CN107543590B

CN107543590B - Measuring system

Info

Publication number: CN107543590B
Application number: CN201710255013.7A
Authority: CN
Inventors: 阿部正治
Original assignee: Musasino Co Ltd
Current assignee: Musasino Co Ltd
Priority date: 2016-06-25
Filing date: 2017-04-18
Publication date: 2020-01-14
Anticipated expiration: 2037-04-18
Also published as: CN107543590A; KR20180001445A; KR102022112B1; JP6263232B2; JP2017228260A

Abstract

The invention provides a measuring system which can realize miniaturization of a device or save an installation space. In a measurement system (10a) according to a first embodiment, data communication between a plurality of nodes (40 a-40 n) and a CPU (20) is enabled via a master device (30) and slave devices (50 a-50 n) in a system support panel (11) not via wires, but via wireless connections. This eliminates the need to provide a cable for data communication between them, and eliminates the need to secure a space for housing the cable in the case. Therefore, the volume of the system support panel (11) can be reduced by the size occupied by the space for accommodating the cables. Thus, the device can be miniaturized or the installation space can be saved.

Description

Measuring system

Technical Field

The present invention relates to a measurement system including a plurality of control units connected to a plurality of sensors.

Background

A measurement system including a plurality of control units connected to a plurality of sensors is disclosed in patent document 1 below, for example. In this system, a plurality of detection control circuits connected to electrode pairs as sensors are provided, and these plurality of detection control circuits are connected to a calculation circuit constituted by a personal computer, for example (patent document 1: paragraph 0021).

[ patent document ]

Patent document 1: japanese patent laid-open publication No. 2013-205311

In a measurement system including a plurality of control units, as in the "liquid level measurement system" disclosed in patent document 1, the plurality of control units and a higher-level control unit (calculation circuit in patent document 1) that processes sensor data and the like to be output from the plurality of control units need to be electrically connected to each other by cables and the like corresponding to the number of control units. For example, when the number of control units is 100, 100 cables need to be arranged and connected to the upper control unit.

In particular, when a plurality of control units connected to a plurality of sensors and a control unit located above the control units are housed in the same housing, it is necessary to secure a space for housing cables for connecting the two in the housing. Therefore, the housing may become large-sized due to the number of cables, and thus a plurality of cables may affect the miniaturization of the device or fail to save space for installing the device.

Disclosure of Invention

In view of the above-described problems, an object of the present invention is to provide a measurement system that can be miniaturized and can save installation space.

To achieve the above object, a measurement system according to the present invention recited in claim 1 of the appended claims is characterized by including: a plurality of first control units respectively connected with the plurality of sensors in a data communication manner; a plurality of second control units connected to the plurality of first control units in a data-communicable manner, and receiving, from the plurality of first control units, each of the sensor data transmitted from the plurality of sensors or sensor information based on the sensor data; the shell is used for accommodating the plurality of first control units and the plurality of second control units; the data communication between the plurality of first control units and the second control unit is wireless data communication in which a polling method is adopted as a communication method performed in the housing, and when a second control unit of the plurality of second control units does not perform polling processing of the polling method, the first control unit of the plurality of first control units that has transmitted the sensor data or the sensor information to the second control unit requests connection establishment to another second control unit of the plurality of second control units, and after the connection establishment is completed, transmits the sensor data or the sensor information in response to polling processing of the another second control unit. The "polling processing" is transmission processing for transmitting a polling frame from the second control unit to the first control unit when the communication method employs the polling method.

The data communication between the plurality of first control units and the plurality of second control units is wireless data communication performed in the housing (the communication method employs a polling method). That is, data communication can be performed between the plurality of first control units and the plurality of second control units by wireless connection without using wires. This eliminates the need to provide a cable for data communication between them, and thus eliminates the need to secure a space for housing the cable in the case. When one of the plurality of second control units does not perform polling processing by the polling method (for example, when there is no polling processing to be performed originally), the first control unit that has transmitted the sensor data or the sensor information to the one second control unit requests the other second control unit (for example, the second control unit that can normally perform polling processing or the like) of the plurality of second control units to establish a connection, and after the connection is established, transmits the sensor data or the sensor information in response to the polling processing of the other second control unit. This makes it possible to suppress transmission failure of sensor data or sensor information due to the first control unit continuously transmitting the sensor data or sensor information to a second control unit that cannot respond due to, for example, a failure or the like. By using the polling method, loss of sensor data due to collision can be prevented, and reliability of sensor data can be improved. In addition, since the polling method does not require a correct Time slot as in the TDMA (Time Division Multiple Access) method, it is not necessary to adopt a synchronization method which is likely to become complicated.

Further, a measurement system according to the present invention recited in claim 2 of the appended claims is characterized by including: a plurality of first control units respectively connected with the plurality of sensors in a data communication manner; a plurality of second control units which are connected with the plurality of first control units in a data communication manner and receive the sensor data sent by the plurality of sensors or the sensor information based on the sensor data from the plurality of first control units; and a housing that houses the plurality of first control units and the plurality of second control units, wherein data communication between the plurality of first control units and the second control units is wireless data communication in which a polling method is used as a communication method performed in the housing, a part of the plurality of second control units and a remaining part of the plurality of second control units perform polling processing in the polling method at different timings, and the part of the second control units receives the sensor data or the sensor information from the part of the plurality of first control units; the remaining second control unit receives the sensor data or the sensor information from the remaining first control units of the plurality of first control units.

In the case where a plurality of (for example, 3) second control units are housed in the housing, for example, 1 of the 3 second control units receives sensor data or sensor information from 30 of the 100 first control units, the other 1 second control unit receives sensor data or sensor information from 30 of the remaining 70 first control units, and the remaining 1 second control unit receives sensor data or sensor information from the remaining 40 first control units. Thus, the present invention can reduce the load of information processing for each unit, compared to the case where 1 second control unit receives sensor data or sensor information from 100 first control units. That is, the load can be dispersed as compared with the case where the second control unit is a single one. By using the polling method, loss of sensor data due to collision can be prevented, and reliability of sensor data can be improved. In addition, since the polling method does not require a correct Time slot as in the TDMA (Time division multiple Access) method, it is not necessary to adopt a synchronization method which is likely to become complicated. Since the polling processing by the polling method is performed by a part of the second control units and a remaining part of the second control units at mutually different timings, it is possible to suppress a failure of polling due to collision of polling frames of the two.

Further, a measurement system according to the present invention recited in claim 3 of the appended claims is characterized by including: a plurality of first control units respectively connected with the plurality of sensors in a data communication manner; 2 second control units connected to the first control units in a data-communicable manner and receiving, from the first control units, sensor data transmitted from the sensors or sensor information based on the sensor data; and a housing that houses the plurality of first control units and the 2 second control units, wherein data communication between the plurality of first control units and the 2 second control units is wireless data communication in which a polling method is used as a communication method performed in the housing, one of the 2 second control units and the other of the 2 second control units perform polling processing of the polling method at mutually different timings, the one second control unit receives the sensor data or the sensor information from a part of the plurality of first control units, the other second control unit receives the sensor data or the sensor information from the remaining part of the plurality of first control units, and when the one second control unit does not perform polling processing of the polling method, the part of the first control units request to establish connection to the other second control unit, and after the connection is established, the sensor data or the sensor information is sent in response to polling processing of the other second control unit; when the other second control unit does not perform the polling processing of the polling method, the remaining first control units request the connection establishment to the one second control unit, and after the connection establishment is completed, the sensor data or the sensor information is sent in response to the polling processing of the one second control unit. The "polling processing" is transmission processing for transmitting a polling frame from the second control unit to the first control unit when the communication method employs the polling method.

In the case of housing 2 second control units in the housing, one of the 2 second control units receives sensor data or sensor information from, for example, 50 first control units (a part of the first control units) out of 100 first control units; the other second control unit receives sensor data or sensor information from the remaining 50 first control units (the remaining first control units). Thus, the present invention can reduce the load of information processing per unit as compared with the case where 1 second control unit receives sensor data or sensor information from 100 first control units, that is, can distribute the load as compared with the case where the second control unit is single. By using the polling method, loss of sensor data due to collision can be prevented, and reliability of sensor data can be improved. In addition, since the polling method does not require a correct Time slot as in the TDMA (Time Division Multiple Access) method, it is not necessary to adopt a synchronization method which is likely to become complicated. Since the polling processing by the polling method is performed by a part of the second control units and a remaining part of the second control units at mutually different timings, it is possible to suppress a failure of polling due to collision of polling frames of the two.

When one second control unit does not perform polling processing by the polling method (when there is no polling processing to be performed originally, for example), 50 first control units that have transmitted sensor data or sensor information to the one second control unit request another second control unit (a second control unit that can normally perform polling processing or the like) to establish a connection, and after the connection is established, the sensor data or sensor information is transmitted in response to polling processing by the other second control unit. When the other second control unit does not perform polling processing by the polling method (in the case where there is no polling processing to be performed, for example), 50 first control units that have transmitted sensor data or sensor information to the other second control unit request the one second control unit (a second control unit that can normally perform polling processing, for example) to establish a connection, and after the connection is established, the sensor data or sensor information is transmitted in response to the polling processing by the one second control unit. This can suppress transmission failure of the sensor data or the sensor information due to the fact that 50 first control units continuously transmit the sensor data or the sensor information to the second control unit of one (or the other) which cannot respond due to, for example, a failure or the like.

In the measurement system according to the present invention as set forth in claim 4 of the claims, the plurality of sensors are liquid level sensors that detect a liquid level position of the liquid stored in the liquid tank of the ship in the measurement system according to any one of claims 1 to 3. This makes it possible to reduce the space for accommodating the cable in the housing or the device in a ship (particularly, a commercial ship) having a limited installation space for mounting the equipment. That is, it is effective to achieve miniaturization of the device or save the installation space.

Since there is no need to provide cables for data communication between the plurality of first control units and the plurality of second control units, there is no need to secure a space for accommodating the cables in the housing. Therefore, the volume of the housing can be reduced by the size occupied by the cable housing space. Thus, the device can be miniaturized or the installation space can be saved.

It is possible to suppress transmission failure of sensor data or sensor information due to the first control unit continuously transmitting the sensor data or sensor information to a second control unit which cannot respond due to, for example, a failure or the like. Therefore, it is possible to avoid the trouble caused by such a second control unit that does not perform predetermined information processing.

The load can be dispersed as compared with the case where the second control unit is a single one. Therefore, the second control unit can perform collection or information processing of sensor data or sensor information at high speed.

Drawings

Fig. 1 is an explanatory diagram showing a configuration example of a measurement system according to a first embodiment of the present invention.

Fig. 2 is an explanatory diagram showing an example of a communication method between the master device and each slave device.

Fig. 3 is an explanatory diagram showing an example in which the measurement system according to the first embodiment is mounted on a ship.

Fig. 4 is an explanatory diagram showing a configuration example of a measurement system according to a modification of the first embodiment.

Fig. 5 is an explanatory diagram showing a configuration example of a measurement system according to a second embodiment of the present invention.

Fig. 6 is an explanatory diagram showing an example of a communication method (in a normal state) between the master device and each slave device.

Fig. 7 is an explanatory diagram showing an example of a communication method (at the time of abnormality) between the master device and each slave device.

Fig. 8 is an explanatory diagram showing a configuration example of a measurement system according to a modification of the second embodiment.

Detailed Description

Hereinafter, embodiments of the measurement system according to the present invention will be described with reference to the drawings.

[ first embodiment ]

First, a first embodiment of a measurement system according to the present invention will be described with reference to fig. 1 to 4. As shown in fig. 1, the measurement system 10a according to the first embodiment is mainly configured by a system support panel 11, a CPU20, a master device 30, a node 40, a slave device 50, a sensor unit 60, and the like.

The system support panel 11 is a device rack, sometimes referred to as a system rack, in which several units or circuit boards may be mounted. The system support panel 11 is generally configured such that a metal plate is attached to a metal frame so as to cover the top surface, the bottom surface, and the side surfaces, and the access surface of the front surface or the back surface thereof can be opened to an external space. In the first embodiment, the CPU20, the master device 30, the node 40, the slave device 50, and other units or boards can be housed. The system support panel 11 corresponds to a "housing" in the claims. The CPU20, the master device 30, the node 40, the slave device 50, and the like may be housed in a sealed (e.g., box-shaped) case.

The CPU20 is, for example, a microcomputer (microcomputer circuit board) in the form of a circuit board (substrate), and is configured by an MPU (Micro-Processing Unit), a memory (DRAM, EEPROM, or the like), an input/output interface, and the like. The CPU20 may be configured to include a single-chip microcomputer including an MPU, a memory, and the like, a dsp (digital Signal processor), and the like.

In the first embodiment, as will be described later, the CPU20 outputs the operation information of each sensor unit 60, or performs an integration process or a statistical process on the sensor data based on the sensor data (digital data) transmitted from each sensor unit 60 via the plurality of nodes 40, and outputs the result to the outside. Therefore, the CPU20 is connected to a display device not shown in the drawings, or connected to a higher-level computer system via the cable 80. The memory (EEPROM or the like) stores program data capable of executing these information processes by the MPU in advance.

The master device 30 is a wireless communication unit capable of data communication by wireless. For example, the master device 30 includes a radio unit configured to be capable of radio communication at a predetermined frequency, a radio controller and an antenna for controlling frequency selection, transmission, and reception of the radio unit, and the like. In addition, a wireless unit, a wireless controller, an antenna, and the like are not shown in the drawings. In the first embodiment, the CPU20 is configured separately from the host device 30. Therefore, the CPU20 and the host device 30 are electrically connected by the cable 13, and data communication is enabled between the two devices.

In the first embodiment, the CPU20 and the master 30 (in the configuration of fig. 1, the CPU20, the master 30, and the cable 13 connecting them) together correspond to "second control means" described in the claims.

The node 40 is configured to transmit the sensor data transmitted from the sensor unit 60 to the CPU20, or perform a predetermined initialization process on the sensor unit 60. Therefore, the node 40 is a sensor controller formed of, for example, a single-chip microcomputer, and is configured in, for example, a circuit board (substrate) shape, as in the case of the CPU 20. In the first embodiment, 1 node 40 is provided for 1 sensor unit 60. That is, the number of the plurality of

nodes

40a, 40b, 40c, … …, 40n corresponds to the number of the sensor units 60, and they are connected to the

sensor units

60a, 60b, 60c, … …, 60n through the cables 90, respectively, to enable data communication. Note that, the node 40 may be configured not to transmit the sensor data transmitted from the sensor unit 60 directly to the CPU20 via the slave device 50 or the like, but to generate sensor information based on the sensor data and transmit the sensor information to the CPU 20. For example, the sensor data may be compared with a predetermined reference value (predetermined threshold value), and quality information (OK or NG) indicating the comparison result may be output as the sensor information.

The slave device 50 is a wireless communication unit capable of performing data communication (dashed line with double arrows shown in fig. 1) with the master device 30 by wireless. Therefore, the slave device 50 is configured by, for example, a radio unit configured to be capable of radio communication at a predetermined frequency, a radio controller and an antenna configured to control frequency selection, transmission and reception of the radio unit, and the like, in almost the same manner as the master device 30. The wireless controller of the slave device 50 is different from the wireless controller of the master device 30 in that identification information (master ID) of the master device 30 that manages the slave device 50 is registered in the slave device 50. In addition, a wireless unit, a wireless controller, an antenna, and the like constituting the slave device 50 are not shown in the drawing. In the first embodiment, the node 40 is integrally formed with the slave device 50. Thus, the number of

slave devices

50a, 50b, 50c, … …, 50n corresponds to the number of

several nodes

40a, 40b, 40c, … …, 40 n. In the first embodiment, the node 40 and the slave 50 together correspond to a "first control unit" in the claims.

In the measurement system 10a having such a configuration, as shown in fig. 2, the master device 30 and the slave device 50 perform wireless communication in the system support panel 11, but before the description thereof, a method of establishing a connection between the master device 30 and the slave device 50 will be described. Further, establishment of connection, polling, acknowledgement (ACK, NACK) thereof, and the like, which will be described below, are performed by the respective wireless controllers of the master device 30 and the slave device 50.

When the slave device 50 is powered on or performs initialization processing, it first transmits a request command frame requesting connection establishment to the master device 30 that manages the slave device 50. The request command is added with identification information (slave ID) of the slave 50 and identification information (master ID) of the master 30. Therefore, when the master device 30 that has received the command requesting the connection establishment determines that the command is a request for establishing a connection with itself, it registers the slave ID added to the request command requesting the connection establishment and transmits a response frame to which a connection establishment response of the slave ID is added. Thereby, the establishment of the connection between the master device 30 and the slave device 50 is completed, and therefore, the master device 30 thereafter transmits a polling frame to the slave device 50 at prescribed time intervals.

That is, as shown in fig. 2, the master device 30 ("M" shown in fig. 2) sequentially transmits polling frames (POL) to a plurality of

slave devices

50a, 50b, 50c, … …, 50n ("Sa", "Sb", "Sc" … … "Sn" shown in fig. 2) managed by itself. The polling frame is appended with a slave ID that can determine the slave device 50. Therefore, when each

slave device

50a, 50b, 50c, … …, 50n receives the polling frame (POL) for itself, it transmits ACK (ACKnowledgement) to the master device 30.

In the communication method shown in fig. 2, transmission of data (downlink data) from the master device 30 to the slave device 50 is not considered, and for example, when command data indicating that the sensor unit 60 is forcibly initialized is transmitted from the master device 30 to the slave device 50, a Negative ACKnowledgement (NACK) for responding when an error occurs in the data or the like may be transmitted from the slave device 50 to the master device 30. Further, in a case where the master device 30 transmits a polling frame to the slave device 50 and the corresponding slave device 50 does not respond thereto (in a case where no ACK is returned), the master device 30 transmits warning information of the corresponding slave device 50 to the CPU20, and conveys information indicating that an abnormality occurs in the corresponding slave device 50 to the CPU 20. Thus, for example, the CPU20 causes a display device connected to the CPU20 to display failure information of the corresponding slave device 50 (for example, causes an icon of the corresponding slave device 50 to change from green when normal to red when abnormal), and reports the occurrence of a failure of the corresponding slave device 50 to the operator.

Further, in the case where sensor DATA is transmitted from the connected sensor unit 60 to the slave device 50, the slave device 50 transmits the sensor DATA (DATA shown in fig. 2) to the master device 30 following ACK. In the first embodiment, wireless communication is performed between the master device 30 and the slave device 50 by such a communication method (polling method). Note that the process of transmitting the polling frame from the master device 30 to the slave device 50 (polling process) corresponds to "predetermined information processing" described in the claims.

The measurement system 10a of the first embodiment can be applied to a level sensor mounted on a tanker, for example. That is, in the first embodiment, as shown in fig. 3, the measurement system 10a is applied to a system for collecting and processing liquid level data (sensor data) from a liquid level sensor 107, the liquid level sensor 107 being used to detect a liquid level position (liquid level) of the liquid 110 in the cargo tank 105 of the hull 101 of the tanker 100. The level sensor 107 is typically for example an FMCW radar type level sensor or an electromagnetic float type level sensor. Each level sensor 107 (

sensor units

60a, 60b, 60c, … …, 60n) is mounted to a top wall 102, the top wall 102 being adapted to enclose an upper portion of the cargo box 105 separated by a partition wall 103. In fig. 3, a section of the cargo box 105 is more visually illustrated by cutting a part of the hull 101. In addition, some of the partition wall 103, the cargo tank 105, the level sensor 107, and the liquid 110 are denoted by reference numerals, and some are not denoted by reference numerals.

The liquid level data (sensor data) detected by each liquid level sensor 107 is transmitted to each node 40 (

nodes

40a, 40b, 40c, … …, 40n) in the system support panel 11 via the cable 90, and the system support panel 11 is installed in an installation space for mounting equipment in the ship. Thus, as described above, the liquid level data (sensor data) detected by each liquid level sensor 107 is wirelessly transmitted from the slave devices 50 (

slave devices

50a, 50b, 50c, … …, 50n) to the master device 30, and is collected by the CPU20 via the master device 30 that receives the data. The CPU20 outputs the operation information of each liquid level sensor 107 based on the liquid level data transmitted from each liquid level sensor 107, performs integration processing or statistical processing on the liquid level data, and outputs the result to the outside, or displays the result on a display device which is not shown in the figure.

As described above, the measurement system 10a according to the first embodiment includes: a plurality of nodes 40a to 40n connected to the plurality of sensor units 60a to 60n, respectively, and capable of data communication; a CPU20 that receives, from a plurality of sensor units 60a to 60n, sensor data transmitted from the plurality of sensor units 60a to 60n connected to the nodes 40a to 40n and capable of data communication; the system support panel 11 houses a plurality of nodes 40a to 40n and a CPU 20. Then, data communication between the plurality of nodes 40a to 40n and the CPU20 is realized wirelessly, not by wire, via the master device 30 and the slave devices 50a to 50n in the system support panel 11. This eliminates the need to provide a cable for data communication (wire saving) between them, and eliminates the need to secure a space for housing the cable in the case. Therefore, the volume of the space in which the cable is housed in the system support panel 11 can be reduced. Thus, the device can be miniaturized or the installation space can be saved.

In the measurement system 10a, the CPU20 is configured separately from the main device 30 and is connected to the main device 30 by the cable 13, but the CPU20 may be configured integrally with the main device 30. That is, as shown in fig. 4, as a modification of the measurement system 10a of the first embodiment, the cable 13 in the system support panel 11 may be omitted (measurement system 10 b). Thus, the measurement system 10b can reduce the number of cables housed in the system support panel 11 as compared with the measurement system 10a described above, and thus can save more electric wires and can further reduce the volume of the system support panel 11. Therefore, it is possible to further achieve miniaturization of the apparatus or further save the installation space.

The measurement system 10b shown in fig. 4 can be applied to, for example, the level sensor 107 mounted on the tanker 100, similarly to the measurement system 10 a.

[ second embodiment ]

Next, a second embodiment of the measurement system of the present invention will be described with reference to fig. 5 to 8. As shown in fig. 5, the measurement system 10c of the second embodiment is different from the measurement system 10a of the first embodiment in that 2

masters

30a and 30b are connected to a CPU 20. Therefore, the same reference numerals as those of the measurement system 10a are given to the same components as those of the measurement system 10a of the first embodiment, and the description thereof is omitted.

As shown in fig. 5, in the measurement system 10c according to the second embodiment, 2 pieces of the master 30a and the master 30b are connected to each other by the cable 13 and also connected to the CPU 20. Thus, one master device 30a of the 2 master devices 30 can manage the

slave devices

50a, 50b, 50c, for example, and the other master device 30b can manage the slave devices 50d, … …, 50n, for example. Specifically, the

master devices

30a, 30b may employ the communication methods shown in fig. 6 and 7. And, it is assumed here that there are 6 slaves 50 in total. Then, the master IDs of the

masters

30a and 30b that manage the slaves 50a to 50n in a default state are registered with the radio controllers of the slaves 50a to 50n, so that one master 30a manages 3

slaves

50a, 50b, and 50c, and the other master 30b manages the remaining 3 slaves 50d, … …, and 50 n.

When the

master devices

30a and 30b that have received the command for requesting connection establishment from the slave devices 50a to 50n determine that the master devices are requests for establishing connection with themselves, they register the slave device ID added to the request command for requesting connection establishment and transmit a response frame to which a connection establishment response is added with the slave device ID. Thereby, the establishment of the connection between the master device 30a and the

slave devices

50a, 50b, 50c is completed, and the establishment of the connection between the master device 30b and the slave devices 50d, … …, 50n is completed. Therefore, from then on, the

master devices

30a, 30b transmit polling frames to the respectively managed slave device 50a and the like at prescribed time intervals.

That is, as shown in fig. 6, one master device 30a ("Ma" shown in fig. 6) sequentially transmits polling frames (POL) to 3

slave devices

50a, 50b, and 50c ("Sa", "Sb", and Sc "shown in fig. 6) managed by itself. Similarly, the other master device 30b ("Mb" shown in fig. 6) transmits polling frames in order to the 3 slave devices 50d, … …, and 50n ("Sd", … …, "Sn" shown in fig. 6) managed by itself. Since the polling frame is appended with a slave ID that can identify the slave device 50, each

slave device

50a, 50b, 50c, … …, 50n transmits an ACK to the master device 30a or the master device 30b when receiving the polling frame for itself.

The master device 30a and the master device 30b adjust the transmission timing so as not to transmit the polling frames at the same time, respectively. For example, the

master devices

30a and 30b can transmit the polling frame by sharing a transmission clock that determines the transmission timing via the cable 13 by the same (common) transmission clock. Therefore, since the polling frames can be transmitted at different timings, it is possible to suppress a failure of polling due to collision of the polling frames. Further, collision of such polling frames can be avoided by the carrier sense circuits provided in the wireless units of the

master devices

30a and 30b, respectively.

Further, in the case where the

master device

30a, 30b transmits a polling frame to the slave device 50 and the corresponding slave device 50 does not respond thereto (in the case where no ACK is returned), the

master device

30a, 30b transmits warning information of the corresponding slave device 50 to the CPU20, and transmits information indicating that an abnormality occurs in the corresponding slave device 50 to the CPU 20. Thus, for example, the CPU20 displays failure information of the corresponding slave device 50 (for example, an icon of the corresponding slave device 50 changes from green when normal to red when abnormal) on the display device connected to the CPU20, and notifies the operator of the failure of the corresponding slave device 50.

When one of the

masters

30a and 30b fails to transmit a polling frame due to a failure or the like, the slave devices 50d, … …, and 50n belonging to the master 30b are managed by the one master 30a, for example, in the following manner. That is, as shown in fig. 7, when there is no polling even if the timing of transmitting the polling frame from the other master device 30b (or the timing of the elapse of the predetermined timeout period after the last reception of the polling frame) has elapsed, the slave devices 50d, … …, and 50n transmit a request command frame (REQ) requesting the establishment of a connection to the other master device 30 a.

The request command is added with the master ID of the master 30a in addition to the slave ID of the slave 50. Therefore, when the master device 30a that has received the command of the connection establishment request determines that it is a request to establish a connection with itself, it registers the slave ID attached to the request command requesting establishment of a connection, and transmits a response frame (RES) to which the connection establishment response of the slave ID is attached. Thereby, the establishment of the connection between the master device 30a and the slave devices 50d, … …, 50n is completed.

After the connection is established, one master device 30a sequentially transmits a polling frame (POL) to the slave devices 50a to 50n, thereby managing all the slave devices 50 and the like. That is, all the slave devices 50 and the like are managed by the master device 30 a. In addition, when one master device 30a cannot transmit a polling frame due to a failure or the like, the

slave devices

50a, 50b, and 50c managed by the master device 30a are changed to be managed by another master device 30b in the same manner.

As described above, according to the measurement system 10c of the second embodiment, one master 30a of the 2

masters

30a and 30b receives sensor data from 3

nodes

40a, 40b, 40c, 40d, … …, and 40n of the 6

nodes

40a, 40b, 40c, 40d, … …, and 40n, and the other master 30b receives sensor data from the remaining 3 nodes 40d, … …, and 40 n. This can reduce the load of information processing for each master 30, compared to the case where 1 master 30 receives sensor data from 6

nodes

40a, 40b, 40c, 40d, … …, and 40 n. That is, the load can be distributed as compared with the case where the master 30 is single.

When one master device 30b does not perform the polling processing, the 3 nodes 40d, … …, and 40n that have transmitted the sensor data to the one master device 30b transmit the sensor data to the other master device 30a that can normally perform the polling processing and the like. When the other master device 30a does not perform the polling process, the 3

nodes

40a, 40b, and 40c that have transmitted the sensor data to the other master device 30a transmit the sensor data to the one master device 30b that can normally perform the polling process and the like. This can suppress a failure in the transmission of the sensor data due to the 6

nodes

40a, 40b, 40c, 40d, … …, and 40n continuously transmitting the sensor data to, for example, one master 30a (or another master 30b) that cannot respond due to a failure or the like.

In the measurement system 10c, the CPU20 is configured separately from the

main devices

30a and 30b, and the two are connected by the cable 13, but the CPU20 may be configured integrally with the

main devices

30a and 30 b. That is, as shown in fig. 8, 1 CPU20 may be added, and one CPU20a may be integrated with the host device 30a, and the other CPU20b may be integrated with the host device 30 b. In this case, the CPU20a and the CPU20b are connected by the cable 13, and the consistency of the management information of the slave device 50 between the two

CPUs

20a and 20b can be ensured. That is, the CPU20a and the CPU20b share the management information of the slave devices 50 (

slave devices

50a, 50b, 50c, 50d, … …, and 50n) so that the slave device 50a and the like managed by the master device 30a and the slave device 50d and the like managed by the master device 30b do not overlap with each other.

Thus, the load of information processing on each CPU20 can be reduced compared to the case where 1 CPU20 performs information processing on sensor data from 6

nodes

40a, 40b, 40c, 40d, … …, and 40 n. That is, the load can be distributed as compared with the case where the CPU20 is single. The number of the CPUs 20 may be 3 or more.

The measurement system 10c according to the second embodiment and the measurement system 10d shown in fig. 8 can be applied to, for example, the level sensor 107 mounted on the cruise ship 100, similarly to the measurement system 10 a.

Note that, in the first and second embodiments, the case where there are several nodes 40 or sensor units 60 has been described as an example for convenience of description, and 100 or more nodes 40 or sensor units 60 may be connected to the master 30 or the like via a wireless circuit.

In the first and second embodiments, the polling method is used as the communication method between the master device 30 and the slave device 50. This can prevent collision of sensor data between the slave devices 50 (e.g., the slave device 50a and the slave device 50b) as compared with the case of using the contention scheme, for example. If the contention mode is used, the greater the number of nodes 40 or sensor units 60, the higher the probability of collision between sensor data. Therefore, by using the polling method, it is possible to prevent the loss of sensor data due to collision, and to improve the reliability of the sensor data. In addition, since the polling method does not require a correct Time slot as in the TDMA (Time Division Multiple Access) method, it is not necessary to adopt a synchronization method which is likely to become complicated. Therefore, for example, when 100 or more nodes 40 or sensor units 60 are connected to the master device 30 or the like via a wireless circuit, the polling method is used, and the quality of sensor data can be maintained stably by a simple method in the case of non-synchronization.

In the first and second embodiments, the liquid level sensor 107 mounted on the tanker 100 has been described as the

sensor unit

60, 60a to 60n, but the measurement system of the present invention may be any sensor (detection unit) capable of measuring a predetermined physical quantity (position, distance, displacement, mass, component or concentration of a substance (gas, liquid, solid), voltage, current, power, temperature, humidity, pressure, flow rate, light (beam, luminosity, illuminance, brightness), magnetism, sound, vibration frequency, speed, acceleration, angular velocity, etc.).

Specific examples of the present invention have been described above in detail, but these are merely examples and do not limit the claims. The techniques recited in the claims include various modifications and changes to the specific examples described above. The technical features described in the specification and the drawings are used singly or in various combinations to achieve technical usefulness, and are not limited to the combinations described in the claims at the time of filing. The techniques in the present specification and the drawings are techniques for achieving a plurality of objects at the same time, and achieving one of the objects has technical usefulness. Note that the parenthesized description in the column of "reference description" is a description that can clearly indicate the correspondence between the technical terms used in the above embodiments and the terms described in the claims.

[ description of reference numerals ]

10a, 10b, 10c, 10d … … measurement system

11 … … System supporting panel (casing)

13. 80, 90 … … Cable

20 … … CPU (second control unit, a part of the second control unit, a second control unit, other second control units, the remaining part of the second control unit, another second control unit)

20a … … CPU (a second control unit, a part of the second control unit, a second control unit)

20b … … CPU (other second control unit, the remaining second control unit, another second control unit)

30 … … Master device (second control Unit)

30a … … Master device (a second control Unit, a part of the second control Unit, a second control Unit)

30b … … Master device (other second control Unit, remaining second control Unit, Another second control Unit)

Node

40, 40a, 40b, 40c, 40d, 40n … … (first control unit)

50, 50a, 50b, 50c, 50d, 50n … … slave device (first control unit)

60, 60a, 60b, 60c, 60d, 60n … … sensor unit (sensor)

100 … … cruise ship (Ship)

105 … … cargo box (reservoir)

107 … … liquid level sensor

110 … … liquid

Claims

1. A measurement system is characterized by comprising:

a plurality of first control units respectively connected with the plurality of sensors in a data communication manner;

a plurality of second control units which are connected with the plurality of first control units in a data communication manner and receive the sensor data sent by the plurality of sensors or the sensor information based on the sensor data from the plurality of first control units; and

a housing that houses the plurality of first control units and the plurality of second control units,

the data communication between the plurality of first control units and the second control unit is wireless data communication using a polling method as a communication method performed in the housing,

when a second control unit of the plurality of second control units does not perform polling processing by the polling method, the first control unit, which has sent the sensor data or the sensor information to the second control unit, of the plurality of first control units requests other second control units of the plurality of second control units to establish connection, and after the connection is established, sends the sensor data or the sensor information in response to polling processing by the other second control units.

2. A measurement system is characterized by comprising:

a part of the plurality of second control units and the remaining second control units among the plurality of second control units perform the polling processing of the polling method at mutually different timings,

the part of the second control units receives the sensor data or the sensor information from a part of the plurality of first control units, and the remaining part of the second control units receives the sensor data or the sensor information from the remaining part of the plurality of first control units.

3. A measurement system is characterized by comprising:

2 second control units connected to the first control units in a data-communicable manner and receiving, from the first control units, sensor data transmitted from the sensors or sensor information based on the sensor data; and

a housing that houses the plurality of first control units and the 2 second control units,

the data communication between the plurality of first control units and the 2 second control units is wireless data communication in which a communication method performed in the housing employs a polling method,

one of the 2 second control units and the other of the 2 second control units perform polling processing of the polling method at timings different from each other,

the one second control unit receives the sensor data or the sensor information from a part of the plurality of first control units, and the other second control unit receives the sensor data or the sensor information from the remaining part of the plurality of first control units,

when the second control unit does not perform the polling processing of the polling method, the first control unit requests the other second control unit to establish connection, and sends the sensor data or the sensor information in response to the polling processing of the other second control unit after the connection is established,

when the other second control unit does not perform the polling processing of the polling method, the remaining first control units request the connection establishment to the one second control unit, and after the connection establishment is completed, the sensor data or the sensor information is sent in response to the polling processing of the one second control unit.

4. A measuring system according to any one of claims 1 to 3,

the plurality of sensors are liquid level sensors for detecting the liquid level position of the liquid stored in the liquid storage tank of the ship.