JP2004234598A - Gas concentration monitoring system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a gas concentration monitoring system capable of effectively utilizing the resources of a device network, thereby transmitting a gas concentration signal high in resolution, detailed status information and sensor information. <P>SOLUTION: The gas concentration monitoring system is provided with: a gas detection unit 1 composed of a gas sensor 10, a controlling and monitoring means 12, a sensor information storage means 14, and a device network use interface 13 for converting the gas concentration signal into the signal based upon the device network; and a central monitoring device 3 composed of a device network use interface 30, a control means 31, display and alarm means 32 and 33, and an input means 34. The gas concentration signal detected by the gas sensor 10 and the signal of the information storage means 14 are respectively transmitted by 16 bits through a communication cable 2. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

【００１１】
各ガス検出ユニット１は、通常のガス監視状態では、ガス濃度信号を構成する１６ビットと、ステータス信号を構成する１６ビットの、合計３２ビットの信号を出力する。この３２ビットの信号は、デバイスネットにより中央監視装置３に伝送される。
ところが、中央監視装置３は、３２ビットで伝送されるこれらガス濃度信号、及びステータス信号の他に、センサ情報を必要とする場合がある。
しかし、デバイスネットで伝送可能な回線幅３２ビットが、ガス検出ユニット１からの信号の伝送のために既に予約されているため、新たなデータであるセンサ情報をセンサユニット１側から伝送することが不可能である。
このため、本発明においては、ステータス信号の１ビット、この実施例ではステータス信号の第４ビットで４特殊コードを指定するように構成されている。
【００１２】
すなわち、特殊コードは、「０」、「１」の２種類のデータの設定が可能となっていて、
通常のガス監視状態では、特殊コードが「０」に設定されていて、第０ビットと第１ビットとにより小数点の位置を、また第２ビットと第３ビットとで濃度単位を特定している。
すなわち、
第０ビット「０」、第１ビット「０」 １／１
第０ビット「０」、第１ビット「１」 １／１０
第０ビット「１」、第１ビット「０」 １／１００
第０ビット「１」、第１ビット「１」 １／１０００
を出力する。
また第２ビットと第３ビットは、
第２ビット「０」、第３ビット「０」 ｖｏｌ％
第２ビット「０」、第３ビット「１」 ％ＬＥＬ
第２ビット「１」、第３ビット「０」 ｐｐｍ
第２ビット「１」、第３ビット「１」 ｐｐｂ
を出力する。
【００１３】
一方、中央監視装置３の入力手段１により第４ビットの特殊コードに「１」が指定されると、第０ビット、第１ビット、第２ビット、及び第３ビットの４ビットにより１６種類の別の情報、つまりセンサ情報記憶手段１４に格納されている他のセンサ情報、つまり第１警報点の濃度、第２警報点の濃度、サプレス値、及び警報遅延時間等のデータを通常のガス監視状態よりも余分に伝送することが可能となる。
これにより、デバイスネットで伝送可能な情報以上の情報を伝送することができ、中央監視装置側での各ガス検出ユニット毎の設定用データの入力作業を大幅に減らすことができる。
【００１４】
なお、従来の装置では、表２に示したようにステータス信号及びガス濃度信号が共に８ビットにより伝送されていたので、分解能が低く、またガスセンサーの詳細な状態を把握することが困難であった。
【００１５】
【表２】

【００１６】
さらには中央監視装置３により定期的にガス検出ユニット１、１、‥‥を呼び出して、各ガス検出ユニット１のセンサ情報記憶手段１１の適宜の情報をデバイスネット２に出力させて伝送させることにより、各ガス検出ユニット１との通信状態を検定することができる。
【００１７】
【発明の効果】
以上、説明したように本発明によれば、センサ情報記憶手段のデータに基づいて各ガス検出ユニットのステータス信号とセンサ情報とを１６ビットで伝送するとともに、ガス濃度信号をも伝送するため、デバイスネットの資源を有効に利用して、中央監視装置でのデータの入力作業を可及的に減少させつつ、各ガス検出ユニットの詳細な情報を表示することができる。
【図面の簡単な説明】
【図１】本発明の一実施例を示す構成図である。
【符号の説明】
１ ガス検出ユニット
２ 通信ケーブル
３ 中央監視装置
１０ ガスセンサ
３２ デイスプレイ
３３ 警報器
３４ 入力手段[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a gas concentration monitoring system suitable for a device net, and more particularly, to a method for transmitting data from a gas detection unit to a central monitoring device.
[0002]
[Prior art]
In the field of the gas concentration monitoring system, a method of allocating 8 bits to the status signal and 8 bits to the concentration signal and transmitting a total of 16 bits of signal in parallel has been adopted.
On the other hand, in the fields of manufacturing industries such as plants, semiconductors, and automobiles, a standardized network, that is, a device network (registered trademark) that exchanges control signals and data for device setting by serial communication is widely used, and limit switches, Communication links that can connect industrial devices such as photoelectric sensors, valve manifolds, motor starters, process sensors, barcode readers, variable frequency drivers, panel displays, and operator interfaces have been constructed.
[0003]
[Problems to be solved by the invention]
The present invention has been made in view of such circumstances, and an object of the present invention is to effectively utilize resources provided by a device net to provide a central monitoring device with a high resolution gas concentration signal. It is an object of the present invention to provide a gas concentration monitoring system that can transmit the sensor information together with the sensor information.
[0004]
[Means for Solving the Problems]
In order to solve such a problem, in the present invention, a gas sensor, a control monitoring unit, and a sensor information storage unit, a gas detection unit including a device network interface for converting to a device network compliant signal, A central monitoring device comprising a device network interface, a control means, a display alarm means, and an input means; a 16-bit gas concentration signal detected by the gas sensor; and a signal and status signal of the sensor information storage means. Is transmitted in 16 bits.
[0005]
[Action]
The status signal and sensor information of each gas detection unit are transmitted in 16 bits based on the data in the sensor information storage means, and the gas concentration signal is also transmitted in 16 bits.
[0006]
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Therefore, the details of the present invention will be described below based on the illustrated embodiment.
FIG. 1 shows an embodiment of the present invention. A gas detection unit 1 disposed in the vicinity of various devices includes a sensor 10 including an electrochemical gas sensor, a semiconductor gas sensor, a hot wire gas sensor, and the like, and an analog sensor. A digital converter 11, a monitoring and control means 12 constituted by a microcomputer, a device net interface 13 for converting a status signal from the analog-to-digital converter 11 and the monitoring and control means 12 into a signal conforming to a device net, and a sensor And an information storage means 14.
[0007]
The sensor information storage means 14 stores concentration unit codes (vol%,% LEL, ppm, ppb) and decimal point codes (1/1, 1/10, 1/100, 1 /) set in each gas detection unit 1. 1000), the data of the density of the first alarm point, the density of the second alarm point, the suppress value, the alarm delay time, and the like are stored in a nonvolatile memory.
[0008]
Each gas detection unit 1 is connected to the central monitoring device 3 via a device network standard cable 2 via an interface 13. The central monitoring device 3 includes a device network interface 30, a control means 31, a display 32, an alarm 33, and an input means 34, receives a gas concentration signal and a status signal from the gas detection unit 1, and controls the gas by the control means 31. Is displayed on the display 32, the alarm 33 is activated when the gas concentration exceeds the reference value, and sensor information is transmitted from the gas detection unit 1 according to a command of the input means 34.
[0009]
The gas concentration signal and the status signal are each transmitted as one block by switching, and in the present invention, as shown in Table 1, are expanded to 16 bits which is the signal width of the device net.
As a result, as shown in Table 1, the gas concentration signal can be transmitted as signed 15-bit data and the status signal can be transmitted by 16 bits, and the gas concentration signal with high resolution accuracy and detailed status transmission can be transmitted. Becomes possible.
[0010]
[Table 1]

[0011]
In the normal gas monitoring state, each gas detection unit 1 outputs a signal of 32 bits, that is, 16 bits forming a gas concentration signal and 16 bits forming a status signal. The 32-bit signal is transmitted to the central monitoring device 3 via the device net.
However, the central monitoring device 3 may need sensor information in addition to the gas concentration signal and the status signal transmitted in 32 bits.
However, since a line width of 32 bits that can be transmitted in the device net is already reserved for transmitting a signal from the gas detection unit 1, sensor information that is new data can be transmitted from the sensor unit 1 side. Impossible.
Therefore, in the present invention, one special bit of the status signal, in this embodiment, the fourth bit of the status signal specifies four special codes.
[0012]
That is, the special code can set two types of data, "0" and "1".
In the normal gas monitoring state, the special code is set to “0”, the position of the decimal point is specified by the 0th bit and the 1st bit, and the concentration unit is specified by the 2nd and 3rd bits. .
That is,
0th bit “0”, 1st bit “0” 1/1
0th bit “0”, 1st bit “1” 1/10
0th bit “1”, 1st bit “0” 1/100
0th bit “1”, 1st bit “1” 1/1000
Is output.
The second and third bits are
2nd bit “0”, 3rd bit “0” vol%
2nd bit “0”, 3rd bit “1”% LEL
2nd bit “1”, 3rd bit “0” ppm
2nd bit “1”, 3rd bit “1” ppb
Is output.
[0013]
On the other hand, when "1" is designated as the special code of the fourth bit by the input means 1 of the central monitoring device 3, 16 kinds of four bits of the 0th bit, the 1st bit, the 2nd bit, and the 3rd bit are provided. Other information, that is, other sensor information stored in the sensor information storage means 14, that is, data such as the density of the first alarm point, the density of the second alarm point, the suppression value, and the alarm delay time, is used for normal gas monitoring. It becomes possible to transmit more than the state.
As a result, more information than can be transmitted on the device network can be transmitted, and the work of inputting setting data for each gas detection unit on the central monitoring device side can be greatly reduced.
[0014]
In the conventional apparatus, since both the status signal and the gas concentration signal are transmitted by 8 bits as shown in Table 2, the resolution is low and it is difficult to grasp the detailed state of the gas sensor. Was.
[0015]
[Table 2]

[0016]
Further, the central monitoring device 3 periodically calls the gas detection units 1, 1,... To output appropriate information of the sensor information storage means 11 of each gas detection unit 1 to the device net 2 for transmission. , The state of communication with each gas detection unit 1 can be verified.
[0017]
【The invention's effect】
As described above, according to the present invention, the status signal and the sensor information of each gas detection unit are transmitted in 16 bits based on the data of the sensor information storage means, and the gas concentration signal is also transmitted. By effectively utilizing the resources of the network, detailed information of each gas detection unit can be displayed while minimizing the data input operation at the central monitoring device.
[Brief description of the drawings]
FIG. 1 is a configuration diagram showing one embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Gas detection unit 2 Communication cable 3 Central monitoring device 10 Gas sensor 32 Display 33 Alarm 34 Input means

Claims (5)

A gas detection unit including a gas sensor, a control monitoring unit, and a sensor information storage unit, and a device net interface that converts the signal into a signal compliant with the device net;
A central monitoring device comprising a device network interface, control means, display alarm means, and input means;
Wherein the gas concentration signal detected by the gas sensor is transmitted in 16 bits, and the signal and status signal of the sensor information storage means are transmitted in 16 bits. 2. The gas according to claim 1, wherein the gas information storage means is configured to store a gas name, a full scale value, an alarm value, an alarm type, and a gas concentration value per digit in a non-volatile memory in a readable manner. Concentration monitoring system. The gas concentration monitoring system according to claim 1, wherein the gas concentration signal is configured as signed 16-bit data. 2. The gas concentration monitoring system according to claim 1, wherein the central monitoring device reads information from the sensor information storage unit of each gas detection unit at a predetermined cycle to determine a connection state between the gas detection unit and a communication line. . 2. The gas concentration monitoring system according to claim 1, wherein a special code is set in the status signal, and other sensor information stored in the sensor information storage unit is transmitted by the special code.

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