JP2003134030A - Communication system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a communication system in which a radio function can be added at low cost and maintenance/check is facilitated. SOLUTION: In the communication system connected with field equipment and system equipment or provided with the field equipment and a cable for communication connected with the field equipment and capable of two-way data communication, this communication system is provided with a communication repeater provided in the middle of the cable for communication and equipped with a connecting terminal part connected to the cable for communication, wired communication device part for exchanging data communication on a wire with the cable for communication through this connecting terminal part, wireless communication device part for exchanging data communication by radio, and arithmetic processing part having a wired/wireless protocol converting function for converting the data communication from the wired communication device part from a wired protocol to a wireless protocol and transmitting the data communication to the wireless communication device part or for converting the data communication from the wireless communication device part from the wireless protocol to the wired protocol and transmitting the data communication to the wired communication device part.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a communication system in which addition of a wireless function can be realized at a low cost with a small development investment and a small installation cost, and maintenance and inspection are easy.

More specifically, the present invention provides analog transmission, for example, superimposing a communication signal on 4-20 mA, or
By installing the fieldbus communication function, the field device has a function that enables two-way data communication with system devices and handheld terminals, as well as a wired / wireless communication protocol conversion function and both wired and wireless communication functions. The present invention relates to a communication system in which the addition of a wireless function can be realized at low cost with a small development investment, small installation cost, and easy maintenance / inspection by using a communication repeater with a built-in.

Here, the field device is a device for measuring and controlling (valve positioner) directly connected to various transmitters such as a pressure gauge, a differential pressure gauge, a thermometer, a level meter, and a flow meter, and a process such as a valve positioner. Say Other than valve positioners are also called (industrial) transmitters.

The system device is a device that receives a signal from a field device to instruct, record, and control. Indicators, recorders, controllers, distributed control systems, alarms, etc. The term "receiver" is used in contrast to the concept of the transmitter described above.

[0005]

2. Description of the Related Art FIG. 8 is a diagram showing the structure of a conventional example that has been generally used. This conventional example is an example having only a wired communication function. The field device 1a and the system device 1b are connected by a wired communication cable 1c.

Field device 1a and system device 1b
Performs data communication A of measured values and setting values via this cable 1c. Also, by connecting the handheld terminal 1d in the middle of the cable 1c, data communication A between the field device 1a and the handheld terminal 1d becomes possible.

FIG. 9 is an explanatory view of the configuration of another conventional example which is generally used in the past. This conventional example is an example in which a wireless communication function is added. The wireless communication device 2c is built in the amplifier case 2b inside the field device 2a itself, and wireless data communication A is performed by the wireless communication device 2c via the sensor unit 2d and the arithmetic processing unit 2e.

FIG. 10 is a diagram for explaining the structure of another conventional example which is generally used in the past. In this conventional example, by connecting the communication repeater 3a to the outside of the field device 3c via the newly wired communication cable 3b,
Wireless data communication A can be performed with system devices and handheld terminals.

3d is an amplifier case, 3e is a sensor section, 3
f is an arithmetic processing unit, 3g is a wire communication device, 3h is a connection terminal for conventional wire communication, 3i is a connection terminal added for the communication repeater 3a, and 3j is a wiring port.

[0010]

However, the conventional example shown in FIG. 8 has the following problems. When the field device 1a is installed in a place that is difficult to access, such as a high place or a dangerous place. In the middle of the wired communication cable 1c, there is no choice but to connect the handheld terminal 1d or to perform the data communication A from a system device in the instrument room apart from the place where the field device 1a itself is installed.

Therefore, the field device 1a cannot be operated while directly looking at it, or the work place is limited because the place where the handheld terminal 1d can be connected is limited. There were few.

FIG. 9 The conventional example has the following problems. In general, the field device 2a is different from a personal computer in that it is not designed in consideration of expandability of functions by adding hardware.

Therefore, in order to incorporate the wireless communication device 2c inside, it is almost always necessary to newly develop a product compatible with wireless communication. New costs will be incurred such as development investment for new designs and certification work for various laws and regulations.

Considering the actual installation work,
When the field device is already installed, it is necessary to remove the field device incompatible with wireless communication and install the wireless compatible device 2a.

In the field device 2a of the type directly connected to the process, it may be necessary to stop the process itself for installation work. In that case, the cost for installation is enormous. Become.

FIG. 10 The conventional example has the following problems. Generally, various arithmetic processing units of the field device 3c
The case 3d for accommodating the (amplifier) 3f is designed to have a necessary minimum size, and an extra space is left so that a terminal 3i for a cable connected to the communication repeater 3a can be additionally accommodated. Almost never.

A cable 3 for connecting to a wireless communication device
Although one additional wiring port 3j is required for b, the field device 3c has only the required minimum number of wiring ports 3j, except for some examples such as electromagnetic flowmeters.

That is, in most cases, it is necessary to newly design the case 3d, and a large development investment is generated as in the conventional example shown in FIG. Further, it is necessary to wire the cable 3b from each field device 3c to the communication repeater 3a.

Therefore, the total wiring cost becomes high, and a plurality of wiring work and maintenance work are very troublesome.

An object of the present invention is to solve the above problems, and to provide a communication system in which the addition of a wireless function can be realized at a low cost with a small development investment and a small installation cost, and maintenance and inspection are easy. is there.

An object of the present invention is to make it possible to access a field device from any place where wireless communication can be used by using a communication repeater for maintenance on site,
(EN) Provided is a communication system that improves the flexibility of inspection work.

That is, by using a communication repeater,
Develop a new field device with a built-in wireless function and replace it with the currently installed field device, or modify the currently installed field device to add a wireless function and add a new communication cable. The present invention provides a communication system in which a wireless communication function is newly added by avoiding the above.

[0023]

In order to achieve such an object, according to the present invention, in the communication system according to claim 1, field equipment and system equipment are connected or field equipment and field equipment are connected. In a communication system including a communication cable capable of bidirectional data communication, a connection terminal portion provided in the middle of the communication cable and terminal-connected to the communication cable, and the connection terminal portion via the connection terminal portion Data communication from a wired communication device unit that transmits and receives the data communication by wire with a communication cable and a wireless communication device unit that transmits and receives the data communication by wireless and data communication from the wired communication device unit is converted from a wired protocol to a wireless protocol. The data communication is transmitted to the wireless communication device unit or the data communication from the wireless communication device unit is disabled. It converted from use protocol to the wired protocol, characterized by comprising a communication repeater and a processing unit having a wired and wireless protocol conversion function for transmitting the data communication to the wired communication device unit.

A second aspect of the present invention is characterized in that the communication system according to the first aspect further comprises a communication repeater assigned with an ID number.

A third aspect of the present invention is characterized in that, in the communication system according to the first or second aspect, a field bus is used as a communication means.

[0026]

DETAILED DESCRIPTION OF THE INVENTION The present invention will be described in detail below with reference to the drawings. FIG. 1 is an explanatory view of the main configuration of an embodiment of the present invention,
FIG. 2 is an operation explanatory diagram of FIG. 1 and 2,
The same symbols as those in FIG. 8 indicate the same functions. Only the parts different from FIG. 8 will be described below.

In FIG. 1, reference numeral 10 is a communication repeater provided in the middle of the communication cable. Communication repeater 10
Has a connection terminal unit 11, a wired communication device unit 12, a wireless communication device unit 13, and an arithmetic processing unit 14.

The connection terminal portion 11 is connected to the communication cable 1c. The wired communication device unit 12 includes the connection terminal unit 1
Data communication A by wire communication with the communication cable 1c is transmitted and received via the communication cable 1.

The wireless communication device section 13 transmits and receives wireless data communication A. The arithmetic processing unit 14 converts the data communication A from the wired communication device unit 12 from a wired protocol to a wireless protocol and transmits the data communication A to the wireless communication device unit 13, or alternatively, the data communication A from the wireless communication device unit 13 is transmitted. It has a wired / wireless protocol conversion function of converting the data communication A from a wireless protocol to a wired protocol and transmitting the data communication A to the wired communication device unit 12.

In the above configuration, the field device 1a
Communication data such as measured value values transmitted from the outside to the outside (system device or handheld terminal compatible with wireless communication) via the communication repeater 10 will be described.

The field device 1a superimposes a communication signal on analog transmission, or transmits communication data A of a wire communication protocol such as a field bus to the communication cable 1c. The communication data A is transmitted to the protocol conversion unit in the arithmetic processing unit 14 via the connection terminal unit 11 of the communication repeater 10 and the wired communication device unit 12, and is converted from the wired communication protocol to the wireless protocol here. It

The communication data A converted into the wireless protocol is transmitted to the wireless communication device section 13, where wireless communication is executed. As described above, the communication data A of the wired protocol transmitted from the field device 1a becomes the communication data A of the wireless protocol via the communication repeater 10 and is received by the external wireless compatible device.

Next, the communication data A such as the set value transmitted from the outside to the field device 1a via the communication repeater 10 will be described. The communication data A of the wireless protocol, which has arrived from the outside to the wireless communication device unit 13 in the communication repeater 10 by wireless communication, is transmitted to the protocol conversion unit in the arithmetic processing unit 14, and here, from the wireless protocol to the communication data A of the wired protocol. To be converted.

This data is transmitted to the field device 1a via the wired communication device unit 12, the connection terminal unit 11, and the communication cable 1c. As described above, the communication data A of the wireless protocol from the outside becomes the communication data A of the wired protocol via the communication relay 10 and is received by the field device 1a.

As a result, in the present invention, it is not necessary to change or modify the existing (only compatible with wired communication) field device itself, and the newly required hardware is the communication repeater 10.
Only.

FIG. 10 Compared with the conventional example, only one cable connection terminal (or two = field device side and system device side) is sufficient and the parts cost is small, and the space of the repeater 10 itself is small. it can.

The communication repeater 10 can be shared without depending on the type of field device as long as the same wireless protocol and wired protocol are combined. Therefore, the development investment is small and the number of types of the communication repeater 10 is small, so that maintenance / inspection work after installation is easy.

According to the present invention, since the communication repeater 10 is arranged in the middle of the existing communication cable 1c, it is not necessary to prepare (purchase) a new cable. -Since the existing cable is used, there is no need to newly secure a cable wiring space.

It can be installed in any part of the existing cable wiring part.・ Since the wiring route itself does not change, the number of cable inspection routes will not increase. There are advantages such as.

The present invention utilizes the conventional wire communication cable 1c to add a wireless communication path. Therefore, due to a failure of system equipment that supports wireless communication,
Even when the wireless communication path is cut off, the conventional wired communication path can be used.

On the contrary, even when the wired communication becomes impossible due to the failure of the wired system device or the like, the wireless communication means remains. As described above, according to the present invention, the communication path can be duplicated and the reliability is improved.

As shown in FIG. 2, for example, in a place designated as a hazardous area B for explosion-proof, etc., field equipment is installed.
(Or modification to add wireless function) and maintenance / inspection work imposes safety restrictions and limits the work flexibility.

For example, only a special power source should be used so as not to blow sparks. The communication repeater 10 of the present invention can be installed at any position on the existing communication cable 1c. For this reason, by installing the communication repeater 10 outside the hazardous area, the degree of freedom of work is not impaired in terms of installation itself and maintenance / inspection after installation.

FIG. 3 is an explanatory view of the essential structure of another embodiment of the present invention. In the present embodiment, the communication repeater is given an ID number.

When there are a plurality of communication repeaters 10 in the vicinity area, in order to avoid a trouble of erroneously communicating with the field device 1a other than the purpose, the communication repeater 10 has I
When the communication is executed, the “ID of the communication relay 10 (Tx in the figure)” and the “ID of the field device 1a (T in the figure) are given.
x) "is specified and then communication is established.

As a result, the target field device 1 is surely obtained.
A communication system capable of communicating with a is obtained.

Therefore, as shown in FIGS. 4 and 5, in the case of fieldbus communication, only one communication repeater 10 is used for a plurality of field devices 1a (due to the multi-drop network topology). It becomes possible to add a communication function.

Note that, as shown in FIGS. 6 and 7, in the case of fieldbus communication, the field device 1a and the field device 1a are composed of only the field device 1a.
It is also possible to install the communication repeater 10 between and.

Further, conventionally, by connecting a handheld terminal in the middle of a communication path, noise was added to a communication signal, which sometimes became a source of communication trouble. However, in the present invention, communication can be performed without directly connecting the handheld terminal to the communication cable 1c.

Further, by disposing an appropriate noise filter in the communication repeater 10, it is possible to further reduce noise.

It should be noted that the above description merely shows specific preferred embodiments for the purpose of explaining and exemplifying the present invention. Therefore, the present invention is not limited to the above embodiments, and includes many modifications and variations without departing from the essence thereof.

[0052]

As described above, according to the first aspect of the present invention.
According to the above, there are the following effects. (1) The field / system device is connected, or the field device / field device is connected and a communication cable capable of bidirectional data communication is provided with a wired / wireless communication protocol conversion function and a wired / wireless communication cable. Since a communication repeater with both communication functions built-in is provided, it is possible to obtain a communication system in which addition of a wireless function can be realized at low cost with small development investment, low installation cost, and easy maintenance and inspection.

(2) Since the existing wired communication cable remains as it is, there are two communication means, wired and wireless, so that the communication path can be duplicated and the communication reliability can be improved.

(3) In areas subject to some restrictions regarding the design (performance) and work of equipment such as explosion-proof hazardous areas,
Even if a field device is installed, according to the present invention, by installing a general-purpose communication repeater that does not comply with the regulation in the middle of the communication cable outside the regulated area, the wireless function can be obtained. Can be added.

That is, it is possible to obtain a communication system in which a wireless communication function can be added without designing a special communication repeater complying with regulations.

(4) Since installation, modification, maintenance, and inspection work can be performed outside the regulated area, a communication system that does not require special work corresponding to the regulation can be obtained.

According to the second aspect of the present invention, there are the following effects. A communication system capable of reliably communicating with a target field device when a plurality of communication repeaters are present in a nearby area can be obtained.

According to claim 3 of the present invention, there are the following effects. A communication system can be obtained in which a wireless communication function can be added to a plurality of fold devices with only one communication repeater.

Therefore, according to the present invention, it is possible to realize a communication system in which the addition of the wireless function can be realized at a low cost with a small development investment and a small installation cost, and the maintenance and inspection are easy.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a main part configuration of an embodiment of the present invention.

FIG. 2 is an operation explanatory diagram of FIG.

FIG. 3 is an explanatory diagram of a main part configuration of another embodiment of the present invention.

FIG. 4 is an explanatory diagram of a main part configuration of another embodiment of the present invention.

FIG. 5 is an explanatory diagram of a main part configuration of another embodiment of the present invention.

FIG. 6 is an explanatory diagram of a main part configuration of another embodiment of the present invention.

FIG. 7 is an explanatory diagram of a main part configuration of another embodiment of the present invention.

FIG. 8 is an explanatory diagram of a main part configuration of a conventional example that is generally used in the past.

FIG. 9 is an explanatory view of a main part configuration of another conventional example which is generally used conventionally.

FIG. 10 is an explanatory diagram of a main part configuration of another conventional example which is generally used conventionally.

[Explanation of symbols]

1a Field equipment 1b System equipment 1c communication cable 10 communication repeater 11 Connection terminal part 12 Wired communication device section 13 Wireless communication device section 14 Arithmetic processing unit A data communication B dangerous place

Claims (3)

[Claims] 1. A communication system comprising: a field device and a system device connected to each other; or a field device and a field device connected to each other; and a communication cable capable of bidirectional data communication. A connection terminal portion provided and terminal-connected to the communication cable, and a wired communication device portion that transmits and receives the data communication by wire with the communication cable via the connection terminal portion and a wireless communication that transmits and receives the data communication by wireless The data communication from the device unit and the wired communication device unit is converted from the wired protocol to the wireless protocol and the data communication is transmitted to the wireless communication device unit, or the data communication from the wireless communication device unit is performed from the wireless protocol. Wired / non-converted to a wired protocol and transmitting the data communication to the wired communication device section A communication system comprising a communication repeater including an arithmetic processing unit having a line protocol conversion function. 2. The communication system according to claim 1, further comprising a communication repeater assigned with an ID number. 3. The communication system according to claim 1, wherein a field bus is used as a communication means.