JP2011019167A - Radio data monitoring system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a radio data monitoring system capable of managing in an optimal radio wave condition without requiring a fine control of a transmission output of a sensor by a system administrator when a use environment changes during the use of a network, and capable of assuring a stable operation of the wireless network and a long life time of a battery.SOLUTION: The radio data monitoring system includes: a base station; a sensor operating with a battery, periodically measuring data to radio-transmit the measured data to the base station; a radio network system including a relay unit for relaying a radio communication path between the base station and the sensor; and a monitoring operation terminal connected to the base station by radio or wired method and monitoring the measured data. The sensor includes a storing means for recording the measured data, and radio network communication information as the information related to the transmission and reception between the base station and the sensor.

Description

  The present invention relates to a wireless data monitoring system using a wireless network in a data monitoring system such as an instrumentation system and an environmental monitoring system.

  2. Description of the Related Art Conventionally, a data monitoring system generally has a configuration in which a controller such as a PLC (Programmable Logic Controller) and a sensor arranged in a field are connected by a wire and data managed by the controller is displayed on a monitoring operation terminal. It was. With the development of wireless technology, a system in which a wireless chip is mounted on a sensor, measured data is transmitted wirelessly, and displayed on a monitoring terminal has become widespread. Since a data monitoring system using a wireless network system can be constructed without wiring, it has been used for various purposes.

  A general wireless data monitoring system includes a base station, a sensor that measures data, transmits the measurement data to the base station, and a repeater that relays a wireless communication path between the base station and the sensor. The base station constructs a wireless network in response to a wireless network construction request from a user interface (monitoring operation terminal) connected to the base station. After construction of the wireless network, the sensor transmits measurement data to the base station with a preset transmission output at a specified intermittent period.

  In a wireless data monitoring system, there is a system in which the transmission output of a sensor is variable in order to achieve stable operation of wireless communication and long battery life (see, for example, Patent Document 1).

JP 2007-158710 A

  However, in the operation of the wireless data monitoring system, if an obstacle that causes deterioration of the wireless environment occurs between the sensor and the base station (including between the sensor and the repeater, between the base station and the repeater), the radio wave condition deteriorates. To do. Since the sensor continues to transmit data at a preset transmission output, in the worst case, the communication between the base station and the sensor is interrupted and the measurement data is lost.

  If the distance between the sensor and the base station (including between the sensor and the repeater, and between the base station and the repeater) is close, and the sensor is transmitting measurement data to the base station with an excessive transmission output, the sensor transmits Since the operation is continued without changing the output, the battery consumption of the sensor is increased and the battery life is shortened.

  For example, in the wireless data monitoring system described in Patent Document 1, although the transmission output of the sensor is variable, the transmission output of the sensor is determined by the situation at the time of network connection, and changes in the usage environment during continuous operation are considered. It has not been.

  The object of the present invention is to solve the above problems, even if the usage environment changes during use of the network, the system administrator can operate in an optimal radio wave situation without requiring fine adjustment of the sensor transmission output. Another object of the present invention is to provide a wireless data monitoring system capable of stably operating a wireless network and extending the battery life.

  In order to achieve the above object, a wireless data monitoring system according to the present invention includes a base station, a sensor that operates on a battery, periodically measures data, and wirelessly transmits the measurement data to the base station, and the base station A wireless data monitoring system comprising: a wireless network system comprising a repeater that relays the wireless communication path of the sensor; and a monitoring operation terminal that is connected to the base station in a wireless or wired manner and monitors the measurement data. Comprises storage means for recording the measurement data and wireless network communication information, which is information relating to transmission and reception between the base station and the sensor.

  In particular, by keeping a history of reception sensitivity of wireless communication as wireless network communication information, the base station transmits the reception sensitivity with respect to transmission from the sensor as incidental information to the reception response of data transmitted from the sensor. The sensor can obtain accurate reception sensitivity. In addition, data monitoring is continued with the optimum transmission output by changing the transmission output based on the determination of the transition change of the reception sensitivity.

  According to the present invention, even if the usage environment changes during the use of the network, the system administrator can operate in an optimal radio wave condition without requiring fine adjustment of the transmission output of the sensor. Long life can be achieved.

It is the schematic which shows the whole structure of one Embodiment of the wireless data monitoring system which concerns on this invention. It is a block diagram which shows the hardware constitutions of a sensor. It is a flowchart which shows operation | movement of a sensor. It is explanatory drawing which shows the measurement data transmission of a sensor, and the step of communication information storage. It is a flowchart which shows the communication diagnostic method of a sensor.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention will be described with reference to the accompanying drawings.

  FIG. 1 is a schematic diagram showing the overall configuration of the wireless data monitoring system of the present embodiment. As shown in FIG. 1, the wireless data monitoring system includes a monitoring console 11 for monitoring data and operating a wireless network, a base station 12 for controlling wireless communication, data measurement, transmission of measurement data, and a base station. A sensor 13 that receives information transmitted from the station 12 and a repeater 14 that relays wireless communication between the base station 12 and the sensor 13 are configured.

  The wireless data monitoring system of the present embodiment is used for measuring predetermined data in a factory, for example. For example, in a food factory, a chemical factory, etc., the sensor 13 is arranged at a manufacturing site or a raw material warehouse, and measures the temperature, humidity, number of dusts, etc. of the manufacturing site or the raw material warehouse and transmits them to the base station 12. The monitoring console 11 and the base station 12 are connected by wires such as Ethernet (registered trademark), and are installed in an office or a monitoring room to monitor measurement data. The repeater 14 is arranged between the base station 12 and the sensor 13. When the sensor 13 is in a position where direct wireless communication with the base station 12 is not possible, the repeater 14 secures a wireless communication path via the repeater 14. Send data. The monitoring console 11 may be wirelessly connected to the base station 12.

  The operation of a data monitoring system using general wireless communication will be described.

  The supervisor issues a wireless network construction request from the monitoring console 11 to the base station 12, and the base station 12 constructs a wireless network. Channels required for network construction, transmission output of wireless communication, etc. are designated by a network construction request from the monitoring console 11 or are individually defined in advance. Next, the power of the sensor 13 that is directly connected to the base station 12 and the repeater 14 that relays the wireless communication path of the sensor 13 that is installed at a location remote from the base station 12 are turned on. Data is transmitted to the base station 12 at a specified intermittent period.

  FIG. 2 is a block diagram illustrating a hardware configuration of the sensor 13. As shown in FIG. 2, the sensor 13 includes a microcomputer 21 that controls the operation of the sensor 13, a built-in sensor unit 22 that measures data, an expansion connector 23 that enables connection with an external device such as an external sensor, Wireless chip 24 and antenna 27 that perform transmission, wireless network communication information (hereinafter simply referred to as “communication information”) that is information relating to transmission and reception of the wireless network, and nonvolatile memory 25 that serves as storage means for storing measurement data, communication It includes an LCD 26 that displays an operating environment such as information and measurement data. Conventionally, the non-volatile memory 25 is generally used to store measurement data so that measurement data at the time of disconnection of wireless communication can be collected again after communication is restored. However, in the present embodiment, the nonvolatile memory 25 stores communication information in addition to accumulation of measurement data. The communication information is the reception sensitivity of the sensor 13 in the base station 12, and the history of reception sensitivity accumulated in the sensor 13 is used as data for changing the transmission output of the sensor 13. As communication information, in addition to reception sensitivity, radio wave intensity and communication quality information may be used.

  Next, the main flow of the sensor 13 will be described. FIG. 3 is a flowchart showing the operation of the sensor 13. As shown in FIG. 3, when the sensor 13 is activated for the first time, in addition to parameters necessary for wireless communication such as a used channel and wireless transmission output, a preset minimum reception sensitivity, recommended reception sensitivity, and reception sensitivity range are stored in a nonvolatile memory. 25 (operation parameter reading 31). The minimum reception sensitivity is the minimum reception sensitivity necessary for the base station 12 to receive data from the sensor 13. The recommended reception sensitivity is higher than the minimum reception sensitivity, and is the optimal reception sensitivity for the base station 12 to receive data from the sensor. The reception sensitivity range (allowable range) is an allowable range of recommended reception sensitivity. When the reception sensitivity of the base station 12 falls outside the allowable range, the sensor 12 increases or decreases the transmission output.

  The initial data value of the network communication information is input in advance through an interface that can be set for each user. The sensor 13 initializes the wireless chip according to the acquired parameters (step 32). When the sensor 13 succeeds in joining the wireless network (step 33), the sensor 13 shifts to a series of processes related to data transmission that loops at an intermittent period. A series of processing related to data transmission refers to communication information (reception sensitivity) transmitted from the base station 12 when the sensor 13 transmits measurement data to the base station 12 (step 34) and the data transmission is normally performed. ) Is stored in the nonvolatile memory 25 and communication diagnosis is performed based on the communication information (step 36). When an abnormality occurs in data transmission, the wireless network is once disconnected (step 38) and the operation parameter is changed (step 39). The content of the change at this time is the maximum transmission output value setting. After changing the operating parameters, the operating parameters are read again 31 and the wireless chip is initialized 32, and the network is re-subscribed 33 with the maximum transmission output to increase the possibility of establishing the return to the network as much as possible.

  FIG. 4 is a flowchart showing steps from data transmission 34 to communication information storage 35. As shown in FIG. 4, the sensor 13 is normally in a sleep state (sleep mode) and suppresses battery consumption (step 401). When the preset data measurement timing is reached, the sensor 13 is activated (step 402), and data is measured and stored from the built-in sensor 22 or an external sensor connected to the expansion connector 23 (step 403). A data packet is transmitted to the station 12 (step 404). When the base station 12 receives the data packet transmitted from the sensor 13 (step 405), the wireless chip 24 acquires the reception sensitivity at the time of data packet reception (step 406). After acquiring the reception sensitivity, the base station 12 transmits a response packet for data packet reception to the sensor 13 using the reception sensitivity as supplementary information (step 407). The sensor 13 receives the response packet (step 408), and obtains reception sensitivity when the response packet is received (step 409). The sensor 13 stores the reception sensitivity included in the response packet in the nonvolatile memory 25 as the reception sensitivity of the base station 12 and the reception sensitivity at the time of receiving the response packet as the reception sensitivity of the sensor 13.

  When transmitting measurement data from the sensor 13 to the base station 12 via the repeater 14, the reception sensitivity of the repeater 14 is required as communication information. In data transmission, the transmission destination is the base station 12, and the repeater 14 only relays the packet and does not create a response packet. For this reason, the sensor 13 receives and accumulates the reception sensitivity of the repeater 14 by packet transmission to the repeater 14, for example, time adjustment.

  The history of reception sensitivity of the base station 12 accumulated in the sensor 13 by the processing of FIG. 4 is used in communication diagnosis (step 36 in FIG. 3). FIG. 5 is a flowchart showing a method for diagnosing communication between the base station 12 and the sensor 13.

  As shown in FIG. 5, the sensor 13 first compares the latest base station reception sensitivity with the minimum reception sensitivity (step 51). If the latest base station reception sensitivity is lower than the minimum reception sensitivity (RSSI ≦ LOW), compare the latest base station reception sensitivity with the minimum reception sensitivity again after a predetermined time, and check whether the base station reception sensitivity is continuously low. Check (step 52). If the latest base station reception sensitivity is lower than the minimum reception sensitivity for the first time only (step 52-> NO), the determination result is judged as normal because the reception sensitivity has been temporarily lowered. Transition to processing. However, when the latest base station reception sensitivity is continuously low (step 52 → YES), it is determined that the communication environment has deteriorated, and a determination is made as to increase the transmission output required (step 54). At this time, it is desirable that the number of times that the communication environment is determined to be deteriorated is not fixed and can be set as appropriate.

  If the latest base station reception sensitivity is higher than the minimum reception sensitivity, the average value of the reception sensitivity of the base station 12 for the past certain period is obtained, and the average value is compared with the recommended reception sensitivity (step 53). If the average value of the reception sensitivity of the base station 12 is lower than the recommended reception sensitivity (step 53 → AVE ≦ RECOMMEND), the transmission output of the sensor 13 is low and wireless communication with the base station 12 may be interrupted. (Step 54). When the average value of the reception sensitivity of the base station 12 is within the reception sensitivity range of the recommended reception sensitivity (step 53 → RECOMMEND <AVE ≦ RECOMMEND + BAND), the sensor 13 is wirelessly transmitting to the base station 12 with an optimal transmission output. It is determined that the current transmission output is maintained (step 55). When the average value of the reception sensitivity of the base station 12 is not within the reception sensitivity range of the recommended reception sensitivity (step 53 → RECOMMEND + BAND <AVE), it indicates that the sensor 13 is performing wireless transmission with an output more than necessary. Then, it is determined to reduce the transmission output of the sensor 13 (step 56).

  Returning to FIG. 3, if it is determined that the transmission output of the sensor 13 is maintained as it is based on the determination result of the communication diagnosis, sleep is performed until the next measurement timing (step 37).

  On the other hand, when it is determined that the transmission output of the sensor 13 is changed based on the determination result of the communication diagnosis, the sensor 13 is removed from the network (step 38) and the operation parameter is changed (step 39).

  Regarding the change of the operation parameter, the changed transmission output value of the sensor 13 is calculated from the average of the reception sensitivity of the sensor 13 and the reception sensitivity of the base station 12. In addition, since the base station 12 and the repeater 14 are driven by an AC power source, there is no concern about battery life, and wireless transmission is normally performed at the maximum output. For this reason, the average value of the reception sensitivity of the sensor 13 is the reception sensitivity at the time of the maximum transmission output, and the expression “average reception sensitivity of the base station: average reception sensitivity of the sensor = transmission output of the current sensor: maximum output” is obtained. be able to. From this comparison, for example, the transmission output of the sensor 13 necessary for changing the reception sensitivity by 1 dBm is obtained, the transmission output for obtaining the ideal reception sensitivity is calculated, and the operation parameter is changed. When the calculated result exceeds the settable range of the transmission output, the minimum or maximum transmission output that can be set is set.

  According to the wireless data monitoring system of this embodiment, the base station 12 changes the communication environment state of the sensor 13 to the sensor 13 even if the use environment such as the reception sensitivity of the base station 12 changes during use of the wireless network. By transmitting and storing the communication information from the base station 12 by the sensor 13, based on the communication information held in the sensor 13, the transmission output of the sensor 13 is held at an optimum output value without the operator's operation. can do.

  In particular, when it is determined that the reception sensitivity of the base station 12 is low, the transmission output of the sensor 13 can be increased to prevent data loss in wireless data communication. When it is determined that the reception sensitivity of the base station 12 is higher than necessary, the transmission output of the sensor 13 can be reduced, the power consumption of the battery provided in the sensor 13 can be suppressed, and the battery life can be extended.

  As described above, the present invention is not limited to the above-described embodiment, and various other ones are assumed.

11 On-site console 12 Base station 13 Sensor 14 Repeater 25 Non-volatile memory

Claims (6)

A wireless network system comprising: a base station; a sensor that operates on a battery, periodically measures data; and wirelessly transmits the measurement data to the base station; and a repeater that relays the base station and a wireless communication path of the sensor When,
In a wireless data monitoring system comprising a monitoring operation terminal that is connected to the base station wirelessly or by wire and monitors the measurement data,
The wireless sensor monitoring system, wherein the sensor includes storage means for recording the measurement data and wireless network communication information that is information relating to transmission / reception of the sensor with the base station.   2. The wireless data monitoring system according to claim 1, wherein the wireless network communication information is reception sensitivity of the base station.   3. The wireless data monitoring system according to claim 2, wherein each time the base station receives the measurement data, the base station transmits the reception sensitivity at that time to the sensor, and the sensor sequentially stores the reception sensitivity. Wireless data monitoring system.   4. The wireless data monitoring system according to claim 3, wherein the sensor adjusts a transmission output of wireless transmission based on the reception sensitivity.   5. The wireless data monitoring system according to claim 4, wherein when the sensor determines that the reception sensitivity of the base station is lower than the reception sensitivity preset in the sensor, the sensor increases the transmission output, The wireless data monitoring system according to claim 1, wherein when the reception sensitivity of the base station is determined to be better than necessary than a preset reception sensitivity, the sensor decreases a transmission output.   6. The wireless data monitoring system according to claim 5, wherein a reception sensitivity range suitable for the base station to perform wireless communication with the sensor is preset in the sensor, and the reception sensitivity of the reception sensitivity transmitted intermittently from the base station is set. When the average value is compared with the reception sensitivity, and the average value is lower than the reception sensitivity range, the transmission output of the sensor is increased, and when the average value is within the reception sensitivity range, the sensor The wireless data monitoring system is characterized in that the transmission output of the sensor is lowered when the average value is higher than the reception sensitivity range without changing the transmission output of the sensor.

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