Programmable controller

• US 20060064511A1
• Filed: 05/28/2003
• Published: 03/23/2006
• Est. Priority Date: 05/28/2003
• Status: Active Grant

• Current Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Original Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Inventors: Fukatsu, Noriyasu
• Granted Patent: US 7,797,461 B2
• Time in Patent Office: Days
• US Class Current: 710/8
• CPC Class Codes: G06F 13/387 for adaptation of different data processing systems to different peripheral devices, e.g. protocol converters for incompatible systems, open system

Abstract

A programmable controller having one or more serial ports (6) for serial communication is characterized by including a switching unit that properly uses the serial port (6) in a first state in which a general-purpose communication protocol which establishes communication in accordance with a specification of a partner equipment can be processed, a second state in which a computer link-only protocol which establishes communication based on a fixed specification can be processed, and a third idling state. The switching unit switches the serial port (6) into the first state by a command that initializes the serial port (6) in a program for the general-purpose communication protocol when the serial port (6) is in the idling state, the switching unit switches the serial port (6) into the second state when the serial port (6) receives a signal from external equipment for starting the communication using the computer link-only protocol. When the serial port (6) is in the first state, the serial port (6) is switched to the idling state by a command that closes the serial port (6) in the program for the general-purpose communication protocol, and when the serial port (6) is in the second state, the serial port (6) is switched to the idling state after the communication with the external equipment using the computer link-only protocol is completed.

Claims

1. A programmable controller having a serial port for serial communication, comprising:

a switching unit that switches the serial port in any one of a first state, a second state, and a third state, the first state being a state in which a general-purpose communication protocol which establishes communication in accordance with a specification of a partner equipment can be processed, the second state being a state in which a computer link-only protocol which establishes communication based on a fixed specification can be processed, and the third state being an idle state, wherein the switching unit switches the serial port to the first state by a command that initializes the serial port in a program for the general-purpose communication protocol when the serial port is in the idling state,

to the second state when the serial port receives a signal from external equipment for starting the communication using the computer link-only protocol,

to the idling state, upon the serial port being in the first state, by a command that closes the serial port in the program for the general-purpose communication protocol, and

to the idling state, upon the serial port being in the second state, after the communication with the external equipment using the computer link-only protocol is completed.

2. The programmable controller according to claim 1, wherein the serial ports are plural and the command that initializes the serial ports and the command that closes the serial ports contains information that designates which serial port from among the serial ports is to be selected.

3. The programmable controller according to claim 2, wherein if the command that initializes the serial port in the program for the general-purpose communication protocol is output when the serial port is in the second state, a user who outputs the command that initializes the serial port is informed that communication can not be established by the general-purpose communication protocol, and the setting of the serial port is not changed.

4. The programmable controller according to claim 3, wherein if a signal which starts communication using the computer link-only protocol is received by the external equipment when the serial port is in the first state, the external equipment is informed that communication can not be established by the computer link-only protocol, and the setting of the serial port is not changed.