GB2266174A - Remote monitoring system for containers - Google Patents

Abstract

A remote monitoring system for containers has a central monitoring device and a communication device housed in each container. The transmission of signals is carried out by serial communication using a power line. Logging-on to said central monitoring device on the connection of a container to the power line makes use of a peculiar number of the container. The central monitoring device detects interference between signals from two or more containers in a log-on procedure, then interrogates the containers on the basis of possible numbers thereof, and logs-on the containers individually on detection of different actual addresses. When the central monitoring device detects that signal transmission for normal monitoring is not possible for a predetermined period of time, it logs-off the container with which communication has been lost. <IMAGE>

Description

SPECIFICATION 1. TITLE OF THE INVENTION REMOTE MONITORING SYSTEM FOR CONTAINERS 2. FIELD OF THE INVENTION AND RELATED ART STATEMENT The present invention relates to a remote monitoring system for containers which transmits information such as a control command and an operation data by a serial communication system using power lines and is applicable to a marine freezing container or the like.

Generally, the remote monitoring system for containers comprises a central monitoring device, a key terminal station and a plurality of sub terminal stations.

In such a system, if connections among the key station and the sub stations are disconnected due to, for example, the maintenance or the movement of a container, a reregistration process (for example, starting of the central monitoring device, the key station and the sub stations) is made for all of the sub stations.

In general, the key station is installed in an office in a container yard or in a monitoring place in an operation room of a ship and the sub stations are installed in the container in combination therewith.

Accordingly, since a distance between the key terminal station and each of the sub terminal stations is far, the key station and the sub stations can not establish the transmission start condition simultaneously. This is the same even in a temporary disconnection due to the movement of the container or the maintenance.

It takes a very large processing time to implement the registration of the sub terminal stations in the key terminal station in the restoration for the temporary disconnection of the sub terminal stations. On the other hand, since the power line is used as transmission means, it is considered that two or more transmission lines such as A and B lines are formed in the same power line. In such a case, The A and B lines are dedicated to only the respective transmission for the respective sub stations connected to the respective corresponding lines.

Further, in a general communication system, since a network address is settled upon the configuration of the system, it can not be applied to the automatic address registration of the terminals in the communication system of the remote monitoring system for the containers of the present invention.

Generally, the registration of many and unspecified terminals on the same network into a center computer is made in accordance with a communication sequence shown in Fig. 11. In Fig. ll, when the center computer issues a registration request permission signal E, terminals 1 to n for registration request issue request signals Ri to Rn simultaneously. Th request signals collide with one another on the network. In order to avoid this collision, in many cases, delay times T1 to Tn are set in the terminals at random to perform communication. This method is not efficient since useless time tl occurs for each communication.

The freezing container is basically moved among owners of goods, the container yard and the container ships.

Accordingly, in the remote monitoring in the container yard and the container ships, it is always required to monitor containers which are newly connected to the communication network or disconnected therefrom. Further, it is difficult to leave the operator of the container to make registration (hereinafter referred to as log on) and administration of cancel (hereinafter referred to as log off) of the container.

3. OBJECT AND SUMMARY OF THE INVENTION The present invention has been made in view of the above problems and an it is an object of the present invention to solve the above former problem and to provide a remote monitoring system for containers using a serial communication system.

It is another object of the present invention to solve the above latter problem and to provide a remote monitoring system for containers capable of automatically registering addresses of terminals in a communication network.

In order to achieve the above objects, the summary of the present invention is as in the following (1) and (2): (l) The remote monitoring system for containers according to the present invention including a central monitoring device, a plurality of key terminal stations for communication control and sub terminal stations each provided on the side of the container so that transmission of signals such as a control command and operation data is made by a serial communication using a power line, is characterized in that the key stations and the sub stations have the function of storing a registration number peculiar to the sub station and two cr more transmission line systems are constituted on the same transmission line.

With such a configuration, the peculiar number of the sub terminal station being in communication is stored in the key terminal station and the information representing that the sub terminal station is in communication is stored in the sub terminal station so that the restoration to the ordinary communication state can be made without the reregistration process in the re-connection of any of the key terminal station and the sub terminal station. At this time, in order to decide whether it is the ordinary initial registration or not, the registration number (serial number) is used and the registration number is stored in the key station and the sub station so that communication between the key station and the sub station can be realized without confusion even if two or more transmission line systems are constituted on the same line.

Further, the key station stores the registration number of the sub station until a predetermined time elapses even if the sub station is disconnected from the transmission line and when the sub station is re-connected to the transmission line within the predetermined time, the communication state is restored to the state before the disconnection so that the restoration from the temporary disconnection such as the movement of the container and the maintenance and the re-communication can be made automatically.

According to the present invention, the :01 lowing effects are obtained.

(a) The restoration from the temporary disconnection such as the movement of the container and the maintenance and the re-communication can be made automatically and the high-speed operation can be achieved.

(b) Even when two or more transmission line systems are constituted on the same line, the normal communication can be made and the constitution of the transmission line is not controlled by the wiring state of the power line system.

(2) Further, the remote monitoring system according to the present invention which transmits operation information for freezing containers on a communication network including a central monitoring device having a computer and a communication modem device and a communication modem included in the freezing container, is characterized in that registration and cancel of the registration to the central monitoring device corresponding to connection and disconnection of the freezing containers are made by using peculiar numbers (terminal address) of the freezing containers for avoidance of collision in request of the registration of a plurality of containers, and when communication for ordinary monitoring is impossible and this state is continued for a predetermined time, the registration is canceled.

More particularly, in the present invention, the communication network using the power line data carrier technique is structured and a main power plug of the freezing container is connected to a receptacle to perform the communication with the central monitoring device. The automatic logging on function by the identification of the container using an identification number of the ISO standard peculiar to the container and the automatic logging off function by continuation of the communication disabling state formed by disconnecting the power plug of the freezing container are added.

With such a configuration, AC 200 V or 400 V line, for example, is used as a data communication line by the power line data carrier technique and mutual communication can be made by means of a master modem device and a slave modem device each including a power line data carrier interface.

Further, a center computer system issues a monitoring command of a designated container to the master modem device and the master modem device takes up a monitoring data from a freezer controller in accordance with a communication protocol previously set with the slave modem device on the basis of the command to transmit the data to the center computer. The computer processes the data and supplies it to an output device. The center computer sequentially receives the monitoring data for other containers and processes the data.

In addition, the container makes connection and disconnection with AC lines in response to movement of cargoes in the container yard or the container ship and the logging on and off processes can be made to the center computer system automatically and efficiently by utilizing the peculiar identification numbers of the containers.

According to the present invention, unskillful computer operation of the container operator is removed and the operation for the remote monitoring in the connection and disconnection of the freezing container is also removed so that mistake by the operator can be excluded and the logging on and off processes to the remote monitoring system of the freezing container can be made exactly.

4. Brief Description of the Drawings Fig. 1 is a block diagram showing a configuration of a first embodiment of the present invention; Fig. 2 is a block diagram showing a case where two transmission lines are mixed on the same signal transmission line; Fig. 3 is a timing chart showing the communication process in Fig. 1; Fig. 4 is a block diagram showing a configuration of a remote monitoring system for freezing containers according to a second embodiment of the present invention; Fig. 5 is a block diagram showing an internal configuration of a modem in a communication interface of Fig. 4; Fig. 6 is a logging on sequence chart in a case of a single unregistered container; Fig. 7 is a logging on sequence chart in a case of two unregistered containers; Fig. 8 is a diagram showing communication data in Figs. 6 and 7;; Fig. 9 is a flow chart showing a program of a microcomputer included in a master modem device of Fig 4; Fig. 10 is a diagram showing a peculiar number of a container; and Fig. 11 is a conventional communication sequence chart.

5. Detailed Description of Preferred Embodiments First Embodiment] Fig. 1 is a block diagram showing a configuration of a first embodiment of the present invention. In Fig. l, numeral 1 denotes a central monitoring device, 2 a computer system, 3 a key station A, 4 a key station R, 5 a sub station No. 1, 6 a container No. 1, 7 a sub station o. 2, 8 a container No. 2, 9 a power line system A, 10 a power line system B, 11 a sub station No. 3, 12 a container No. 3, 13 a sub station No. 4, 14 a container No. 4.

Fig. 2 shows a case where a plurality of transmission lines are mixed on the same line and Fig. 3 is a timing chart of the embodiment shown in Fig. 1. In Fig. 2, numeral 15 denotes a sub station No. 1A, 16 a container No.

lA, 17 a sub station No. 3A, 18 a container No. 3A, and 19 a common power line system.

In Figs. 1 to 3, registration and deletion of a registration number are made by the central monitoring device 1 and storage (data backup) of the registration number is made by the key stations 3 and 4 and the sub stations 5, 7, 11 and 13.

When the sub stations 5, 7, 11 and 13 are first connected, since the presence of a new connection is checked for each monitoring cycle from the central monitoring device 1, the connection between the key stations 3 and 4 and the sub stations can be achieved. At this time, the key stations 3 and 4 and the sub stations 5, 7, 11 and 13 store the same registration number. More particularly, when the registration number is determined as, for example, 001 between the key station 3 and the sub station 5, the key station 3 stores the sub station of OG1 and the sub station 5 stores 001 as its own registration number.

Thereafter, this registration number is used to perform transmission.

At this time, if the No. 1 sub station 5 is disconnected due to any reason, the key station A3 does not cancel the registration number of the No. 1 sub station 5 until a predetermined time T1 has elapsed. Thus, when there is reconnection within the time Tt, the connection state is returned to the communication state before the disconnection immediately.

Further, as shown in Fig. 2, in the common power line system 19 in which a plurality of lines (in this example, two lines) are connected to the same line, No. 3A sub station 17 is registered to any one of the key station A3 or B4.

In Fig. 1, when No. 4 sub station 13 is moved from the line 10 of the power line system B to the line 9 of the power line system A. that is, when the connection of No. 4 sub station 13 having a plug inserted into a plug socket of the B line 10 must be changed from the B line to the A line due to movement of the installation place in the yard of No.

container 14 or modification of the system or the like by unbalanced consumption power in a ship, calling of the registration number for backup in o. 4 sub station 13 is not mad and when this no-calling state is continued for a time T2, the registration for the power line system B10 is canceled and the registration for the power line system A9 is newly made.

In this manner, No. 4 sub station 13 is automatically moved from the line 10 of the power line system B to the line 9 of the power line system A.

second Embodiment] Fig. 4 is a block diagram showing a configuration of a remote monitoring system for marine freezing containers according to a second embodiment of the present invention The system uses AC 200 V or 400 V power line 109 as a data communication line by the power line data carrier technique, and mutual communication can be made by means of a master modem device 103 and a slave modem device 106 each including a power line data carrier interface.

A center computer 102 issues a monitoring command for a designated container 105 to the master modem device 103. The master modem device 103 takes out a monitoring data from a freezing controller 107 in accordance with a communication protocol established with the slave modem device 106 on the basis of the command and transmits .ne data to the center computer system 102. The center computer system 102 processes the data and supplies the processed data to an output device 104. Thus. the center computer system 102 can receive the monitoring data of other containers lOSa' and 105b' successively and process te data.

The container is connected to or disconnected from AC line due to movement of cargoes in the container yard or the container ship.

In the present invention, the identification numbers peculiar to the containers are used in the connection and the disconnection to perform the logging on process and the logging off process for the center computer system 109 automatically and efficiently.

The hardwares of the master modem device 103 and the slave modem device 106 for use in communication are the same and have the following function. In Fig. 5, transmission and receipt of data with the center computer system 102 or the freezing controller 107 is made through an RS232C interface by one-chip microcomputer 111.

Communication between the master modem device 103 and the slave modem device 106 is made by frequency modulating a serial data produced from a TxD terminal of the one-chip microcomputer 111 by a high-frequency modulator 112 and supplying the modulated signal from the modulator 119 through a transmission amplifier 113, a high-frequency transformer 114, a high-frequency bypass condenser 11D and a power connector 108 of the freezing container to the power line 109 of AC power supply.This signal is transmitted to all of the slave modem devices 106 connected to the power line 109 and is further transmitted through the power connector 108 of the slave modem device 106, the highfrequency bypass condenser 115, the high-frequency transformer 114 and a received signal amplifier 116 to a demodulator 117 to be converted into the original serial data and be supplied to a receive terminal RxD of the onechip microcomputer 111. The demodulator 117 can detect a data modulation signal from the power line 109 separately from the received data and the detected signal is supplied to the one-chip microcomputer 111. A master modem control program 119 is incorporated into a modem to form the master modem device 103 and a slave modem control program 120 is incorporated into a modem to form the slave modem device 106.The modulator 112 and the demodulator 117 can utilize various modulation and demodulation methods.

Figs. 6 and 7 show the logging on sequence according to the present invention using the modem. Fig. 8 shows operation codes and transfer data formats between the modems. Fig. 9 is a program flow chart of the master modem device.

Fig. 6 shows the logging on sequence in the case where runly one container is connected to AC power source.

The center computer system 102 periodically transmits to the master modem device 103 a logging command I L.C1 for detecting containers 105, 105a and 105b connected newly to AC line. The master modem device 103 receives this command and transmits a logging on request inquiry command I El I to AC line constituting the communication network. The slave modem device 106 for an unregistered container which has received the command I EI returns a response signal I Rl .

The container number is added in the signal Em and the master modem device 103 can detect the container number. The master modem device 103 transmits the logging on request I rF! to the center computer system 102 and the center computer system 102 transmits a registration permission response I DN to the modem. The master modem device 103 transmits a logging on completion notification LP r77l to the slave modem device 106 and consequently the slave modem device 106 confirms that the logging on has been made in the center computer system 102.Subsequently, the slave modem device 106 transmits the peculiar data of the container through the master modem device 103 to the center computer system 102 by means of the container I.D. data transmisslon (mi. to complete a series of logging on sequence.

Thereafter the logged on container makes communication or monitoring periodically by the center computer system lfTh2.

Fig. 7 is a diagram showing the logging on sequence in the case here a plurality of new containers are connected to AC line. In this case. there is a problem as follows. The containers 1 and 2 transmit the logging on request I R in response to the logging on request inquiry E of the master modem simultaneously and consequently the container number can not be detected by collision of the data.The collision of data can be detected by a received state of a start code I STxl an end code I FTxl , a bit error detection check code or the like shown in the data format of Fig. 8. Even when data can not be received exactly, the one-chip microcomputer 111 of the master modem device 103 can detect the high-frequency signal on the AC line and detect that at least one or more new containers have transmitted the logging on request response I Rl . The master modem device 103 enters into the search sequence immediately after the detection. The search sequence is made by the peculiar number of the container. The peculiar number of the container is specified by ISO 6346 as shown in Fig.

10.

A code of a company having the container of the peculiar number and a serial number can be used to recognize the individual containers. The present invention is to make the search sequence efficiently. In Fig. 7, after detection of the collision, the master modem device 103 first inquires by a search command I S..l whether a container having a first digit equal to "1" exists or not. If no response, the first digit is converted into '2" and the inquiry is made by the command I Sl.l . Fig. 7 shows a case where two containers have "2" in the first digit and since the logging on request responses I R are issued simultaneously, the collision is again detected by the master modem device 103.

When the collision is detected, the container number for search is carried and a search command I So i77I having the first digit of "2" and the second digit of "1" is issued. In the example of Fig. 7, when the second digit is "5", the slave modem 106 can first transmit the logging on request response tff independently and the master modem device 103 can receive exactly. Thus, the slave modem 106 can recognize the peculiar number of the container included in the response Em . The subsequent sequence is the same as that in the previously-described case where the single container is connected.

The search sequence is made until the response I R1 from the slave modem 106 is exactly received by carrying the container number while detecting the response from the slave modem 106. The search of the code for each company of the peculiar number of the container is made by one previously registered character of alphabetic letter.

As described above, in the present invention the peculiar number of the container is not used as data for the container search but is used for avoidance of the collision upon request of the logging on. The logged on container enters into the ordinary interval monitoring mode.

When the container is disconnected from the AC power source, the communication for the monitoring is normally impossible (no response) and when this state is continued for a fixed time, the center computer system 102 cancels the registered container number. This operation is named the logging off.

The present system can be used even for automatic logging on of the terminals of the system having a dedicated communication line without use of the modem device.

Claims (1)

1. 6. CLAIMS:

   1 A remote monitoring system for containers which transmits operation information for freezing container in a communication network including a central monitoring 1.ev!:e having a computer and a communication modem device an 1 communication modem included in the freezing container characterized in that registration and cancel of the registration to the central monitoring device corresponding to connection and disconnection of the freezing containers are made by using peculiar numbers (terminal address) '.' ne freezing containers for avoidance of collision in reques: : 'f the registration of a plurality of containers, and When communication for ordinary monitoring is impossible and tflis state is continued for a predetermined time, the registration is canceled.