JPH0535622B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a transmission system between a master station and a plurality of slave stations using a power distribution line, and is particularly suitable for detecting changes in the status of a power distribution line system. The present invention relates to a signal transmission device using power distribution lines.

[Background of the invention]

A polling method is generally known as a method of transmitting an information signal indicating a change in status of a switch on a power distribution line using a power distribution line. The polling method is a method in which information from each slave station is acquired and monitored by sequentially inquiring all the slave stations connected to the master station as to whether there is a change in the state of the switch. However, in the case of this polling method, the master station makes inquiries to each slave station each time, so the problem is that the time required to detect a status change increases in proportion to the number of slave stations. There is. In addition, unless the master station inquires of the slave station about the status change, the slave station cannot transmit the status change of the switch to the master station, so the master station periodically informs the slave station about the status of the switch. There was a constraint that it was necessary to inquire about changes, and the system had the disadvantage of inefficient operation.

One method for transmitting and receiving signals between a master station and a slave station using the above polling method is a combination method of a ripple control method and a current answer back method. That is, in order to prevent crosstalk of transmission signals, the transmission methods for signals from the master station to the slave station (downlink signal) and signals from the slave station to the master station (uplink signal) are made different. Generally, a ripple control method is used to transmit downlink signals.
A current answer back system is adopted for the transmission of upstream signals.

Here, referring to FIG. 7, the ripple control method is a method that utilizes fluctuations in the line voltage of the distribution line, in which the master station 1 installed on the high-voltage distribution line 5 The transmission signal I _Q is outputted to the voltage generator 4, and the voltage sending device 4 slightly fluctuates the line voltage of one of the three-phase power lines in response to the transmission signal I _Q , thereby converting the ripple into the line voltage. The receiving unit 9 of the slave station 7 installed in the same system receives the above-mentioned line voltage fluctuations, that is, the ripples, from the secondary side of the PT 6 as the received voltage.
This is a method in which the ripple portion of the received voltage is processed as a transmission signal. On the other hand, the current answer back method utilizes fluctuations in the line current of the power distribution line, so that the slave station 17 installed on the high-voltage power distribution line 5 responds to the transmission signal _IA by the transmitter 8. hand
The secondary side of PT6 is switched to vary the single-phase line current of the three-phase power line, and the receiving unit 3 of the master station 1 installed in the same system receives the above-mentioned line current as a received current by CT10, and receives the received current. This method processes changes in current as transmission signals. This method is mainly used when transmitting signals from the slave station 7 to the master station 1.

According to the above combination method, since the transmission methods for the downlink signal and the uplink signal are different, it is possible to receive while transmitting, but there are the following problems.
First, when a slave station sends a signal to a master station, I _A
As shown in the flow, the transmission signal is not transmitted to other slave stations after the transmitting slave station. This means that the slave station can generate an interrupt signal to the master station, but cannot reliably transmit the interrupt to other slave stations. Second, all slave stations can receive signals from the master station, but when a slave station is transmitting to the master station, other slave stations that want to interrupt the slave station currently transmitting There is no guarantee that the signal will be received. For this reason, in the conventional combination method described above, there is a problem that a specific slave station cannot reliably transmit signals to all slave stations in the system, and this is difficult to achieve when transmitting emergency situations at high speed. It was difficult to respond adequately.

[Purpose of the invention]

The present invention provides a communication system that transmits and receives status signals via a signal transmission path using power distribution lines.
Provided is a signal transmission device using a power distribution line that enables high-speed transmission by enabling an interrupt based on a transmission request from a specific slave station without transmitting an inquiry from a master station to a slave station as to whether or not an emergency interrupt is necessary. The purpose is to

[Summary of the invention]

In order to achieve the above object, the emergency interrupt transmission method according to the present invention uses a power distribution line as a signal transmission path, and when a transmission signal of a format different from that used in the communication system is received, the signal is transmitted. In a communication system including a master station and a slave station to be stopped, when emergency interrupt transmission is required, the slave station requiring the emergency interrupt transmission transmits a transmission signal of a different format as described above. Has characteristics. In this method, it is preferable that the transmission signals of different formats are transformed with regularity, and more specifically, they are created by inserting an interrupt flag by inverting the logic of a specific bit of the transmission signal of the normal format. .

To summarize the present invention as described above, a transmission error state is generated by intentionally changing the format of a signal being transmitted, and this transmission error is used as an interrupt signal.

[Embodiments of the invention]

Next, an embodiment of the emergency interrupt transmission system according to the present invention will be described based on the drawings.

In the following embodiments, it is assumed that a zero-phase carrier transmission method is used as the signal transmission method. first,
This zero-phase carrier transmission system will be described below. The zero-phase carrier transmission method is based on the fact that the zero-phase voltage changes by forcibly generating a minute ground in one phase of the three-phase power line and causing a slight change in the ground voltage of that phase. be. In other words,
A communication system using the zero-sequence voltage as a transmission signal is possible by configuring the transmitter for generating a micro-ground in one phase and the receiving section for detecting a change in the zero-sequence voltage. Moreover, since the zero-sequence voltage is generated in the same way on the same distribution line, there is no distinction between upstream and downstream signals as in the combination method shown in Figure 1, and the equipment at the master station and slave stations have the same configuration. be able to. FIG. 1 shows the flow of transmission signals when the master station 1 transmits in this zero-phase carrier transmission system. As is clear from FIG. 1, data transmitted by the master station 1 can be received by all the slave stations 7A to 7D at the same time, and at the same time, the master station 1 itself can also receive the data. This also applies even when the slave stations 7A to 7D are transmitting, meaning that the transmitting station can receive its own transmitted data. Furthermore, since the transmission signal uses a commercial frequency obtained from the grid power supply, it is possible to achieve periodicity when the master station or all the slave stations transmit. Therefore, all stations can interrupt the transmission signal to any bit while receiving the transmission signal. For example, as shown in FIG. 2, when transmission signal _S1 is being transmitted from slave station 7A, if an interrupt signal _S2 for an interrupt request is generated from slave station 7B, all stations A signal _S3 will be received.

Next, an emergency interrupt transmission system in the above zero-phase carrier transmission system will be explained. The applicable wiring system is configured as follows. Reference numeral 11 indicates a power distribution substation, and a control circuit 12 is connected to the power distribution line 19 via a high voltage coupling part 15.
The control circuit 12 includes a zero-phase signal generator 13 for sending signals to each of the slave stations 18A to 18N via a high-voltage coupling unit 15, and a zero-phase signal receiver for receiving signals from each of the slave stations 18A to 18N. 14. On the other hand, in the slave station 18A, a control unit 17A is provided to monitor and control the switch 16A connected to the distribution line 19, and this control signal 1
7A is a zero-phase signal generator 13A for sending the status signal of the switch 16A to the distribution line 19 via the high-voltage coupling section 15A, and a zero-phase signal for receiving signals from the master station 11 and other slave stations. It includes a receiving section 14A. Note that the zero-phase signal generating sections 13 and 13A have the same configuration, and the zero-phase signal receiving sections 14 and 14
The same applies to A. In addition, other slave stations 8
B...8N also has a similar configuration, so illustration and description will be omitted.

Next, in the above configuration, a procedure for transmitting a state change of the switch 16A from the slave station 18A to the master station 11 will be explained. That is, the present invention provides the master station 11
It is possible to make an interrupt from a slave station without having to inquire whether an emergency interrupt is necessary for each slave station 18A to 18N, and for this purpose,
A slave station requesting an emergency interrupt (18 in this example)
A) transmits a signal in a format different from the signal format normally transmitted on the distribution line (hereinafter referred to as positive phase format) (hereinafter referred to as different phase format), and when this signal is transmitted, the master station 11 and other slave stations 18B to 18N stop transmission and stand by.

The heteromorphic formats mentioned here are as follows:
There may be cases where the signal format itself is completely different, or where the logic of specific bits is inverted. In order to reduce the missed error rate and ensure reliability, it is preferable to use both in combination. In this embodiment, a signal format such as a fixed mark signal (with a fixed bit) method or an inverted two-continuous feed method is used, for example. In other words, data that does not have a fixed mark or two consecutive inversions is treated as defective data. If the slave station receives bad data during reception from the master station, no operation is performed. Furthermore, if the master station 11 receives bad data from 18A during reception from slave stations 18B to 18N,
It is determined that the operation is defective, and a retry process is performed to execute the desired operation.

FIG. 4 shows an example of a transmission signal in which 8 bits constitute one word, _s C ₄ is a fixed mark, and ²⁴ bits are fixed bits. In the case of _s C ₄ , there are 70 different signals, but since 1 bit is fixed, the positive phase signal
35 types and 35 types of antiphase signals can be identified. In other words,
They can be roughly divided into fixed bits 20 for the positive transmission signal "1" and fixed bits 21 for the anti-phase signal "0".

Next, an example in which an emergency interrupt occurs in a slave station will be described with reference to FIGS. 5 and 6.

(1) Assume that at time _t1 , a state change occurs in the switch 16A, and the slave station 18A needs to transmit a notification to that effect. At this time, if the master station 11 or any of the other slave stations 18B to 18N is transmitting a transmission signal, the slave station 18A requests an interrupt.
is the antiphase signal of the signal currently being transmitted (21 in Figure 4).
1 in order to change the fixed bit “0” of
A bit-only interrupt flag is generated (FIG. 5a).

(2) Meanwhile, the master station 11 or slave station 1 that is transmitting the signal
Any one of 8B to 18N constantly monitors the transmission signal generated by its own station, and if only the unique bit of the transmission signal changes from "0" to "1",
This is recognized as a state change in the switch in the power distribution system, and the current transmission is immediately stopped. As a result, the slave station 18A that has generated the emergency interrupt can transmit the emergency content to the master station 11, and the master station 11 can receive it. In other words, after an emergency interrupt is generated and the current transmission is stopped, it is possible to continue transmitting the emergency content.

(3) After the master station 11 detects that only the fixed bit of the anti-phase signal changes from "0" to "1" during transmission or reception, it closes the switch for all slave stations 8A to 8N. A command to return the status of is generated (time t ₂ in FIG. 5b). In response to this command, the slave station 8A whose state has changed does not generate an interrupt flag in the anti-phase signal.

(4) When each of the slave stations 8A to 8N receives a command for simultaneous monitoring of switch states from the master station, it responds by coordinating time using the address of its own station as a function (FIG. 5c).

(5) The master station 11 receives replies from slave stations 8A to 8A in order.
The content of the status change can be detected by the transmission signal from 8N, and at the same time, the content of the status change can be detected from the slave station 8N.
A can also be recognized.

(6) In the operation (2) above, if emergency interrupts occur simultaneously in a plurality of slave stations, it is conceivable that signals will interfere when transmitting emergency content. Therefore, when there is a possibility that an emergency interrupt may occur from multiple slave stations (for example, 18A, 18N), the master station 11 that has received the emergency interrupt will interrupt all slave stations as shown in FIG. 6b. A check signal is generated to inquire whether an emergency interrupt is necessary. Of all the slave stations that received this check signal, only the slave station that needs to make an emergency interrupt (multiple slave stations are possible)
As shown in FIG. 6c, time coordination is calculated using the own address as a function, and a response is made. In this way, the master station 11 receives the transmission signal from the slave station.
This allows you to individually recognize the slave stations you want to interrupt. Thereafter, the master station can individually inquire about the content of the emergency interrupt to the slave station. (If there is no response from all slave stations to the emergency interrupt check signal, it means that there is no emergency interrupt, and the master station executes normal processing.) When a state change occurs in the slave station 16A, the slave station 18A can transmit the occurrence of the state change to the master station 11.

In the above embodiment, an example in which an interrupt flag is generated at a specific bit of a transmission signal has been explained, but the transmission signal does not need to be a fixed mark, and of course does not need to be an inverted two-continuous transmission method, and is not limited to this. It's not something you can do. In other words, it goes without saying that when an emergency interrupt is required in a transmission system, the purpose can be achieved by artificially setting the signal currently being transmitted by the station in question as a defective signal.

Thus, according to the above emergency interrupt transmission method,
First, since there is no need for the master station to inquire of the slave stations as to whether or not an emergency interrupt is necessary, the master station can only perform tasks that require specific operations, improving the processing capacity of the transmission system. . Second, the reliability of checks such as constant mark/reverse double feed decreases only for fixed bits of out-of-phase data;
The master station simultaneously monitors all slave stations to see if emergency processing is necessary, and in the case of a bit error due to noise, etc., all slave stations recognize that there is no situation that requires urgent processing. This is not a problem that spreads to the entire transmission system, and there is no loss in reliability. Thirdly, since the slave station receives the positive phase signal from the master station first, it is also possible to prohibit the slave station that needs emergency processing from interrupting the negative phase signal. It is also possible to continue executing the operation currently being transmitted while accepting the interrupt. Fourth, when an emergency interrupt occurs and the master station simultaneously monitors all slave stations to see if there is a need for urgent processing, it is possible to recognize unresponsive slave stations based on the response position from the slave stations. . In other words, it can also be used as a means of early detection of disconnections in the transmission line. Fifth, changing the fixed bit of the anti-phase signal is
This is naturally possible from the master station, and if it is urgently necessary to issue another command, the slave station can stop transmitting and the master station can issue the desired command.

〔Effect of the invention〕

As described above, according to the present invention, in a communication system that sends and receives status signals via a signal transmission path using a power distribution line, a master station transmits an inquiry to a slave station as to whether or not an emergency interrupt is necessary. It is possible to provide an emergency interrupt transmission method that enables high-speed transmission by enabling an interrupt based on a transmission request from a specific slave station without having to do so.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing the signal flow in the zero-phase carrier transmission system applied in the present invention, Fig. 2 is a block diagram showing the interrupt signal in the zero-phase carrier transmission system, and Fig. 3 is a block diagram showing the signal flow in the zero-phase carrier transmission system applied in the present invention. System diagram of the communication system. Figure 4 is an explanatory diagram showing an example of _{the s} C ₄ constant mark code. Figure 5 is a time chart of the transmission signal at the time of an emergency interrupt. Figure 6 is the time chart when there are multiple emergency interrupts. FIG. 7 is a block diagram showing an example of a conventional combination transmission system. 11... Master station, 13, 13A... Zero-phase signal generating section, 14, 14A... Zero-phase signal receiving section, 16A...
...Switch, 18A to 18N...Slave station, 19...Distribution line, 20...Fixed bit of positive phase signal, 21...
Fixed bit of anti-phase signal.

Claims (1)

[Claims] 1. Between a master station connected to a distribution line and a plurality of slave stations,
In a signal transmission device using a distribution line that uses the distribution line as one shared transmission path to transmit signals using signals that comply with a predetermined agreement, a master station and a plurality of slave stations transmit signals that comply with the predetermined agreement over the distribution line. The multiple slave stations have the function of sending the necessary signals in response to a call from the master station, and the function of receiving a signal in an emergency during signal transmission using the distribution line. The master station has a function of injecting a signal that disturbs the predetermined agreement into the distribution line when the transmission is desired, and a function of stopping the signal transmission from itself when the signal transmission in the distribution line does not comply with the predetermined agreement. A function that calls the slave stations in the order of A signal transmission device using a distribution line, characterized by having a restart function.