JPH063919B2 - Load control system - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a load control system for data transmission according to a bus configuration, and in particular, abnormal bus disconnection by bus diagnosis suitable for use in a distributed control system or the like. System load control system.

[Prior Art] FIG. 4 is a block diagram showing a load control system according to a conventional abnormal bus disconnection method disclosed in, for example, Japanese Patent Laid-Open No. 61-22494. In the figure, (1) is a sub-bus (transmission bus), (7) is a plurality of transmission devices connected to the sub-bus (1), and this transmission device (7) is a sub-bus monitoring control circuit (16) and a switch circuit ( 22).

The sub-bus monitoring control circuit (16) includes a transmission circuit (17),
It comprises a receiving circuit (18), a transmission control circuit (19), a central processing unit (hereinafter abbreviated as CPU) (20), and a watchdog timer (21), and the CPU (20) performs timeout detection. Watchdog, timer (2
The input side of 1) is connected. The switch circuit (22) for connecting and disconnecting the sub-bus monitoring control circuit (16) with respect to the sub-bus (1) is composed of a relay contact (23) and a relay coil (24).

Next, the operation will be described. The transmission control circuit (19)
The output sub-bus (1) of the CPU (20) is converted into a transmission format defined and sent to the transmission circuit (17), and the received data from the reception circuit (18) is restored and error-controlled to the CPU (20). Forward.

When data is being transmitted, a normal transmission signal is periodically output from the CPU (20) to the watchdog timer (21), and the watchdog timer (21) is reset to the initial state. At this time, the watchdog timer (21) is set to the abnormality detection level, but the abnormality detection level is not reached because it is periodically reset.

Therefore, the output of the watchdog timer (21) excites the relay coil (24) and the relay contact (23) is always closed.

However, for example, (a) another transmission device (7), (b)
When a failure occurs in any of the sub-bus (1), (c) transmission circuit (17), reception circuit (18), and (d) transmission control circuit (19), data transmission is interrupted.

When the data transmission is interrupted, the CPU (20) does not output the transmission normal signal to the watchdog timer (21).
When the watchdog timer (21) does not receive a transmission normal signal for a certain period of time or more, it reaches the abnormality detection level and the output disappears, the relay coil (24) is de-energized, the relay contact (23) is opened, and the sub-bus monitoring control is performed. Circuit (1
6) is disconnected from the sub bus (1).

[Problems to be Solved by the Invention] Since the conventional load control system is configured as described above, it is necessary for each transmission device to have a sub-bus monitoring control circuit and a switch circuit separately. However, there is a problem that it is difficult to construct a load control system having a hierarchical structure using a plurality of sub-buses.

The present invention has been made in order to solve the above problems, and a transmission device itself does not require a sub-bus monitoring control circuit and a switch circuit, and a hierarchical structure is formed by using a plurality of sub-buses. It is an object of the present invention to make it possible to easily obtain a load control system having the same.

[Means for Solving the Problems] In order to achieve the above object, a load control system according to the present invention includes one or a plurality of sub-buses in which a plurality of transmission devices are connected in parallel, and the sub-buses arranged in parallel with each other. ,
A main bus monitoring device that hierarchically connects the plurality of sub-buses, and one or a plurality of power feeding paths that feed power to the transmission device. The main bus monitoring device is configured to connect the plurality of sub-buses in parallel. One or a plurality of switch circuits that are connected to the connected main bus and each of the power supply paths and that control power supply to the transmission device that is connected to each of the sub-buses, and are connected to the main bus and all the switch circuits. And a control circuit that finds the sub-bus causing the abnormality by performing opening / closing control of the switch circuit when an abnormality is found on the main bus. In addition, the internal circuit of the transmission device is reset.

Further, according to another invention, in the above invention, the transmission of the control signal by the main bus and the sub-bus and the power feeding to the transmission device by the power feeding path are performed on the same transmission path.

According to another invention, in the above invention, the switch circuit has a manual opening means for supplying power to the power supply path.

Further, according to another invention, in the above invention, the main bus monitoring device resumes power supply after a lapse of a fixed time after stopping power supply to the sub-bus that is the cause of the abnormality, and in that state, performs a bus monitoring operation. Is performed again.

[Operation] In the main bus monitoring device according to the present invention, the control circuit monitors the main bus, and when an abnormality is detected, the switch circuit stops power supply to the transmission device connected to the abnormal sub bus. By doing so, it is not necessary to provide a sub-bus monitoring control circuit or the like in the transmission device itself connected to the sub-bus, the configuration is simplified, and it is easy to configure a load control system having a hierarchical structure using a plurality of sub-buses. To do.

[Embodiment] An embodiment of the present invention will be described below with reference to the drawings. In FIG. 1 in which the same parts as those in FIG.
(2) is a main bus (transmission bus) in which a plurality of sub-buses (1) are connected in parallel, and (3) is a main bus monitoring device.

The main bus monitoring device (3) has a main bus monitoring control circuit (6), a switch circuit (8) provided for each sub-bus (1), and a power feeding circuit (9). Each sub-bus (1) has a power supply line (10) installed in parallel,
Each power feeding path (10) is connected to a power feeding circuit (9) via a switch circuit (8). Each sub-bus (1)
Electric power is supplied to the transmission device (7) connected to the power supply line (10) by the power supply path (10).

The switch circuit (8) comprises a relay contact (4) and a relay coil (5). The supervisory control circuit (6) includes a transmission circuit (12), a reception circuit (13), and a transmission control circuit (1).
4) and a CPU: central processing unit (15). Each relay contact (4) is controlled by a supervisory control circuit (6) via a separate control line (11).

In each transmission device (7), reference numeral (25) is a power feeding circuit, which is connected to the power feeding path (10) and feeds power to the sub-bus monitoring control circuit (16).

Each of the above sub-buses (1) constitutes a subsystem such as security, device control, and video device control. The control signal transmission method of these subsystems has the same protocol and electrical conditions.

Next, the operation will be described. A main bus monitoring control circuit (6) that monitors the state of the main bus (2) when data transmission is normally performed on all the sub buses (1) connected to the main bus (2). Is the control line (11)
The relay coil (5) is excited through the relay coil (5) and the relay contact (4) is always closed. Therefore, the transmission device (7) connected to each sub-bus (1) is
0) can receive power, communication can be performed via the main bus (2), and the transmission device (7) operates in conjunction with each other, resulting in a more convenient system.

Here, if an abnormality occurs in the transmission device (7) connected to the sub-bus (1) or the sub-bus (1) itself,
The main bus monitoring control circuit (6) detects an abnormality on the main bus (2) from a signal other than a predetermined protocol input to the CPU (15) through the receiving circuit (13).

When an abnormality of the main bus (2) is detected, the opening / closing control of the switch circuit (8) according to the flow of FIG. 2 is performed to detect the sub-bus (1) in which the abnormality has occurred. The main bus supervisory control circuit (6) operates the transmission control circuit (14) by the output of the CPU (15), and the relay coil (5) is sequentially operated.
Is de-excited and the relay contacts (4) are sequentially opened, and the main bus (2) is monitored every time the relay contacts (4) are opened.

When the relay contact (4) is opened in this way, the power supply path (10) connected to the opened relay contact (4)
The transmission devices (7) connected to the respective sub-buses (1) arranged in parallel with each other cannot receive power from the power feeding path (10) and stop all operations such as communication.

When the main bus (2) is monitored again with one relay contact (4) open, if an abnormality is detected again on the main bus (2), the relay contact not opened. Power supply line (10) connected to (4)
It is possible to detect that an abnormality has occurred on the sub-bus (1) or the main bus (2) provided in parallel with each other. Then, the relay coil (5) is excited and the relay contact (4) is closed. In this way, power feeding is started from the power feeding path (10) to the transmission device (7) connected to each sub-bus (1). At this time, the transmission device (7) can resume operations such as communication, but at the same time, all the internal circuits of the transmission device (7) can be reset and the sequence can be restarted from the beginning.

Here, when no abnormality is detected on the main bus (2) in a state where a certain relay contact (4) is opened, the sub-bus (1) juxtaposed to the separated power supply path (10) is provided. Alternatively, it can be detected that an abnormality has occurred in the transmission device (7). This open relay contact (4)
Keep the relay coil (5) corresponding to
With the relay contact (4) open, the sub-bus (1)
It is output from the CPU (15) that the abnormality has occurred and the transmission circuit (12) notifies the transmission device (7) on the sub-bus (1) connected to the main bus (2), or The output of the CPU (15) notifies the main bus monitoring device (3) to detect the abnormal sub-bus (1) (steps 301 to 306 and 309).

If the main bus (2) or two or more sub-buses (1)
If an abnormal bus cannot be detected by the control flow described above, such as when there is an abnormality in the main bus monitoring control circuit (6)
Is the transmission control circuit (14) by the output of the CPU (15)
Is operated to make all relay coils (5) non-excited and open all relay contacts (4). Therefore, the transmission device (7) connected to each sub-bus (1) cannot receive power from the power feeding path (10) and stops all operations such as communication. In this way, the main bus (2) is monitored with all relay contacts (4) open (step 30).
7, 308).

If an abnormality is detected again on the main bus (2), all relay contacts (4) are kept open, and the main bus (2) indicates that there is an abnormality by the output of the CPU (15). The bus monitoring device (3) is notified (step 309).

When no abnormality is detected, the relay coil (5) is sequentially excited by the output of the CPU (15), all the relay contacts (4) in the open state are sequentially closed, and they are connected to the respective sub-buses (1). The transmitting device (7) in operation starts power feeding from the power feeding path (10). At this time, the transmission device (7)
Can resume the operation of communication and the like, but at the same time, all the internal circuits of the transmission device (7) can be reset, and the sequence can be restarted from the beginning when the internal circuits run away. Thus, the main bus (2) is monitored every time the relay contacts (4) are sequentially connected.

When no abnormality is detected on the main bus (2), the relay contact (4) remains connected. When an abnormality is detected, the relay contact (4) is opened again, the power supply to the transmission device (7) connected to the abnormal sub-bus (1) is stopped, and all operations such as communication are performed. Stop.

After opening the relay contact (4), the CPU (15) outputs that an abnormality has occurred on the sub-bus (1), and the transmission circuit (12) connects the sub-bus (1) to the main bus (2). ) The above transmission device (7) is notified or the main bus monitoring device (3) is notified by the output of the CPU (15) to detect the bus in which an abnormality has occurred (steps 401 to 407).

It is more effective if the transmission device (7) or the main bus monitoring device (3) that receives this notification is configured to display this result.

Further, even when data transmission is normally performed, the main bus control circuit (6) stops power supply to the transmission device (7) partially connected to the sub-bus (1) to reduce the number of operable devices. Energy saving can be realized by reducing the number. Further, after detecting the abnormal sub-bus (1) and stopping the power supply, the power supply is restarted after a lapse of a certain time, the main bus (2) is monitored, and if no abnormality is detected again, it is left as it is. According to the method in which the operation of stopping the power supply when the power supply is detected is repeated up to a certain number of times, it is possible to return the subsystem, which has been able to operate normally by the internal reset when the power supply is stopped, to the entire system.

In the above embodiment, the main bus (2) and the sub bus (1) are used.
Although the case of providing the power supply path (10) different from the above has been described, power may be supplied to the main bus (2) and the sub bus (1) and the control signal may be superimposed. In this case, if a power supply circuit (9) is provided for each sub-bus (1), the main bus (2) can be separated by the main bus control circuit (6) once even if data transmission is normally performed. ) It is possible to configure a subsystem that can operate separately from the system.

FIG. 3 is a block diagram showing another example of the switch circuit (8) applied to the present invention. By adding a power source (9) as a manual opening / closing means and a manual switch (26), power is supplied due to a failure or the like. Resumption of power supply to the transmission device (7) connected to the sub-bus (1) that cannot be supplied with power from the line (10), or transmission device (7) connected to another sub-bus (1) Since it is possible to stop the power supply to the device connected to the specific sub-bus (1) without affecting the above, it is possible to easily replace or change the entire subsystem or a part of the device.

[Effects of the Invention] As described above, according to the present invention, a plurality of sub-buses are connected in parallel to a main bus, and the sub-bus is connected based on the control circuit for monitoring the main bus and the output of the control circuit. The main bus monitoring device, which has a switch circuit that controls the power supply to the transmission device, is configured to be connected to the main bus.Therefore, it is not necessary to provide a sub-bus monitoring control circuit etc. to the transmission device itself connected to the sub bus. The structure is simplified, and a load control system having a hierarchical structure can be easily obtained by using a plurality of sub-buses.

Further, by controlling the opening / closing of the switch circuit, it is possible to control the power supply to the transmission device connected to the sub bus. This makes it possible to detect an abnormality that has occurred in the sub bus or the transmission device. Furthermore, since the internal circuits of the transmission device can be reset collectively, it is possible to restart the sequence from the beginning when the internal circuits run out of control.

In addition, if the control signal is transmitted by the main bus and the sub bus and the power is supplied to the transmission device by the power supply path on the same transmission path, some of the sub buses form a subsystem different from the main bus system. It becomes possible to do.

Also, if each switch circuit is provided with a manual opening means and a power supply is added to this, power supply can be stopped without affecting the transmission devices connected to other sub-buses.
It is possible to easily replace the entire device or a part of the transmission device and change the setting.

[Brief description of drawings]

FIG. 1 is a block diagram showing a load control system according to an embodiment of the present invention, FIG. 2 is a flow chart for explaining the operation of the system of FIG. 1, and FIG. 3 is another example of a switch circuit applied to the present invention. FIG. 4 is a block diagram showing a conventional load control system. In the figure, (1) is a sub bus, (2) is a main bus,
(3) is a main bus monitoring device, (4) is a relay contact,
(5) is a relay coil, (6) is a main bus monitoring control circuit, (7) is a transmission device, (8) is a switch circuit, (9)
Is a power supply circuit, and (26) is a manual switch. In the drawings, the same reference numerals indicate the same or corresponding parts.

Claims (4)

[Claims] 1. One or a plurality of sub-buses in which a plurality of transmission devices are connected in parallel, one or a plurality of power supply lines that are arranged in parallel to each of the sub-buses and supply power to the transmission devices, and a plurality of the sub-buses. And a main bus monitoring device that hierarchically connects the main bus monitoring device and the main bus monitoring device, wherein the main bus monitoring device is connected to each of the power supply paths and to each of the sub buses. One or a plurality of switch circuits for controlling power supply to the transmission device, which is connected to the main bus and all the switch circuits, and opening / closing control of the switch circuits when an abnormality is detected on the main bus. And a control circuit for finding the sub-bus that is causing an abnormality by performing the internal circuit of the transmission device when controlling the opening and closing of the switch circuit. Load control system, characterized in that resetting the road. 2. The control signal transmission by the main bus and the sub-bus and the power feeding to the transmission device by the power feeding path are performed on the same transmission path. Load control system. 3. The load control system according to claim 1, wherein the switch circuit has a manual opening means for supplying power to the power supply path. 4. The main bus monitoring device, after stopping power supply to a sub-bus causing an abnormality, restarts power supply after a lapse of a certain time, and performs the bus monitoring operation again in that state. The load control system according to claim 1.