JPH04268901A - Communication equipment - Google Patents

Abstract

PURPOSE:To attain 1:N communication adopting a computer as a master station without using a converter. CONSTITUTION:A computer provided with only an RS232C interface is used as a master station. Among the master station and plural programmable controllers to be slave stations, 1:N communication is executed. These programmable controllers are respectively provided with RS232C and RS458 interfaces 1, 2. Through one of the programmable controllers, the computer is connected to other programmable controllers to execute 1:N communication.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a communication device that performs 1:N communication between a master station and a plurality of slave stations having interfaces different from that of the master station.

0002

2. Description of the Related Art In programmable controllers that control the operation of load equipment according to user programs, RS458 is used as an interface to enable 1:N communication between programmable controllers.

0003

By the way, in this type of programmable controller, when performing 1:N communication with computer A having only an RS232C interface as the master station, as shown in FIG. It was necessary to provide an RS232C/RS458 converter C between the programmable controller B and the computer A. In addition, in the case of Fig. 6, in order to incorporate programmable controller B which only has an RS232C interface, RS232C/RS4
58 converter C is used. Also, Figure 7 shows RS232C
2 is a diagram showing a specific configuration of an interface between a /RS458 converter C and a programmable controller B. FIG.

The present invention has been made in view of the above points, and its purpose is to provide a communication device that can be used as a master station without using a converter. be.

[0005]

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a slave station with a master station interface and also includes data transfer means for transferring data between the interfaces. Note that if the slave station is provided with a control circuit that transfers data between interfaces, the slave station's C
This is preferable because it can reduce the burden on the PU.

[0006]

[Operation] By configuring the present invention as described above,
This makes it possible to perform 1:N communication between a master station and other slave stations by relaying one of the slave stations, thereby eliminating the need to use a converter. Note that if a slave station is provided with a control circuit that transfers data between the above interfaces, the control circuit will be responsible for data transfer between the master station and slave stations other than the own station, and the CPU of the own station will perform 1:
It is only necessary to execute the same software as in the case of one communication, and the load on the CPU of the local station can be reduced.

[0007]

[Embodiment] (Embodiment 1) An embodiment of the present invention is shown in FIGS. 1 and 2. In this embodiment, as shown in FIG. 1, a programmable controller B as a slave station includes an interface 1 consisting of an RS232C driver and a receiver.
An interface 2 consisting of an RS458 driver and receiver is provided.

In this embodiment, computer A, which has only an RS232C interface, is used as a master station.
:N communication, as shown in FIG. communicate. In other words, in programmable controller B that performs 1:1 communication with computer A, data transmitted from computer A is transmitted via RS232C.
interface 1 for the CP, and then send it to the CP via serial I/O (hereinafter referred to as SIO) 4.
RS from CPU3 through the other SIO4
458 interface 2 and to each other programmable controller B. Further, data from the programmable controller B as another slave station is transferred to the RS232C interface 1 and sent to the computer A in a manner opposite to that described above. In addition,
Data for the own station is responded using the RS232C interface 1. If you do this, RS232C
/RS458 converter not required. Moreover, in this case, programmable controller B has 1:1 communication,
Both 1:N communication can be performed.

(Embodiment 2) Another embodiment of the present invention is shown in FIGS. 3 to 5. When the programmable controller B is provided with both the RS232C and RS458 interfaces 1 and 2 as in the above embodiment, the CPU 3 is required to process the respective data, which increases the burden on the CPU 3. Furthermore, in the case of 1:N communication, data is transferred between the interfaces 1 and 2, so it is necessary to use different software for the CPU 3 in the case of 1:1 communication and in the case of 1:N communication. Furthermore, since independent circuits are provided for 1:1 communication and 1:N communication, there is a problem of increased cost.

Therefore, in this embodiment, as shown in FIG.
A control circuit 5 is provided between each interface 1, 2 and the SIO 4, and this control circuit 5 improves the above points. The control circuit 5 operates as follows. now,
When data from computer A is input, Figure 5 (
As shown in a), the data received at the RS232C interface 1 is input to the SIO4, and the RS4
58 to another programmable controller B via interface 2.

When data from another programmable controller B is input, as shown in FIG. 5(b), R
The data received by interface 2 for S458 is transferred to SI.
It is input to O4 and transferred to computer A via RS232C interface 1. When transmitting data from the local station to computer A, the data is output from the RS232C and RS458 interfaces 1 and 2, respectively. Note that even if the data to be transmitted to computer A is sent to another programmable controller B in this way, no problem occurs because the other programmable controllers will not accept this data.

FIG. 4 shows a specific configuration of the control circuit 5 that performs the above operation. In this control circuit 5, four AND circuits A
D1 to AD4 and two selector circuits 61 and 62
It is composed of If configured as in this embodiment, the CPU
3 can be burdened by the control circuit 5, and therefore the burden on the CPU 3 can be reduced. In other words,
This is because the control circuit 5 is responsible for data transfer between the computer A and the other programmable controller B, so that the CPU 3 of the own station only needs to execute the same software as in the case of 1:1 communication. Further, since the data is transferred between the RS232C and RS458 without passing through the CPU 3, there is an advantage that the transfer speed becomes faster. Furthermore, RS23
It is also possible to reduce costs compared to providing independent circuits for 2C and RS458.

[0013]

Effects of the Invention As described above, in the present invention, a slave station is provided with a master station interface and is also provided with a data transfer means for transferring data between the interfaces. It is possible to perform 1:N communication between the terminal and other slave stations, and there is no need to use a converter.

[0014] Furthermore, if a control circuit for transferring data between the above interfaces is provided in the slave station, the control circuit is responsible for data transfer between the master station and slave stations other than the own station.
The CPU of the local station only needs to execute the software as in the case of 1:1 communication, and the load on the CPU of the local station can be reduced.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the main part configuration of a programmable controller according to an embodiment of the present invention.

FIG. 2 is a system diagram when performing 1:N communication using the same as above.

FIG. 3 is a block diagram showing the main part configuration of a programmable controller according to another embodiment.

FIG. 4 is a specific circuit diagram of the control circuit same as above;

[Figure 5]
(a) to (c) are operation explanatory diagrams of the control circuit.

FIG. 6 is a system diagram when performing 1:N communication using a conventional computer as a master station.

FIG. 7 is a circuit diagram showing a specific configuration of the converter and the slave station interface.

[Explanation of symbols]

A. Computer B Programmable controller 1, 2 Interface 5 Control circuit

Claims (2)

[Claims] Claim 1. A communication device that performs 1:N communication between a master station and a plurality of slave stations having interfaces different from that of the master station, in which the slave stations are provided with an interface of the master station, and 1. A communication device comprising a data transfer means for transferring data between devices. 2. The communication device according to claim 1, wherein a control circuit for transferring data between the interfaces is provided in the slave station.