JPS58182341A - Data transmitter - Google Patents

Abstract

PURPOSE:To provide time margin, by collecting data quickly by collecting predetermined data only by master stations, not transferring the data immediately when the transfer request of data exists and transferring the data at the next polling signal. CONSTITUTION:Subordinate stations 21, 22, 23 transmit the content of data TEXT to be changed such as arbitrarily determined measuring and setting values in advance to a master station 1 by each one sequentially at each polling to polling signals P1, P2, P3, P1... from the master station 1. The master station 1 generates an acknowledgement signal ACK when the data of the subordinate stations 21, 22, 23 is received. When the master station 1 desires to read out the data required especially to the specific subordinate station 21, for example, or to write, a transfer request signal or a write request signal P1 is transmitted to the subordinate station 21 for interruption and the subordinate station 21 generates the signal ACK. The slave station 21 answers back the data TEXT according to the next polling signal P1.

Description

DETAILED DESCRIPTION OF THE INVENTION a) Field of the Invention The present invention relates to a data transmission device in which a slave station transmits data in response to a polling signal from a master station.

G) Prior Art As a slave station, there is a calculation device such as a digital controller that collects process variables such as temperature, performs predetermined calculations, and generates control signals and the like. and.

If a slave station must transmit specified data in response to an interrupt signal from the master station, the slave station must simultaneously perform two functions: data collection and calculation, and communication with the master station. First, there were problems in that the burden on slave stations increased and prompt data transmission and data processing were difficult.

G4) Purpose of the Invention In view of one or more points, the purpose of the present invention is to provide a data transmission device that enables rapid and reliable data transmission.

(4) Examples of the invention FIG. 1 is a configuration diagram showing an embodiment of the present invention.

1 is the main station, and 21, 22, and 23 are slave stations consisting of arithmetic devices such as digital controllers that input process quantity commands such as temperature, compare them with set values, and generate predetermined control outputs. and the slave stations 21, 22, and 23 are connected by a transmission line t.

Here, the data that master station 1 wants to collect is
, 23 input values, setting values, and other changing data.

By arbitrarily predetermining some of these and transmitting the data in order in response to polling from the main station 1, necessary data can be collected quickly. Note that the data to be transmitted during polling can be arbitrarily selected, and can be set using the data stored in memory and setting switches.

As shown in FIG. 2, polling signals Pi, P2 . P3. For PI, ..., slave station 21
゜22 and 23 are measured values arbitrarily determined in advance.

The data content TEXT, which changes such as setting values, is sent to the main station IK one by one every polling. When the master station 1 receives the data from the slave stations 21, 22, and 23, it generates an acknowledgment signal ACK.

Next, when the main station 1 wants to read out particularly necessary data from a special table to a specific slave station 21, for example.

Or, if you want to write, do the following:

As shown in FIG. 3, instead of the normal polling signal, the slave station 21 generates an acknowledge signal (ACK). and by the secondary polling signal P1.

The slave station 21 transmits or writes the request data TEXT and packs the data T'EXT f: answer. When the interruption is completed, the process returns to normal operation in 9.

Note that when there are successive write requests from the master station 1, the slave station 21 writes the contents one after another, and answers back only the last written data with the last polling signal.

FIG. 4 shows the main components of the arithmetic unit 21. The first microcombination unit 221 inputs process variables such as temperature, compares them with set values, and generates control outputs. It operates to store the set values and the latest input values in the first memory MIK. The second microcomputer 222 is
While receiving the polling signal P1 from the main station 1, the first! First memory M of microcomputer 221
Only predetermined data from 1 is stored in its own second memory M2K and transmitted.

For example, when a transfer request is received from the main station l, the second microcomputer 222 sends an acknowledgment signal ACK to the outside, and also retrieves the necessary data from the first memory Ml of the first microcomputer 221. This data is stored in the second memory M2 of the main station and transferred to the main station IK in response to the primary polling signal.

However, if you do this, the burden on the subordinate station will be reduced.
It is lighter, faster, and allows the main station to collect the latest data.

(5) Summary of the Invention This invention has nine features: During normal operation, the slave station transmits data arbitrarily determined in advance to be transmitted in response to a polling signal from the master station, and receives data that is particularly required from the master station. This data transmission device is designed to transmit or answer back the requested data at the next time when there is a transfer request or a write request.

(6) Effects of the Invention ■ Since the higher-level main station collects only predetermined data, it is possible to collect data quickly.

■When a data transfer request is made, the data is not transferred immediately but is transferred using the primary polling signal, allowing a one-hour margin, reducing the burden on lower-level slave stations. The latest data can be collected.

■Data writing is confirmed by answerback, so it is accurate.

[Brief explanation of the drawing]

1 and 4 are configuration explanatory diagrams showing one embodiment of the present invention, and FIGS. 2 and 3 are signal diagrams for explaining the operation. 1...Main station, 21, 22.23...Slave station, t...
・Transmission line patent applicant Chino Seisakusho Co., Ltd.

Claims (1)

[Claims] 1. In a data transmission device in which a slave station transmits data in response to a polling signal from a master station, the slave station normally:
In response to a polling signal from the main station, data that is arbitrarily determined to be sent is transmitted, and if there is a request to transfer or write particularly required data from the main station, the requested data is sent at the time of the secondary polling. A data transmission device characterized in that the data transmission device is configured to transmit or answer back. z. The data transmission device according to claim 1, wherein the slave station continuously writes data when there are continuous write requests from the master station.