulse width is long. The communication means can be controlled so as to start the transmission and reception of signals on the power line, and the transmission side and the reception side can always perform communication at the same timing, resulting in extremely high communication reliability.

Example An example of the present invention will be described below with reference to the drawings.

FIG. 1 shows an internal configuration diagram of a power line communication device in an embodiment of the present invention. In FIG. 1, 5 is a power line which is a signal transmission path, and 6 is a communication means for transmitting and receiving signals on the power line 5. Reference numeral 7 is a zero volt pulse generating means for generating a pulse in the vicinity of zero volt of the AC power source on the power line 1, and 8 is a zero volt pulse width measuring means for receiving the output of the zero volt pulse generating means 7 and measuring the width of the zero volt pulse. 9 is a zero volt generating means 7
The end edge of the zero volt pulse is detected by using the output of the above as an input, and after the end edge is detected, after the lapse of a predetermined time having a correlation with the width of the zero volt pulse obtained from the output of the zero volt pulse width measuring means 8 as described later It is an arithmetic and control unit that controls the communication unit 6 so as to start transmission and reception of a signal on the power line 5.

The operation of the power line communication device configured as described above will be described below with reference to FIG. 2 showing transmission / reception timing. Now of timing (d) in FIG.
Let T ₅ be the standard zero volt pulse width. The operation at this time is exactly the same as that of the conventional example. First, the arithmetic control means 9 detects the trailing edge of the zero volt pulse by the output of the zero volt pulse generation means 7. Then, the arithmetic control means 9 confirms that the output of the zero volt pulse width measuring means 8 is equal to the standard zero volt pulse width T ₅ ,
After the lapse of T ₁ time, when the data “0” is transmitted, the communication means 6 is controlled so as to transmit the carrier wave on the T ₂ time power line 5, and when receiving the data, the carrier wave on the T ₂ time power line 5 is received. The communication means 6 is controlled. And after T ₃ hours had passed, the arithmetic control unit 9 the data "1" when transmitting the control communication unit 6 to transmit the carrier to the T ₄ hours power line 5 above, the upper T ₄ hours power line 5 when receiving The communication means 6 is controlled to receive the carrier wave. Above is the zero volt pulse width standard T ₅
Is the operation of the AC power supply half cycle. Next, (e) and (f), which are times T ₆ and T ₇ in which the zero-volt pulse width is different from the standard T ₅ , will be described. (E) is the case where the zero volt pulse width is T ₆ hours shorter than the standard, and (f) is the case where T ₇ hours is also longer than the standard. First, regarding (e), after the arithmetic control means 9 detects the zero volt pulse end edge, it is detected that the output T _{6 of} the zero volt pulse width measurement means 8 is shorter than the standard zero volt pulse width T ₅ , and T ₈ =
Controlling the _{T 1 + (T 5 -T 6} ) / communication means 6 so as to start transmission or reception of data "0" after a lapse of 2 hours. Regarding (f), after the arithmetic control means 9 detects the zero volt pulse end edge, it is detected that the output T _{7 of} the zero volt pulse width measurement means 8 is longer than the standard zero volt width T ₅ , and T ₉ = T ₁ − (T ₇ −T ₅ ) / 2 The communication means 6 is controlled to start transmission of data “0” or start transmission after 2 hours. Regarding the subsequent transmission / reception operation, both (e) and (f) are the same as in the case of (d), so the description thereof will be omitted.
When the zero volt pulse width is shorter than the standard, it is slow, and when it is long, it starts to send and receive signals on the power line early. Let x be the time of the zero volt pulse width at this time, and T be the time from the end edge of the zero volt pulse to the start of transmission / reception of a signal on the power line. T = T ₁ + (T ₅ −x) / 2 …… (1) Can be expressed as

As described above, according to the present embodiment, even if the zero volt pulse width differs between the transmitting side and the receiving side, after the time T calculated by the equation (1) has elapsed from the end edge of the zero volt pulse (that is,
Since the transmission and reception of the signal on the power line is started after a lapse of time having a correlation with the zero-volt pulse width), the transmitting side and the receiving side can always perform communication at the same timing, and the communication reliability is very high.

According to the present embodiment, the zero volt pulse generating means is directly connected to the power line. However, this is configured to generate a zero volt pulse from the secondary side of the power transformer for the purpose of insulating the circuit. Good. In this case, the zero-volt pulse width changes due to a change in the load connected to the secondary side of the power transformer, so that the effect of the present invention is more remarkably exhibited. Further, although the zero-volt pulse is set to the HIGH level, even if the zero-voltage pulse is set to the LOW level, the end edge becomes the rising edge and does not affect the gist of the present invention.

EFFECTS OF THE INVENTION As described above, the present invention provides a communication means for transmitting and receiving a signal on a power line, a zero volt pulse generating means for generating a pulse in the vicinity of zero volt of an AC power source on the power line, and a zero volt pulse for measuring the width of the zero volt pulse. After the width measuring means and the detection of the end edge of the zero volt pulse, if the zero volt pulse width is shorter than the standard time, the reception of the signal on the power line or the transmission of the signal on the power line is started after a long time, and the width of the zero volt pulse is Is longer than the standard time, even if the transmission side and the reception side have different zero volt pulse widths by having an arithmetic control means for controlling the communication means to start the transmission and reception of signals on the power line after a short time has passed, It is a highly reliable communication that can always communicate at the same timing, and its practical effect is great. There is.

[Brief description of drawings]

1 is an internal configuration diagram of a power line communication device according to an embodiment of the present invention, FIG. 2 is a transmission / reception timing diagram of the power line communication device having the configuration of FIG. 1, and FIG. 3 is an internal configuration diagram of a conventional power line communication device. 4 is a transmission / reception timing chart of the power line communication device having the configuration of FIG. 5 ... Power line, 6 ... Communication means, 7 ... Zero volt pulse generating means, 8 ... Zero volt pulse width measuring means, 9 ...
... arithmetic control means.

Claims (1)

[Claims] 1. A communication means for transmitting and receiving a signal on a power line, a zero volt pulse generating means for generating a pulse in the vicinity of zero volt of an alternating-current power source of the power line, and an output of the zero volt pulse generating means being input to determine the width of the zero volt pulse. Zero volt pulse width measuring means for measuring, and the output of the zero volt pulse generating means is input to detect the end edge of the zero volt pulse, and after detecting the end edge, T = T ₁ + (T ₅ −X) / 2 where T: Output signal of arithmetic control means, that is, the time from the end of this zero volt pulse to the start of communication T ₅ : The time of standard zero volt pulse width T ₁ : The standard time from the end of zero volt pulse to the start of communication X: Zero volt pulse width measurement The signal reception or the power on the power line after the elapse of T time calculated by the relational expression of the pulse width measured by the means Power line communication apparatus and a calculation control means for controlling said communication means so as to initiate the transmission of a signal onto.