JPH0651881A - Communication unit - Google Patents

Abstract

PURPOSE:To simplify configuration and to reduce cost by dealing with the communication system of an RS232C system or an RS422 system while using one common connector. CONSTITUTION:This communication unit to perform data communication between a main body 1 of a control equipment such as a programmable controller and a peripheral equipment according to the RS232C system or the RS422 system is provided with a system changeover switch 6 for switching the communication system to one of both systems while freely connecting the communication cables of both of communication systems with the common connector. Other wise, this unit is provided with an automatic conversion circuit for converting the signals of both of communication systems to a prescribed signal and for inputting it to the main body of the control equipment.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a communication unit for performing data communication between a control device body such as a programmable controller and peripheral devices.

[0002]

2. Description of the Related Art Conventionally, in this type of communication unit for performing data communication between a control device body such as a programmable controller and peripheral devices, which communication system, RS232C system or RS422 system, is used for data communication. In order to make it selectable, a connector was provided to connect the communication cables of each communication method.

[0003]

However, in such a conventional example, since a dedicated connector is provided corresponding to each communication system, two connectors are required, the configuration becomes complicated and the cost is reduced. There was the problem of becoming expensive. The present invention has been made in view of the above points, and an object thereof is to provide a RS23 with a single common connector.
An object of the present invention is to provide a communication unit that is compatible with the 2C system or the RS422 system, has a simple configuration, and can be manufactured at low cost.

[0004]

A communication unit according to the present invention includes a RS232C system or RS4 between a control device body such as a programmable controller and peripheral devices.
A communication unit for performing data communication by the 22 system, in which communication cables of both communication systems can be freely connected by a common connector, and a system changeover switch for switching between the two communication systems is provided.

According to a second aspect of the present invention, in a communication unit similar to that of the first embodiment in which a communication cable of both communication systems can be connected by a common connector, a signal of both communication systems is converted into a predetermined signal for control. It is provided with an automatic conversion circuit for inputting to the device body.

[0006]

In the present invention, the control device main body and the peripheral device are connected to each other by R
In a communication unit that performs data communication by the S232C system or the RS422 system, a communication cable for both communication systems can be freely connected with a common connector, and a system changeover switch for switching between the two communication systems is provided. The common connector can support the RS232C system or the RS422 system, and the configuration is simple and the cost can be reduced.

According to a second aspect of the present invention, in a communication unit similar to that of the first embodiment in which a communication cable of both communication systems can be connected by a common connector, the signals of both communication systems are converted into a predetermined signal for control. Since the automatic conversion circuit for inputting to the device body is provided, the communication system can be switched by simply connecting the communication cable of the predetermined communication system to the connector with the common connector, and the connection switching operation can be simplified.

[0008]

1 and 2 show an embodiment of the present invention, in which data communication is performed between a control device body 1 such as a programmable controller and peripheral devices 2a and 2b by the RS232C system or the RS422 system. In the communication unit X, the communication cables 3a and 3b of both communication systems are freely connectable by a common connector 4, and a system changeover switch 6 for switching between the communication systems is provided, and the data signal is a driver. It is transmitted and received by the receivers 5a and 5b. FIG. 2 shows an example of the pin arrangement.

Now, the communication cables 3a, 3 for both communication systems
b can be freely connected by the common connector 4 having the pin arrangement as shown in FIG. 2, and can be directly connected by the common connector 4 regardless of the communication system with the peripheral device on the communication partner side, and the system changeover switch 6 can be used. Data communication can be performed simply by switching the communication method to either one. In this case, RS232C system or RS422 with one common connector 4
It can be applied to any communication system, and the configuration is simple and the cost can be reduced.

FIG. 3 shows another embodiment. In a communication unit X similar to that of the first embodiment in which the communication cables 3a and 3b of both communication systems are freely connectable by a common connector 4, signals of both communication systems are transmitted. Control device body 1 converted to a predetermined signal
Is provided with an automatic conversion circuit 7 for input to the pull-up resistors Ra and Rb and an OR circuit OR.
It consists of and. The pin arrangement of the common connector 4 is the same as that in the first embodiment.

Now, in the automatic conversion circuit 7, the communication method is R
In the case of the S422 system, the receiver output of the driver receiver 5a is set to the "H" level signal when the receiver output is open, and in the case of the RS232C system, the pull-up resistor Rb is connected to the receiver output of the driver receiver 5b to provide the "H" level signal. Both driver receiver 5
The receiver outputs of a and 5b are automatically discriminated (logical sum) by the OR circuit OR and input to the control device body 1. Therefore, unlike the first embodiment, it is not necessary to perform the operation of switching the communication system by the system changeover switch 6, and the communication system can be automatically switched only by connecting the communication cables 3a and 3b of the predetermined communication system with the common connector 4. Done,
The connection switching operation can be simplified.

[0012]

The present invention is configured as described above,
In a communication unit that performs data communication by RS232C system or RS422 system between the control device body and peripheral devices, the communication cable of both communication systems can be connected with a common connector and the communication system can be switched to either system. Since the switch is provided, there is an effect that one common connector can support the communication system of the RS232C system or the RS422 system, the configuration is simple, and the cost can be reduced.

According to a second aspect of the present invention, in a communication unit similar to that of the first embodiment in which communication cables of both communication systems are freely connectable by a common connector, signals of both communication systems are converted into a predetermined signal for control. Since the automatic conversion circuit for inputting to the device body is provided, the communication system can be switched by simply connecting the communication cable of the predetermined communication system to the connector with the common connector, and the connection switching operation can be simplified.

[Brief description of drawings]

FIG. 1 is a block circuit diagram of an embodiment of the present invention.

FIG. 2 is a diagram showing a pin arrangement of the common connector of the same.

FIG. 3 is a block circuit diagram of another embodiment.

[Explanation of symbols]

 1 Control device body 2a, 2b Peripheral device 3a, 3b Communication cable 4 Common connector 5a, 5b Driver receiver 6 Method changeover switch 7 Automatic conversion circuit

Claims (2)

[Claims] 1. A communication unit for performing data communication between a control device body such as a programmable controller and a peripheral device by an RS232C system or an RS422 system, wherein communication cables of both communication systems can be freely connected by a common connector. , A communication unit characterized by being provided with a method changeover switch for changing the communication method to either of the two methods. 2. A communication unit for performing data communication between a control device body such as a programmable controller and a peripheral device by RS232C system or RS422 system, wherein communication cables of both communication systems can be freely connected by a common connector. 2. The communication unit according to claim 1, further comprising an automatic conversion circuit for converting a signal of both communication systems into a predetermined signal and inputting the signal into a control device body.