JPH0447826A - Master communication control equipment - Google Patents

Abstract

PURPOSE:To prevent a malfunction in respective communication control equipments caused by the generation of abnormality by transmitting control information for instructing the slave communication control equipment to transmit a data indicating the state, and transmitting the initial value data of this slave communication control equipment to all the stations when no response is present thereon even after the lapse of fixed time. CONSTITUTION:Assuming that the abnormality such as power supply interruption is generated in a slave station 22 at a certain time point, any data is not transmitted from the slave station 22 because of the abnormality generation in the slave station 22 even when control information C2 is transmitted from a master station 1. When the control information C2 is transmitted to the slave station 2, a slave station monitoring function part 16 in the master station 1 counts the time and when any data is not returned even after the lapse of fixed time, it is considered that the abnormality is generated in the slave station 22. An initial value data transmitting function part 17 receiving an abnormality signal from the slave station monitoring function part 16 transits a data including the initial value data of the slave station 22 onto a communication medium L in place of the slave station 22. The respective stations receiving this data hold it on the mapping of a storing function part as the latest data of the slave station 22.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention provides a communication system in which at least two or more child communication control devices are installed in a communication medium, and a parent communication device that manages and controls these child communication control devices. Regarding the control device, specifically, the present invention is intended to improve the operation of a parent communication control device when an abnormality is detected in a child communication control device.

<Prior art> For example, when exchanging contact information between multiple programmable controllers, one parent communication control device is determined as a communication means, and several child communication control devices are controlled via a communication medium. Build a communication system such as installing equipment. That is, each communication control device sequentially sends out data representing the state of its own device onto the communication medium at regular intervals, and all other devices receive this data. Then, each device stores and updates these data as a mapping on its internal storage device, and
Cyclic transmission is used to refer to this storage device when necessary.

In such a system, since the data on the mapping is always updated to the latest data, there is no need to confirm data delivery on the communication medium, and it is possible to increase the speed of communication and simplify the communication protocol.

<Problems to be Solved by the Invention> However, in the above-mentioned system, once an abnormality occurs in a certain communication control device and data transmission from that device stops, the storage devices in other communication control devices The data corresponding to the faulty device is retained at the value immediately before the fault occurred, making it impossible to detect the fault in the faulty device.
Otherwise, there were problems such as other devices malfunctioning due to old data.

As a method to solve such problems, each communication control device monitors each data update time on the internal storage device, and if the data is not updated within a predetermined time, this data is set to the initial value. However, in such a method, the data update interval must be monitored for each data item or each communication control device, which is difficult to implement when there are a large number of communication stations.

The present invention aims to solve the above problems,
The purpose is to promptly detect an abnormality in a child communication control device in a parent communication control device, and to prevent malfunctions of each communication control device due to the occurrence of an abnormality.

Means for Solving the Problems> The present invention, which has solved the above problems, is a device that is connected to a communication medium,
In a parent communication control device that manages and controls at least two child communication control devices each having a storage function section that stores status data of other communication control devices sent out on this communication medium as a mapping, each of the child communication control devices a control information sending function unit that sends control information to the communication medium instructing the device to send data representing the state of the child communication control device; and a control information sending function unit that sends the control information to the child communication control device; A child communication control device monitoring function unit that monitors the time until the child communication control device sends data representing its state and determines that the child communication control device is abnormal after a certain period of time has elapsed; and a child communication control device monitoring function unit that detects an abnormality in the child communication control device. The parent communication control device is characterized in that it has an initial value data sending function unit that sends initial value data corresponding to the child communication control device when the child communication control device performs the initial value data.

Effect〉 The operation of the parent communication control device of the present invention is as follows.

Sends control information that instructs the child communication control device to send data representing the status, and if there is no response even after a certain period of time has elapsed after outputting this control information, the child device is considered to be abnormal, and this child communication control device is Sends the initial value data of the control device to all stations.

<Example> Hereinafter, an example of the parent communication control device of the present invention will be described using the drawings.

For example, as shown in FIG. 2, the parent communication control device of the present invention includes one parent communication control device 1 and a plurality of (three in this example) child communication control devices 21, 22, 23, as shown in FIG. It manages and controls communication systems such as those installed.

FIG. 1 is a block diagram showing the configuration of a parent communication control device of the present invention.

In this figure, a master communication control device 1 of the present invention is connected to a communication medium through a transmission function section 11 and a reception function section 12 that transmit and receive signals, and has a microprocessor and the like, and has a unique function unique to this device. A functional section 13 is provided.

Furthermore, the parent communication control device 1 of the present invention includes a storage function section 14, which holds the states of other child communication control devices received by the reception function section 12 as a mapping, and reads them out to the specific function section 13 as needed. A control information sending function unit 15 sends control information instructing the control device to send data to the communication medium via the sending function unit 11, and monitors and keeps the time from sending the control information until the data is returned to a constant value. When data is not sent even after a period of time, the corresponding slave communication control device is considered to be abnormal.Slave station monitoring function unit 16. Initial value data of the slave communication control device that is determined to be abnormal based on instructions from the slave station monitoring function unit 16. It has an initial value data sending function part 17 which sends the data to a communication medium via the sending function part 11.

Next, the operation when the parent communication control device of the present invention configured as described above is used in a communication system as shown in FIG. 2 will be explained using the time chart shown in FIG. 3. Note that for the sake of simplicity, the communication control device will be simply referred to as a station below.

First, the master station 1 transmits control information C1 from the control information transmitting function section 15 to the slave station 21 to instruct the slave station 21 to transmit status data. The slave station 21 that has received this control information C1 transmits data D1 representing the status of the slave station 21 onto the communication medium.

Each of the stations 1, 22, and 23 that received the data 01 retains this data on its internal storage function section, and uses this as a mapping of the state of the slave station 21.

Then, the master station 1 sequentially sends the control information C2, C3 to the slave stations 22.23 as well, and in response, the slave stations 22.23 transmit the data D2. Send D3. As a result, the status data of all other stations is stored as a mapping in the storage function section within each station.

Control information is sent to the slave stations for all three stations,
When the data transmission of the slave station completes one cycle, the master station 1 again transmits the control information C1 to the slave station 1, and in response, the slave station 21 transmits the data D1 over the communication medium. Thereafter, control information transmission from the master station 1 and data transmission from the slave stations are repeated in the same manner, and the mapping in the storage function section of each station is updated to the latest data.

Here, it is assumed that an abnormality such as a power cut occurs in the slave station 22 at a certain time point p.

Due to the occurrence of an abnormality in the slave station 22, data is not transmitted from the slave station 22 even if the control information C2 is transmitted from the master station 1.

The slave station monitoring function unit 16 in the master station 1 counts the time at the time when the control information C2 is sent to the slave station 22, and calculates - a fixed time T.
If no data is returned even after the elapse of time, it is assumed that an abnormality has occurred in the slave station 22.

The initial value data sending function section 17 that receives the abnormality signal from the slave station monitoring function section 16 transmits data D2'' containing the initial value data of the slave station 22 instead of the slave station 22 over the communication medium.This data Each station that receives D2'' holds it in the mapping of the storage function unit as the latest data of the slave station 22.

This allows each station to detect abnormalities in the slave station 22 and prevent malfunctions due to old data in the slave station 22.

As described above, the communication system having the parent communication control device of the present invention can detect abnormalities in the child communication control device and can prevent malfunctions of the system.

<Effects of the Invention> As described above, according to the parent communication control device of the present invention,
Obtain the following effects.

When an abnormality occurs in a child communication control device, the corresponding data in the storage function section in each communication control device is updated to initial value data, so each communication control device can detect the occurrence of the abnormality. Furthermore, it is possible to prevent past data from continuing to be held on the mapping, and malfunctions due to old data can be prevented.

Furthermore, the parent communication control device of the present invention can be realized without adding any special functions to other communication control devices in the communication system.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of the configuration of a parent communication control device implementing the present invention, FIG. 2 is a diagram showing a communication system in which the device of the present invention is installed, and FIG. 3 is an operation of the communication system in which the device of the present invention is installed. It is a time chart showing. 1... Parent communication control device, 11... Transmission function section, 12
...reception function section, 13..specific function section, 14.
...Storage function section, 15...Control information sending function section,
16...Slave station monitoring function unit, 17...Initial value data sending function unit, L...Communication medium, 21, 22.23...Slave station. Figure Figure - + N G-r~ ~ N Snow hM')t-h

Claims (1)

[Claims] (1) Parent communication control that manages and controls at least two child communication control devices that are connected to a communication medium and have a storage function unit that stores state data of other communication control devices sent onto this communication medium as a mapping. In the device, a control information sending function unit that sends control information to the communication medium instructing each of the child communication control devices to send data representing the state of the child communication control device; and the child communication control device a child communication control device monitoring function unit that monitors the time from when the child communication control device sends the control information to when the child communication control device sends data representing its state, and determines that the child communication control device is abnormal after a certain period of time has elapsed; A parent communication control device comprising: an initial value data sending function unit that sends initial value data corresponding to the child communication control device when an abnormality in the child communication control device is detected.