JPS6149863B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a transmission line short-circuit protection device used for the purpose of preventing the entire system from going down when a short-circuit accident occurs at a key point in a signal path in a multiplex transmission remote control system. It is something.

FIG. 1 shows an example of the configuration of a remote monitoring and control system that is the premise of the present invention. The base unit 1 is connected to a large number of terminal units 3 ₁ , 3 ₂ via a signal path 2 wired in a branched manner.
..., and from this base device 1 to each terminal 3 ₁ , 3 ₂
...individually called and monitored and controlled. Each terminal 3
₁ , 3, ₂ ... are set as independent channels, and base unit 1 sends control signals for each channel.
It also receives and processes return signals for each channel.
The terminal devices 3 ₁ , 3 ₂ . . . each output a control driver output for driving a relay for controlling a controlled load, and also input monitoring inputs from monitored objects such as a control switch and various sensors. can be,
Data indicating the status of monitoring input from these monitored objects is sent from the terminals 3 ₁ , 3 ₂ . . . to the base unit 1 as a return signal. Thus, in the case of the remote monitoring and control system as described above, the controlled loads on the terminals 3 ₁ , 3 ₂ . However, in such a remote monitoring and control system, signal path 2
If a short circuit occurs in the base unit 1 and each terminal unit 3 ₁ , 3
_2. There was a problem in that the input and output of... would be short-circuited, resulting in a loss of all functions of the system, not just the part where the short-circuit occurred.

The present invention has been provided in view of the above-mentioned points, and is intended to be inserted at an appropriate location in a signal path of a remote monitoring and control system, to appropriately divide this signal path, and to prevent loss of function due to the effects of a short-circuit accident. The purpose of the present invention is to provide a transmission line short-circuit protection device that is capable of maintaining the remote monitoring and control function on other signal paths even if the short-circuit occurs only in the section of the signal path where the short-circuit accident has occurred. It is.

An embodiment of the present invention will be described in detail below with reference to the drawings.
FIG. 2 shows an example of a remote monitoring and control system similar to that shown in FIG. When inserting and connecting the protection device A, it is inserted so as to divide the signal path 2 into appropriate lengths, and when it is branched into multiple systems as in the illustrated example, it is inserted at the branch point of each branch path. are inserted and arranged respectively. In this way, if a short circuit accident occurs in section B in the figure, the transmission line short circuit protection device A placed at the branch of the branch path having this section B performs the operation of cutting and separating the signal path 2, and All other signal paths 2 are disconnected from the short-circuited point in section B, and normal remote monitoring and control operations are performed on these disconnected signal paths 2.

FIG. 3 shows an example of the configuration of a transmission line short-circuit protection device A according to an embodiment of the present invention, in which contacts 6 of a relay 5 are inserted into a signal path 2 and cut and separate the signal path 2 into the base unit 1 side and the terminal side. A barrel opening/closing means, a voltage detection means as a rectifier bridge 7 that detects the voltage at both ends of the signal path on the side of the main unit 1 from this contact 6, and a microcomputer (hereinafter referred to as CPU) that inputs the output of this rectifier bridge 7 and performs sequence operation. ) 8, the relay 5 is driven by the output O of the CPU 8 via the driver 9, and the output of the rectifying bridge 7 is charged via the current limiting resistor 10 and the diode 11 to short-circuit the transmission line. The protection device A includes a battery 4 that supplies power to the internal circuit of the protection device A. Thus, in the example circuit of FIG. 3,
The signal on signal path 2 is rectified by rectifier bridge 7,
Connected to input terminal i of CPU8. Therefore, when a signal (baseband signal) between the base unit 1 and the terminals 3 ₁ , 3 _{2 .} . . is applied to the signal path 2, a voltage is applied to the input terminal i of the CPU 8.
Although illustration is omitted in the embodiment of FIG. 3 to simplify the explanation, the output of the rectifier bridge 7 is converted to a logic level by an appropriate means, and
Therefore, when a signal is applied to signal path 2, CPU 8
The input terminal i becomes "1", and when no signal is applied to the signal path 2, the input terminal i becomes "0". Also, when there is a signal on the signal path 2, the battery 4 is charged by the output of the rectifier bridge 7, and when there is no signal on the signal path 2, the power of the battery 4 is used to charge the battery 4.
CPU 8 etc. are operated, and this battery 4
will realize the embodiment of claim 4 of the present invention.

FIG. 4 shows a flowchart of the embodiment circuit of FIG. 3, and the case where the circuit of FIG. 3 is operated according to the flowchart of FIG. This corresponds to an example. now
When the CPU 8 starts, it first checks whether the input i is "1" or not, and when the input i becomes "1", it moves to the next step. Therefore, before the main unit 1 is first powered on, the signal output is not output, so the input i is "0".
In this BL ₁ , it becomes NO and loops here. When the base unit 1 is powered on and a baseband transmission signal is output to the signal path 2, its input i becomes "1" and the next step is started as described above.
Moving to BOX ₁ , the output O of the CPU 8 is set to "1", the relay 5 is energized via the driver 9, and the signal path 2 is connected by closing the contact 6. Next, while checking whether input i has become “0”
This means that it will loop at BL ₂ , and in normal use it will loop at BL ₂ . If a short circuit occurs at points B ₁ and B ₂ on the terminal side of the signal path 2, the input of the rectifier bridge 7 will become zero volts due to the influence of this short circuit.
Input i of CPU8 becomes “0”, and CPU8
Move to BOX ₂ , set the output O to "0", open the connection 6 of the relay 5, and connect the short circuit that occurred in the signal path 2 on the terminal side to the signal path 2 on the base unit 1 side from the contact 6, which is the opening/closing means. This prevents the signal path 2 closer to the base unit 1 than the opening/closing means from being affected by a short circuit.
Next, in BL ₃ , input i of CPU8 is “1” again.
Check whether At this time, since the signal path 2 is separated from the short-circuit points B ₁ and B ₂ by the contact 6, the input i of the CPU 8 returns to "1". In this way, the operation of CPU 8 will be transferred to BL ₄ , and with the above operation, the short-circuited point of signal path 2 will be changed to signal path 2 on the base unit 1 side.
will be separated from the After this, when the short circuit is restored, in this embodiment, after that,
The recovery operation is performed by once turning off the power to the base unit 1 and then turning it on again. That is, when the main unit 1 is powered off, the input i becomes "0", so the control moves to BL ₁ in the flowchart of FIG. 4. After this, when the main unit 1 is powered on again, the input i becomes "1" and goes to BOX ₁ , the output O becomes "1", the contact 6 of the relay 5 is closed, and the signal path 2 is connected. and return to normal condition. Also, if a short circuit occurs on the base unit 1 side of the signal path 2, or if the power to the base unit ₁ is turned off, the input
becomes "0", so contact 6 of relay 5 is opened once in BOX ₂ to disconnect signal path 2, but when input i is checked in BL ₃ , input i is "0" at this time as well, so the output is Set O to "1", connect signal path 2 again, and move to BL ₁ . That is, in this case, there is no need to disconnect signal path 2, so signal path 2 is cut again.
is connected, the program moves to the first judgment routine BL ₁ , and waits in BL ₁ for a signal to appear on signal path 2. After this, when a transmission signal is applied to signal path 2, it passes through BOX ₁ and waits for the next signal to disappear at BL ₂ . In this case, since the contact 6 of the relay 5 has already been made in BOX ₃ , virtually no processing is performed in BOX ₁ . As described above, the present invention can provide reliable protection against short circuits in the signal path without requiring any control signals from other sources. It can provide short circuit protection.

The flowchart in FIG. 5 shows another embodiment of the present invention in which the flowchart in FIG. 4 is modified in the embodiment circuit in FIG. 3, and the circuit in FIG. 3 is operated according to the flowchart in FIG. This case corresponds to the embodiment described in claim 2 of the present invention. As shown in FIG. 6, there are transmission line short-circuit protection devices A 1 in series in multiple stages in the signal path 2 from the base unit ₁ ,
If A ₂ is inserted and connected, among the transmission line short circuit protectors A ₁ and A ₂ , the transmission line short circuit protector A ₂ that is farthest from the base unit 1 may operate in the same way as the one in the flowchart in Figure 4. , the transmission line short-circuit protection device A1 on the side closer to the base unit ₁ needs to perform a program operation as shown in the flowchart of FIG.
This means that if a short circuit occurs at point _B in Figure 6, transmission line short-circuit protection device A ₂ must disconnect signal path 2, and transmission line short-circuit protection device A ₁ must maintain the connection state of signal path 2. This is because there is a
If the operation program of the transmission line short-circuit protection device _A1 on the side is as shown in the flowchart in Figure 4,
In this transmission line short circuit protection device _A1 , the signal path 2
There is a risk that amputation may occur. Thus, the flowchart in Figure 5 is similar to the flowchart in Figure 4.
BOX ₂₁ and BL ₂₁ are added between BL ₂ and BOX ₂ . In other words, in the flowchart of FIG. 5, when the signal on signal path 2 disappears and the input i of CPU 8 becomes "0" in the normal usage state where BL ₂ is looped, the case of FIG. Instead of immediately moving to BOX ₂ and disconnecting signal path 2, the input i is checked again at BL ₂₁ after a certain time delay at BOX ₂₁ . If the cause of the loss of the signal is due to a short circuit at _two points B in Figure 6, then during the fixed time delay in Box ₂₁ above, a short circuit occurs in the transmission line farthest from base unit 1. protection device
Since A ₂ disconnects signal path 2, when input i is checked at BL ₂₁ , this input i has already been restored to "1", so it returns to BL ₂ and returns to normal usage. It turns out. However, if a short circuit occurs at point B in Figure ₆ ,
Even after a certain time delay, input i is “0” at BL ₂₁ , so we move to BOX ₂ , set output O to “0”, open contact 6 of relay 5, and disconnect signal path 2. This allows the transmission line short-circuit protection devices A ₁ and A ₂ to be connected to signal path 2.
Even when the transmission line short-circuit protection devices A ₁ and A 2 are connected in series, normal operation of each transmission line short-circuit protection device A 1 and A ₂ can be obtained.

Next, when three or more transmission line short-circuit protection devices A... are connected in cascade to one signal path 2, the fifth
The fixed delay time in BOX ₂₁ of the flowchart is set to 0 for the one farthest from base unit 1.
The delay time may be increased by a certain amount of time as the device gets closer to the base device 1. 7a and 7b show modifications of the flowchart of FIG. 5 and the circuit of FIG. 3 in the above case. However, the scope of the claim is the case where the circuit shown in FIG. 3 is modified as shown in FIG. 7b, and then the modified circuit is operated according to the flowchart shown in FIG. This corresponds to the embodiment of Section 3. That is, in FIG. 7, BOX ₂₁ in the flowchart in FIG. 5 is replaced with the flowchart in FIG. 7a, and the output of the digital switch 12 is input to the CPU 8 in the circuit of the embodiment in FIG. Here, the digital switch 12 sets the order of the cascade connection of the transmission line short-circuit protection devices A... and inputs it to the CPU 8, and this order is set with the transmission line short-circuit protection device A farthest from the base unit as the 0th order. The second one is set as the first order, and the next order is set so that it increases by 1 as it approaches the base unit 1. In the flow chart of FIG. 7a, the CPU 8 sets the digital switch 12 Read the above-mentioned order set in , reduce the repetition parameter nx by 1, and repeat the delay for a certain period of time until nx becomes 0. Thus, in the flowchart of FIG. 7a, a delay of the time multiplied by the above-mentioned order occurs with respect to the constant delay time, and by doing this, the transmission line short circuit protection device A... is arranged in three stages. The signal path 2 is connected in cascade to the above.
Short-circuit protection can be achieved in each smaller area.

FIG. 8 shows an embodiment circuit of the second invention described in claims 5 and 6 of the present invention, and this embodiment circuit of FIG. 8 operates according to the flowchart of FIG. 9. . In the embodiment circuit of FIG. 8, in addition to the rectifying bridge 7 connected to the signal path 2 on the base unit 1 side from the contact 6 of the relay 5 serving as the opening/closing means, the rectifier bridge 7 is connected to the signal path on the terminal side from the contact 6. The outputs of the rectifier bridges 7 and 13 are input to the input terminals _i2 and _i1 of the CPU 8, respectively, and the output of the rectifier bridge 13 is connected to the current limiting resistor. 10 and a diode 11 to charge the battery 4,
The output O ₁ of the CPU 8 operates the relay 5 via the driver 9, and the output O ₂ operates the relay 15 via the driver 14, and the contact 16 of the relay 15 connects the battery 4 to the signal path 2. The application of voltage is controlled.

Therefore, when the CPU 8 starts in the circuit of FIG. 8, the output O ₂ is set to "0" in BOX ₅₁ in the flowchart of FIG. Break the connection. Next, BL ₁ checks input i ₂ , and BL 1 loops until this input i ₂ becomes "1", that is, until base unit 1 is powered on and a signal is sent to signal path ₂ . I'm waiting. In this way, when voltage is generated on the signal path 2 due to the main unit 1 being powered on, the input i ₂ of the CPU 8 becomes "1", and therefore the O ₁ output is set to "1" in BOX ₅₂ , and the relay 5 , and close the contact 6, which is the opening/closing means. After this, input i ₂ is checked in BL ₂ , and the loop waits in this BL ₂ until input i ₂ becomes "0". In other words, the state in which this BL ₂ is looped is the normal usage state, and the input may be interrupted due to a short circuit in signal path 2, etc.
The above loop in BL ₂ will be continued until i ₂ becomes "0". In this state, if a short circuit occurs at a point on the opposite side of the signal path 2 from the base unit 1 (for example, point B), the input i ₂ of the CPU 8 becomes "0", so the program execution exits BL ₂ and the BOX ₅₃
By setting the output _O1 to "0" and breaking the relay 5, the contact 6, which is the opening/closing means, is disconnected. Furthermore, in BOX ₅₄ , the output O ₂ of the CPU 8 is set to "1", the relay 15 is energized, and its contact 16 is turned on.
The signal is applied from the opening/closing means to the signal path 2 on the terminal side via the opening/closing means. However, in this case, since a short circuit has occurred at point B in FIG. 8, input i ₁ is "0" and the process proceeds from BL ₃ to BOX ₅₇ . Thus, in BOX ₅₇ , the output O ₂ is set to "0", the contact 16 of the relay 15 is turned off, and the application of the battery 4 voltage to the signal path 2 is cut off. By the above operation, the signal path 2 on the terminal side in which a short circuit has occurred can be separated from the signal path 2 on the base unit 1 side. Then, BL ₄ checks input i ₂ and loops at BL ₄ until input i ₂ becomes "0".

In this embodiment, as in the previous embodiment, after repairing and restoring the short circuit at point B, the circuit is restored by turning off the power to the base unit 1 and then turning it on again. . That is, when the power is turned off in the base unit 1, the input i ₂ becomes "0" in BL ₄ , and the process moves to BL ₁ . When the power is turned on again, i ₂ becomes "1", contact 6 of relay 5 is connected in BOX ₅₂ , and BL ₂
The circuit enters a loop waiting for the next short circuit and returns to normal state. Furthermore, if a short circuit does not occur at point B in Fig. 8, but a short circuit occurs in the signal path 2 from the contact 6 to the base unit 1 side, or the power supply to the base unit 1 side is cut off, the output of the rectifier bridge 7 When becomes zero, the input i ₂ of CPU 8 becomes "0", so the program execution moves from BOX ₅₃ to BOX ₅₄ , BL ₃ ,
BOX ₅₅ , BOX ₅₆ , and BL ₁ are moved in this order, so signal path 2 is reconnected at BOX 56, and the signal path 2 is connected again at BOX ₅₆ , and the signal path 2 is short-circuited on the base unit 1 side. Input in BL ₁ due to restoration repair
_i2 becomes "1", passes through BOX ₅₂ , enters a loop waiting for the next short circuit at _BL2 , and returns to the normal state. However, since the output O ₁ in BOX ₅₆ is "1" at this time, the processing in BOX ₅₂ is the same as doing nothing. Thus, in the embodiments shown in FIGS. 8 and 9, in the check after a short circuit occurs, the voltage of the battery provided as a test power source is applied to the signal path 2 to check for a short circuit. To have the effect that, compared to the case of the invention, there is no need to force the base unit 1 to short-circuit the signal path 2 at the time of short-circuit check, and to charge the battery with the signal voltage of the signal path in normal conditions. Therefore, there is no need for a special power supply device to obtain a test power supply.

Since the present invention is configured as described above, it is possible to automatically detect a short circuit by checking the voltage state of the signal path without requiring any special control operation, and to disconnect the signal path to provide short circuit protection. It has the effect of easily obtaining an appropriate short-circuit protection function. Further, in the second invention, since the test power supply is provided inside,
This has the effect that the base unit is not forced to generate a signal path short-circuit state when checking for short circuits, and the base unit can be more securely protected when a short circuit occurs.

[Brief explanation of the drawing]

Fig. 1 is a system diagram of a general remote monitoring and control system, Fig. 2 is a system diagram of a remote monitoring and control system in which the transmission line short-circuit protection device of the present invention is inserted, and Fig. 3 is a system diagram of a remote monitoring and control system according to the first invention of the present invention. A block diagram of an embodiment implementing the embodiment of claim 4, FIG. 4 is a flowchart of the same, FIG. 5 is a flowchart of the embodiment of claim 2, and FIG. The figure is a system diagram of a remote monitoring and control system showing a state in which two stages of the transmission line short-circuit protection device of the present invention are connected in cascade to a signal path. The main part flowchart and main part block diagram for carrying out the embodiment, FIG. 8 are the claims 5 and 6.
9 is a flowchart of the embodiment according to the second aspect of the invention, 1 is a base unit, 2 is a signal path, 3 ₁ , 3 ₂ . . . is a terminal device, and 4 is a battery.

Claims (1)

[Scope of Claims] 1. A switching means inserted into a signal path that branches and connects a large number of terminal devices to a base unit that always applies a predetermined voltage to the signal path after power is turned on; The main device side includes a voltage detection means for detecting the voltage of the signal path, and a control means that inputs the output of the voltage detection means and operates in sequence. By detecting a short circuit in the signal path, the switching means disconnects the signal path, and when the signal path is disconnected by the switching means, the signal path voltage on the main unit side from the switching means is detected by the voltage detection means. When the detected voltage value of the lever is normal, it is determined that there is a short circuit in the terminal side signal path and the switching means is maintained as the disconnecting means, and when the detected voltage value is decreased, it is determined that there is no short circuit in the terminal side signal path and the switching means is activated. A transmission line short-circuit protection device characterized in that the transmission line short-circuit protection device is configured to control the connected state. 2. Once a voltage drop in the signal path is detected, the signal path voltage is detected again after a certain period of time has elapsed, and the switching means is opened only when a voltage drop is detected when the signal path voltage is detected again. A transmission line short-circuit protection device according to claim 1, characterized in that the transmission line short-circuit protection device comprises: 3. Claims characterized in that the time from detection of a drop in signal path voltage to detection of signal path voltage again is successively extended by a constant multiple according to the level from the terminal side of the cascade connection to the signal path. The transmission line short-circuit protection device according to item 2. 4. The transmission line short-circuit protection device according to any one of claims 1 to 3, characterized in that the control means is operated using a battery charged by the signal path voltage under normal conditions as a power source. 5. After the power is turned on, a switching means is inserted into a signal path that branches and connects a large number of terminal devices to a base unit that always applies a predetermined voltage to the signal route, and a signal path is connected to the base unit side of this switching means. a voltage detecting means for detecting the voltage of the voltage detecting means; a control means for inputting the output of the voltage detecting means and operating in sequence; and a test power supply for applying a voltage to a signal path on the terminal side from the opening/closing means under the control of the control means. comprising, in the control means;
By detecting a voltage drop in the signal path using the voltage detection means, a short circuit in the signal path is detected, and the signal path is cut by the switching means, and when the signal path is disconnected by the switching means, a signal on the terminal side is transmitted from the switching means. The test power supply voltage is applied to the signal path, the signal path voltage is detected by a second voltage detection means connected to the terminal side signal path, and when this detected voltage value is decreasing, a short circuit in the terminal side signal path is detected. A transmission line characterized in that the switching means is maintained in a disconnected state by determining whether the signal path on the terminal side is not short-circuited when the detected voltage value is a normal value, and the switching means is controlled to be in a connected state. Short circuit protection device. 6. The transmission line short-circuit protection device according to claim 5, wherein the test power source is constituted by a battery that is charged by the signal path voltage under normal conditions.