JP2004240497A - Fieldbus system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fieldbus system which eliminates risk during maintenance, and permits an inspection with individual measuring instrument removed. <P>SOLUTION: The fieldbus system comprises a branch line circuit to which a disconnector is attached. In the system, by attaching the disconnector such as a switch and a disconnecting terminal which can be operated easily to every branch line circuit, the branch line of an object measuring instrument can be detached from a main line without touching a hot branch line when the maintenance is required. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a fieldbus system used for two-way digital communication.
[0002]
[Prior art]
In a field bus used for two-way digital communication, up to thirty or so branch lines are connected to one trunk line, and individual instruments are connected to the branch lines.
If one of the instruments breaks down, it is necessary to remove and install it, but it will affect other instruments that share the main line, so it is necessary to work in the hot line state . At that time, there is a concern that erroneous operation during inspection may affect all instruments connected to the main line.
On the other hand, equipment other than the intrinsically safe explosion-proof structure cannot be opened in the energized state in a hazardous area (hereinafter referred to as a hazardous area) specified in the factory electrical equipment explosion-proof guidelines where flammable substances are present, so that removal and installation work cannot be performed.
[0003]
[Problems to be solved by the invention]
In view of the above situation, an object of the present invention is to provide a field bus system which eliminates these dangers at the time of maintenance, and allows individual instruments to be removed and inspected.
[0004]
[Means for Solving the Problems]
The present inventor has conducted various studies on the solution of the above-described problems, and as a result, if a disconnector is attached to the branch line circuit of the field bus, when maintenance is necessary, the branch line can be easily moved from the main line without touching the live line. The present inventors have found that they can be separated and completed the present invention.
That is, the present invention provides a fieldbus system characterized in that a disconnector is attached to a branch line circuit.
[0005]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, a field bus system according to an embodiment of the present invention will be described with reference to FIG.
[0006]
In the fieldbus system for instrument monitoring and control, a main line 2 is connected to a fieldbus branch terminal 4 in an instrument panel or a junction box 3 from a fieldbus interface 1 in an instrument room, and divided into a number of branch lines 5 to a number of instruments 6 respectively. Two-way digital communication is performed between each instrument 6 and the fieldbus interface 1 in the instrument room. In the instrument room, monitoring and control of the instrument 6 can be performed by the personal computer terminal 7 through the CPU from the fieldbus interface 1.
[0007]
However, when a failure occurs in any of the instruments 6, it is necessary to perform operations such as removal and attachment, but since the trunk line 2 is shared, these operations must be performed in a live state. However, it is not possible to open the energized equipment in a dangerous place where some other erroneous operation affects the operation of all other instruments, or where there is a combustible material.
[0008]
Therefore, in the present invention, a switch, a disconnection terminal, etc., which can be easily operated, is attached to all the branch line circuits, so that when maintenance is necessary, the target instrument can be connected without touching the live branch line. The field bus system was designed so that the branch line could be disconnected from the main line.
[0009]
It is preferable to install the disconnector 8 in a branch circuit between the fieldbus branch terminal 4 of the main line and the instrument 6 in the instrument panel or the junction box 3 from the viewpoint of easy disconnection operation.
When the instrument panel or the junction box 3 is located in a non-hazardous location, the disconnector 8 may be provided with a switch, a disconnecting terminal, or the like, but when located in a hazardous location, an explosion-proof switch should be provided. is there.
[0010]
【The invention's effect】
Since each branch line circuit is equipped with a switch, disconnecting terminal, and other equipment that has disconnection functions, maintenance work such as removal and inspection of individual instruments with failures, etc., even in danger areas while the trunk line is in use. Can be performed safely.
[Brief description of the drawings]
FIG. 1 is a conceptual diagram of a field bus system of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Fieldbus interface 2 Trunk line 3 Instrument panel or junction box 4 Fieldbus branch terminal 5 Branch line 6 Instrument 7 PC terminal 8 Disconnector

Claims (1)

A field bus system comprising a disconnector attached to a branch line circuit.

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