JPH0281886A - Communication expanding method for elevator - Google Patents

Abstract

PURPOSE:To prevent a noise entering a bus buffer from an outside by making the communication of the bus buffer impossible except when the bus buffer for expanding and communicating can be inputted and outputted. CONSTITUTION:When a central processing unit 2 issues an address for selecting an expanding and communicating board 12, signal decoded in a decode circuit 3 is outputted. The decoded signal allows the expanding and communicating bus buffer 7 of a microcomputer to be inputted or inputted and outputted. There by, since the microcomputer 1 prevents noise entering from the expanding and communicating bus buffer when the expanding and communicating board 12 is not communicated from entering the bus of the microcomputer 1, a malfunc tion due to the noise is not generated.

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention relates to communication between a microcomputer and an elevator communication target, particularly when the number of communications increases, such as when the number of elevator floors increases or communication with a manager's room. The present invention relates to an elevator communication expansion method suitable for.

[Conventional technology]

In the conventional technology, the bus buffer of a microcomputer is always in an input/output enabled state.

Also, JP-A-51-108444, JP-A-53-282
No. 4.

There is a method of connecting the elevator maintenance device using a connecting device as described in Japanese Patent Application No. 55-123704, and furthermore, there is a method of connecting the elevator maintenance device by a connecting device as described in Japanese Patent Application No. 54-30552. When it was determined that there was a connection method that enabled the operation of the extended maintenance equipment.

[Problem to be solved by the invention]

The above-mentioned conventional technology does not take into account noise that enters the microcomputer from the bus buffer, and has the problem of adversely affecting the operation of the microcomputer.

An object of the present invention is to prevent noise from entering from the bus buffer of a microcomputer.

[Means to solve the problem]

The above object is achieved by providing a decoding circuit on the address bus of the central processing unit, and allowing the decoding output to be input to or output from a bus buffer.

[Operation] When the central processing unit issues an address for selecting an expansion communication board, a signal decoded by the decoding circuit is issued. The decoded signal enables input or input/output of the microcomputer's expansion communication bus buffer. This prevents the noise coming from the expansion communication bus buffer from entering the microcomputer bus when the microcomputer is not communicating with the expansion communication board, so that malfunctions due to noise will not occur.

〔Example〕

An embodiment of the present invention will be described below with reference to FIG. A decoding circuit 3 for selecting an extended communication board 12 is built into a microcomputer 1, and when a central processing unit 2 selects the extended communication board 12, a bus buffer 5 is enabled for output and a bus buffer 6 is enabled for input/output.

According to this embodiment, expansion communication boards can be added without changing the microcomputer 1 within the range that allows input/output of the bus buffers 5 and 6, and expansion can be facilitated.

(Effects of the Invention) According to the present invention, bus buffer communication is disabled except when input/output of the extended communication bus buffer becomes possible, thereby preventing noise from entering the bus buffer from the outside. Because you can.

Malfunctions of the central processing unit due to noise can be prevented.

[Brief explanation of the drawing]

FIG. 1 shows an embodiment of the present invention, and is a block diagram in which a decoding circuit for a data bus buffer and an address bus buffer is built into a microcomputer. FIG. 2 also shows an embodiment of the present invention, and shows a data bus buffer. FIG. 2 is a block diagram in which an address bus buffer decoding circuit is built into an expansion communication board. DESCRIPTION OF SYMBOLS 1... Microcomputer, 2... Central processing unit, 3... Decoding circuit, 4... Microcomputer transmission/reception circuit, 5... Address bus buffer, 6...
- Data bus buffer, 7... Bus buffer of expansion communication board. Figure 1

Claims (1)

[Claims] 1. Between a central processing unit that performs central control, a microcomputer with a built-in bus buffer for extended communication to the outside, and objects of communication in the elevator such as cars, halls, and manager's rooms. In an elevator communication system that performs communications necessary for operation and management, when the transmitting and receiving circuit is expanded using an expansion communication board with a built-in transmitting and receiving circuit, communication is performed with the communication target of the elevator via the expansion communication board. A method for expanding communications in an elevator, characterized in that the bus buffer of the microcomputer is enabled for input or input/output only occasionally. 2. The elevator communication expansion method according to claim 1, characterized in that an address for expansion communication is determined in the microcomputer, and a plurality of expansion communication boards are provided within the range of the address. 3. In claim 1, when the expansion communication board is selected from the microcomputer, a selection signal is sent from the expansion communication board to the microcomputer to open the bus buffer of the microcomputer. A method for expanding communication in an elevator, characterized in that: