JPS6362928B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a communication monitoring device, and more specifically, the present invention is configured to transmit a response from a lower CPU to a higher CPU only when a command is transmitted from a higher CPU to a lower CPU. The present invention provides a device effective for monitoring abnormal communication conditions in an asynchronous communication system.

One type of communication method between a higher CPU and a lower CPU is an asynchronous communication system that is configured to transmit a response from the lower CPU to the higher CPU only when an instruction is transmitted from the higher CPU to the lower CPU. be.

FIG. 1 is a conceptual configuration diagram of such a system, in which 10 is an upper CPU and 20 is a lower CPU. An instruction is transmitted from the upper CPU 10 to the lower CPU 20, and a response is transmitted from the lower CPU 20 to the upper CPU 10. Focusing on the transmission state in such a system, in a normal operating state, commands and responses are transmitted alternately, but in an abnormal operating state, only commands or only responses are transmitted consecutively.

Conventionally, in order to monitor the transmission status in such a system, a memory is provided to store all transmitted data, and a device is used to trace this data or to monitor or check the transmitted data. was being connected to the transmission line.

However, such conventional methods require a relatively large capacity memory and a separate device for connecting to the transmission line, resulting in a complex configuration and high cost. There was a drawback.

The present invention solves these conventional drawbacks, and is suitable for use as a device for monitoring abnormal communication conditions in the above-mentioned asynchronous communication system.
A first memory that sequentially stores at least command and response communication procedures among the information transmitted between the CPU and the lower CPU; Communication monitoring is performed by combining an abnormality detection circuit that detects an abnormality in the alternating transmission, and a second memory that sequentially stores the communication procedure indicating the abnormality in the alternating transmission read out from the first memory according to the abnormality detection signal. The device is characterized by comprising:

Hereinafter, it will be explained in detail using the drawings.

FIG. 2 is a block diagram of the essential parts of an embodiment of a system using a communication monitoring device according to the present invention, and shows an example in which a measurement system is configured by an upper CPU 10 and a lower CPU 20.

In FIG. 2, 30 is a communication monitoring device according to the present invention, and 40 is a measuring section controlled by the lower CPU 20. The communication monitoring device 30 is connected to the upper CPU 1
A first memory 31 that sequentially stores at least command and response communication procedures among the information transmitted between the CPU 0 and the lower CPU 20;
Consisting of an abnormality detection circuit 32 that detects an abnormal state of alternating transmission with the CPU 20, and a second memory 33 that reads communication procedures indicating an abnormality of alternate transmission from a first memory and sequentially stores them in accordance with an abnormality detection signal. has been done.

The operation of the system configured in this way will be explained.

When communicating between the upper CPU 10 and the lower CPU 20, the upper CPU 10 and the lower CPU 20 are
The CPU 10 is given the initiative. Upper CPU1
0 data transmission request command, the lower CPU 20
responds by sending data. If the lower CPU 20 cannot understand an instruction from the upper CPU 10, the lower CPU 20 responds to that effect to the higher CPU 10.
Further, in response to a setting command from the upper CPU 10, the lower CPU 20 responds to the upper CPU 10 to inform whether the setting has been correctly performed. i.e. upper CPU
Only when an instruction from 10 is received, the lower CPU
20 is configured to respond. On the other hand, when focusing on the operation of the communication monitoring device 30, the lower CPU
20 receives a command from the upper CPU 10 and sends communication procedure information indicating that the command has been received from the upper CPU 10 to the first memory 31 .
Then, it executes an operation according to the command, and when the operation is completed, it sends communication procedure information indicating that it has responded to the command to the first memory 31. As a result, the first memory 31 has the upper CPU 1
0 and the lower CPU 20, communication procedure information representing a command and a response is stored alternately and sequentially, and if an abnormality occurs in the alternate transmission, communication procedure information representing a command or a response is stored. Communication procedure information will be stored one after another, and its arrangement will change. In other words, if two or more commands continue, the upper CPU 10 may have sent the commands consecutively without following the communication procedure, or the lower CPU 20 may
indicates that the CPU did not respond, and if two or more responses continue, the lower CPU 10 does not respond.
This indicates that the CPU 20 has responded to the higher-level CPU 10 in succession. When the abnormality detection circuit 32 detects such a change in the arrangement of the communication procedure information, it reads out the communication procedure information representing the abnormality of these alternate transmissions from the first memory 31 and stores it in the second memory 33 according to the abnormality detection signal. Store sequentially. The second memory 33 is configured to be battery backed up so that information will not be lost even in the event of a power outage, and not to be initialized when the power is turned on.
When the second memory 33 becomes full, it stops writing information and retains its full state until the operator initializes it after printing the stored information or storing it in an external storage device such as a cassette tape. do. This allows the second memory 3
3 can store the information that caused the occurrence of the communication procedure abnormality.

Note that the first memory 31 and the second memory 3
3 includes time information related to each communication procedure, command and response type information, and lower CPU 20 as necessary.
Information indicating the operating mode and status of the lower CPU2
It is possible to store margin information such as 0. Thereby, abnormality analysis of communication procedures as described above can be performed efficiently in a short time. Moreover, by storing each of these pieces of information, it is also possible to store the operating information at that point in time in the second memory 33 by generating a pseudo abnormality detection signal. Note that even if each of these pieces of information is stored, the amount of information to be stored can be significantly reduced compared to the conventional case where all data is stored and traced, and memory can be saved.

Furthermore, depending on the system, a large amount of measurement data sent out from the measuring section 40 may have to be transmitted to the upper CPU 10 via the lower CPU 20. In such a case, the upper CPU1
If a large amount of data is continuously sent as one response from the lower CPU 20 to one command from 0, and the communication monitoring device 30 is configured to monitor only the relationship between these commands and responses. good. Note that if the upper CPU 10 wants to stop data reception, it may issue a data transmission stop command to the lower CPU 20, and the lower CPU 20 may send a response to the higher CPU 10 indicating whether or not the command has been received.

As described above, according to the present invention, it is possible to realize a communication monitoring device that is effective in monitoring abnormal communication conditions in an asynchronous communication system with a relatively small memory configuration, and is particularly effective for monitoring communication abnormalities in a communication system using a microprocessor. suitable for

[Brief explanation of drawings]

FIG. 1 is a conceptual diagram of an asynchronous communication system, and FIG. 2 is a block diagram of essential parts showing an embodiment of a system using a communication monitoring device according to the present invention. 10... Upper CPU, 20... Lower CPU, 30
...Communication monitoring device, 31...First memory, 32
... Abnormality detection circuit, 33 ... Second memory, 40
...Measurement section.

Claims (1)

[Claims] 1. A communication monitoring device that monitors abnormal communication conditions in an asynchronous communication system configured to transmit a response from a lower CPU to a higher CPU only when a command is transmitted from a higher CPU to a lower CPU, which A first memory sequentially stores at least command and response communication procedures among the information transmitted between the upper CPU and the lower CPU based on the communication procedure stored in the first memory.
It consists of an abnormality detection circuit that detects an abnormality in alternating transmission with the CPU, and a second memory that sequentially stores a communication procedure indicating an abnormality in alternating transmission that is read from the first memory in accordance with an abnormality detection signal. A communication monitoring device characterized by: