JPH09261257A - Duplicate bus converter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize the duplicate bus converter in which performance of the bus converter is improved. SOLUTION: A changeover means 5 gives a switching signal to connection means 41 , 42 to connect either of duplicated bus converters 31 , 32 to a subordinate bus 2 and to disconnect the other from the subordinate bus 2. When either of communication control means 61 , 62 has its own bus converter connected to the subordinate bus 2 based on a switching signal, the communication control means discriminates to be a control side to make communication as a control side. When the bus converter of itself is disconnected from the subordinate bus 2, the communication control means discriminates to be a standby side to make communication as a standby side.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention has a bus converter for relaying communication between a high-order bus and a low-order bus having different protocols, and this bus converter is duplicated and the duplicated bus converter is provided. One of the devices is a control side and the other is a standby side. More particularly, it relates to a dual bus converter with improvements to improve the performance of the bus converter.

[0002]

2. Description of the Related Art In order to improve the reliability of a bus converter, it is usual to duplicate the bus converter and back up with another bus converter even if one bus converter fails. A bus converter having such a configuration is called a dual bus converter. Generally, in a dual bus converter, 2
It is necessary for the bus converters of the respective units to know the address, the state (whether the control side or the standby side) of the other bus converter. Furthermore, since each bus converter internally has a database such as a tag list that changes in real time, it was necessary to match the databases among the bus converters. For this reason, it is necessary to communicate between the two bus converters, so that a dedicated protocol has to be created. However, when a dedicated protocol is generated between the two bus converters, the performance of the bus converters deteriorates because the two bus converters must constantly monitor the other party.

[0003]

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-mentioned problems, and by operating two bus converters independently of each other without being aware of their respective states, the bus It is an object to realize a dual bus converter with improved converter performance.

[0004]

SUMMARY OF THE INVENTION The present invention has a bus converter for relaying communication between an upper bus and a lower bus having different protocols, and the bus converter is duplicated and duplicated. In a duplicated bus converter in which one of the bus converters operates as a control side and the other as a standby side, a connection means is provided for each bus converter, which connects or disconnects the bus converter with respect to a lower bus. Switching means is provided in each bus converter, which supplies a switching signal to each connection means, connects one of the duplexed bus converters to the lower bus and disconnects the other from the lower bus. In addition, when a certain bus converter is connected to the lower bus, it judges that the other side is the control side, communicates with the control side, and the certain bus converter is disconnected from the lower bus. When Determining that side where there is itself a stand-by side is a duplex bus converter characterized by comprising a communication control means for performing communication of the standby side.

[0005]

According to the present invention, the switching means applies the switching signal to the connecting means to connect one of the duplexed bus converters to the lower bus and disconnect the other from the lower bus. Based on the switching signal, the communication control means determines that the side where the bus converter is located is the control side and communicates with the control side when the bus converter is connected to the lower bus. When a certain bus converter is cut off from the lower-order bus, it is determined that the other side is the standby side, and the standby side communicates.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings. FIG. 1 is a configuration diagram showing one embodiment of the present invention.

In FIG. 1, 1 is an upper bus and 2 is a lower bus. The upper bus 1 and the lower bus 2 communicate using different protocols. The upper bus 1 is composed of, for example, a V-net, and the lower bus 2 is composed of, for example, an HF bus. 3 ₁ and 3 ₂ are bus converters, which relay communication between the upper bus 1 and the lower bus 2. The bus converters 3 ₁ and 3 ₂ have the same configuration, and they are duplicated. Reference numerals 4 ₁ and 4 ₂ are connection means for connecting or disconnecting the bus converters 3 ₁ and 3 ₂ to or from the lower bus 2. The connecting means 4 ₁ and 4 ₂ are composed of, for example, HF bus couplers, which are connected when an enable signal is given to the coupler, and cut off when a disable signal is given. In addition,
The bus converters 3 ₁ and 3 ₂ are always connected to the host bus 1. Numeral 5 is a switching means for applying a switching signal to each of the connection means 4 ₁ and 4 _{2 so} that one is connected and the other is disconnected. Thus, the bus converter 3 ₁ which is duplicated, 3 ₂ of one is connected to the lower bus 2, the other is cut off from the lower bus 2. The switching means 5 is composed of, for example, a flip-flop. Reference numerals 6 ₁ and 6 ₂ denote communication control means, and based on the switching signal from the switching means 5, when a bus converter having the bus controller is connected to the lower bus 2, the side having the bus controller is the control side. If the bus converter performs the operation on the control side, and the bus converter with which it is connected is cut off from the lower-order bus 2, it determines that the side with itself is the standby side and waits on the bus converter. Let the side perform the action. Reference numerals 7 ₁ and 7 ₂ denote database memories provided inside the bus converter. The databases in the database memories 7 ₁ and 7 ₂ are real-time databases such as tag lists. Reference _numerals 8 ₁ and 8 ₂ denote memory control means for controlling reading and writing of the database memories 7 ₁ and 7 ₂ .

The operation of the apparatus shown in FIG. 1 will be described. FIG. 2 shows FIG.
FIG. 3 is an operation explanatory view of the device of FIG. FIG. 2 shows an example in which the bus converter 3 ₁ is on the control side and 3 ₂ is on the standby side.

In FIG. 2, the switching means 5 turns on the connecting means 4 ₁ and turns off the connecting means 4 ₂ by a switching signal. Based on the switching signal, the communication control means 8 ₁ determines that its own bus converter 3 ₁ is on the control side. Based on this judgment, the communication control means 8 ₁ refers to / sets the database shown in (1) communication from the upper bus 1 to the lower bus 2 and (2) message communication from the lower bus 2 to the upper bus 1. This communication is similar to a normal bus converter. The communication control means 8 ₂ has its own bus converter 3 ₂ based on the switching signal.
Is the standby side. Based on this determination, the communication control means 8 ₂ performs communication on the standby side. That is, since the communication from the upper bus 1 to the lower bus 2 shown in is cut off, the transmission to the lower bus 2 and the reply to the upper bus 1 are not performed.
In the message communication from the lower bus 2 to the upper bus 1 shown in (1), only the message of the bus converter 3 ₂ itself is transmitted to the upper bus 1. Therefore, the status of the station connected to the lower bus 2 is not notified to the upper bus 1. For access to the database shown in, only set the data. By setting the data, the standby database, which changes in real time, can be maintained at the same timing as the control database. For example, the tag list can be equalized on the control side and the standby side at the same timing.

In this way, the two bus converters 3 ₁ , 3
₂ operates independently of each other without being aware of the other party, based only on whether or not it is connected to the lower bus 2 or cut off. Therefore, it is not necessary to communicate with each other between the _two bus converters 3 ₁ and 3 ₂ to confirm the state of the other party. Since the two bus converters 3 ₁ and 3 ₂ operate independently of each other, the operation can be continued even if the control side is switched.

[0011]

According to the present invention, the two bus converters operate independently of each other without being aware of the other party, based only on whether or not the bus converters are connected to or disconnected from the lower bus. . For this reason, it is not necessary to communicate with each other between the two bus converters to check the status of the other party, and the performance of the bus converter can be improved.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing one embodiment of the present invention.

FIG. 2 is an explanatory diagram of the operation of the apparatus of FIG. 1;

[Explanation of symbols]

1 Upper Bus 2 Lower Bus 3 ₁ , 3 ₂ Bus Converter 4 ₁ , 4 ₂ Connection Means 5 Switching Means 6 ₁ , 6 ₂ Communication Control Means

Claims (1)

[Claims] 1. A bus converter for relaying communication between a high-order bus and a low-order bus having different protocols, wherein the bus converter is duplicated, and one of the duplicated bus converters is a control side. , In the duplicated bus converter that operates as the standby side, the other is provided for each bus converter, and connecting means for connecting or disconnecting the bus converter to or from the lower-order bus, and switching signals are given to these connecting means, respectively. Switching means for connecting one of the duplexed bus converters to the lower bus and disconnecting the other from the lower bus; and a bus conversion provided in each bus converter, based on the switching signal When the device is connected to the lower bus, it determines that the other side is the control side and communicates with the control side, and when the certain bus converter is disconnected from the lower bus, the other side is On the standby side A duplex bus converter, comprising: a communication control unit that determines that there is a communication and performs communication on the standby side.