JP2520113B2 - Track abnormality monitoring system - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a line abnormality monitoring system that detects a short circuit in a line and disconnects the short-circuited portion from the power supply side.

(Prior Art) A conventional line abnormality monitoring system known as a short circuit isolator system is shown in FIG. 2, for example.

In FIG. 2, reference numeral 1 denotes a receiver including a power supply circuit and a reception circuit, and a plurality of terminal loads such as a sensor or a repeater are provided between the pair of power source / signal lines 2a and 2b drawn from the receiver 1. 3 are connected in parallel, and signal lines 2a and 2 that also serve as power sources
b is connected to the terminal load 3 in parallel and then returned to the receiver 1 side to form a loop line.

In this way, in the middle of the power supply / signal lines 2a, 2b loop-connected to the receiver 1, the receiver 1 side and the predetermined terminal 3 are provided.
For each group, line abnormality monitoring devices 4a, 4b, 4c, 4d known as short circuit isolators are provided.

FIG. 3 shows the line abnormality monitoring device of FIG. 2 taken out, and has a switch 5 to be inserted and connected to the plus-side power source / signal line 2a side. The voltage of the line is input to the short circuit detection circuit 6 which detects a short circuit of the line from the drop of the line voltage, and the short circuit detection circuit 6
Is output to the switch control circuit 7 to control the switch 5 to turn on and off. Further, a resistor R is connected in parallel with the switch 5 so that when the power is turned on by the receiver 1, the switch 5 in the off state is bypassed so that the power supply voltage can be supplied to the line and the line monitoring and monitoring device located in the subsequent stage. There is.

The operation of the system of FIG. 2 provided with such line abnormality monitoring devices 4a to 4d is as follows.

First, when the power of the receiver 1 is turned on, the line abnormality monitoring device
Since each of the switches 5 provided in 4a to 4d is in the off state, the power supply voltage is supplied through the resistor R connected in parallel to the switch 5. If the power supply / signal lines 2a and 2b are normal, the detection output of the short circuit detection circuit 6 cannot be obtained, so the switch control circuit 7 turns on the switch 5 to turn on the line abnormality monitoring devices 4a to 4d. Power is supplied to the terminal load 3 via the switched switch 5, and the terminal load enters a monitoring state such as a fire.

On the other hand, in the steady monitoring state, for example, the signal lines 2a and 2b that also serve as power sources
If a short circuit accident occurs at point A, the section where the short circuit occurs
The line voltage of L2 drops to approximately zero volt, and the line voltage of sections L1 and L3 where no short circuit occurs also drops to approximately zero volt, and this line voltage drop is caused by line abnormality monitoring devices 4a, 4b, 4c, 4
This is detected by the short circuit detection circuit 6 of d, and the switch 5 is turned off by the switch control circuit 7.

For this reason, with the line abnormality monitoring device 4b that caused a short circuit at point A
The line of section L2 between 4c is separated from the lines of normal sections L1 and L3.

Further, when the short circuit at the point A is detected, the switch 5 of the line abnormality monitoring device 4b, 4c is turned off to disconnect the short-circuited section L2, and the line of the section L1, L3 is connected via the resistance R of the line abnormality monitoring device 4a, 4d. To the line abnormality monitoring device 4a, 4
The switch 5 of d is turned on again, the line voltage of the sections L1 and L3 is restored to the normal power supply voltage, and the termination of the terminal load 3 due to a short circuit is minimized.

(Problems to be Solved by the Invention) However, in such a conventional line abnormality monitoring system, in the line of the section L4 between the receiver 1 and the line abnormality monitoring devices 4a and 4d, for example, at the point B. When a short-circuit accident occurs, all the line abnormality monitoring devices 4a, 4b, 4c, 4d will be located on the load side from the point B where the short-circuit accident occurred, so disconnect the short-circuit location B point from the power supply side. However, there is a problem that all the power supply voltages in the sections L1, L2, L3, and L4 are lowered.

(Means for Solving Problems) The present invention has been made in view of such conventional problems. Even when a short circuit accident occurs in the loop line near the receiver connection, the short circuit line is connected to the power source side. It is an object of the present invention to provide a line abnormality monitoring device which can be disconnected from a power line to supply a power supply voltage to a normal line section.

In order to achieve this object, according to the present invention, a receiver and a plurality of terminal devices are connected in a loop through a signal line that also serves as a power source, and a plurality of terminal devices are connected in parallel to the loop line, and one or a plurality of terminal devices are connected. In a line anomaly monitoring system in which a plurality of line anomaly monitoring devices are inserted and connected, which separates the loop line on the short-circuit side from the loop line on the power supply side when a line short circuit is detected for each terminal, A pair of line abnormality monitoring devices that are connected to the side terminals and disconnect the short-circuited line is provided.

(Operation) According to such a configuration of the present invention, even if a short-circuit accident occurs between the terminal lines in the immediate vicinity of the receiver, the line abnormality monitoring device on the short-circuit side provided in the receiver and the load-side line at the short-circuit point are provided. The line anomaly monitoring device is operating to disconnect the short-circuited line, and the line anomaly monitoring device on the non-short-circuited side in the receiver supplies the power supply voltage to the line in the normal terminal section to bring down all terminal sections. It is possible to reliably prevent it.

(Embodiment) FIG. 1 is a system explanatory view showing an embodiment of the present invention.

First, the configuration will be described. 1 is a receiver, which has a built-in power supply and a receiving circuit 1a. From the receiver 1, a line composed of a pair of power source / signal lines 2a and 2b is drawn to the terminal side.
This line is returned to the receiver 1 side again to form a loop connection.

A terminal load 3 such as a repeater or a sensor is connected in parallel between the lines 2a and 2b that are loop-connected to the receiver 1, and a line abnormality occurs at each line position with a predetermined number of terminal loads 3 as one group. By connecting the monitoring devices 4a and 4b, the line abnormality monitoring device 4
Loop line connected to receiver 1 by inserting a and 4b
2a and 2b are divided into sections L1, L2 and L3.

Further, in this embodiment, the receiver 1 is provided with a pair of line abnormality monitoring devices 15a and 15b, and the power line side terminals 9 and 10 of the line abnormality monitoring devices 15a and 15b provided in the receiver 1 are commonly used. Connected to the power supply and the receiver circuit 1a, and the load side terminals 11 and 12 of the line abnormality monitoring devices 15a and 15b are loops for the receiver 1 of the pair of lines 2a and 2b drawn to the load side. It becomes a connection terminal.

Each of the line abnormality monitoring devices 4a and 4b inserted and connected to the loop line on the load side and the line abnormality monitoring devices 15a and 15b provided in the receiver 1 are different from the conventional device as shown in FIG. It has the same configuration.

Next, the operation of the embodiment shown in FIG. 1 will be described. First, if a short circuit accident occurs at the point A of the line in the section L2 between the line abnormality monitoring devices 4a and 4b, the line voltage in the sections L1, L2 and L3 will drop to approximately zero volt, and this drop in line voltage will occur. The line anomaly monitoring devices 4a and 4b which are detected and the switch 5 of the line anomaly monitoring devices 15a and 15b provided in the receiver 1 are turned off, and the line anomaly monitoring devices 4a and 4 located on both sides of the short circuit point A are detected.
When the switch 5 of b is turned off, the line of the short-circuit section L2 is disconnected, so the receiver 1 is connected to the lines of the normal sections L1 and L3.
The power supply voltage is supplied again via the resistor R (see FIG. 3) connected in parallel to the switch 5 of the line abnormality monitoring devices 15a and 15b. The short circuit detection circuit 6 receives the supply of this power supply voltage.
When the detection output of is lost, the switch 5 of the line abnormality monitoring devices 15a and 15b provided in the receiver 1 is turned on again, and the power supply voltage is supplied to the lines of the normal sections L1 and L3. The terminal load 3 that stops due to a short circuit at the point is minimized.

The line abnormality monitoring devices 4a and 4b are the line abnormality monitoring devices 5a and 5b.
Although the power is supplied from the side, the short-circuit current flows through the resistor R to the short-circuit point A, so that the short-circuit detection circuit 6 detects the short circuit, and the switch 5 remains off.

On the other hand, if a short-circuit accident occurs at the line section L1 or L3 on the receiver 1 side, for example, at point B of the line section L3,
The line voltage of L1, L2, L3 drops to approximately zero volt, and the respective switch 5 of the line abnormality monitoring devices 4a, 4b provided on the load side line and the line abnormality monitoring devices 15a, 15b provided in the receiver 1 are turned off. Switch to the state. At this time, the line abnormality monitoring device inserted and connected to the load side lines located on both sides of the short-circuit point B
4b switch 5 and line abnormality monitoring device provided in the receiver 1
When the switch 5b of 15b is turned off and the short-circuit section L3 is disconnected, the line abnormality monitoring device 4a inserted and connected to the load side line and the switch 5 of the line abnormality monitoring device 15a provided on the receiver 1 side are connected.
The power supply voltage is supplied to the normal line sections L1 and L2 through the resistor R (see FIG. 3) connected in parallel with the line.
Therefore, when the short circuit detection circuit 6 (see FIG. 3) provided in the line abnormality monitoring devices 4a and 15a loses the detection output, the switch 5 is turned on, and only the short circuit section L3 is monitored by the line abnormality monitoring device. The switches 5b of 4b and 15b are turned off, and the normal line sections L1 and L2 are provided in the sections L1 and L2 by supplying the power supply voltage normally by turning on the switch 5 of the line abnormality monitoring devices 15a and 4a. The terminal load 3 in operation is set to the operating state.

The operation of disconnecting such a short circuit section is performed on the section on the receiver 1 side.
The same applies to short-circuit accidents on the L1 line.

Since the power supply in the receiver 1 and the line connection between the receiving circuit 1a and the line anomaly monitoring devices 15a and 15b are made in the receiver 1, the line is not drawn from the receiver 1 to the terminal side. There is almost no possibility of a short circuit accident as compared to the sections L1, L2, L3 in which the short circuit occurs, and it is not necessary to consider a short circuit between the power supply / reception circuit 1a and the line abnormality monitoring devices 15a, 15b.

Further, in the present embodiment, the power source / signal lines 2a and 2b drawn from the receiver 1 have been described, but power source lines or signal lines may be used.

(Effects of the Invention) As described above, according to the present invention, a line connected to a terminal is loop-connected to a receiver, a plurality of terminal devices are connected in parallel to the loop line, and one or a plurality of terminals are connected. When a short-circuit line is detected for each terminal, the line on the short-circuit side is separated from the line on the power supply side.In a line-abnormality monitoring system in which a plurality of line-abnormality monitoring devices are connected, it is inserted in the receiver at each end of the loop line receiver Even if a short circuit accident occurs on the load-side line immediately after the receiver, the pair of line abnormality monitoring devices connected to each other is located on the load side as seen from the line abnormality monitoring device inside the receiver and the short-circuit point. It is possible to normally supply power from another line abnormality monitoring device installed in the receiver on a normal section line by disconnecting it by the operation of the line abnormality monitoring device. It is possible to reliably prevent the power supply voltage of all the line sections from being lowered due to a short circuit accident that has occurred on the load side line.

[Brief description of drawings]

FIG. 1 is a system explanatory view showing an embodiment of the present invention, FIG. 2 is an explanatory view of a conventional system, and FIG. 3 is a circuit block diagram showing an example of the line abnormality monitoring device of FIG. 1: Receiver 1a: Power supply and reception circuit 2a, 2b: Power supply signal line 5: Switch 6: Short circuit detection circuit 7: Switch control circuit 9,10: Power supply side terminal 11, 12: Load side terminal 4a, 4b, 15a , 15b: Line abnormality monitoring device R: Resistance

Claims (1)

(57) [Claims] 1. A receiver and a plurality of terminal devices are connected in a loop through a signal line that also serves as a power source, the plurality of terminal devices are connected in parallel to the loop line, and the line is provided for each one or a plurality of terminals. In a line abnormality monitoring system in which a plurality of line abnormality monitoring devices that disconnect the loop line on the short-circuit side from the loop line on the power supply side when a short circuit is detected are inserted and connected, in the receiver, at the terminal device side terminal of the loop line A line abnormality monitoring system comprising a pair of line abnormality monitoring devices that are inserted and connected to disconnect a short-circuited line.