JPS5817750A - Data collection system - Google Patents

Abstract

PURPOSE:To collect data at all terminals to a central device efficiently, by constituting a group of a terminal group and the central device which can make transmission and reception mutually to the terminal impossible of direct transmission and reception with the central device, and transferring data between terminals in the group or the central device and the terminal. CONSTITUTION:Communication with a weak radio wave can be made between terminals 1, 2, 5, 6 and 8 and a central device C, but such communication to be held directly is impossible between terminals 2, 3 and 7 and the device C. As to the terminal 2 which can not directly communicate, data is transferred to the device C via the terminal 2, as to the terminal 3, via the terminals 1 and 2, and as to the terminal 7, via the terminal 6. All the terminals are distinguished into groups ofI-V depending on the difference of the propagation path. All the terminal data can be collected by repetitively designating the terminals 1, 2, 5, 6 and 8 from the device C.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a data collection system that uses weak radio waves to intensively collect data from terminal devices into a solid device.

Compared to wired transmission, wireless transmission is relatively inexpensive because it does not require wiring costs, but the range of the radio waves is short in the case of weak radio waves that do not violate laws and regulations.・Relayers are often installed in the middle of terminals where weak radio waves cannot reach them, but in addition to having to install a new one, frequency conversion is also required to prevent normal relaying from occurring due to interference. There is a need.

The present invention (↓) If there is at least one terminal to which weak radio waves can reach without relaying to a certain terminal, that terminal is used as a data relay point, and the frequency of the radio waves used is One type is sufficient. This method makes it possible to reduce the manufacturing cost of equipment by making the control procedures common for each terminal. Also, as a special case, when each terminal and solid equipment can communicate directly, However, it also has the advantage that it can be used without changing the control procedure.

Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

FIG. 1 shows the arrangement of a solid device C and a plurality of terminal devices B. In FIG. Communication between terminals 1, 4, 5, 6.8 in the figure and solid device C is possible using weak radio waves, whereas communication between terminal 2.8.7 and solid device C is possible. This represents a situation where direct communication using weak radio waves is impossible. In this embodiment, data is sequentially transferred to the solid device C via terminal 1 for terminal 2, which cannot communicate directly, via terminals 2 and 1 for terminal 3, and terminal 6 for terminal 7. Take. Based on the differences in intermediate stops, all terminals are divided into groups IV as shown in the figure. Solid device C collects all terminal data by repeatedly specifying terminals 1, 4, 5, 6.8. The specific procedure will be explained below, taking Group ■ as an example.

For other groups, the same procedure as for group ■ may be followed.

Figure 2 (6), (0, ■) shows the control procedure of the solid device C and the terminal devices 1, 2.8 in group ■, respectively. A simple example is the one shown in Figure 3. In this format, the most significant bit distinguishes between address and data. In the example, "0" is an address and "1" is data. The data sent from a certain terminal matches the address of a certain terminal, and works to prevent radio waves from being transmitted from multiple terminals at the same time.The next pin 1-EO5 of the address is a solid After device C specifies terminal summer,
Solid device C-terminal 1. Terminal 1 - Terminal 2゜Terminal 2 - Terminal 3
This indicates whether the data has been shifted once in the order of
-2-1- - Notify solid device C that one shift has been completed by sending the message back to the solid device, and then solid device C specifies terminal 1 (or the first terminal of another group) It gives you the timing to do so. The next bit (P) END of the data indicates whether the data belongs to the last terminal in the group. When data with this bit set is received, the data is sent to all the terminals in the group. It notifies you that data collection is complete and gives you the timing to start collecting data for the next group.

Assuming that the number of address and data bits is 8, the solid device C first sends an address (code=φI
H) is sent. Terminal 1 receives it and transmits the terminal 1 data. Only solid device C receives this data. Since this data is not the data of the last terminal, terminal 1 receives the address (code -φ2) that specifies terminal 2.
H) and waits for data reception from terminal 2. At this time, the solid device C is waiting to receive a one-time shift completion code (hereinafter referred to as an EOS code with address) 4φH.

On the other hand, terminal 2, which has received the address designation from terminal 1 and has finished transmitting data, sends an address (code =
φ8H) and receives data. After transmitting the data, terminal 3 does not transmit the address specifying the next terminal because the data is the data of the last terminal.
Send EOS code (4αH) with address α. Terminal 2 receives this, and thereafter the EOS code with address is sequentially sent to terminal 2, terminal l, and solid device C. After that, solid device C transmits the address specifying terminal 1 again.

Then, by performing the same steps as above,
Data of terminal 2 is transferred to solid device C via terminal 1, and data of terminal 3 is transferred to solid device C via terminals 2 and 1. Finally, the solid device C that received the EOs code with address φ (code -4φH) transfers control to the next group, collects data for each other group using the same procedure, and completes the collection of all terminal data. .

Note that if no data is received or an error occurs in the received data despite specifying a certain terminal and transmitting an address, appropriate recovery procedures must be taken. One method is to repeat address retransmission an appropriate number of times, and if a large amount of data is not received as a result, data collection within that group is temporarily suspended and data collection for the next group is started. After the remaining data collection is completed, data collection for the interrupted group may be resumed.

As can be seen from the control procedure in FIG. 2, the advantage of the present invention is that the control procedure for each terminal other than the last terminal is, for example, (B).
, (C), etc., and for example, (D), as long as the terminal has one bit of information indicating that it is located at the end of the group, it is the same as other terminals. This means that it can be treated as follows. Furthermore, as can be easily understood, when the total number of terminals is constant, the greater the number of terminals included in one group, the slower the data transfer speed to the solid device. Therefore, it is necessary to reduce the number of terminals in one group as much as possible, but a special case in which all terminals and solid devices can communicate directly can be handled without changing the control procedure.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the arrangement of a solid device and a terminal device in an embodiment of the present invention, and FIG.
[)1 is a flowchart showing the control procedure of the solid device in Fig. 1 and the terminal 1゜2.8 in group ■, respectively;
The figure shows the code format of addresses and data. C...solid device, B...terminal device, ■~V...group. (A) Sugur-2＼ (D) (B) (C) Fig. 2

Claims (1)

[Claims] 1. In a method that centrally transfers data from terminal devices to a solid device, for terminals that cannot directly send and receive data to and from the solid device, a group is created between the terminals that can send and receive data to and from the solid device, and the solid device. All terminals execute common control procedures, transfer data between terminals within a group, or between a solid device and a terminal, and finally centralize data from all terminals to the solid device. A data collection system characterized by: