JP2830486B2 - Communication device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a communication apparatus comprising a plurality of communication stations connected via a connector to a communication bus provided on a backboard, and more particularly to a communication apparatus having a plurality of communication stations connected to a communication bus. The present invention relates to a communication device having an address setting circuit for setting an address representative of the communication station in each communication station.

[0002]

2. Description of the Related Art When a plurality of communication stations are connected to a communication bus, an address for designating the communication station is set for each communication station. Conventionally, as a method for setting an address in each communication station, a switch is provided in each communication station (device), an address is set by the switch, a nonvolatile memory is provided inside the device, and an address is written there. There is a method to put.

[0003]

However, in any of the methods, it is necessary to individually set an address for each communication station, and when a large number of communication stations are connected to a communication bus, the operation is difficult. The task of address setting is not easy. The present invention has been made in view of such a point,
The purpose is to attach each communication station to the backboard, so that the address unique to that communication station can be automatically set from the backboard side. An object of the present invention is to realize a communication device which is not affected by a malfunction due to a circuit failure or the like.

[0004]

SUMMARY OF THE INVENTION To achieve the above object, the present invention provides a communication apparatus having a plurality of communication stations having a communication function, and a backboard on which the communication stations are mounted via connectors. On the backboard side, connect multiple connector terminals to which each communication station is attached to a common potential, or
Different address information is set depending on the combination of the communication stations, and a plurality of connectors in which parity information of the address signal is set at any one of the connector terminals. A parity check circuit that receives address information and parity information input from a plurality of connector terminals when attached to the backboard and performs a parity check on the address information; and the address information and the address information from the parity check circuit are normal. And a communication interface for stopping a communication function when receiving a signal indicating whether the signal is abnormal.

[0005]

In the plurality of connectors on the backboard, different address information for each connector is set in advance by a combination of connecting or not connecting the connector terminal to the common potential. When a communication station is mounted on the connector on the backboard, address information preset on the connector is applied to the communication station at the same time, and the parity check circuit checks the applied address information and parity information. A parity check is performed on the basis of the parity check, and the function of the communication interface is controlled.

[0006]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a conceptual diagram of the configuration of the device of the present invention.
A plurality of communication stations (in this example, a plurality of input / output devices for inputting a signal from a process and outputting a signal to the process) 1 are configured to be mounted on the backboard 2. ing. Communication station 1 on backboard 2
Is mounted on the connector 3, address information and parity information are applied via the connector 3, and communication data can be transmitted and received. Here, different address information is set for each connector. FIG. 2 is a configuration block diagram showing an embodiment of the present invention. On the backboard 2 side, reference numeral 3 denotes a connector, and when the communication station is mounted on the backboard 1, the two connector terminals come into contact with each other. In this connector 3, A0 to A4 are a plurality of connector terminals, and different address information is set depending on whether each terminal is connected to a common potential point (ground line) or not. In this example, 5-bit address information is set using five connector terminals, and the connector terminal A
Address “21” is set by connecting 0, A2, and A4 to the ground and opening A1 and A3. P0 is a connector terminal in which parity information of address information is set, and in this example, is opened to generate odd-numbered parity information.

In the communication station 1, R is a pull-up resistor having one end connected to each connector terminal, and BF is a buffer for inputting address information and parity information from each connector terminal. A parity check circuit 11 receives address information and parity information input via each buffer BF and performs a parity check on the address information.
Receives address information and a signal indicating whether the address information is normal or abnormal from the parity check circuit 11,
This is a communication interface that stops a communication function when receiving a signal indicating an abnormality. The communication interface 12 receives the signal indicating that the address information is normal, and exchanges communication data via the connector 3.

[0008] The operation of the apparatus thus constructed will be described below. In the back board 2, address information unique to each connector is set in advance to a plurality of connector terminals A0 to A4 of each connector 3. Further, parity information corresponding to the set address information is set in the connector terminal P0. When the communication station 1 is mounted on the backboard 2, when each terminal of the connector contacts, address information and parity information unique to the mounting position are applied to the parity check circuit 11 via each buffer BF. The parity check circuit 11 receives the address information and the parity information and checks the parity. If the result is normal, the parity check circuit 11 transmits an active signal indicating that the address is normal and the address information to the communication interface 1.
Output to 2. The communication interface 12 receives an active signal indicating normal address from the parity check circuit 11, and performs a normal communication operation while the active signal is active, that is, an address signal transmitted through the connector 3, and
It performs collation with address information output from the parity check circuit 11 and assigned to its own station, and exchanges other communication data. When receiving an inactive signal indicating an address abnormality from the parity check circuit 11, the communication interface 12 stops all communication operations. This state is maintained until an active signal indicating normal address is received from the parity check circuit 11.

Here, the following are causes of the parity check circuit 11 detecting a parity error. (a) Disconnection of address signal wiring on backboard, (b)
Poor connection of the connector 3, (c) failure of the input buffer BF of the address signal on the communication station side, (d) failure of the pull-up resistor,
(e) Failure of the parity check circuit 11. In this embodiment, the signals transmitted via the connector 3 are address information, parity information, communication data, and the like. You may make it perform through.

[0010]

As described above in detail, according to the present invention, an address unique to the communication station can be automatically set from the backboard side only by mounting the communication station on the backboard. In addition, it is possible to provide a highly reliable communication device in which a malfunction due to a failure in mounting the device on the backboard or a failure in the address setting circuit does not affect the entire system.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram of the configuration of the device of the present invention.

FIG. 2 is a configuration block diagram showing one embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Communication station 2 Backboard 3 Connector 11 Parity check circuit 12 Communication interface A0 to A4, P0 Connector terminal R Pull-up resistor BF Input buffer

Claims (1)

(57) [Claims] 1. A communication apparatus having a plurality of communication stations having a communication function and a backboard to which the communication stations are mounted via connectors, wherein a plurality of connectors to which each communication station is mounted on the backboard side. Different address information is set depending on whether the terminals are connected to a common potential or not, and a plurality of connectors in which parity information of the address signal is set in any one connector terminal are provided. On the communication station side, a parity check circuit that receives address information and parity information input from a plurality of connector terminals when the communication station is mounted on the backboard, and performs a parity check of the address information; When receiving a signal indicating whether the information and its address information are normal or abnormal, and receiving a signal indicating that it is abnormal Communication device characterized in that a communication interface for stopping the communication function.