JPS6238053A - Connection system for loop bus control system - Google Patents

Abstract

PURPOSE:To preclude the possibility of increase in the hardware of each slave station by designing the system that a return terminal has only to be added to a slave station in extending or decreasing number of slave stations so as to eliminate the need for the provision of a special circuit. CONSTITUTION:In extending a slave station S4 at the post-stage of a slave station S3, a cable b4 to be connected to the slave station S3 and a return cable a4 arranged nearly in parallel with it are installed and a route loopback cable of the lowest-order is the same as a return cable (c) used for the slave station S3. That is, a terminal for return is added to each slave station, then a return loop data reaches a master station through each slave station sequentially. Thus, the forward cable and the return cable pass the same route.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a cable connection method in a loop bus control system.

(Conventional technology) FIG. 2 shows the configuration of a conventional loop bus control system.

In the figure, M indicates a master station, and Sl and S2 to So indicate slave stations. Also, the cable from master station M to slave station S1 is bl, the cable from slave station S1 to slave station S2 is b2, and the cable from slave station S, -1 to slave station 8 is
The cable to Sn is represented by bo, and the return cables from the slave station to the master station are represented by al and a2 to a, respectively. The loop bus interface section of the slave station S in this case will be explained using FIG. 3.

Third, in the figure, RxD is the master station or upper slave station S, -1
, TxD is the data output terminal of the loop bus to the lower slave station S The return output terminal of the return loop bus to 5IIl-1, SWO is the return output terminal TxR
SWI is the data output terminal Tx.
A data changeover switch to D is shown.

When the slave station Sl is at the lowest position and 4 (m<n), the switching switch SWO sends the data from the return input terminal RxR to the return output terminal TxR, and the changeover switch SW1 sends the output data to the data output terminal TxD. Set to send. Further, when the slave station 5IIl is at the lowest position (m=n), the changeover switches SWO and SW1 are set to send the output data to the return output terminal TxR.

(Problem to be Solved by the Invention) Therefore, in the conventional loop bus control system, in order to increase or reduce the number of slave stations, all the slave stations are equipped with changeover switches swo and s.
It is necessary to provide a switching means such as Wi, which not only increases the cost of the slave stations but also complicates the work when adding or reducing the number of slave stations.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems and to provide a connection method for a loop bus control system that allows easy addition or reduction of slave stations with a small amount of hardware.

(Means for Solving the Problems) In order to solve the above-mentioned problems, the present invention provides a slave station equipped with a data input terminal from a master station or a higher-level station and a data output terminal to a lower-level station. In a connection method of a loop bus control system in which a loop bus is connected to form a loop-shaped bus, at least one of the slave stations that is planned to be added or reduced is provided with a return bus that is bypass-connected within the slave station. An input terminal and a return output terminal are provided, and a loop going from the master station or higher-level station to the lower-level station is formed by connecting the data output terminal to the data input terminal of the lower-level station, and the data output terminal of the lowest-level slave station is connected to the lower station. A loop from the lower station to the upper station or the master station is formed by connecting the return output terminal to the return input terminal of the upper station or the input terminal of the master station. I did it.

(Function) According to the present invention, when expanding, the data output terminal of the lowest slave station is connected to the data input terminal of the added slave station, and the return input terminal is connected to the return output terminal of the added slave station. However, on the added slave station side, this is done by connecting the data output terminal and return input terminal, and when reducing, the data output terminal and return input terminal of the slave station one level higher than the lowest This is done by disconnecting the data input terminal and return output terminal of the slave station, and connecting the data output terminal and return input terminal.

(Embodiment) FIG. 1 shows an embodiment of the loop bus control system of the present invention, and in the figure, the same components as in the conventional example are denoted by the same symbols. That is, M is a master station, and Sl is a master station.

82~So are slave stations, a 1.82~a n are cables,
b, b, . . . -bo are return cables, and C is a return cable.

In such a loop bus control system, slave station S
When adding a slave station S4 to the subsequent stage, as shown in Figure 4(a),
As shown in (b), a cable b4 for connecting to the slave station S3 and a return cable a4 arranged approximately in parallel with this are installed, and the lowest route return cable is used for the slave station S3. You can use the same return cable C that you used.

Next, the loop bus interface section of the m-th slave station 5IIl will be explained with reference to FIG.

In FIG. 5, RxD is the master station or upper slave station 5Il-1
TXD is the data output terminal of the loop bus to the lower slave station S, -1, RxR is the input terminal of the return loop bus for sending back to the master station, TxR
indicates the output terminal of the return loop bus to the master station or upper slave station 5ID-1, and the RxR terminal and TxR terminal are bypass-connected.

At the slave station S, the rule coming from the upper slave station 5IIl-1 is
The data is input to the RxD terminal through cable b and drawn into the slave station. The loop data processed within the slave station is sent from the TXD terminal to the lower slave station SIn+1 via the connection cable b to the next station, and is sent to the lower slave station SIn+1. On the other hand, the lube data sent to the lowest slave station becomes return data to the master station M as it is by connecting the TxD terminal and RXR terminal of the lowest slave station with an external cable. As shown in the figure, the signal reaches the master station M via each slave station.

That is, the return data from the lower slave station 5IIl+1 is sent to the return cable ALL! +1 to the RXR terminal, the data is bypassed as it is to the TXR terminal, and is sent from this terminal to the upper station A S m -1 through the cable a connected to the upper station.

By adding a return terminal to each slave station in this manner, the return loop f-1 reaches the master station via each slave station in sequence. Therefore, both the outbound and return cables can be routed through the same route. Further, since the return terminal at the lowest level can be used with an external cable, it can be realized without adding the above-mentioned switching circuit or the like.

Therefore, when installing cables, it is only necessary to consider only the connection method with adjacent slave stations, without complicating the configuration of the slave stations due to the installation or reduction of the jpI of the slave stations. For this reason, not only is there no need to consider cable connection methods with remote master stations and slave stations, but each slave station also serves as a repeater, greatly limiting the line length of the loop bus. It can be extended to

FIG. 6 shows a further embodiment of the present invention.

Here, the first to third slave stations among each slave station are the basic system, and it is impossible to add or reduce the number of slave stations. In this case, no terminal for return is set, The slave station S3 is configured to return directly to the master station M, and a return input terminal and an output terminal are provided after the slave station S3, which may be expanded or reduced by options, etc., and the cable a4. Even if b4 is installed, the same effect as in the above embodiment can be obtained.

(Effects of the Invention) As explained above, according to the present invention, it is not necessary to provide a special circuit in the slave station by adding a return terminal to the slave station. There is no risk of increasing the amount of hardware at the station, cables can be installed easily, and it can be used in systems using optical buses that require special processing on the cables, such as optical loop buses. There are advantages.

[Brief Description of the Drawings] Fig. 1 is a block diagram showing an embodiment of a loop bus control system to which the method of the present invention is applied, Fig. 2 is a block diagram of a conventional loop bus control system, and Fig. 3 is a block diagram of a conventional loop bus control system. A configuration diagram showing a loop bus interface section, FIGS. 4(a) and 4(b) are diagrams showing a method for adding slave stations according to the present invention, and FIG. 5 shows a loop bus interface section according to the present invention. Diagram,
FIG. 6 is a diagram showing another embodiment of the loop bus control system of the present invention. M-...Master station, S, S2~So...Slave station, al. a2~a n...Return loop bus cable, bl
, b2-bn...Loop bus cable, C...Return cable of lowest slave station, RxD...Loop bus data input terminal from master station or upper slave station, TxD...
Loop bus data output terminal to lower station, RXR... Input terminal of return loop bus for sending back to master station, TxR
is the output terminal of the return loop bus to the master station or higher-level slave station. Patent Applicant Oki Electric Industry Co., Ltd. Representative Patent Attorney Yoshi EB Seiko M-Rakusu, % C sheer pull duck, b2 ~ brl garble conventional root tow S quasi 1 young P system system ω configuration diagram Q 71
Figure 3 shows the loop bus interface building in Shibarai.
Figure shows the loop nose interface of the present invention.

Claims (1)

[Claims] Loop bus control in which slave stations each having a data input terminal from a master station or a higher-level station and a data output terminal to a lower-level station are connected to the master station to form a loop-shaped bus. In the system connection method, at least one of the slave stations that is planned to be expanded or reduced is provided with a return input terminal and a return output terminal that are bypass-connected within the slave station, and a lower station than a master station or a higher-level station A loop going to the lower station is formed by connecting the data output terminal to the data input terminal of the lower station, and at the lowest slave station, the loop is looped by connecting the data output terminal to the return input terminal. Alternatively, a connection method for a loop bus control system, characterized in that a loop directed to a master station is formed by connecting the return output terminal to a return input terminal of a higher-level station or an input terminal of a master station.