JPH05344141A - Loop type signal transmission system - Google Patents

Abstract

PURPOSE:To provide the loop type signal transmission system which can automatically, easily and speedily continue the operation of an entire system even when an optical fiber cable is disconnected. CONSTITUTION:This system is provided with a monitor line 18 for successively connect a controller 3 reversely to an optical fiber cable 4, and a CPU 1 to detect abnormality when there is no input from the optical fiber cable 4 to the controller 3 for prescribed time, and to detect an abnormal signal when there is no input from the monitor line 18 to the controller. Then, when the CPU 1 detects any abnormality, the controller 3 connects the optical fiber cable 4 and the monitor line 18 to form a new loop.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention detects an abnormality such as a wire break in a signal transmission system in which a central control unit and a terminal control unit are connected in a loop, and automatically forms a new loop to control the terminal. The present invention relates to a loop type signal transmission system for normal operation of a device.

[0002]

2. Description of the Related Art Conventionally, a system has been widely used which detects an abnormality occurring in a terminal control device arranged in a LAN system or the like and notifies the central control device of the abnormality. Where L
The AN system generally connects a terminal control device (terminal computer and various intelligent terminals) centered around a host computer in a local area so that data can be transmitted and received between each device and the host computer. It refers to a system, and the local area is considered to indicate a limited area such as the same site or the same building.

FIG. 14 shows the configuration of a loop type signal transmission device which has been conventionally used. The host computer 10, which is a central control unit, has seven terminal control units 17a, 17
b, 17c, 17d, 17e, 17f and 17g are sequentially connected by an optical fiber cable 4 which is a signal line. The optical fiber cable 4 is used as a transmission path for serial data. The host computer 10 is a device that sends address data and manages I / O data sent from the terminal control device 17.

Next, the operation of the conventional loop signal transmission system having the above configuration will be described. Host computer 10
Transmits the serial data shown in FIG. 13 via the optical fiber cable 4 in order to collect the data and the like of each terminal device connected to each terminal control device 17. The serial data to be transmitted has a start flag 11 followed by data 12, followed by an FCS (frame check sequence) 13 for checking an error such as data, and then an end flag 14. Terminal control device 17
Receives serial data via serial I / O, and
The PU stores the received data in the RAM.

Next, an operation check is performed by the FCS to determine whether the received data has an error. Then, if there is no error, the CPU reads the command of the host computer 10 from the data, and based on the command and the control program stored in the ROM, reads the status data of the terminal device from the parallel I / O, and serially reads the data. Write status data to the data. On the other hand, when an error is detected, as shown in FIG. 15, the start flag 11 is followed by an error message 15, and the terminal control device 17 that has detected the error.
Address is set as the faulty terminal address 16 and FCS
13 and the end flag 14 are continued to create serial data.

Then, the serial data in which the status data of the device terminal and the error data are recorded is transferred to the next terminal control device 1 via the serial I / O and the optical fiber cable 4.
Sent to 7. The host computer 10 reads the serial data and, if the data is normal, grasps the state of each terminal device from the data. When an error message is output, the error occurrence is displayed on the outside and the address of the failed terminal where the failure is detected is displayed. The display enables the user to know where the failure has occurred and to promptly repair the failure.

[0007]

However, the conventional loop type signal transmission device has the following problems. That is, when the optical fiber cable 3 is broken at one place, the I / O data is not returned to the host computer 10, so that there is a problem that the operation of the entire system is stopped. This means not only the disconnection of the optical fiber cable 4, but also when replacing the terminal device such as a motor connected to one terminal control device 17, the power supply of the terminal control device 17 should be turned off to perform the work. Because there are many
There was a problem in that the entire system stopped, and the other terminal control devices 17 desired to perform normal operation were also stopped.

As a means for solving the above problems, the host computer 10 constantly monitors the entire loop type signal transmission system, detects and specifies the location where the wire breakage occurs, and interrupts the occurrence of a failure by a method such as interruption. Terminal control device 1
It has been known to notify No. 7 and form a new loop or the like to secure a signal transmission path. However, since the new loop formation is all performed according to the instruction of the host computer 10, the program of the host computer 10 is extremely complicated, and the cost is increased due to the extra memory. Further, the time required for recovery is as long as 10 to 20 seconds, and there is a possibility that trouble due to the system stop may occur during that time, which is a problem. Therefore, in actuality, when replacing a terminal device, the entire system is stopped. In addition, even when the wire break was recovered, it took a lot of manpower to return to the normal loop, which required a complicated procedure and a long time.

The present invention has been made to solve the above-mentioned problems of the prior art. Even if the optical fiber cable is broken, the operation of the entire system can be continued automatically, easily and quickly. It is an object to provide a loop type signal transmission system.

[0010]

In order to achieve the above object, the loop type signal transmission system of the present invention comprises one central control unit and two or more terminal control units which are looped by a unidirectional optical fiber cable. When the central control unit transmits data to one terminal control unit, the terminal control unit that receives the data sequentially transmits the data to another terminal control unit while changing its own data, and finally transmits the data. A loop-type signal transmission method for returning to the central control unit, wherein a monitor line for sequentially connecting the terminal control unit from the central control unit in a direction opposite to the optical fiber cable, and an optical fiber cable for the central control unit and the terminal control unit Abnormality detection means for detecting an abnormality when there is no input for a predetermined time, and an abnormality signal when there is no input from the monitor line for the central control unit and terminal control unit. And a monitor means for output, when the abnormality detection means and monitoring means detects an abnormality, the central control device and the terminal control device is connected to the optical fiber cable and the monitor line to form a new loop.

[0011]

When the terminal control device of the loop type signal transmission system of the present invention having the above-mentioned configuration receives data transmission from the central control device or another terminal control device, another terminal control device sequentially changes its own data. It transmits the data to the device and finally returns the data to the central controller. The central control device reads the serial data and, if the data is normal, grasps the state of each terminal device from the data.

Further, the abnormality detecting means of the central control unit and the terminal control unit detects the abnormality when there is no input from the optical fiber cable to the central control unit and the terminal control unit for a predetermined time. Further, the monitor means detects the abnormal signal when there is no input from the monitor line to the central controller and the terminal controller for a predetermined time. When the CPU and the monitor means detect an abnormality, the central controller and the terminal controller connect the optical fiber cable and the monitor line,
Form a new loop. Therefore, even if the optical fiber cable is broken, a new loop is automatically formed.
The loop signal transmission method can continue normal operation.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will now be described in detail with reference to the drawings. FIG. 5 is an explanatory diagram showing the overall configuration of the loop signal transmission system of this embodiment.
The main station D3, which is a central controller, has three terminal controllers A
3, B3, C3 are sequentially connected by the optical fiber cable 4.

Main station controller D3 used in this embodiment
The basic configurations of the terminal control devices A3, B3 and C3 are the same as shown in FIGS. FIG. 3 conceptually shows a signal transmission path in the control device. The respective input and output optical fiber cables 4 are connected to the control device 3 via a light receiver 5 and a light projector 6, respectively. Also,
A monitor line 18 made of an optical fiber cable is connected to the control device 3 via the light receiver 7 and the light projector 8.
That is, the data input H is input from the light receiver 5, and the data output J is output from the isolator 6. The monitor input K is input from the light receiver 7, and the monitor output I is output from the isolator 8.

A specific circuit configuration of the control device 3 of the main station and the terminal is shown in FIG. The optical fiber cable 4 is connected to the optical data link 24 via the light receiver 5 and the light projector 6. Further, the monitor line 18 is connected to the optical data link 25 via the light receiver 7 and the light projector 8. The optical data links 24, 25 are each connected to a processing circuit 26. The processing circuit 26 is connected to the CPU 1, the selector 22, and the waveform shaping amplifier circuit 23. Further, the pulse generation circuit 21 is connected to the selector 22. CPU1
In the RO, the control program of the terminal control device is stored.
M and a RAM (not shown) for temporarily storing data etc. are connected.

Next, the operation of the loop type signal transmission system having the above configuration will be described. The master station control device D3 and each terminal control device A3, B3, C3 perform the following operations in order to collect data and the like of the terminal equipment. FIG. 5 shows a conceptual diagram of the loop type signal transmission system when the normal operation is performed. Here, the P0 output of the CPU 1 shown in FIG. 1 is at a high level H and the P1 output is at a low level L. Then, as shown in FIG. 2, the processing circuit 26 enters the state of 3a.

The operation of the processing circuit in the state of 3a is shown in FIG.
(A) of. That is, the data input M input from the light receiver 5 is input to the IN terminal of the CPU 1 and the usual necessary processing is performed. That is, the command of the master station control device D3 is read from the data, the status data of the terminal device is read based on the command and the control program stored in the ROM, and the status data is written in the serial data. Then, of the serial data, the data required by its own terminal device is read and stored in the RAM. Then, the data output I is output from the OUT terminal and output from the projector 6.

On the other hand, the monitor signal is sent by the master station controller D3.
A predetermined pulse signal is generated. The monitor signal is input from the light receiver 7 as the monitor input J, and the monitor output K is output from the equalizer 8 via the monitor 2. At the same time, the monitor input J is input to the monitor input terminal MO of the CPU 1. When the data signal is normal, the monitor 2 performs the shaping amplification processing of the input monitor input J by the waveform shaping amplification circuit 23 and outputs it as the monitor output K.

Next, the operation of the present invention when a failure occurs, which is the main part of the present invention, will be described. A case where the optical fiber cable 4 and the monitor wire 18 are disconnected at the location shown in 9 of FIG. 6 will be described. In this case, no data is input to the terminal control device B3. When no data signal is input for a predetermined time or more, the CPU 1 determines that an abnormality such as a break has occurred in the optical fiber cable 4 immediately before, and the output of PO is set to low level L.
Then, the output of P1 is changed to the high level H.

Then, the processing circuit 26 is set so that the state of the terminal control device B3 performs the operation shown in FIG. 4 (b), as shown in the overall state of the loop type signal transmission system in FIG. That is, the monitor input J from the monitor line 18
Is input to the IN terminal of the CPU 1. Further, the data input M from the optical fiber cable 4 is input to the MO terminal of the CPU 1. As a result, the data input is input to the CPU 1 as a monitor input, and one loop can be restored.

Further, when an abnormality is detected, the CPU 1 sets the error message 15 following the start flag 11 and the address of the terminal control device 17 in which the error is detected to the faulty terminal address 16 as shown in FIG. FCS13
And the end flag 14 in succession to create and output serial data. Then, the serial data in which the status data of the device terminal and the error data are recorded is transmitted to the next terminal control device C3 via the serial I / O and the optical fiber cable 4.

Further, the terminal control device C3 uses the error message 1
When 5 is received, the monitor signal is checked, and if the monitor signal can be received, the state of 3a is maintained and the serial data shown in FIG. 15 is output as it is. Further, when the error message 15 is received, the master station control device D3 checks the monitor signal. If the monitor signal can be received, the serial data is read and the state of each terminal device is grasped from the data.

Further, the master station control device D3 externally displays the occurrence of an error and the address of the faulty terminal where the fault is detected. The display enables the user to know where the failure has occurred and to promptly repair the failure. However, if the optical fiber cable 4 is broken immediately before the master station control device D3, the address is not sent, so only the error is displayed when the error is detected, and the address is not displayed.

Next, the terminal control device A3 will be described. The disconnection 9 stops the input of the monitor signal. When an error signal is input, the CPU 1 changes the output of PO to low level L and the output of P1 to high level H.

As a result, the processing circuit 26 is set so that the state of the terminal control device B3 performs the operation shown in FIG. 4 (b), as shown in the overall state of the loop type signal transmission system in FIG. That is, the monitor input J from the monitor line 18 is input to the IN terminal of the CPU 1. Further, the data input M from the optical fiber cable 4 is input to the MO terminal of the CPU 1. Then, the data input is input to the CPU 1 as a monitor input, the remaining one loop is restored, the entire loop is connected, and signal transmission can be restarted. By the above operation, the optical fiber cable 4 and the monitor line 1
Even if 8 are disconnected at the same time, the loop can be recovered in a short time of 1 second or less, so the system reliability is improved.

Next, the case where the disconnection 9 of the optical fiber cable 4 and the monitor wire 18 is restored will be described. When the disconnection is restored, as shown in FIG. 9, the data signal M to the terminal control device B3 is restored and input to the monitor terminal MO of the CPU1. With this, the CPU 1 confirms the return, sets PO to the high level H and P1 to the low level L, and sets the processing circuit 2
The state of 6 is returned to the state of FIG. Also, CPU1
Sends a recovery command.

In the terminal control device A3, the monitor signal K is restored and input to the monitor terminal MO of the CPU1. CPU
1 confirms the return by this, and sets PO to high level H, P
1 is set to the low level L, and the state of the processing circuit 26 is returned to the state of FIG. Further, when the master station control device D3 receives the recovery command, it stops the error display. By the above operation, when the disconnection of the optical fiber cable 4 and the monitor line 18 is recovered, the loop can be automatically restored to the normal state in a short time of 1 second or less, so that the system reliability is improved.

Next, a case where only the optical fiber cable 4 is broken as shown in FIG. 10 will be described. Again,
Data will not be input to the terminal control device B3. And
When no data signal is input for a predetermined time or longer, the CPU 1 determines that an abnormality such as disconnection has occurred in the immediately preceding optical fiber cable 4, changes the output of PO to low level L, and changes the output of P1 to high level H. .. Then, the processing circuit 26 is set so that the state of the terminal control device B3 performs the operation shown in FIG. 4B, as shown in the overall state of the loop type signal transmission system in FIG.

When the CPU 1 judges an abnormality, the monitor signal K is stopped, and the state of the terminal control device A3 is set so as to perform the operation shown in FIG. 4 (c). The operations of the terminal control device C3 and the master station control device D3 are the same as when the optical fiber cable 4 and the monitor line 18 are disconnected at the same time, and a description thereof will be omitted. Then, as shown in FIG. 11, both sides of the loop are connected and restored so that the entire loop is connected and signal transmission can be restarted. By the above operation, even when the optical fiber cable 4 and the monitor line 18 are simultaneously broken, the loop can be restored in a short time of 1 second or less, so that the system reliability is improved. The restoration is the same as the case where the optical fiber cable 4 and the monitor line 18 are disconnected at the same time, and the description thereof will be omitted.

Next, a case where only the monitor line is broken as shown in FIG. 12 will be described. Since the data signal M is sent normally, the master station controller C3 and each terminal controller A
3, B3 and C3 perform normal data transmission / reception. Since the monitor signal K is not input to the terminal control device A3, the terminal control device A3 confirms that the error signal is not sent as the data signal M even after the lapse of a predetermined time, and outputs the monitor error as the data signal. In addition, the terminal control device A3
Switches the selector 22 to output a pulse signal as a monitor output to the monitor line 18. The monitor signal is output because the terminal control device cannot receive the monitor signal from the master station control device due to the disconnection of the monitor line 18.

Upon receiving the monitor error signal, the terminal control device B3 outputs the warning signal and its own address as a data signal. The master station control device D3 displays a warning display and an address in order to indicate the abnormality of the monitor line. As described above, when the monitor line 18 is disconnected, the normal signal transmission is continued, the monitor line disconnection is displayed on the master station control device D3, and the user is warned. When the user restores the monitor line 18, it is restored in the same manner as when the optical fiber cable 4 and the monitor line 18 are simultaneously disconnected.

As described above, according to the loop type transmission system of this embodiment, the optical fiber cable 4 and the monitor line 1 are used.
Even if any of 8 breaks at any position, the circuit of the terminal control device itself automatically forms a new loop.
Since the entire system stops for 1 second or less, it is possible to continue operating the terminal equipment connected to the individual terminal control device. Further, when the terminal device connected to one terminal control device is replaced, even if the power of the terminal control device is turned off, the other terminal control devices can be operated as they are, and the usability of the entire system is improved. To do.

The present invention is not limited to the above embodiments, and various modifications and improvements can be made without departing from the gist of the present invention. That is, the processing circuit 26
It is also possible to perform by a program.

[0034]

As described above, according to the loop type signal transmission system of the present invention, the central control unit sequentially connects the terminal control unit in the direction opposite to the optical fiber cable, and the monitor line,
Abnormality detection means for detecting an abnormality when there is no input from the optical fiber cable to the central control unit and terminal control unit, and an abnormality signal when there is no input from the monitor line to the central control unit and terminal control unit When the abnormality detecting means and the monitoring means detect an abnormality, the central control unit and the terminal control unit connect the optical fiber cable and the monitor line to form a new loop. Even if the optical fiber cable 4 is broken, the entire system is stopped for a short time, and the terminal equipment connected to the individual terminal control device can continue to operate. Further, when the disconnection or the like is restored, the normal operation can be restored automatically and quickly.

When the terminal equipment connected to one terminal control device is replaced, even if the power supply to the terminal control device is turned off, the loop can be immediately restored, so that the other terminal control devices can be operated as they are. It is possible to improve the usability of the entire system.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing an internal configuration of a control device used in a loop signal transmission system according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing control conditions of a CPU.

FIG. 3 is a conceptual diagram showing a signal transmission path of a control device used in a loop type signal transmission system according to an embodiment of the present invention.

FIG. 4 is a conceptual diagram showing a change of a signal transmission path of a control device used in a loop type signal transmission system according to an embodiment of the present invention.

FIG. 5 is a conceptual diagram showing a normal state of a loop signal transmission system according to an embodiment of the present invention.

FIG. 6 is a first explanatory diagram showing a disconnection state of the loop signal transmission system.

FIG. 7 is a second explanatory diagram showing a disconnection state of the loop signal transmission system.

FIG. 8 is a third explanatory diagram showing a broken state of the loop signal transmission system.

FIG. 9 is a fourth explanatory diagram showing a broken state of the loop signal transmission system.

FIG. 10 is a fifth diagram showing a broken state of the loop signal transmission system.
FIG.

FIG. 11 is a sixth diagram showing a disconnection state of the loop signal transmission system.
FIG.

FIG. 12 is a seventh diagram showing a disconnection state of the loop signal transmission system.
FIG.

FIG. 13 is an explanatory diagram showing a data signal in a normal state.

FIG. 14 is a conceptual diagram showing a conventional loop signal transmission system.

FIG. 15 is an explanatory diagram showing a data signal in an abnormal state.

[Explanation of Codes] 1 CPU 2 Monitor 3 Control Device 4 Optical Fiber Cable 22 Selector 26 Processing Circuit A3 Main Station Control Circuit B3 Terminal Control Device C3 Terminal Control Device D3 Terminal Control Device

Claims (1)

[Claims] 1. A central control unit and two or more terminal control units are connected in a loop by a unidirectional optical fiber cable, and data is transmitted from the central control unit to one terminal control unit. In the loop type signal transmission system, in which the received terminal control device sequentially changes its own data and transmits the data to another terminal control device, and finally returns the data to the central control device, wherein the central control device sequentially A monitor line that connects the control device in the opposite direction to the optical fiber cable, and an abnormality detection unit that detects an abnormality when there is no input from the optical fiber cable to the central control device and the terminal control device for a predetermined time, The central control unit and the terminal control unit, and monitor means for detecting an abnormal signal when there is no input from the monitor line for a predetermined time, When the detection means and the monitoring means detects an abnormality, the central control device and the terminal control device is connected with said monitoring line and said optical fiber cable,
A loop-type signal transmission method characterized by forming a new loop.