JPH09312657A - Data transmission device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the reliability of data transmission with simple constitution by making a response to an information request code of a 1st management device, outputting data with an response code to a bus by a transmission device, and making a 2nd management device not request a bus of information. SOLUTION: Analog signal data on temperature, etc., which are inputted to an input device 1 is given a device number unique to the device 1 and sent out to the bus L as output data. Necessary data of data sent through this bus L are inputted to an output device 2 and an arithmetic unit 3. To this bus L, 1st and 2nd management devices 4 and 5 are connected as operation display devices, and when the device 1 is requested of specific information, data that the device 1 has are grasped and displayed on the display devices. This requested information is predetermined as a code indicating priority and when the 2nd management device 5 receives this code, the device quits requesting the transmission device of information for a specific time to prevent the bus L from being congested.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for transmitting data such as a process amount.

[0002]

2. Description of the Related Art Conventionally, as a data transmission method, process data such as temperature collected by a slave station is transmitted by a slave station to a master station via a transmission line in response to a polling signal from the master station. There is a polling method in which after the processing, a polling signal is transmitted to another slave station again.

[0003]

However, in the polling method, the master station is always required and the polling signal is always required, so that the apparatus is complicated, the response takes time, and the communication speed is insufficient. is there.

Further, when many devices are connected to a transmission line, communication is performed between a higher-level device and a specific lower-level device, and when another device attempts to perform information communication, the line communication is congested. Therefore, the reliability of data transmission may be reduced.

In view of the above points, an object of the present invention is to provide a data transmission device having a simple structure and improving the reliability of data transmission of a bus to which the transmission device is connected.

[0006]

According to the present invention, there is provided a transmission device for outputting data having a response code to a bus in response to an information request code of a first management device, and the information request code or response flowing through the bus. The data transmission device is provided with a second management device that does not request information from the bus for a predetermined time when a code is received.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is an explanatory diagram showing the configuration of an embodiment of the present invention. In FIG. 1, for example, an input device 1, an output device 2, an arithmetic device 3, and the like as a transmission device are connected to a bus L such as a common network as a transmission line. The output device 2,..., The arithmetic device 3,. Each of these devices is assigned a device number unique to the device, and data and the like can be transmitted using this device number.

The analog signal data such as temperature input to the input device 1 is subjected to necessary processing such as linearization and the like, and is given a unique device number of the input device 1 and output to the bus L as output data. Is output.

Of the data flowing on the bus L in this way, the output device 2 and the arithmetic device 3 take in the necessary data. For this reason, these capture devices include:
A device number assigned to output data of an input device or the like required by the capture device is set in advance as a capture number depending on which input device or the like needs output data.

For example, assuming that the data of the input device 1 is fetched by the output device 2 and the arithmetic device 3, the output device 2 and the arithmetic device 3 take the same number as the device number "01" of the input device 1 and obtain the input number " 01 ".

The output device 2 matches the input number “01” of the data flowing through the bus L and corresponds to the input device 1.
Only the data with the device number "01" is discriminated and selected, taken in, and output to the outside after predetermined processing.

Further, the arithmetic unit 3 outputs the input device 1 corresponding to the acquisition number “01” of the data flowing through the bus L.
Only the data with the device number “01” is selected, determined and imported. Then, after performing other necessary calculations such as averaging, the unique device number “03” of the arithmetic unit 3 is added to the data.
And output to the bus L.

By the way, to the bus L, management devices 4 and 5 as operation display devices are connected, for example, a certain management device 4
Therefore, it is assumed that a specific information request, for example, a setting data request is made to the input device 1 as the transmission device having the specific device number “01”. In this case, the setting data request code "SD"
And the following message including the device number “01” is output to the bus L.

SD 01 Then, the input device 1 as a transmission device having the corresponding device number “01” receives this setting data request code “SD” and its own device number “01”, and the setting data request is sent to itself. Then, the following data including the response code “SDA”, its own device number “01” and the setting data “X ... Y ...” is transmitted and output to the bus L.

SDA 01 XXXX, YYYYYY, ... Then, the management device 4 receives and takes in the above data information for the device number “01”, grasps the setting data and the like of the input device 1, and displays it on the display means. It can be displayed and recognized by humans.

At this time, the information request code "SD" or the response code "SDA" is preliminarily agreed with the code indicating the priority, and the other management device 5 has the code "SD" or "SDA" having the priority. When it receives the message, it stops requesting information from the transmission device for a predetermined time and prevents the bus L from being congested. Examples of such information requests include a request for setting value information, a request for menu information such as explanations used when listing the contents of each device, and a data display information request for indicating alarm contents.

That is, the other management device 5 does not output data to the bus L for a predetermined time when it receives the information request code or the response code having the priority right flowing through the bus L.
Even in this case, the output device 2, the arithmetic device 3, and the like, which are other transmission devices, transmit and receive data in real time. Then, when the information having the priority right does not exist on the bus L after a predetermined time elapses, the management device 5 restarts the original data transmission / reception.

The output device 2 as another transmission device,
When the arithmetic unit 3 or the like receives the information request code or the response code having the priority flowing through the bus L, it does not output the data to the bus L for a predetermined time to prevent the bus L from being congested. May be.

The other management device 5 is the management device 4
The data output from the transmission device 1 to the bus L in response to the information request can be received and the required data can be taken in, and the management device 5 can maintain the same contents as the management device 4.

[0020]

As described above, according to the present invention, the transmission device for outputting the data having the response code to the bus in response to the information request code of the first management device, and the information request code flowing through the bus. Alternatively, the data transmission device is provided with a second management device that does not request information from the bus for a predetermined time when the response code is received. For this reason, the main station is not required, and the communication speed can be made sufficiently high. From the configuration consisting of a minimum of two devices and a bus, tens or hundreds or more of data and devices can be combined as far as the numbers permit. Can be easily, arbitrarily, and flexibly configured, and can easily and sufficiently cope with various systems, which is rich in flexibility and expandability, and effectively and efficiently. Also, when data is preferentially exchanged between the management device and a specific transmission device, other transmission devices do not output data to the bus, so the bus does not become overcrowded in communication and reliable transmission is possible. It can be carried out quickly, the transmission reliability can be improved,
Extremely user-friendly and easy for anyone to use,
Flexible, flexible, and highly reliable system.

[Brief description of drawings]

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

[Explanation of symbols]

 1 Input device 2 Output device 3 Arithmetic device 4, 5 Management device L bus

Claims (1)

[Claims] 1. A transmission device for outputting data having a response code to a bus in response to an information request code of a first management device, and a bus for a predetermined time when the information request code or response code flowing through the bus is received. And a second management device that does not request information from the data transmission device.