JPH08249258A - Communication controller among computrs - Google Patents

Abstract

PURPOSE: To distinguish a state where a communication route is detached from a state where the power supply to a computer is cut. CONSTITUTION: This controller is provided with the communication route 30 connected through a first connector 35 to one computer A, connected through a second connector 36 to the other computer B and provided with a communication signal line 31 connected to the transmission/reception circuits 11 and 21 of the respective computers and a communication signal feedback line 32 for supplying the reference potential of the communication signal line 31, monitoring signal terminals 15 and 25 respectively provided in the computers and connected through a resistor R to the power supply voltage Vcc of the present computer and grounded terminals 16 and 26 for supplying the reference potential of the present computer. Then, the communication route 30 is provided with monitoring signal lines 37 and 38 for which the monitoring signal terminal of one and the grounded terminal of the other are mutually cross-connected and the respective computers are provided with connection state discrimination circuits 12 and 22 for inputting the potential of the monitoring signal terminal of the present computer. It is judged as normal when the potential of the monitoring signal terminal is '0', and it is judged that the communication route 30 is cut off when it is '1'.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a communication control device between computers having a one-to-one communication path, and more particularly to an improvement capable of simultaneously detecting disconnection of the communication path regardless of the power states of both computers.

[0002]

2. Description of the Related Art In a computer, as disclosed in Japanese Patent Application Laid-Open No. 4-137165 proposed by the present applicant, a plurality of computers are connected by using a communication path such as a bus. There is. In that case, since a disconnection or a short circuit is likely to occur in the communication path, the wiring inspection device disclosed in Japanese Patent Laid-Open No. 62-9276 proposed by the present applicant is used. However, since such a general-purpose inspection apparatus is expensive and the inspection efficiency is not good, the following method is used.

2A and 2B are block diagrams showing a conventional connection state inspection of a communication path. FIG. 2A shows a state in which computers AB are connected by a communication path, and FIG. 2B shows a state in which the communication path is removed. In the figure, a communication path 30 is a computer A
A connector 35 connected to the computer B and a connector 36 connected to the computer B are provided at both ends. The connector 35 is
It has a communication terminal 13, a common terminal 14, a supervisory signal terminal 15, and a ground terminal 16. The connector 36 has a communication terminal 23, a common terminal 24, a monitor signal terminal 25, and a ground terminal 26. Communication signal line 31 is communication terminal 1
Transmitter / receiver circuit 1 of each computer A, B via 3, 23
It is connected to 1 and 21 and transmits H and L logic signals. The communication signal feedback line 32 is grounded by the common terminals 14 and 24, and determines the reference of the potential transmitted through the communication signal line 31. The monitor signal terminals 15 and 25 are connected to the power supply voltage Vcc through the resistor R, and the ground terminal 1
6, 26 are grounded. The short-circuit wires 18 and 28 short-circuit the monitor signal terminals 15 and 25 and the ground terminals 16 and 26 inside the connectors 35 and 36. Connection status determination circuit 1
2.22 determines the normality / abnormality of the signal path based on the potentials of the monitor signal terminals 15 and 25.

The operation of the apparatus thus configured will be described. When the computers AB are connected to each other via the communication path 30, the connection state determination circuit 12.22 outputs a logic "0" to indicate that the communication path 30 is normal. On the other hand, assume that the communication path 30 is connected to the computer A by the connector 35, but the connector 36 is detached and disconnected from the computer B. Then, the connection state determination circuit 22 outputs a logic "1" to detect that the communication path 30 has been disconnected, but the connection state determination circuit 12 outputs a logic "0" and the communication path 30 is normal. Will output a false signal. This is because the failure mode in which one of the connectors 35 remains connected is not taken into consideration.

Therefore, a configuration for inspecting the connection state of another communication path shown in FIG. 3 is adopted. Here, FIG. 3 (A)
Is a state in which computers AB are connected by a communication path,
(B) shows a state in which the communication path is removed, and (C) shows a case where the computer A is powered off. Here, the communication path 30 is provided with monitoring signal lines 33 and 34 in addition to the communication signal line 31 and the communication signal feedback line 32. Connector 3
5 is a communication terminal 13, a common terminal 14, a supervisory signal terminal 1
5 and a discrimination terminal 17. The connector 36 is
It has a communication terminal 23, a common terminal 24, a supervisory signal terminal 25 and a discrimination terminal 27. The determination terminals 17 and 27 are connected to the input terminals for determining the connection state of the connection state determination circuits 12 and 22, respectively. The supervisory signal line 33 connects the supervisory signal terminal 15 and the discrimination terminal 27, and transmits the power supply voltage Vcc on the computer A side to the connection state discrimination circuit 22. The supervisory signal line 34 connects the supervisory signal terminal 25 and the discrimination terminal 17, and transmits the power supply voltage Vcc on the computer B side to the connection state discrimination circuit 12.

The operation of the apparatus thus configured will be described. When the computers AB are connected by the communication path 30, the connection state determination circuit 12.22 outputs a logic "1" to indicate that the communication path 30 is normal. On the other hand, in the state where the communication path 30 is connected to the computer A by the connector 35, but the connector 36 is detached and disconnected from the computer B, all the connection state determination circuits 12.22 are logic "0". Is output to indicate that the communication path 30 is abnormal.

[0007]

However, in the case of the conventional method shown in FIG. 3, even when the power of the computer A is cut off, each of the connection state determination circuits 12.22 outputs a logic "0" and both There was a problem that the failure modes of could not be distinguished. The present invention solves such a problem, and an object of the present invention is to provide a communication control device between computers capable of distinguishing between a state where a communication path is removed and a case where the computer is powered off.

[0008]

According to the present invention, which achieves the above object, a computer A on one side is connected via a first connector 35, and a computer B on the other side is connected via a second connector 36. In addition, a communication path 30 having a communication signal line 31 connected to the transmission / reception circuits 11 and 21 of each computer and a communication signal feedback line 32 for giving a reference potential of the communication signal line, and a communication path 30 provided in each of the computers. , A communication control device between computers having monitor signal terminals 15 and 25 connected to a power supply voltage Vcc of the own device through a resistor R, and ground terminals 16 and 26 for providing a reference potential of the own device, in the communication path. To the first monitor signal line 37 for connecting the monitor signal terminal of one computer to the ground terminal of the other computer, and the monitor signal terminal of the other computer. The second monitor signal line 38 for connecting the ground terminal of the computer is provided, and the connection state determination circuits 12 and 22 for inputting the potential of the monitor signal terminal of the own machine are provided in the computer, respectively. It is characterized in that if the potential is “0”, it is determined to be normal, and if the potential is “1”, it is determined that the communication path is disconnected.

[0009]

According to the structure of the present invention, when the two computers are connected by the communication path, the monitor signal terminal of the own machine is connected to the ground terminal of the other machine through the monitor signal line. You can see that it is connected. On the other hand, when the communication path is disconnected between the two computers, the monitor signal terminal of the own machine is opened and the power supply voltage of the own machine appears, so that the disconnection can be detected. If the power of one computer is cut off, the potential of the monitor signal terminal of its own computer in the connection state determination circuit of the other computer becomes "0", and the communication path is disconnected between both computers. The potential is different from the case.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings. FIG.
1A and 1B are configuration diagrams for inspecting a connection state of a communication path according to an embodiment of the present invention. FIG. 1A shows a state in which computers AB are connected by a communication path, and FIG. 1B shows a state in which the communication path is removed. . Incidentally, in FIG. 1, the elements having the same functions as those in FIG. 2 and FIG. In the figure, the connector 35 includes a communication terminal 13 and a common terminal 1.
4. It has a monitor signal terminal 15 and a ground terminal 16. The connector 36 includes a communication terminal 23, a common terminal 24,
It has a monitor signal terminal 25 and a ground terminal 26. In addition to the communication signal line 31 and the communication signal return line 32, the communication path 30 is provided with monitoring signal lines 37 and 38.

The monitor signal line 37 connects the monitor signal terminal 15 and the ground terminal 26, and the power supply voltage Vcc on the computer A side is grounded on the computer B side. The supervisory signal line 38 connects the supervisory signal terminal 25 and the ground terminal 16 so that the power supply voltage Vcc on the computer B side is grounded on the computer A side. Connection state determination circuit 12,
Reference numeral 22 inputs the potentials of the monitor signal terminals 15 and 25 to detect the connection state of the communication path 30 to the computers A and B.

The operation of the thus constructed device will be described below. In the state where the computers AB are connected by the communication path 30, the connection state determination circuit 12.22 is logical
0 "is output to indicate that the communication path 30 is normal. On the other hand, the communication path 30 is connected to the computer A by the connector 35, but the connector 36 is detached and disconnected from the computer B. In the state of
Each of the connection state determination circuits 12.22 outputs logic "1" to indicate that the communication path 30 is disconnected. Furthermore, even when the power of one computer A is cut off,
Each of the connection state determination circuits 12.22 outputs a logic "0", indicating that the communication path 30 is disconnected. Therefore, it is possible to distinguish between the power interruption and the state in which the communication path 30 is separated.

[0013]

As described above, according to the present invention, the supervisory signal line for connecting one supervisory signal terminal and the other ground terminal to each other in the communication path 30 connecting the computers A and B to each other is provided. 37 and 38 are provided, and the connection state determination circuits 12 and 22 input the potential of the monitor signal terminal of the own machine, so that the state in which the communication path is disconnected from the computer and the state in which the other computer is powered off are distinguished and determined. It is possible to use it for communication control.

[Brief description of drawings]

FIG. 1 is a configuration diagram for inspecting a connection state of a communication path according to an embodiment of the present invention.

FIG. 2 is a configuration diagram for performing connection state inspection of a conventional communication path.

FIG. 3 is a configuration diagram for performing connection state inspection of another conventional communication path.

[Explanation of symbols]

 11 Transmitter / Receiver Circuit 12 Connection State Discrimination Circuit 30 Communication Path (Cable) 31 Communication Signal Line 32 Communication Signal Feedback Line 35 Connector 37 Monitoring Signal Line

Claims (1)

[Claims] 1. A computer (A) on one side is connected via a first connector (35), and a computer (B) on the other side is connected via a second connector (36). A communication path (30) having a communication signal line (31) connected to the transmission / reception circuits (11, 21) and a communication signal feedback line (32) for giving a reference potential of the communication signal line, and provided in the computer respectively. A computer having a monitor signal terminal (15, 25) connected to the power supply voltage (Vcc) of the own machine via a resistor (R) and a ground terminal (16, 26) for giving a reference potential of the own machine. A communication control device between the first and second monitoring signal lines (37) for connecting a monitoring signal terminal of one computer and a ground terminal of the other computer to the communication path, and a monitoring signal end of the other computer. A second monitor signal line (38) for connecting the child and the ground terminal of one computer is provided, and a connection state determination circuit (12, 22) for inputting the potential of the monitor signal terminal of the own machine is provided to each of the computers. A communication control device between computers, which is provided and determines that the potential of the monitor signal terminal is "0" when it is normal, and that it is "1" when the communication path is disconnected.