Battery powered wireless communication system

Abstract

To provide a radio communication system capable of sensing a plurality of slave units at the same time or at an arbitrary designated time.SOLUTION: The wireless communication sensor system 1 includes a plurality of slave units 20a, 20b, 20c,., 20n driven by a battery, and a master unit 10 for performing wireless communication with the plurality of slave units. Each of the plurality of slave devices 20 includes a timer for setting the time information received from the master device 10, each of the plurality of slave devices 20 enters a sleep state according to the time information set in the timer, and the master device 10 can sequentially access the slave devices in synchronization with wake-up from the sleep state. A master unit 10 transmits a timer setting command for setting a wake-up time for simultaneously waking up each of a plurality of slave units to a timer to all the slave units 20 by a broadcast address.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a wireless communication system for wirelessly communicating between a master unit and a plurality of slave units, and more particularly to wireless communication between a master unit and a slave unit powered by a battery. [Background technology]

[0002] In a wireless communication system consisting of a base unit and multiple terminals, when a battery is used as a power source for the terminals, it is desirable to reduce power consumption as much as possible and extend the battery life. For example, in the battery-powered wireless communication system disclosed in Patent Document 1, the time when the base unit accesses each of the multiple terminals is synchronized with the sleep time of the terminals, and the terminals' sleep time is canceled only during necessary time periods, thereby saving power consumption of the terminals' batteries. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6251363 Summary of the Invention [Problem to be solved by the invention]

[0004] The synchronous wireless communication system disclosed in Patent Document 1 includes one master device and multiple slave devices, and the master device sequentially accesses the slave devices at a fixed cycle, and the slave devices are in a sleep state when they are not accessed by the master device. The slave devices wake up from the sleep state when they are accessed by the master device, and transmit a message (including, for example, a detection value of a sensor mounted on the slave device) to the master device in response to a query from the master device.

[0005] In such battery-powered synchronous wireless communication systems, there is a demand for simultaneous information collection from multiple slave units (for example, sensing operations of various sensors) and for sensing to be performed at any specified time, but the slave units are in a sleep state during periods when they are not accessed by the master unit, and there is a problem in that such demands cannot be met.

[0006] The present invention is intended to solve such conventional problems, and has an object to provide a wireless communication system that can cause a plurality of slave units to perform sensing at the same time or at any designated time. [Means for solving the problem]

[0007] The present invention realizes a sleep state for the slave unit, extends the battery life of the slave unit, and realizes simultaneous sensing operations of multiple slave units while online, as well as sensing operations at any specified time; these features do not exist in conventional wireless communication systems.

[0008] The wireless communication system of the present invention comprises a plurality of battery-powered sub-units and a base unit that communicates wirelessly with the plurality of sub-units, each of which includes a timer that sets time information received from the base unit, and each of which goes into a sleep state according to the time information set in the timer, and the base unit is capable of accessing the sub-units sequentially in synchronization with their wake-up from the sleep state, and the base unit transmits a timer setting command to all sub-units via a broadcast address to set a wake-up time on the timer that will wake up each of the plurality of sub-units at the same time.

[0009] In one aspect, the parent device accesses the child devices at regular intervals and calculates the wake-up time based on the number of accesses. In another aspect, the parent device determines the interval and the number of accesses based on settings for waiting times for all child devices. In another aspect, the parent device transmits a sensing command to all child devices via a broadcast address in response to the time at which each child device wakes up, causing them to perform a sensing operation. In another aspect, all child devices set the wake-up time received from the parent device in a timer, start the timer, enter a sleep state, and wake up when the timer expires. In another aspect, the parent device further transmits a command to each child device via a unicast address to read information sensed by each child device. In another aspect, the parent device further transmits the timer setting command along with the sensing command.

[0010] Furthermore, the wireless communication system of the present invention comprises a plurality of battery-powered slave units and a master unit that communicates wirelessly with the plurality of slave units, each of the plurality of slave units including a timer that sets time information received from the master unit, each of the plurality of slave units going into a sleep state according to the time information set in the timer, and the master unit being capable of sequentially accessing the slave units in synchronization with waking up from the sleep state, and the master unit transmitting a timer setting command to all slave units by broadcast address to set a designated sensing time in the timer that will cause each of the plurality of slave units to perform sensing at a designated time.

[0011] In one aspect, all of the slave devices set the designated sensing time received from the master device in a timer, start the timer, and then go into a sleep state, and perform the sensing operation when the timer times out. In another aspect, the master device further transmits a command to each of the multiple slave devices by unicast address to read out the information sensed by each of the multiple slave devices. [Effects of the Invention]

[0012] According to the present invention, the parent unit transmits a timer setting command for setting a wake-up time on the timer that will wake up each of the multiple child units at the same time, or a timer setting command for setting a designated sensing time on the timer that will cause each of the multiple child units to sense at a designated time, so that the multiple child units can be sensed at the same time or at a designated time. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is a diagram showing the overall configuration of a wireless communication sensor system according to an embodiment of the present invention; [Figure 2] FIG. 2 is a block diagram showing the configuration of a master unit according to an embodiment of the present invention; [Figure 3] FIG. 2 is a diagram illustrating an example of a functional configuration of a polling program according to an embodiment of the present invention. [Figure 4] 10A and 10B are diagrams illustrating examples of formats of query information and response message information from a slave device. [Figure 5] FIG. 10 is a diagram illustrating the functions of function codes related to sleep time. [Figure 6] FIG. 2 is a block diagram showing the configuration of a slave unit according to an embodiment of the present invention. [Figure 7] FIG. 10 is a diagram illustrating an example of a functional configuration of a response program according to an embodiment of the present invention. [Figure 8] FIG. 2 is a block diagram showing a configuration of a host according to an embodiment of the present invention. [Figure 9A] FIG. 2 is a diagram illustrating a communication protocol from a parent device to a child device in the present embodiment. [Figure 9B] FIG. 2 is a diagram illustrating a communication protocol from a parent device to a child device in the present embodiment. [Figure 10A] FIG. 2 is a diagram illustrating a communication protocol from a slave device to a master device according to the present embodiment. [Figure 10B] FIG. 2 is a diagram illustrating a communication protocol from a slave device to a master device according to the present embodiment. [Figure 11] 10 is a diagram illustrating an example of a sequence between a master device and a slave device in the wireless communication sensor system of the present embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0014] Next, an embodiment of the present invention will be described in detail with reference to the drawings. A wireless communication system according to the present invention includes a plurality of battery-powered slave units, a master unit that performs two-way wireless communication with the plurality of slave units, and a control device (host device) connected to the master unit. The wireless communication system of the present invention is preferably a monitoring system that monitors information detected by the plurality of slave units. The slave units are located in remote locations and are capable of detecting various types of information from the remote locations. For example, the slave units may include a temperature sensor, a humidity sensor, a water level sensor, a soil moisture sensor, a rain gauge, a pressure sensor, an air pressure sensor, etc. The master unit performs two-way wireless communication with the plurality of slave units, and transmits information to the plurality of slave units or receives information from the plurality of slave units. The master unit is further connected to a control device that controls the entire wireless communication system and is capable of transmitting instructions to the plurality of slave units in response to commands from the control device. [Example]

[0015] 1 is a diagram showing the overall configuration of a wireless communication sensor system according to an embodiment of the present invention. The wireless communication sensor system 1 according to this embodiment includes a master device 10, a plurality of slave devices 20a, 20b, 20c, ... 20n (n is an integer of 2 or more), and a host device 30. Note that the slave devices 20a to 20n are collectively referred to as slave devices 20.

[0016] The master device 10 performs two-way wireless communication (e.g., 920 MHz frequency band) with each of the multiple slave devices 20. When the master device 10 transmits a query (inquiry) Qa to the slave device 20a, the slave device 20a replies with a response message Ra in response to the query Qa. Similarly, when the master device 10 transmits a query Qb to the slave device 20b, the slave device 20b replies with a response message Rb in response to the query Qb. In the system of this embodiment, when the master device 10 accesses the slave devices 20, it transmits queries Qa, Qb, Qc, ... Qn to all of the slave devices 20a, 20b, 20c, ... 20n in a predetermined order (e.g., from the lowest address) to a predetermined number n of the slave devices 20, and receives response messages from each of the slave devices. The slave devices 20 wake up in synchronization with a period during which they are accessed by the master device, minimizing battery consumption. Even if some of the slave units are disconnected, the master unit 10 does not skip the disconnected slave units but accesses a predetermined number n of slave units 20, thereby preventing the loss of synchronization between the master unit and the slave units.

[0017] When the slave device 20 receives a query Q from the master device 10, it creates a response message R in response to the query Q and transmits this to the master device 10. The slave device 20 is powered by a battery and has a sleep state (low power consumption state) in which only the minimum necessary operations are performed, and a normal operating state in which it wakes up from the sleep state. In the normal operating state, all functions included in the slave device can operate fully, and in the low power consumption information, some functions included in the slave device can operate.

[0018] The host device 30 is connected to the parent device 10 by wire or wirelessly. The host device 30 can be a computer, a notebook computer, a portable communication terminal, a tablet communication terminal, or the like. The host device 30 issues necessary instructions to the parent device 10 to monitor or control the entire system, and also collects information about the child devices 20 from the parent device 10. The host device 30 may be connected to the parent device 10 via a network such as the Internet or an intranet, for example.

[0019] 2 is a block diagram showing an example of the configuration of the parent device according to this embodiment. The parent device 10 includes an input unit 100 (for example, various switches and buttons attached to the parent device 10, a touch panel input, a power on / off switch, etc.), a wireless communication unit 110, an external connection unit 120, a storage unit 130, a display unit 140, and a control unit 150. Note that this configuration is an example, and the parent device may include other components.

[0020] The wireless communication unit 110 includes a wireless module (hereinafter, sometimes referred to as WM) for performing two-way wireless communication with the slave devices 20. Wireless communication between the master device 10 and the slave devices 20 is performed using a protocol that allows the master device 10 to access multiple slave devices 20, and for example, a communication method based on the Modbus (registered trademark) protocol is adopted. In this communication method, only the master device 10 can issue queries, and the master device 10 performs unicast communication to issue queries to addressed slave devices. Each slave device creates a response message in response to the query from the master device and transmits this to the master device 10.

[0021] The external connection unit 120 establishes a wired or wireless connection with the host device 30, or establishes a connection with other networks, etc. The connection between the parent device 10 and the host device 30 is made asynchronously with the wireless communication with the child device 20. The wired connection can be, for example, an RS232C cable, a USB cable, or a wired LAN, and the wireless connection can be, for example, WiFi (registered trademark), WiMAX, wireless LAN, or Bluetooth (registered trademark).

[0022] The memory unit 130 can store various data such as programs executed by the control unit 150, queries to the slave unit 20, response messages from the slave unit 20, commands from the host device 30, etc. The display unit 140 is a display medium such as a liquid crystal display attached to the master unit 10, and can display warning messages indicating the status of the master unit 10, response messages from the slave unit 20, connection information with external devices, etc.

[0023] In a preferred embodiment, the control unit 150 is configured with a microcontroller or microprocessor (MPU) or the like, and the control unit 150 executes a communication control program or sequence that controls two-way wireless communication between the base unit 10 and the handset 20.

[0024] 3 is a diagram showing the functional configuration of a communication control program or sequence executed by the control unit 150. The communication control program (or communication control sequence) 200 includes a query creation unit 210, a sleep information setting unit 220, a query transmission unit 230, a response message reception unit 240, a child device information provision unit 250, and a simultaneous sensing control unit 260.

[0025] The query generation unit 210 generates a query to be issued to each of the slave devices 20. Fig. 4(A) shows the transmission format of the query. As shown in the figure, the query includes a device address, a function code, query data, and an error check.

[0026] The device address is unique identification information assigned to each of the slave devices 20, and the master device specifies the device address of the slave device when accessing the slave device 20. For example, when sending a query to the slave device 20a in FIG. 1, the master device specifies the device address of the slave device 20a, and when sending a query to the slave device 20b, the master device specifies the device address of the slave device 20b.

[0027] The function code includes, for example, various commands conforming to the Modbus standard. For example, there are commands to read the on / off state of the slave unit's output, commands to read the on / off state of the slave unit's input, commands to read the contents held in the slave unit's register, and commands to change the contents of the slave unit's register. Furthermore, in this embodiment, a unique function code Fn is provided as shown in FIG. 5. The function code Fn is a command to instruct the slave unit to set a sleep time and to poll the slave unit. This function code Fn is always included when the master unit 10 accesses the slave unit 20.

[0028] The query data can include various information, such as the setting or modification of the sensor threshold value of the slave device, as well as the sleep information required to set the sleep time for the function code Fn. The error check includes information for detecting and correcting errors in the transmitted data.

[0029] The sleep information setting unit 220 sets sleep information necessary for the slave devices 20 to set a sleep time. In one preferred example, the sleep information is a period T (hereinafter also referred to as a status notification interval) at which the master device accesses all of the slave devices 20. When the number of slave devices 20 is n, the master device 10 accesses one slave device at a time interval of T / n. The status notification interval T is instructed to the master device 10 by the host device 30, but if no such instruction is received, the master device 10 can set a default value as the status notification interval T.

[0030] The query sending unit 230 sends the created query to all the slave devices 20 via the wireless communication unit 110, for example, in ascending order of slave device addresses (for example, in the order of slave devices 20a, 20b, 20c, ... 20n in Figure 1).

[0031] The response message receiving unit 240 receives a response message sent from the slave device 20 in response to a query. The transmission format of the response message is shown in FIG. 4(B). The confirmation device address is the address of the slave device that created the response message, the confirmation function code is the function code executed by the slave device, and the response data is information including the content of the response to the query. The slave device information providing unit 250 provides the response data received by the response message receiving unit 240 to the host device 30.

[0032] The simultaneous sensing control unit 260 includes a function to transmit, to all the slave devices by broadcast address, commands for waking up each of the slave devices at the same time, commands for causing each of the slave devices to perform sensing operations, commands for causing each of the slave devices to perform sensing operations at a specified time, and data required for these, in addition to the access of each of the slave devices by the unicast address described above. Details of this function will be described later.

[0033] Next, the slave device 20 of this embodiment will be described. FIG. 6 is a block diagram showing the functional configuration of the slave device 20. The slave device 20 generally includes a sensor module 300, a wireless communication module 310, a power supply module 320, and a control module 330. The sensor module 300 includes a sensor circuit for detecting necessary information at the location where the slave device 20 is installed, a memory circuit for storing the information detected by the sensor circuit, and the like. The wireless communication module 310 includes a communication circuit for performing two-way wireless communication with the master device 10, and the like. The power supply module 320 includes a circuit for controlling the transfer of power supplied from a battery to each component, and the like. The control module 330 includes a circuit for controlling the entire slave device 20, and the like.

[0034] 7 is a diagram showing the circuit configuration of the main parts of the slave device 20. In the figure, dashed lines indicate power lines and solid lines indicate signal lines. The sensor module 300 is not shown in detail. The slave device 20 includes a rechargeable secondary battery 400, which supplies a voltage VB (e.g., 3.6 to 3.7 V) to each part. The voltage VB from the battery 400 is supplied to DC / DC converters 402 and 404, reset circuits 410 and 412, and a sleep timer 420.

[0035] When the voltage VB of the battery 400 is applied, the reset circuit 410 responds by outputting a reset signal RESET1 to the power supply load control circuit 440. The power supply load control circuit 440 is power-on reset in response to the reset signal RESET1 and outputs an enable signal EN to the DC / DC converter 402. Upon receiving the enable signal EN, the DC / DC converter 402 converts the voltage VB of the battery 400 to the desired voltage V1 and supplies the converted voltage V1 to the control unit 430 and the reset circuit 412. The reset circuit 412 outputs a reset signal RESET2 to the control unit 430 in response to the voltage V1. When the control unit 430 receives the voltage V1 from the DC / DC converter 402 and the reset signal RESET2 from the reset circuit 410 as an input, it is power-on reset and initializes its internal components. The control unit 430 further initializes the wireless module 470 and outputs a reset signal RESET3 and a power-on signal PWRON to the wireless module 470 to turn on the power.

[0036] Meanwhile, the DC / DC converter 404 is operated by the voltage VB from the battery 400 and outputs the converted desired voltage V2 to the wireless module 470. The wireless module 470 is in the power-down mode when the voltage V2 is simply input, but when the power-on signal PWRON is input from the control unit 430 as described above, it enters the power-on mode. When the wireless module 470 is in the power-on mode, the wireless module 470 can receive a query from the master device 10. The wireless module 470 can also receive a command from the control unit 430, and can transition from the power-on mode to the sleep mode and from the sleep mode to the power-on mode in response to the command. When the wireless module 470 is in the sleep mode, the power supply to the RF circuit of the wireless module 470 is turned off, and the wireless module 470 enters a low-power consumption state. When in the sleep mode, the wireless module 470 cannot receive a query from the master device 10.

[0037] Sleep timer 420 is enabled to operate by voltage VB from battery 400. Sleep timer 420 monitors the sleep time of control unit 430 by counting the sleep time of child device 20. The sleep time of sleep timer 420 is set by control unit 430. In a preferred example, control unit 430 calculates the sleep time based on the access cycle T included in the query of parent device 10, sets the calculated sleep time Tslp in sleep timer 420, and starts counting.

[0038] After transmitting a response message to the parent device, the control unit 430 outputs a control signal STP to the power supply load control circuit 440 to stop the operation of the DC / DC converter 402. Upon receiving the control signal STP, the power supply load control circuit 440 outputs a disable signal to the DC / DC converter 402, causing the operation of the DC / DC converter 402 to stop. As a result, voltage V1 is no longer supplied to the control unit 430, and the control unit 430 effectively enters a power-off state. Furthermore, upon counting the elapsed sleep time, the sleep timer 420 outputs a time-over signal TMO to the power supply load control circuit 440. Upon receiving the time-over signal TMO, the power supply load control circuit 440 again outputs an enable signal EN to the DC / DC converter 402, causing the DC / DC converter 402 to operate. As a result, the control unit 430 enters a power-on state.

[0039] Address storage unit 450 stores the addresses of the slave devices and provides the address information to control unit 430. This address information is referenced, for example, when creating a response message to a query. The method for setting the address in address storage unit 450 is arbitrary, but the address can be set or changed using, for example, a DIP switch or the like.

[0040] When the wireless module 470 receives a query addressed to itself, the interrupt control unit 460 outputs an interrupt signal INT to the control unit 430, waking up the control unit 430 from a sleep state.

[0041] Next, the main functions of the control unit 430 will be described. As shown in FIG. 8, the control unit 430 includes a query receiving unit 500, a command executing unit 510, a sleep time calculating unit 520, a sleep time setting unit 530, a sleep / wake-up executing unit 540, a response message creating unit 550, and a response message transmitting unit 560. These functions may be performed by software (programs), hardware, or a combination of software and hardware. When the control unit 430 includes, for example, a microprocessor MPU including ROM and RAM, the above main functions can be operated by executing a program in the ROM or RAM.

[0042] The query receiving unit 500 receives a query addressed to the local station via the wireless module 470. In one example, the control unit 430 enters a sleep state by executing a program command (sleep command), and when the wireless module 470 receives a query addressed to the local station from the master device 10 while the control unit 430 is in the sleep state, the wireless module 470 causes the interrupt control unit 460 to output an interrupt signal INT. Upon receiving the interrupt signal INT, the control unit 430 wakes up from the sleep state. The wireless module 470 extracts a device address included in the query and determines whether the query is addressed to the local station.

[0043] When the query receiving unit 500 receives a query, the command executing unit 510 executes the function code included in the query. For example, although not shown, the command executing unit 510 performs operations such as setting a threshold value for a sensor included in the slave device and reading values ​​detected by the sensor from a register. Since the query always includes the function code Fn shown in FIG. 5, the command executing unit 510 causes the sleep time calculating unit 520 to calculate a sleep time. Furthermore, the command executing unit 510 decodes commands transmitted from the simultaneous sensing control unit 260 (described later) and performs control based on the commands. For example, upon receiving a command to wake up all slave devices at the same time, the control unit 430 sets the wake-up time received from the master device in the sleep timer 420. Alternatively, upon receiving a command to perform sensing operations on all slave devices at a specified time, the control unit 430 sets the specified time received from the master device in the sleep timer 420.

[0044] The sleep time calculation unit 520 calculates the sleep time Tslp based on the access cycle T (status notification interval T) included in the query. The sleep time Tslp is calculated using the following formula: where Trst is the reset time inside the slave device, Tini is the initialization time inside the slave device, Trcv is the transmission time of the master device plus the reception time of the slave device, and Tst is the time between the sleep timer setting and the timer start. The times Trst, Tini, Trcv, and Tst are, for example, held in advance in a register or the like as default values. However, the master device can also change the times Trst, Tini, Trcv, and Tst stored in the register using a desired function code. Tslp=T-Trst-Tini-Trcv-Tst

[0045] The sleep time setting unit 530 sets the calculated sleep time Tslp via the signal line SLT in the sleep timer 420. The sleep time setting unit 530 also sets a wake-up time or a specified time transmitted together with a command from a simultaneous sensing control unit 260 of the parent device (described later) in the sleep timer 420. When the sleep time is set, the sleep timer 420 starts counting, and outputs a time-out signal TMO to the power supply load control circuit 440 when the counting ends.

[0046] The sleep / startup execution unit 540 puts the control unit 430 into a sleep state in accordance with a predetermined operation sequence. In one example, the sleep / startup execution unit 540 enters the sleep state by executing a sleep command in a program. When the control unit 430 enters the sleep state, for example, a counter, a clock, and the like included in the control unit 430 are turned off, and the control unit 430 enters a low power consumption state. Furthermore, when an interrupt signal INT is input from the interrupt control unit 460, the sleep / startup execution unit 540 executes a wakeup command and starts up the control unit 430 from the sleep state.

[0047] The response message creation unit 550 creates a response message in response to the query. For example, if the query is a request for a sensor detection value, the response message creation unit 550 creates a response message including the sensor detection value. The response message transmission unit 560 returns the created response message to the parent device. The transmission format of the response message is as shown in FIG. 4(B).

[0048] The host device 30 instructs the master device 10 to set or change the threshold value of the sensor of the slave device 20, notifies the master device 10 of the status notification interval T, or receives the contents of the response message of the slave device 20 provided by the master device 10. Note that although the master device 10 and the host device 30 are configured separately here, they may also be configured as a single device.

[0049] Next, simultaneous sensing by multiple slave units in the wireless communication sensor system of this embodiment will be described. Figures 9A and 9B are diagrams showing the communication protocol from the master unit to the slave units used in simultaneous sensing by multiple slave units. As shown in the figures, the master unit transmits data consisting of 14 bytes to the slave units. SA (Source Address): The address of the parent device. DA (Destination Address): The address of the client device Unicast (individual client address): 0x01x~0x10 Broadcast address: 0xFF CMD (Command) Bit 0: STMER (Set Timer) Instructs the child device to set TMU (Timer Upper) / TML (Timer Lower) TMU / TML is the waiting time for access from the parent unit to the child unit. Addressing method: Broadcast or Unicast Bit 1: STLTM (Set Limit) Instructs the child device to set LTMU (Limit Upper) / LTML (Limit Lower) Addressing method: Broadcast or Unicast Bit 5: SSNST (Set Sensing Timer) Specify the sensing execution time for the child device (SNSHr / SNSMIN / SNSSEC; when specified) time) Addressing method: Broadcast or Unicast Bit 6: SENSE Sends sensor measurement instructions to the child device Addressing method: Broadcast Bit 7: READ Sending measurement data to the slave unit Addressing method: Unicast SCL (Set Cycle time) 0x00:244.14μs 0x01:15.625ms 0x02:1 seconds 0x03x:1 minute 0x04x:1 hour

[0050] 10A and 10B are diagrams showing a communication protocol from a child device to a parent device. As shown in the diagrams, the child device transmits data consisting of 16 bytes to the parent device. SA (Source Address): Individual address of the client device DA (Destination Address): The address of the parent device HED (Header): 0x80: Normal frame DVTYP (Device Type): Function of the handset 0x01: Strain gauge sensing 0x03: Seismic sensor sensing 0x04: Radiation sensor sensing STS (Status) Bit 0: UPERR (Upper Error): Upper threshold error Bit 1: LWERR (Lower Error): Lower threshold error Bit 2: SCRCE (Slave CRC Error): CRC error detected on the slave device Bit 3: MCRCE (Master CRC Error): CRC error detected on the master device

[0051] Next, we will explain the sequence between the master and slave devices in simultaneous sensing of multiple slave devices in this embodiment. Figure 11 shows an example of a sequence in a battery-powered wireless communication sensor system, and we will first explain the basic operation using this example. This system is configured with one master, up to 16 slave devices, and a host. Communication between the master and each slave device begins with the master issuing a "query" to the slave device. The query also includes the slave device's address and sleep time. If the received address matches its own address, the slave device sends a response message to the master device in response to the query. The slave device calculates the sleep time Tslp described above from the received sleep time, sets this as the slave device's sleep time in a timer, starts the timer, and enters sleep mode. The sleep mode continues until the timer times out. The timeout occurs before the master device can access the slave device, and the slave device wakes up and enters an operable state. The master device performs this type of communication with all slave devices. This completes the basic operation of this system. In communication between the parent device and the host, the parent device notifies the host of response messages (sensor values ​​or abnormalities) from the child devices. In communication from the host to the parent device, it notifies the child device of sleep time, setting data, etc. The parent device always accesses all child devices in order, starting with the child device with the lowest address. The access order does not change even if there are gaps in the middle and there are no child devices.

[0052] [Simultaneous timing and sensing operations] A. When starting up the system The timing of powering on each slave unit is arbitrary, and slave units may be added some time after the system is installed. (1) If necessary, the host sets the waiting time for the child device (15 minutes to 2 hours in 15-minute intervals) and instructs the parent device to set this information in the TMU & TML of the parent device → child device protocol. Note that the default value here is 15 minutes, but this is optional. This setting can be made at any time, not just at system startup. The sequence in Figure 11 is an example when the setting value S = 15 minutes. Also, the bottom of Figure 11 shows examples of the calculation results of the parent device's WT (waiting time value) according to the number of counts when S = 900 seconds and when S = 1800 seconds. (2) The parent device calculates the following from the settings from the host: S:TMU & TML setting value C: Counter C = S / (3*60) 3*60: Interval between accesses from the parent device to the child device (180 seconds) N = Timing No. (1, 2, 3, 4, 5, C) When N=C, substitute N=0 WT = S-180*N-30 30:30 seconds (3) When all powered-on slave devices are powered on, they initialize themselves and wait for the broadcast address and CMD of 0x01 (STMER: Set Timer) or 0x20 (SSNST: Set Sensing Timer) from the master device. The following explains CMD=0x01. CMD=0x20 will be explained in the section on specified time sensing operation.

[0053] B. Normal time The parent device executes the sequence shown in FIG. 11 for all the child devices. (1) The parent device accesses the child device with the Set Timer command and broadcast address at 3-minute (180-second) intervals. The access is performed N times. The latency value for each N is calculated as WT = S-180*N-30. The reason for executing the access N times is that it is unknown when the power of the slave unit will be turned on or when it will be added, and the unnecessary power-on time of the slave unit is reduced as much as possible to reduce battery consumption. SA: Parent device address DA:0xFF (broadcast address) CMD:0x01(STMER);Set Timer SCL:0x02:1 seconds TMU / TML:WT Hr / MIN / SEC:Current time LMTU / LMTL: Disabled SNSHr / SNSMIN / SNSSEC: Disabled (2) When the slave receives a Set Timer command from the master via the broadcast address, it sets the received TMU and TML to its internal timer, starts the timer, and goes into sleep mode. The next time it waits for access from the master, it sends a 0x41 (SENSE & STMER (Set Timer)) command via the broadcast address. (3) When C is reached, the parent device sets N to 0, calculates the waiting time of the child devices as WT = S - 180 + 0 - 30, and uses this as TMU / TML to send a broadcast address and a 0x41 (SENSE & STMER (Set Timer)) command to all child devices to instruct them to sense and set their timers (TMU / TML). This makes it possible for multiple child devices to sense simultaneously. (4) When the internal timer that sets the TMU / TML times out, an interrupt occurs in the child device, causing it to exit sleep mode. The child device waits for a 0x41 (SENSE & STMER (Set Timer)) command at the broadcast address. When it receives this command, it collects sensing information and sets the contents of the TMU / TML in the internal timer. It then waits for a 0x80 (READ) command at the unicast address (measurement & measurement data read period in Figure 11). (5) The parent device guarantees time for the child devices to collect sensing information, and accesses the child devices in ascending order of child device number using the unicast address and 0x80 (READ) command (measurement and measurement data read period in Figure 11). (6) When the child device receives the 0x80 (READ) command from the parent device at its unicast address, it returns the following information to the parent device in response (measurement and measurement data read period in Figure 11). SA: Sub-device address DA: Master unit address HED:0x80 DVTYP: STS: State at that time SNSU / SNSL: Sensing information BATU / BATL: Remaining battery level (for notifying when it's time to replace the battery) TEMPU / TEMP: Internal temperature of the handset (for monitoring abnormal internal temperatures) TEMOU / TEMOL: External temperature measured by thermocouple (used for temperature correction of sensing data, etc.) Hr / MIN / SEC: Sensing information collection time (7) The parent device transmits the information received from the child device to the host (measurement and measurement data readout period in FIG. 11). (8) The host returns a response, and displays, saves, and analyzes the received information (measurement and measurement data readout period in FIG. 11). (9) After receiving a reply from the host, the parent unit repeats steps (5) to (8) for each child unit. (10) After all the slave devices have been accessed, the process returns to (1) and repeats the process.

[0054] [Specified time sensing operation] A. When starting up the system The timing of powering on each slave unit is arbitrary, and slave units may be added some time after the system is installed. (1) If necessary, the host sets the sensing time of the slave unit and instructs the master unit to set the above information in the SNSHr / SNSMIN / SNSSEC of the master unit → slave unit protocol. This setting can be done at any time, not just at system startup. (2) The parent device sets the sensing time specified by the host to SNSHr / SNSMIN / SNSSEC of the parent device → child device protocol. (3) When all powered-on slave devices are powered on, they initialize themselves and wait for the broadcast address and CMD of 0x01 (STMER; Set Timer) or 0x20 (SSNST; Set Sensing Timer) from the master device. (4) The parent device accesses the child device at 3-minute intervals using the following parent device ⇒ child device protocol: SA: Parent device address DA:0xFF (broadcast address) CMD:0x20(SSNST):Set Sensing Timer SCL: Disabled TMU: Disabled TML: Disabled Hr / MIN / SEC:Current time LMTU / LMTL: Disabled SNSHr / SNSMIN / SNSSEC: Sensing time (5) When the child device receives CMD=0x20 (SSNST) from the parent device at its broadcast address, it sets the internal timer to the SNSHr / SNSMIN / SNSSEC values ​​of the specified time and goes into sleep mode until the specified time is reached. (6) The parent unit repeats (4) at 3-minute intervals. (7) When the designated sensing time arrives, the child device wakes up from sleep mode, performs sensing operations, collects sensing data, and waits to receive a CMD=0xA0 (READ & Set Sensing Timer) command from the parent device at its unicast address. (8) When the designated sensing time arrives, the master unit guarantees the sensing time of the slave units and then accesses each slave unit using the following protocol: The master unit waits for a response from the slave units. SA: Parent device address DA: Unique address of each slave unit (0x01 to 0x10) CMD:0xA0(READ & Set Sensing Timer) SCL: Disabled TMU: Disabled TML: Disabled Hr / MIN / SEC:Current time LMTU / LMTL: Disabled SNSHr / SNSMIN / SNSSEC: Sensing time setting (add Set Sensing Timer command if changing) (9) When the slave device receives CMD = 0x80 or 0xA0 via unicast, it judges the CMD. In the case of the 0xA0 (READ & Set Sensing Timer) command, it sets the contents of SNSHr / SNSMIN / SNSSEC to the internal time timer and sets the collected sensing data to SNSU / SNSL of the slave device ⇒ master device protocol. Next, reply to the parent device using the following protocol. After completing the reply, the slave device goes into a sleep state until the next designated sensing time. SA: Sub-device address DA: Master unit address HED:0x80 DVTYP: STS: State at that time SNSU / SNSL: Sensing information BATU / BATL: Remaining battery level (for notifying when it's time to replace the battery) TEMPU / TEMP: Internal temperature of the handset (for monitoring abnormal internal temperatures) TEMOU / TEMOL: External temperature measured by thermocouple (used for temperature correction of sensing data, etc.) Hr / MIN / SEC: Sensing information collection time (10) The parent device transmits the received sensing data to the host and waits for a response from the host. (11) The host returns the table information (such as the designated sensing time) of the corresponding child device to the parent device. (12) The parent device updates the table information of the child devices received from the host, and repeats steps (8) to (12) for the number of child devices. After receiving the sensing data from all the slave units, the master unit returns to (4) and repeats the process. This also enables sensing at a specified time.

[0055] The wireless communication sensor system of this embodiment has the following advantages. - Battery operation is possible with two-way communication between the parent and child units. - Two-way communication between the parent and child units is possible, so information can be set and changed on the child units while the system is online. - Each time the parent device issues a query to all child devices, it calculates the sleep time of the child device and sends it to the child device, which then uses it as a sleep timer, ensuring the accuracy of the timer. Simultaneous sensing and simultaneous sensing by multiple slave units is possible, enabling simultaneous sensing by various sensors, and by analyzing multiple sensors, sensing accuracy is improved. -Sensing at a specified time allows you to narrow down the sensing to a time when a certain change is large.

[0056] 1, the wireless communication sensor system 1 is directly connected to the parent device 10 and the child device 20 by wireless communication, but a repeater that mediates wireless communication may be included between the parent device 10 and the child device 20. This allows the system to be configured in a manner similar to the wireless communication sensor system 1 in terms of functionality, even if the parent device 10 and the child device 20 are far enough apart that direct wireless communication is not possible.

[0057] Although the preferred embodiments of the present invention have been described in detail above, the present invention is not limited to the specific embodiments, and various modifications and variations are possible within the scope of the gist of the present invention as described in the claims. [Explanation of symbols]

[0058] 1: Wireless communication sensor system 10: Parent device 20 (20a to 20n): Child device 30: Host device 200: Communication control program 210: Query creation unit 220: Sleep time information setting unit 230: Query sending unit 240: Response message receiving unit 250: Handset information providing unit 400: Battery 402, 404: DC / DC converter 410, 412: Reset circuit 420: Sleep timer 430: Control unit (MPU) 440: Power supply load control circuit 450: Address holding unit 460: Interrupt control unit 470: Wireless module

Claims

1. A wireless communication system comprising a plurality of battery-powered slave units and a master unit that performs wireless communication with the plurality of slave units, each of the plurality of slave units including a timer that sets time information received from the master unit, each of the plurality of slave units going into a sleep state in accordance with the time information set in the timer, and the master unit being capable of sequentially accessing the slave units in synchronization with wake-up from the sleep state, A wireless communication system in which a parent device transmits to all child devices via a broadcast address a wake-up time for waking up each of the child devices at the same time, and a timer setting command for setting the wake-up time in the timer.

2. 2. The wireless communication system according to claim 1, wherein the master unit accesses the slave unit at regular intervals and calculates the wake-up time according to the number of accesses.

3. 3. The wireless communication system according to claim 2, wherein the master device determines the interval and the number of accesses based on a set value relating to a waiting time of all slave devices.

4. 2. The wireless communication system according to claim 1, wherein the master device transmits a sensing command to all the slave devices by broadcast address in response to a time when each of the slave devices wakes up, for causing the slave devices to perform a sensing operation.

5. 2. The wireless communication system according to claim 1, wherein all the slave devices set the wake-up time received from the master device in a timer, enter a sleep state after starting the timer, and wake up when the timer times out.

6. 5. The wireless communication system according to claim 4, wherein the master device further transmits a command to each of the plurality of slave devices by a unicast address to read out information sensed by each of the plurality of slave devices.

7. The wireless communication system according to claim 4 , wherein the master unit further transmits the sensing command and the timer setting command together.

8. A wireless communication system comprising a plurality of battery-powered slave units and a master unit that performs wireless communication with the plurality of slave units, each of the plurality of slave units including a timer that sets time information received from the master unit, each of the plurality of slave units going into a sleep state in accordance with the time information set in the timer, and the master unit being capable of sequentially accessing the slave units in synchronization with wake-up from the sleep state, A wireless communication system in which a parent device transmits a timer setting command to all child devices by broadcast address, for setting a designated sensing time in the timer to cause each of the child devices to perform sensing at a designated time.

9. 9. The wireless communication system according to claim 8, wherein all the slave devices set the designated sensing time received from the master device in a timer, start the timer, then enter a sleep state, and perform the sensing operation when the timer times out.

10. 10. The wireless communication system according to claim 9, wherein the master device further transmits a command to each of the plurality of slave devices by a unicast address to read out information sensed by each of the plurality of slave devices.

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