JPS63187832A - Evading method for collision of transmission signal - Google Patents

Abstract

PURPOSE:To prevent the collision of a signal in an overhead earth line by providing a preceding carrier layer to a head of an outgoing signal, providing a reservation carrier layer and a non-carrier layer succeeding thereto to the head of an incoming signal and using the non-carrier layer so as to confirm the presence of the outgoing signal. CONSTITUTION:The outgoing signal has a format where a precedence carrier layer 10 by 20ms exists at its head station 4 and a data layer 11 follows the precedence carrier layer 10. Moreover, the incoming signal has a format where a reserved carrier layer 12 by 15ms exists at its head, the non-carrier layer 13 of 20ms follows the reserved carrier layer 12 and the data layer 14 follows the non-carrier layer 13. In sending the outgoing signal, it is sent when a carrier on a communication line is confirmed again after 15ms after the discrimination of the presence of the carrier and no carrier exists. The incoming signal is sent when the carrier on the communication line is confirmed again at 25ms after the discrimination of the presence of the carrier and no carrier exists. Moreover, when the incoming signal and the outgoing signal are sent at the same time onto the communication line, the transmission of the outgoing signal has priority.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a transmission signal collision avoidance method suitable for use in a distribution line remote monitoring and control device using an overhead ground wire.

[Conventional technology]

FIG. 3 is a circuit diagram showing the main parts of a distribution line remote monitoring and control device using an overhead ground wire. This distribution line remote monitoring and control device uses an overhead ground wire 2 of a high-voltage distribution line 1 as a communication line between a master station 3 and a slave station 4, and a lightning arrester 5 is installed at each ground point of the overhead ground wire 2. Connections are arranged. That is,
An impact current is discharged to the ground by a lightning arrester 5 against a lightning surge invading the overhead ground vA2, and overvoltage is limited so that the effect of the overhead ground wire 2 is not impaired.

The lightning arrester 5 can be of high impedance to the signal voltage level injected into the overhead ground wire 2 via the master station 3 and slave station 4, and the surge arrester 5 can be of high impedance to the signal voltage level injected into the overhead ground wire 2 for monitoring and control purposes. The current ■ runs at high speed (12
00bps) signal transmission. In addition, in the same figure, 6
is a substation, 7 is a pole switch (D, M), and the slave station 4 and the pole switch 7 are electrically connected.

Normally, the master station 3 is located within a business office and plays a central role in monitoring and controlling power distribution lines. The distribution lines to be monitored and controlled are usually several circuits, and a signal distributor is used to distribute transmission signals to the distribution lines to be monitored and controlled.

In FIG. 4, this signal distributor is inserted and placed after the master station 3, and is designated by reference numeral 8 in the figure. Trunk repeaters 9 are placed every few kilometers along the overhead ground wire 2, and the transmission signals are amplified in the trunk repeaters 9. A plurality of slave stations 4 are arranged in each area between these trunk repeaters 9, and are electrically connected to the pole switch 7 (Fig. 3) to be monitored and controlled. Configure a communication circuit between them to monitor each pole switch 7 (ON/OFF
status) and control (ON/FF operation).

[Problem that the invention attempts to solve]

However, in conventional distribution line remote monitoring and control equipment that uses such an overhead ground wire, the master station 3 is connected to the overhead ground wire 2.
When there are two or more transmission signals from the slave station 4 to the master station 3 and from the slave station 4 to the master station 3, these transmission signals are connected to the overhead ground wire 2.
There was a problem with collisions at the top.

In other words, if we assume that the transmission signal going from the master station 3 to the slave station 4 is the downlink signal, and the transmission signal going from the slave station 4 to the master station 3 is the uplink signal, a collision between the upstream signal and the upstream signal (from two slave stations) (collision between transmitted signals), collision between downstream and upstream signals,
Also, a collision between the leakage signal and the upstream signal or downstream signal occurs.

FIG. 5 1a) and (bl) show a collision state between a downstream signal and an upstream signal, and the portion where the two overlap is the collision area.

[Means for solving problems]

The present invention has been made in view of the above problems, and the transmission signal from one side to the other side is a downstream signal, the transmission signal from the other side to one side is an upstream signal, and the beginning of the downlink signal is a downstream signal. A preceding carrier layer for a predetermined time S1 is provided, a reserved carrier layer for a predetermined time S2 is provided at the beginning of the upstream signal, and a non-carrier layer for a predetermined time S3 is provided following this reserved carrier layer, and when this uplink signal is sent, The presence or absence of the downlink signal is confirmed in the non-carrier layer of the carrier, and if it is confirmed that the downlink signal is present, the transmission of the uplink signal is interrupted.

[Effect]

Therefore, according to the present invention, when it is confirmed that a downlink signal is present in the carrier-free layer of an uplink signal, the downlink signal is transmitted with priority over the uplink signal.

〔Example〕

Hereinafter, the transmission signal collision avoidance method according to the present invention will be explained in detail. FIG. 2 ta+ and (bl are the formats of the downlink signal and uplink signal. That is, the downlink signal is
The format is such that a 20 ms leading carrier layer 10 is provided at the beginning, and a data layer 11 continues after this leading carrier layer 10. The upstream signal has a 15 ms reserved carrier layer 12 at the beginning, a 2 Qms non-carrier layer 13 follows this reserved carrier layer 12, and a data layer 14 continues after this non-carrier layer 13. It has become. Here, the master station side and the slave station side transmit and receive transmission signals in a 1:1 connected state,
In addition, when transmission/reception is being performed between one of the N slave stations and the master station side, the other slave stations shall stop their transmission.

Next, a method for avoiding collisions between transmission signals using uplink signals and downlink signals will be described. First, before sending out a transmission signal, the presence or absence of a carrier on the communication line is checked. If it is determined that there is a carrier, the transmission of the transmission signal is stopped.

In this case, the transmission signal is retransmitted by the following procedure.

(A) After determining that there is a carrier for transmitting a downlink signal, reconfirm the carrier on the communication line 15m5 later, and if there is no carrier, transmit the downlink signal.

(b) After determining that there is a carrier for transmitting an uplink signal, reconfirm the carrier on the communication line 25 ms later, and if there is no carrier, transmit the uplink signal.

Furthermore, when an uplink signal and a downlink signal are transmitted simultaneously on a communication line, priority is given to the transmission of the downlink signal in the following manner. That is, at point a in FIG. 1, both the master station side and the slave station side check whether there is a carrier on the communication line. At this time,
Since there is no carrier on the communication line, the master station and slave stations simultaneously send out up and down signals (point b in FIG. 1). The slave station first sends out the reserved carrier layer 12, and then checks in the non-carrier layer 13 whether or not there is a carrier on the communication line (point 0 in FIG. 1).

At this time, if the slave station determines that "there is a carrier" on the communication line (point d in FIG. 1), the slave station suspends transmission of upstream signals and gives priority to transmission of downstream signals. This is called downlink signal priority. In this case, the uplink signal is transmitted again 15 ms after the carrier disappears on the communication line.

In addition, when checking the downlink signal in the carrier-less layer 13, if it is determined that there is no carrier on the communication line, the slave station will not transmit the uplink signal! ! Continue. Further, devices that generate uplink signals are provided with a signal collision determination function, but devices that generate downlink signals are not provided with a signal collision determination function. Furthermore, in this embodiment, the upstream signal has a reserved carrier layer and a non-carrier layer, but the downstream signal may also have these carrier layers, and in this case, the upstream signal will have a leading carrier layer, and the format will be reversed.

〔Effect of the invention〕

As explained above, according to the transmission signal collision avoidance method according to the present invention, the transmission signal from one flight to the other side is
The transmission signal from the other side to the one side is an upstream signal, and a preceding carrier layer for a predetermined time S1 is provided at the beginning of the downlink signal, and a reserved carrier layer for a predetermined time S2 and this reserved carrier are provided at the beginning of the upstream signal. A non-carrier layer for a predetermined time S3 following the layer is provided, and the presence or absence of the downlink signal is confirmed in the non-carrier layer when transmitting the uplink signal, and if it is confirmed that there is a downlink signal, the transmission of the uplink signal is interrupted. As a result, when a downlink signal is confirmed in the carrier-free layer of an uplink signal, the downlink signal is transmitted with priority over the uplink signal, and collisions between the uplink signal and the downlink signal are avoided.

[Brief explanation of the drawing]

FIG. 1 is a diagram illustrating the operation when an uplink signal and a downlink signal are transmitted simultaneously in an embodiment of the transmission signal collision avoidance method according to the present invention, and FIG. Signal and downlink signal formants, Figure 3 is a circuit diagram showing the main parts of a distribution line remote monitoring and control device that uses an overhead ground wire, and Figure 4 is a circuit diagram showing the main parts of a distribution line remote monitoring and control device that uses a signal distributor in this distribution line remote monitoring and control device. The system diagram, FIG. 5, is a diagram showing a collision area between an upstream signal and a downstream signal. l... High voltage distribution line, 2... Overhead ground wire, 3... Master station, 4... Slave station, 7... Pole switch, 10... Leading carrier layer, 12...・Reservation carrier layer, 13...No carrier layer.

Claims (1)

[Claims] The transmission signal from one side to the other side is a downlink signal, the transmission signal from the other side to one side is an uplink signal, and a preceding carrier layer for a predetermined time S1 is provided at the beginning of the downlink signal, and
A reserved carrier layer for a predetermined time S2 and a non-carrier layer for a predetermined time S3 following this reserved carrier layer are provided at the beginning of the uplink signal, and the presence or absence of the downlink signal is checked in the non-carrier layer when the uplink signal is sent. A transmission signal collision avoidance method characterized in that, when it is confirmed that there is a downlink signal, transmission of this uplink signal is interrupted.