JPS62178043A - Data communication system - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a one-step synchronization data communication system, and in particular, it is possible to differentiate the type of communication by changing the width of the start-stop synchronization bit (start bit). The present invention relates to a data communication method that performs the following.

[Conventional technology]

Conventionally, communication systems for unmanned transportation systems, etc.
Communication is performed using communication data and communication control commands (hereinafter referred to as commands) for controlling automatic switching of communication lines, automatic retransmission in the event of a communication error, etc. In this case, if there is only one communication path, it is necessary to send communication data and commands through this communication path, and the command is inserted between the communication data, and an identification code is used to identify the communication data and command. It can be attached to both communication data and commands.

[Problem that the invention seeks to solve]

However, the frequency of occurrence of communication data and commands is much higher for communication data (as mentioned above, in the conventional example, an identification code must be added to communication data, so there was a problem that communication efficiency was low.

The present invention has been made in view of the above-mentioned problems, and its purpose is to provide a data communication system with good communication efficiency.

[Means and effects for solving the problem] In order to achieve the above object, the present invention makes the width of the start bit of communication data by the audience step synchronization method different depending on the type of communication, and It is characterized in that the type of communication is determined according to the width of the communication.

〔Example〕

An embodiment of the present invention will be described in detail below based on the drawings.

FIGS. 1(a) and 1(b) are format diagrams of communication data and commands used in this embodiment. As shown in FIG. 1(a), after the stop bit 1 of the communication data, 1.
There is a 5-bit wide start bit 3, after which 1 bit 5 communication data 7 is placed, and after that a stop bit 9 is placed. - Power cylinder 1 As shown in Figure (b), on the command side, there is a 2.5-bit wide start bit 13 after the stop bit 11 of the communication data, and a command 17 is placed after the next 1 bit 15. A stop bit 19 is placed after that. In this way, communication data 7
The start bit 3 of the command is 1.5 bits, and the command 17
The start bit 13 was set to 2.5 bits.

Figure 2 shows the reception method on the receiving side. When it is determined that the start bit width is 1.5 bits wide (step 21), it is assumed that the start bit of the communication data has been detected and the reception of the communication data is started. Start (Step 23)
. If the start bit width is not 1.5 bits, it is determined whether the start bit width is 2.5 bits (
Step 25), if this is 2.5 bits, it is assumed that the start bit of the command has been detected, and command reception is started (step 27).

In this way, in this embodiment, since identification codes are not provided for each communication data and command as in the conventional case, data communication efficiency can be improved.

Furthermore, when several bytes of communication data are communicated as one block, generally several bytes are communicated as one block as shown in FIG. That is, a code 5TX100 (start of text) indicating the beginning of the block is attached to the first byte of the block, and the block is treated as one block until the next STX appears. In this case, as shown in FIG. 3, the width of the start bit 31 of the first byte is 2.5 bits, and the other start bits 33, 35, 37 . By setting . . . to 1.5 bits, the beginning of the block can be indicated without providing STX. As a result, STX, which does not contribute to communication data, can be omitted and communication efficiency can be improved.

〔Effect of the invention〕

As explained in detail above, according to the present invention, efficient communication can be performed by making the width of the start bit of communication data or the width of the start bit of the first block of communication data different from the width of other start bits. can.

[Brief explanation of drawings]

Fig. 1 is a format diagram of communication data and commands according to the first embodiment of the present invention, Fig. 2 is a flowchart of a receiving method, and Fig. 3 is a diagram of communication data when a plurality of blocks are combined into communication data. Format Diagram FIG. 4 is a conventional format diagram of communication data when a plurality of blocks are combined into communication data. 3.13...Start bit, 7...Communication data,
17...Command, 31.33, 35.37...Start bit. Figure 1 Figure 2 +00 Figure 4

Claims (1)

[Scope of Claims] The present invention is characterized in that the width of the start bit of communication data based on the start-stop synchronization method is made different depending on the type of communication, and the type of communication is determined according to the width of the start bit. data communication method.