JPH01226243A - Bus type network system - Google Patents

Abstract

PURPOSE:To re-compose a transmission line in accordance with the state of a network by constituting the bus type network, in which an enlargement device is used, so that the enlargement device itself can decide whether to detach the terminator of the transmission line based on the constitution of the network and an operation state when a fault occurs in the enlargement device. CONSTITUTION:When the terminator 2 of the transmission line in the enlargement device 1 is connected to the transmission line 3, it operates as a terminating equipment, and electric matching cannot be executed and an electric abnormality occurs in the transmission line when the terminator is detached. With a terminator switching control circuit 10 which recognizes the constitution and the operation state of the network in the enlargement device 1, the enlargement device can learn whether the transmission line of the network is multiplexed or whether standby system of the multiplexed transmission line can be operated. With deciding to disconnect the terminator of the transmission line in accordance with the condition of the network when the abnormality has occurred in the enlargement device, the terminator is detached when the transmission line can be switched and respective node stations 16 detect the electric abnormality of the transmission line, whereby the transmission lines are simultaneously switched to the standby system.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a bus-type network system using an expansion device and an expansion device for a bus-type network. The present invention relates to an expansion device suitable for workpiece abnormality recovery.

[Conventional technology]

Conventional devices had a terminator in the expansion device, for example, as in JP-A-21412/17, and there was a concept of switching this when expanding the network, but the expansion device itself At the age of 10, no consideration had been given to what to do in the event of a malfunction due to a power outage, etc.

In consideration of this point, the present invention is characterized in that by switching the terminator according to the network situation, an optimal means for recovering from an abnormality in the network 1-71 is provided.

[Problem to be solved by the invention]

The conventional technology does not take into account the operation of the expansion device itself when a failure occurs, and there is a problem in that it does not provide any concrete means for recovering the network from an abnormal state after a failure.

The purpose of the present invention is to provide a bus-type network that presents the functions of an expansion device necessary for the network to recover from an abnormal state after a failure of an expansion device, and allows the network to recover quickly through its actions. Our objective is to provide expansion devices for systems and bus-type networks.

[Means to solve the problem]

The above purpose is to have a means for recognizing the configuration and operational status of the terminators and networks of multiple transmission lines connected within the expansion device, and to determine whether to disconnect the terminators according to the network status when the expansion device fails. This can be achieved by

[Effect]

In the present invention, when the terminator of the transmission line inside the expansion device is connected to the transmission line, it operates as a termination device of the transmission line, but on the other hand, when it is turned off by πF, electrical matching cannot be achieved. Electrical abnormalities will occur in the transmission line.

In addition, by means of recognizing the network I/work configuration and operational status in the expansion device, the expansion device can check whether the network 1-work transmission path is multiplexed or not, and whether the standby system of the multiplexed transmission path is You can know whether it is operational or not.

By using the above two means, it is determined whether or not to cut off the terminator of the transmission line according to the network situation when an abnormality occurs in the expansion device, and the terminator is cut off when the transmission line can be switched. At this time, each node station has a function of detecting an electrical abnormality in the transmission line and a function of switching the transmission line when an abnormality is detected, and switches the transmission line to the standby system all at once. On the other hand, if switching is not possible, leaving the terminators intact will separate each transmission path, allowing quick network recovery.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 to 7.

FIG. 1 is a block diagram of an embodiment of an expansion device based on the present invention, in which 1 is the expansion device main body, 2 is a transmission line terminator, and 3 is a block diagram of an embodiment of the expansion device according to the present invention.
is a transmission path, 4 is a receiver, 5 is a FIFO register, 6 is a transmitter, 7 is a directional coupler, 8 is a timing extractor, 9 is a timing generator, 10 is a terminator switching control circuit,
11 is a power supply device, 12 is a status signal line of the power supply device 11 as described later, 13 is an external interface line, and SW is a switch for connecting the terminator 2 to the transmission line 3.

FIG. 2 is a block diagram of a system to which the present invention can be applied.
1 is a branching device, 15 is a transmission line terminator, and 16 is a node station.

The operation of the expansion device of the present invention will be explained using FIG.

In Fig. 1, in order to make the explanation @1) 1, we have taken a case where two transmission lines are connected -11, but even if three or more transmission lines are connected, the basic configuration of expansion device 1 changes. There isn't. Since the terminator 2 is normally connected to the transmission line 3, the signal flowing through the two transmission lines 3 connected by the expansion device 1 is sent to the receiver via the directional coupler 7 without causing any electrical abnormality. 4 and demodulated. Here, the directional coupler 7 transmits the signal input from the transmission path 3 to the receiver 4, and transmits the signal input from the transmitter 6 to the transmission path 3, and from the transmitter 6 to the receiver 4. The signal propagation routes 1 to 1 are cut.

The signal input via the receiver 4 is written into the FIFO register 5 using the clock extracted by the timing extraction circuit 8. On the other hand, the data is read out from the FIFO register 5 using a clock generated by the clock generator 9 included in the expansion device 1, modulated by the transmitter 6, and sent to the other transmission line 3.

The second is the operation of the expansion device 1 in its normal state.

FIG. 3 shows a more specific embodiment of the terminator switching control circuit 10 and changeover switch SW, which are the characteristic parts of the present invention in FIG. 1.

The terminator switching control circuit 10 includes a dip switch 1
01. It is composed of AND gates 102 to 105 and a NOT gate 106, and the date switch 101 sets the configuration of the transmission path.For example, in a switch that can set 8-bit switch information, 1 bit is used to , if the transmission line is a dual system, set it to "1", and if it is a single system, set rOJ. A PAVL signal indicating that the power supply device 11 is normal and a signal POP indicating a transient state of power on←off are output from the power supply device 11 to a power state signal line 12. The relationship between the on/off state of the power supply device 11 and PAVL, POI is as shown in FIG. 4, and POP is output only in a transient state.

In a transient state, even when the power supply 11 is off, I'
) Ol) signal is output at (point ■ in Figure 4)
]), although the power supply has not reached the positive state, the voltage is at a certain level.

The changeover switch SW has coils a and b, and the coil a+
When a pulse current flows through b, the contacts of the switch change over, and this state is maintained as long as no current flows.

When a pulse current flows through coil a, the switch contacts (
Switch to the a) side and disconnect terminator 2 from transmission line 3. On the other hand, when a pulse current flows through the coil, the contact of the switch is switched to the (b) side, and the terminator 2 is connected to the transmission path 3.

When the power is turned off → on, the pop signal shown at point P in FIG. 4 is output in that transient state, and )'AV1. is “0”
Therefore, NOT Gamegoo 106. ANII Game 1 Goo 1
05, a pulse current is applied to the coil)), and the terminator 2 is connected to the transmission line 3 side. On the other hand, P.A.V.
T-4 is output to an external interface line to notify an external expansion device that this expansion device is operating normally.

Also, when the power is turned on→off, (]) When the setting information of the dip switch 101 is a dual system and the pAV T-4R output from another system is normal.

In a transient state, when POP shown at point Q in FIG. 4 is output, AND game], 02. ．． ], 04 causes a pulse current to flow through the coil a, and the terminator 2 is separated from the transmission line 3.

(2) When the setting information of dip switch 1.01 is a dual system and the other system is abnormal (power off).

The POP shown at the point in Figure 4 is output, but from the outside (
7) Since P A V L is “0”, A N
I) The output of the gate 102 becomes "o", and the AND gate 1
-104 output pulse is not generated, so terminator 2
remains connected to the transmission line 3.

(3) If the setting information of deep switch 10 is tlL
-When system.

Since the output of A N I) Goo1-]02 is always "0", the terminator 2 is the transmission line: 3, as in (2) above.
remains connected to.

A specific example will now be described with reference to FIGS. 5 to 7.

If it is not multiplexed as shown in Figure 6, the same figure (a
), if a failure occurs in the expansion device 1, the expansion device 1
stops operation with terminator 2 connected to transmission line 3. In this case, as a system, the transmission line is divided into two segments I as shown in Figure 1(b), but communication is possible between the node stations connected to each segment I, and the expansion device IT ] can avoid the worst situation where the entire system goes down due to a failure.

If the transmission line is duplexed (the same goes for multiplexing three or more lines) and the expansion device fails, the terminator switching control circuit 10 will switch the system 15 based on the above information.
If the system is duplexed and the standby system is determined to be operational, first disconnect terminator 2 from transmission line 3 to connect it to the active transmission line, as shown in Figure 7. Causes electrical abnormalities. This abnormality is a branching device"4
The information is simultaneously transmitted to all node stations 16 connected to the system via. As a result, each of No. 1 to Station No. 1 switches the transmission path from the active system to the standby system and starts communication. When the transmission paths are multiplexed in this manner, by switching the transmission paths all at once, communication is possible between each node station 16 without being divided into segments 1-.

FIG. 5 clearly shows the flow of the second operation.

〔Effect of the invention〕

According to the present invention, when an expansion device fails in a bus type network 1 to work mode using an expansion device, the expansion device itself determines whether to disconnect the terminator of the transmission path based on the network configuration and operational status. (1) Transmission paths can be reconfigured according to network conditions.

(2) When switching the transmission path, the failure of the expansion device can be electrically notified to the node station, allowing for quick switching and simultaneous notification, allowing masterless switching.

It is.

[Brief explanation of the drawing]

FIG. 1 is a functional block diagram of an embodiment of an expansion device according to the present invention, FIG. 2 is a configuration diagram of an embodiment of a system to which the present invention can be applied, and FIG. 3 further illustrates the characteristic parts of the present invention in FIG. A detailed circuit diagram, FIG. 4 is a time chart for explaining the operation, and FIG. 5 is a flowchart 1 for explaining the operation of the expansion device.
・FIGS. 6 and 7 are diagrams showing examples of transmission path reconfiguration when the present invention is applied. DESCRIPTION OF SYMBOLS 1... Expansion device, 10... Terminator switching control circuit, 12... Status signal line of power supply device, 13... External ink 5th

Claims (1)

[Claims] 1. In a bus type network system in which a plurality of node stations are connected to a transmission line via a branching device and data is exchanged between each node station, at least two transmission lines are connected by an expansion device. electrically connected,
The expansion device has a function of outputting input data from one transmission line to another transmission line when each node station transmits data, and a terminator for each of the plurality of transmission lines connected. A bus-type network characterized in that the expansion device itself determines whether or not to disconnect the terminator from the transmission path based on predetermined conditions when an abnormal failure such as a power outage is detected. work system. 2. An expansion device for expanding a bus-type network in which a plurality of node stations are connected to a transmission path via a branching device and data is exchanged between each node station. When transmitting data, it has the function of outputting the input data from one transmission line to another transmission line, and has a terminator for each of the multiple transmission lines connected, and the expansion device itself has a power supply 1. An expansion device for a bus-type network, characterized in that when an abnormal failure such as a disconnection is detected, it is determined based on predetermined conditions whether or not to disconnect the terminator from the transmission path. 3. In a bus-type network system in which a plurality of node stations are connected to multiplexed transmission lines via branching devices and data is exchanged between each node station, expansion in which at least two sets of transmission lines correspond to each other. electrically connected by a device, the expansion device comprising:
When each node station transmits data, it has the function of outputting the input data from one transmission line to another transmission line, and the terminator for each of the multiple transmission lines connected. The expansion device also has an external interface line that exchanges its own status signals with other expansion devices, and when the expansion device itself detects an abnormal failure such as a power outage, the expansion device automatically terminates the terminator according to the contents of the external interface line. 1. A bus-type network system, characterized in that it determines whether or not to disconnect a bus from a transmission path. 4. The bus type network system according to claim 1, wherein each node station detects an electrical abnormality occurring in the transmission line via a branching device and switches the transmission line. 5. The expansion device according to claim 3 has a means for setting whether or not the connected transmission path is multiplexed, and the expansion device itself determines whether the transmission path is multiplexed or not when an abnormal failure such as a power cut is detected. Provided that the expansion devices of other transmission lines are not faulty, each terminator of the transmission line is disconnected from the transmission line, an electrical failure is caused in the disconnected transmission line, and the transmission line is switched simultaneously at each node station. A bus-type network system is characterized in that it is configured to perform the following operations. 6. The expansion device according to claim 3 includes means for setting whether or not connected transmission paths are multiplexed, and mutually exchanging status signals of the expansion device itself with other multiplexed expansion devices. The expansion device itself has an external interface line for
A bus-type network characterized in that when an abnormal state of a power supply, etc. is detected, if an expansion device of another multiplexed transmission line is out of order, the connection state of the terminator to the transmission line is maintained. system. 7. The terminators according to claims 1 to 3 are each connected to the transmission line via a terminator switching means, and the terminator switching means has a first coil and a second coil, and the terminator switching means has a first coil and a second coil.
A bus type network system characterized in that a terminator is connected to a transmission line side by a current flowing through a second coil, and the terminator is separated from a transmission line side by a current flowing through a second coil. 8. The terminator switching means according to claim 7 comprises a first,
Terminator switching means, characterized in that when the current flowing through the second coil becomes zero, the connection state at that time is maintained. 9. The current flowing through the first and second coils according to claim 7 is a pulse current only for a certain period indicating a transient state in which the power source switches from an on state to an off state or from an off state to an on state, and the terminator is connected. 1. A bus-type network system characterized in that when a single transmission path is used, current flowing through the second coil is blocked.