JP5649423B2 - Wireless communication system and wireless communication method - Google Patents

Description

  The present invention relates to a wireless communication system and a wireless communication method.

  In general, in a wireless LAN, a network is composed of one master station called an access point (AP) and a plurality of slave stations under the access point called a station (STA). In a general wireless LAN, each slave station autonomously sets a random waiting time by random numbers, and after that waiting time, if no other slave station is performing communication, DCF (Distributed Coordination) that transmits data is used. Function) mode. In this DCF mode, each slave station autonomously determines and performs data transmission, so there is a possibility that data collision will occur between the master station and each slave station and between the slave station and other slave stations. In addition, since each slave station transmits data after waiting for a waiting time uniquely determined, there is a problem that the data transmission timing fluctuates. In order to improve this problem, a PCF (Point Coordination Function) mode is provided in which the master station centrally controls communication with each slave station. In this PCF mode, data collision does not occur between the stations, but there is a problem that the period at which each slave station transmits data fluctuates depending on the amount of data to be transmitted.

  In Patent Document 1 below, a system that uses both the DCF mode and the PCF mode has a means for counting data that requires priority transmission, and performs communication in the PCF mode according to the amount of data with high priority. There is disclosed a technique for preferentially transmitting data that requires priority transmission by adjusting the time to be performed and the time to perform communication in the DCF mode.

Japanese Patent Laid-Open No. 2004-187021

  As described above, in the wireless LAN communication using the conventional DCF mode, there is a problem that data collision occurs and communication with a certain period cannot be performed depending on the amount of transmission data. Also, in the conventional technology using the PCF mode including Patent Document 1 described above, the time occupied by each slave station during data transmission also varies depending on the amount of data. There was a problem that it was not possible to guarantee communication between the two.

  The present invention has been made in view of the above, and an object of the present invention is to provide a wireless communication system and a wireless communication method capable of performing communication at a constant cycle.

In order to solve the above-described problems and achieve the object, a wireless communication system according to the present invention is a wireless communication system including a parent station and a plurality of child stations under the parent station, station, the transmission allowable time to allow transmission of data set at a constant of the communication cycle with respect to each slave station, wherein the child and the command data is an instruction command and the transmission permissible time for each slave station Each slave station performs processing on the command data to generate response data, and based on the data amount of the response data and the transmission rate between the own station and the parent station Determining whether the response data can be transmitted within the allowable transmission time, and determining that transmission of the response data is impossible within the allowable transmission time, discarding the response data and Stop sending The features.

  According to the present invention, it is possible to perform communication at a constant period.

FIG. 1 is a diagram illustrating a configuration example of a wireless network between industrial devices in the FA (Factory Automation) field. FIG. 2 is a diagram illustrating an example of a data transmission / reception sequence in the wireless communication method according to the first embodiment. FIG. 3 is a diagram of a configuration example of a slave station in the wireless communication system according to the first embodiment. FIG. 4 is a flowchart of an example of processing on the slave station side in the wireless communication system according to the first embodiment. FIG. 5 is a flowchart of an example of processing on the slave station side in the wireless communication system according to the second embodiment. FIG. 6 is a diagram illustrating an example of a message format of a transmission disable notification transmitted from the slave station to the master station. FIG. 7 is a diagram illustrating an example of a table defining the priority for each type of remaining data. FIG. 8 is a flowchart of an example of processing on the slave station side in the wireless communication system according to the third embodiment. FIG. 9 is a diagram illustrating an example of a message format of the division response data notification transmitted from the slave station to the master station. FIG. 10 is a diagram illustrating an example of a data retransmission sequence. FIG. 11 is a diagram of a configuration example of a master station in the wireless communication system according to the fourth embodiment. FIG. 12 is a flowchart showing an example of transmission processing of command data and transmission permission time notification on the master station side. FIG. 13 is a diagram illustrating an example of time frame allocation within a communication cycle. FIG. 14 is a flowchart showing an example of processing after data reception on the master station side. FIG. 15 is a sub-flowchart illustrating an example of the allowable transmission time reassignment process in the cycle management unit. FIG. 16 is a diagram illustrating an example of the remaining data management table. FIG. 17 is a diagram illustrating an example of a communication cycle in which a time frame for emergency communication is set. FIG. 18 is a flowchart illustrating an example of processing of the master station and the slave station when an event requiring an emergency stop occurs in the slave station. FIG. 19 is a flowchart showing an example of processing of the master station and the slave station when any abnormal radio wave is received at the master station. FIG. 20 is a flowchart illustrating an example of processing of the master station and the slave station when any abnormal radio wave is received at the slave station.

  A wireless communication system and a wireless communication method according to embodiments of the present invention will be described below with reference to the accompanying drawings. In addition, this invention is not limited by embodiment shown below.

Embodiment 1 FIG.
FIG. 1 is a diagram illustrating a configuration example of a wireless network between industrial devices in the FA (Factory Automation) field. As shown in FIG. 1, a control device that controls the device and a controlled device to be controlled each have a wireless communication function such as a wireless LAN, and are wireless master stations (hereinafter simply referred to as “parent”) that are control devices. Stations) 11 and a plurality of wireless slave stations (hereinafter simply referred to as “slave stations”) 12 and 13 which are controlled devices, perform wireless communication with a fixed period.

  FIG. 2 is a data transmission / reception sequence diagram in the wireless communication method according to the first embodiment. In the example shown in FIG. 2, each slave station (here, slave stations 12 and 13) under its own station finishes transmission of response data during a fixed communication cycle 22 set in advance by the master station 11. Show. As shown in FIG. 2, the master station 11 transmits command data A, which is an instruction command for each of the slave stations 12 and 13, by broadcast communication (step ST101). Each of the slave stations 12 and 13 that have received the data A performs processing of its own device in response to the instruction command, and generates response data.

  Next, the master station 11 transmits to the slave station 12 a permissible time notification designating a permissible transmission time that the slave station 12 can use for transmission (step ST102). The slave station 12 that has received the allowable time notification transmits the response data B to the master station 11 during the allowable transmission time 19 (step ST103).

  Next, the master station 11 transmits to the slave station 13 a permissible time notification designating a permissible transmission time that the slave station 13 can use for transmission (step ST104). The slave station 13 that has received the allowable time notification transmits the response data C to the master station 11 during the transmission allowable time 20 (step ST105).

  The master station 11 transmits / receives data to / from each slave station (here, the slave stations 12 and 13) under its own device during a certain communication cycle 22, and then each slave station in the next communication cycle. Is transmitted (step ST106). As described above, in the present embodiment, data transmission / reception for one command is performed within a certain period between the master station and each slave station, and the process is repeated at a predetermined communication period, thereby enabling wireless communication. Implements periodic communication with.

  FIG. 3 is a diagram of a configuration example of a slave station in the wireless communication system according to the first embodiment. As shown in FIG. 3, the slave station 31 includes a wireless data receiving unit 32 that receives wireless data from the parent station, a transmission determination unit 33 that determines whether or not response data can be transmitted, and processing according to command data from the parent station. And a wireless data transmission unit 35 for transmitting wireless data to the master station.

  Next, the operation on the slave station side in the wireless communication system according to the first exemplary embodiment will be described with reference to FIGS. 3 and 4. FIG. 4 is a flowchart of an example of processing on the slave station side in the wireless communication system according to the first embodiment.

  When the command data A is received from the master station (step ST201), the wireless data receiving unit 32 transmits the command data A to the transmission determining unit 33 (step ST202). The transmission determination unit 33 receives the command data A (step ST203), and transmits the command data A to the command processing unit 34 (step ST204). The command processing unit 34 receives the command data A (step ST205), performs processing based on the command (step ST206), and transmits the processing result as response data B to the transmission determination unit 33 (step ST207).

  The transmission determination unit 33 receives the response data B (step ST208), and suspends the transmission of the response data B to the parent station until receiving an allowable time notification for the child station 31.

  Next, when receiving the allowable time notification from the master station (step ST209), the wireless data receiving unit 32 transmits the allowable time notification to the transmission determining unit 33 (step ST210). When the transmission determination unit 33 receives the notification of the allowable time (step ST211), the transmission determination unit 33 divides the data length of the response data B received from the command processing unit 34 by the transmission rate usable in the own station, thereby The transmission time is calculated, and it is determined whether or not the transmission time falls within the allowable transmission time specified in the allowable time notification, that is, whether or not the response data B can be transmitted within the allowable transmission time (step ST212). . Here, the transmission rate that can be used in the own station may be set in advance in the transmission determination unit 33, or the transmission rate specified by the parent station in the notification of the allowable transmission time to the child station 31 may be specified.

  If the transmission determination unit 33 determines in step ST212 that the response data B can be transmitted within the allowable transmission time (step ST212; Yes), the transmission determination unit 33 transmits the response data B to the wireless data transmission unit 35 (step ST213). The wireless data transmission unit 35 receives the response data B (step ST214), and transmits the response data B to the master station (step ST215).

  Further, when it is determined in step ST212 that the response data B cannot be transmitted within the allowable transmission time (step ST212; No), the transmission determination unit 33 discards the response data B (step ST216). In this embodiment, if the master station does not receive response data from the slave station within the transmission allowable time specified in the allowable time notification, the transmission allowable time specified for the slave station is insufficient. Recognize that

  As described above, according to the wireless communication system and the wireless communication method of the first embodiment, the master station designates the allowable transmission time for each slave station under its control, and the slave station is designated by the master station. Since the response data is transmitted within the allowable transmission time, it becomes possible to perform communication between the master station and each slave station at a constant period.

  In addition, if the slave station cannot transmit the response data within the allowable transmission time, the transmission of the response data is stopped, so that communication delay does not occur due to the amount of response data transmitted from the slave station. It becomes possible to perform communication between the master station and each slave station at regular intervals.

Embodiment 2. FIG.
In the present embodiment, an explanation will be given of an example in which the slave station notifies the master station that transmission of response data is impossible when the slave station determines that the response data cannot be transmitted within the allowable transmission time. To do. Note that the configuration of the slave station in the wireless communication system according to the second embodiment is the same as the configuration of FIG. 3 described in the first embodiment, and thus the description thereof is omitted here.

  The operation on the slave station side in the wireless communication system according to the second exemplary embodiment will be described with reference to FIGS. 3, 5, 6, and 7. FIG. FIG. 5 is a flowchart of an example of processing on the slave station side in the wireless communication system according to the second embodiment. FIG. 6 is a diagram showing an example of a message format of a transmission impossible notification transmitted from the slave station to the master station. FIG. 7 is a diagram illustrating an example of a table defining the priority for each type of remaining data.

  In FIG. 5, the processing from step ST201 to step ST215 is the same as the flowchart of FIG. 4 described in the first embodiment, and thus the description thereof is omitted here.

  In the present embodiment, when it is determined in step ST212 that the response data B cannot be transmitted within the allowable transmission time (step ST212; No), the transmission determination unit 33 holds the response data B as remaining data, According to the message format shown in FIG. 6, a transmission impossible notification is generated (step ST217). As shown in FIG. 6, this transmission impossible notification includes, for example, a master station identifier 41, a slave station identifier 42, a message type (here, transmission impossible notification) 43, a message length 44, and remaining data (here, response data B). Data such as the remaining data length 45 indicating the amount of data and the priority 46 of the remaining data is stored as remaining data information. Here, the priority 46 for each type of remaining data is set in advance in a common table as shown in FIG. 7 between the master station and each slave station. The transmission determination unit 33 refers to the table, determines the priority 46 of the remaining data, and stores it in the message format shown in FIG.

  Then, the transmission determining unit 33 transmits a transmission impossible notification to the wireless data transmitting unit 35 (step ST218), the wireless data transmitting unit 35 receives the transmission disabled notification (step ST219), and transmits the transmission disabled notification to the master station. (Step ST220). In this embodiment, when the master station receives this transmission impossible notification, the master station recognizes that the allowable transmission time designated for the slave station is insufficient, and also determines the data length and priority of the remaining data. Recognize degrees.

  As described above, according to the wireless communication system and the wireless communication method of the second embodiment, when the slave station cannot transmit response data to the master station, the transmission permission specified by the master station is allowed. Since the transmission impossible notification storing the remaining data information such as the data length and priority of the remaining data is transmitted within the time, it becomes possible to perform communication between the master station and each slave station at a fixed period. At the same time, the master station can obtain necessary information such as the data length and priority of the remaining data.

Embodiment 3 FIG.
In the present embodiment, the response data is divided into divided response data for the data length that can be transmitted within the allowable transmission time and remaining data for the data length that cannot be transmitted, and the divided response data, the remaining data information, An example will be described in which a divided response data notification in which is stored is transmitted to the master station. Note that the configuration of the slave station in the wireless communication system according to the third embodiment is the same as the configuration of FIG. 3 described in the first embodiment, as in the second embodiment, and thus the description thereof is omitted here.

  The operation on the slave station side in the wireless communication system according to the third exemplary embodiment will be described with reference to FIG. 3, FIG. 8, and FIG. FIG. 8 is a flowchart of an example of processing on the slave station side in the wireless communication system according to the third embodiment. FIG. 9 is a diagram illustrating an example of a message format of the division response data notification transmitted from the slave station to the master station.

  In FIG. 8, the processing from step ST201 to step ST215 is the same as the flowchart of FIG. 4 described in the first embodiment, and thus the description thereof is omitted here.

  In the present embodiment, when it is determined in step ST212 that the response data B cannot be transmitted within the allowable transmission time (step ST212; No), the transmission determining unit 33 can transmit the response data B within the allowable transmission time. The response data is divided into the response data corresponding to the length of the data and the remaining data corresponding to the length of the data that cannot be transmitted (step ST221), the remaining data is retained, and the notification of the response response data is generated according to the message format shown in FIG. (Step ST222). As shown in FIG. 9, the divided transmission data includes, for example, a master station identifier 41, a slave station identifier 42, a message type (in this case, divided response data notification) 43, a message length 44, a divided response data length 47, a remaining data The remaining data length 48 indicating the data amount, the remaining data information such as the priority 46 of the remaining data, and the transmittable division response data 49 are stored.

  Then, the transmission determination unit 33 transmits the division response data notification to the wireless data transmission unit 35 (step ST223), the wireless data transmission unit 35 receives the division response data notification (step ST224), and transmits the division response data notification. Is transmitted to the master station (step ST225). In the present embodiment, when the master station receives the split response data notification, the master station acquires the split response data, and the transmission allowable time specified for the slave station is insufficient. Recognize possible data length, priority, etc.

  As described above, according to the wireless communication system and the wireless communication method of the third embodiment, when the slave station cannot transmit the response data to the master station, the transmission permission specified by the master station is allowed. Since the division response data notification storing the divided response data for the data length that can be transmitted and the remaining data information such as the data length and priority of the remaining data that cannot be transmitted is transmitted within a certain period of time. It becomes possible to communicate between the master station and each slave station, and the master station needs the division response data for the transmittable data length and the data length and priority of the remaining data that cannot be transmitted. Information.

Embodiment 4 FIG.
In the first to third embodiments, the operation on the slave station side has been described. In the present embodiment, the operation on the master station side will be described.

  FIG. 10 is a diagram illustrating an example of a data retransmission sequence. In the example shown in FIG. 10, when the master station 81 cannot normally receive the response data transmitted from the slave station 82, transmission / reception including retransmission of the response data is performed during the communication cycle 83 set in advance by the master station 81. An example of termination is shown.

  As shown in FIG. 10, the master station 81 transmits command data A to the slave station 82 (step ST301), and then transmits a transmission allowable time notification specifying the allowable transmission time 84 of the slave station 82. (Step ST302).

  The slave station 82 transmits response data B to the command data A to the master station 81 (step ST303). When the master station 81 cannot normally receive the response data B, the master station 81 transmits NACK (Negative Acknowledgement) data to the slave station 82 as a non-reception confirmation response (step ST304).

  When the slave station 82 receives the NACK data from the master station 81, the slave station 82 determines again whether or not the response data can be transmitted within the allowable transmission time, and determines that the response data can be transmitted within the allowable transmission time. Response data B is transmitted again to station 81 (step ST305). When the master station 81 normally receives the response data B, the master station 81 transmits ACK (Acknowledgement) data to the slave station 82 as a reception confirmation response (step ST306). As described above, in the present embodiment, data transmission is confirmed by transmitting and receiving ACK data and NACK data within the transmission allowable time 84 between the master station 81 and the slave station 82, and the slave station 82 When NACK data from the station 81 is received, the same response data is transmitted again, thereby improving communication reliability.

  Further, the master station can count the number of retransmission occurrences for each slave station by counting the number of NACK data transmissions to each slave station. From the number of retransmission occurrences, the master station recognizes that the communication environment between the master station and the slave station with a large number of retransmission occurrences is bad. As a technique for retransmitting data by sending and receiving delivery confirmation information between each communication device, a technique for performing data retransmission by not transmitting ACK data within a specified time in a wireless LAN is generally used. Although used, in this embodiment, retransmission of data is performed within a certain communication cycle by transmitting NACK data and retransmitting response data.

  FIG. 11 is a diagram of a configuration example of a master station in the wireless communication system according to the fourth embodiment. As shown in FIG. 11, the master station 91 has a command generation unit 92 that generates command data, a communication cycle management, and a cycle for determining an allowable transmission time of each slave station 1-1 to 1-n (n is a natural number). The management unit 93 transmits wireless data to each of the slave stations 1-1 to 1-n, and also generates a ACK data and NACK data for delivery confirmation, and each of the slave stations 1-1 to 1-1. A radio data receiving unit 95 that receives radio data from -n and a received data analysis unit 96 that analyzes data from each of the slave stations 1-1 to 1-n are provided.

  Next, the transmission operation of the command data and the transmission allowable time notification on the master station side will be described with reference to FIG. 11, FIG. 12, and FIG. FIG. 12 is a flowchart showing an example of transmission processing of command data and transmission permission time notification on the master station side. FIG. 13 is a diagram illustrating an example of time frame allocation within a communication cycle.

  The command generator 92 generates command data for each of the slave stations 1-1 to 1-n (step ST401) and transmits it to the cycle manager 93 (step ST402). When the cycle management unit 93 receives the command data (step ST403), the cycle management unit 93 transmits the command data to the wireless data transmission unit 94 at the start of a certain communication cycle (step ST404). 94 receives the command data (step ST405) and transmits the command data to the slave station (step ST406).

  On the other hand, cycle management section 93 transmits command data to wireless data transmission section 94 in step ST404 and activates a communication cycle timer that counts a certain communication cycle (step ST407). The next command data is transmitted to the wireless data transmission unit 94 using the timing when the communication cycle timer times out as the start time of the next communication cycle, and transmitted to each slave station via the wireless data transmission unit 94. become.

  Next, the cycle management unit 93 calculates a transmission allowable time for each of the slave stations 1-1 to 1-n under its own station to generate a transmission allowable time notification (step ST408), and each of the slave stations 1-1 to 1-1. In 1-n, a transmission allowable time notification transmission waiting timer is started that counts the time until the time at which the transmission allowable time notification is transmitted to the first child station (substation 1-1 in this case) (step ST409). A method for calculating the transmission allowable time will be described later with reference to FIG. When the transmission allowable time transmission waiting timer for the slave station 1-1 times out (step ST410), the cycle management unit 93 transmits a transmission allowable time notification for the slave station 1-1 to the wireless data transmission unit 94 (step ST411). Radio data transmission section 94 receives notification of allowable transmission time for slave station 1-1 (step ST412), and transmits the notification of allowable transmission time to the slave station (step ST413).

  On the other hand, in step ST411, the cycle management unit 93 transmits a transmission permissible time notification for the slave station 1-1 to the wireless data transmission unit 94 and starts a timer corresponding to the permissible transmission time (step ST414). When time-out occurs (step ST415), the processing returns to step ST411, and a transmission allowable time notification for the next slave station (here, the slave station 1-2) is transmitted to the wireless data transmission unit 94 (step ST411). Thereafter, the processing of step ST411 to step ST415 is repeated to transmit a transmission allowable time notification to each of the slave stations 1-1 to 1-n.

  Here, a method for calculating the allowable transmission time for each slave station will be described with reference to FIG. As shown in FIG. 13, a fixed value is set in advance in the master station 91 for the communication cycle 121 serving as the command data transmission interval, and the master station 91 and each of the slave stations 1-1 to 1- 1 are set during this communication cycle 121. Communicate with n. The communication cycle 121 includes a command processing completion time 122, transmission allowable times 123-1 to 123-n for the respective slave stations 1-1 to 1-n, and transmission allowable time reassignment time 124.

  The command processing completion time 122 includes a command data transmission time A when the master station transmits command data, and a time B until each slave station 1-1 to 1-n completes processing for the command (hereinafter referred to as “command processing time”). It is obtained by the following equation (1).

  Command processing completion time = command data transmission time A + command processing time B (1)

  In the above equation (1), the command data transmission time A is obtained by dividing the command data length by the transmission time, and the command processing time B is set to a fixed value in the master station 91 in advance.

  The allowable transmission times 123-1 to 123-n for the slave stations 1-1 to 1-n are all the same, and are calculated by the following equation (2).

Allowable transmission time = (communication cycle-command processing completion time-allowable transmission time reassignment time)
÷ Number of slave stations (n) (2)

  The permissible transmission time reassignment time 124 is a time for reassigning the permissible transmission time to the slave station that cannot communicate with each permissible transmission time, and a fixed value is set in advance in the master station 91. .

  Next, the operation after data reception on the master station side will be described with reference to FIG. 11, FIG. 14, FIG. 15 and FIG. FIG. 14 is a flowchart showing an example of processing after data reception on the master station side. FIG. 15 is a sub-flowchart illustrating an example of the allowable transmission time reassignment process in the cycle management unit. FIG. 16 is a diagram illustrating an example of the remaining data management table.

  When receiving data from each of the slave stations 1-1 and 1-n (step ST501), the wireless data receiving unit 95 determines whether or not the data is normal (step ST502). When it is determined that the data is not normal (step ST502; No), the wireless data receiving unit 95 transmits a NACK data transmission request to the wireless data transmitting unit 94 (step ST503), and the wireless data transmitting unit 94 receives the NACK data. A data transmission request is received (step ST504), and NACK data is transmitted to the slave station (step ST505). On the other hand, wireless data reception section 95 notifies period management section 93 of the occurrence of retransmission together with the identifier of the slave station as a notification of occurrence of retransmission (step ST506).

  If it is determined in step ST502 that the data is normal (step ST502; Yes), the wireless data reception unit 95 transmits the data to the reception data analysis unit 96 (step ST507), and transmits an ACK data transmission request wirelessly. The data is transmitted to data transmitter 94 (step ST508), wireless data transmitter 94 receives the ACK data transmission request (step ST504), and transmits ACK data to the slave station (step ST505).

  Reception data analysis section 96 receives data from wireless data reception section 95 (step ST509), analyzes the type of the data, and determines whether it is response data or divided response data notification (step ST510). . If it is determined that the data type is response data or divided response data notification (step ST510; Yes), the received data analysis unit 96 generates a command for the divided response data stored in the response data or divided response data notification Transmit to unit 92 (step ST511).

  In addition, when the data is a divided response data notification, or as a result of the data type analysis in step ST510, the received data analysis unit 96 determines that the type of the data is not response data or divided response data (that is, a transmission impossible notification). (Step ST510; No), the remaining data information is extracted from the division response data notification or the transmission impossible notification (Step ST512), and notified to the cycle management unit 93 together with the slave station identifier (Step ST513). ). Here, the remaining data information indicates the remaining data length indicating the remaining data amount and the priority of the remaining data.

  When the period management unit 93 receives the retransmission occurrence notification from the wireless data reception unit 95 and the remaining data information from the reception data analysis unit 95, the cycle management unit 93 proceeds to the transmission allowable time reassignment processing 600 shown in FIG.

  Period management section 93 receives the retransmission occurrence notification from wireless data reception section 95 and the remaining data information from reception data analysis section 95 (step ST601), analyzes the type of the received data, and is the retransmission occurrence notification. (Step ST602), and if it is a retransmission occurrence notification (step ST602; Yes), the number of retransmissions is incremented for each corresponding slave station and stored (step ST603). If the received data is a remaining data information notification (step ST602; No), the slave station identifier, the remaining data length indicating the remaining data amount, and the transmission required to transmit the remaining data in the order of priority of the information. The remaining data information such as the required time is stored (step ST604). Here, the required transmission time required to transmit the remaining data is obtained by dividing the remaining data length by the transmission rate.

  Period management section 93 determines whether or not the allowable transmission time set for each of slave stations 1-1 to 1-n has elapsed (step ST605), and if the allowable transmission time has not elapsed (step ST605). No), returning to the process of step ST601, the processes of step ST601 to step ST605 are repeatedly executed to create the remaining data management table shown in FIG. When the permissible transmission time has elapsed (step ST605; Yes), the period management unit 93 reassigns the transmission permissible time (hereinafter referred to as “reassignment transmission permissible time” to the slave station that has not received the response data and holds the remaining data. Is calculated) (step ST606).

  Here, a method of calculating the reallocation allowable transmission time will be described with reference to FIG. In the example shown in FIG. 16, the remaining data information for each slave station is arranged in order of priority 51, and the slave station identifier 52, the number of retransmissions 53, the remaining data length 54, and the required transmission time 55 corresponding to each remaining data are associated. Manage. In the example shown in FIG. 16, the smaller the priority 51, the higher the priority.

  The reassignment of the allowable transmission time for each slave station is performed using the allowable transmission time reassignment time 124 shown in FIG. The cycle management unit 93 refers to the remaining data management table shown in FIG. 16 and first assigns the required transmission time 55 as a reassignment allowable transmission time.

  Next, if the allowable transmission time reassignment time 124 remains after assigning the allowable reassignment transmission time to each slave station holding the remaining data, the cycle management unit 93 assigns the remaining data having a high priority 51. The reassignment transmission permissible time is doubled in order from the slave station having the largest number of retransmission occurrences 53 with respect to the held slave stations. For example, in the example shown in FIG. 16, first, among the slave stations 1-1 and 1-3 that hold the remaining data with the priority 51 value of “1”, the slave station 1 that has a large number of retransmission occurrences 53. -3, the allowable transmission time for reassignment is doubled to 2 msec. Since the number of retransmission occurrences 51 is “0”, the slave station 1-1 keeps the reassignment transmission allowable time at 2 msec. Thereafter, the process of doubling the allowable reassignment transmission time is repeated in order from the slave station holding the remaining data with the higher priority 51 until the allowable transmission time reassignment time 124 disappears. In the example illustrated in FIG. 16, the number of retransmissions 53 of the slave stations 1-5 is “3”. However, since no remaining data is generated in the current communication cycle, the transmission allowable time is not reassigned. .

  When the allowable transmission time reassignment time is exhausted, cycle management section 93 completes the reallocation transmission allowable time calculation process in step ST606, and notifies reassignment transmission allowable time notification to child station 1-1 by wireless data transmission section 94. (Step ST607), a timer corresponding to the allowable reassignment transmission time for the slave station 1-1 is started (step ST608), and when the timer times out (step ST609), the processing returns to step ST607, and the next A reassignment transmission permissible time notification for the slave station (slave station 1-3 in this case) is transmitted to wireless data transmission section 94 (step ST607). Thereafter, the processing of step ST607 to step ST609 is repeated, and a reassignment transmission permissible time notification for each slave station holding the remaining data is transmitted to the wireless data transmission unit 94. Note that the remaining data management table shown in FIG. 16 is created for each communication cycle, and is cleared at the start of the next communication cycle, and the remaining data management table in the communication cycle is created again.

  Returning to the flowchart shown in FIG. 14, the wireless data transmission unit 94 receives a reassignment transmission permissible time notification for each child station holding the remaining data (step ST514), and allows reassignment transmission permission for the corresponding child station. A time notification is transmitted (step ST515). Each slave station holding the remaining data transmits the remaining data held in the transmission determination unit 33 to the master station 91 within the reassignment transmission allowable time assigned to each slave station.

  On the other hand, when receiving the response data or the divided response data (step ST516), the command generation unit 92 generates command data in the next cycle (step ST517) and transmits it to the cycle management unit 93 (step ST518).

  When the cycle management unit 93 receives the command data from the command generation unit 92 (step ST519), the cycle management unit 93 suspends transmission of the command data until the start timing of the next communication cycle, and the command at the start timing of the next communication cycle. The data is transmitted to the wireless data transmission unit 94 (step ST520), and the wireless data transmission unit 94 receives the data (step ST521) and transmits it to each of the slave stations 1-1 to 1-n subordinate to the master station 91. Command data is transmitted to the terminal (step ST522).

  As described above, according to the radio communication system and radio communication method of the fourth embodiment, ACK data and NACK data are transmitted / received between the master station and the slave station within the allowable transmission time calculated by the master station. If the slave station receives the NACK data from the master station, it re-determines whether the response data can be transmitted within the allowable transmission time, and the response data is transmitted within the allowable transmission time. When it is determined that it is possible, the same response data is transmitted again, so that communication between the master station and each slave station can be performed at a fixed period, and communication reliability is improved. Can do.

  In addition, the master station counts the number of times NACK data is transmitted to each slave station and totals the number of retransmission occurrences for each slave station, so that the communication environment between the master station and the slave station with a large number of retransmission occurrences is poor. I can recognize that.

  In addition, the master station provides a transmission allowance time reassignment time for reassigning the transmission allowance time for each slave station holding the remaining data within the communication cycle, so that the slave station cannot transmit or divide the transmission. Transmit according to the data amount and priority of the remaining data held by each slave station obtained by response data notification, or the number of retransmission occurrences for each slave station obtained by counting the number of NACK data transmissions to each slave station Since the reassignment transmission permissible time for each slave station within the permissible time reassignment time is set, and each slave station transmits the remaining data within the reassignment transmission permissible time set in its own station, Response data for command data can be transmitted and received during a fixed communication cycle.

Embodiment 5 FIG.
In the present embodiment, an example will be described in which a time frame for emergency communication is provided as a communication time frame for detecting that an event requiring an emergency stop has occurred in a master station or a slave station. Note that the configuration of the slave station in the wireless communication system according to the fifth embodiment is the same as the configuration of FIG. 3 described in the first embodiment, and similarly, the configuration of the master station has been described in the fourth embodiment. Since it is the same as that of FIG. 11, description is abbreviate | omitted here.

  FIG. 17 is a diagram illustrating an example of a communication cycle in which a time frame for emergency communication is set. As shown in FIG. 17, in the communication cycle 171, a fixed value is set in advance in the master station 91 in the same way as the communication cycle 121 shown in FIG. 13, the command processing completion time 122, and each of the slave stations 1-1 to 1. -N includes each transmission allowable time 123-1 to 123-n, a transmission allowable time reassignment time 124, and further includes an emergency communication time 175. The emergency communication time 175 has a fixed value set in advance in the master station 91. Further, an emergency communication start time 176 that is a time until the start of the emergency communication time 175 is determined by the cycle management unit 93 in the master station 91.

  Next, operations of the master station and the slave station when an emergency occurs in the slave station will be described with reference to FIG. 11, FIG. 17, and FIG. FIG. 18 is a flowchart illustrating an example of processing of the master station and the slave station when an event requiring an emergency stop occurs in the slave station.

  On the master station 91 side, the command generation unit 92 transmits the command data to the cycle management unit 93 (step ST701), and the cycle management unit 93 adds emergency communication start time information to the command data (step ST702). It transmits to the slave station 31 via the wireless data transmitter 94 (step ST703). On the slave station 31 side, the wireless data receiving unit 32 transmits the command data to the transmission determining unit 33 (step ST704), and the transmission determining unit 33 stores the emergency communication start time added to the command data. (Step ST705), command data is transmitted to the command processing unit 34 (step ST706), and the command processing unit 34 performs processing based on the command (step ST707).

  If some trouble occurs during execution of the command processing in step ST707 and an event requiring an emergency stop occurs (step ST708), the command processing unit 34 transmits an emergency notification to the transmission determining unit 33 (step ST709). The transmission determination unit 33 receives the emergency notification, holds the emergency notification until the emergency communication start time 176 elapses (step ST710), and transmits the emergency notification when the emergency communication start time 176 elapses. It transmits to the master station via the data transmitter 9493 (step ST711).

  On the master station 91 side, the wireless data reception unit 95 transmits the emergency notification to the reception data analysis unit 9695 (step ST712), and the reception data analysis unit 9695 sends an emergency notification to the cycle management unit 93 and the command generation unit 92. Is transmitted (step ST713, step ST714). Upon receiving the emergency notification, command generation unit 92 stops generating a new command (step ST715), cycle management unit 93 generates an emergency stop instruction (step ST716), and transmits the emergency stop instruction to the wireless data transmission unit. 94 to the slave station via step 94 (step ST717). The emergency stop instruction may be generated and transmitted by the command generator 92.

  On the slave station side, the wireless data receiving unit 32 that has received the emergency stop instruction transmits the emergency stop instruction to the command processing unit 34 via the transmission determining unit 33 (step ST718), and the command processing unit 34 Stop (step ST719). The emergency stop instruction transmitted from the master station 91 is transmitted to each slave station under the master station 91 by broadcast communication, and the emergency stop instruction is received for each slave station (step ST720), and the process is emergency stopped. (Step ST721).

  As described above, according to the wireless communication system and the wireless communication method of the fifth embodiment, the emergency communication time is used as a communication time frame for detecting that an event requiring an emergency stop has occurred in the master station or the slave station. Is provided within the communication cycle, it is possible to perform emergency stop processing within a certain communication cycle even when an event requiring an emergency stop occurs in the master station or the slave station.

Embodiment 6 FIG.
In the present embodiment, an example in which some abnormal radio wave is received at the master station will be described. Note that the configuration of the slave station in the wireless communication system according to the sixth embodiment is the same as the configuration of FIG. 3 described in the first embodiment. Similarly, the configuration of the master station has been described in the fourth embodiment. The communication cycle having the same configuration as that of FIG. 11 and the time frame for emergency communication set is also the same as the communication cycle of FIG. 17 described in the fifth embodiment, and thus description thereof is omitted here.

  FIG. 19 is a flowchart showing an example of processing of the master station and the slave station when any abnormal radio wave is received at the master station. In FIG. 19, the processing from step ST701 to step ST703 is the same as the flowchart of FIG. 18 described in the fifth embodiment, and thus description thereof is omitted here.

  In the present embodiment, on the master station 91 side, cycle management section 93 adds emergency communication start time information to the command data (step ST702) and transmits it to the slave station via wireless data transmission section 94 (step ST702). (ST703), the wireless data receiving unit 95 is notified of the emergency communication start time (step ST801).

  When the emergency communication start time has elapsed, wireless data reception section 95 starts emergency communication reception processing (step ST802). When receiving an abnormal radio wave from a radio device of another radio communication system other than the emergency notification from the slave station during the emergency communication time (step ST803), the radio data receiving unit 95 determines that the radio wave interference is present. Then, an emergency notification is transmitted to received data analysis section 96 (step ST804). Since the subsequent processing of step ST713 to step ST721 is the same as the flowchart of FIG. 18 described in the fifth embodiment, description thereof is omitted here. The reception of some abnormal radio wave here means receiving a radio wave having a radio wave strength of a predetermined level or higher at a frequency used by the own station.

  As described above, according to the wireless communication system and the wireless communication method of the sixth embodiment, when the master station receives some abnormal radio wave within the emergency communication time, the master station and each slave station under the master station Therefore, the emergency stop process can be performed during a certain communication cycle even when radio wave interference from other systems occurs.

Embodiment 7 FIG.
In the present embodiment, an example in which some abnormal radio wave is received at the slave station will be described. Note that the configuration of the slave station in the wireless communication system according to the seventh embodiment is the same as the configuration of FIG. 3 described in the first embodiment, and similarly, the configuration of the master station has been described in the fourth embodiment. The communication cycle having the same configuration as that of FIG. 11 and the time frame for emergency communication set is also the same as the communication cycle of FIG. 17 described in the fifth embodiment, and thus description thereof is omitted here.

  FIG. 20 is a flowchart illustrating an example of processing of the master station and the slave station when any abnormal radio wave is received at the slave station. In FIG. 20, the processing from step ST701 to step ST706 is the same as the flowchart of FIG. 18 described in the fifth embodiment, and thus the description thereof is omitted here.

  In the present embodiment, on the slave station 31 side, the transmission determining unit 33 transmits command data to the command processing unit 34 (step ST706) and notifies the wireless data receiving unit 32 of the emergency communication start time (step ST901). ). When the emergency communication start time has elapsed, wireless data reception unit 32 starts an emergency communication reception process (step ST902).

  When receiving an abnormal radio wave from a radio device of another radio communication system during the emergency communication time (step ST903), the radio data receiving unit 32 transmits an emergency radio wave reception notification to the transmission determining unit 33 (step ST904). The transmission determination unit 33 transmits an emergency stop instruction to the command processing unit 34 (step ST905), and the command processing unit 34 receives the emergency stop instruction and stops the process urgently (step ST906). Note that the reception of any abnormal radio wave here means receiving radio waves with a radio field strength or higher at a frequency used by the local station, and abnormal radio waves from other wireless communication systems. This includes not only the case of receiving, but also the case of receiving an emergency notification transmitted by another child station under the master station 91.

  As described above, according to the wireless communication system and the wireless communication method of the seventh embodiment, when the slave station receives some abnormal radio wave within the emergency communication time, the processing of the local station is urgently stopped. Therefore, if radio wave interference from other systems or an event that requires an emergency stop occurs at a slave station other than the local station, the local station performs an emergency stop process during a certain period of processing based on the slave station's judgment. It becomes possible.

  Note that the configuration shown in the above embodiment is an example of the configuration of the present invention, and can be combined with another known technique, and a part thereof is omitted without departing from the gist of the present invention. Needless to say, it is possible to change the configuration.

  As described above, the wireless communication system and the wireless communication method according to the present invention are useful as an invention capable of performing communication at a constant period.

1-1, 1-2,..., 1-n, 12, 13, 31, 82 Slave station 11, 81, 91 Master station 19, 20, 84, 123-1, 123-2,. Allowable time 22, 83, 121, 171 Communication cycle 32 Wireless data receiver (slave station)
33 Transmission determination unit 34 Command processing unit 35 Wireless data transmission unit (slave station)
41 Master station identifier 42, 52 Slave station identifier 43 Message type 44 Message length 45, 48, 54 Remaining data length 46, 51 Priority 47 Division response data length 49 Division response data 55 Required transmission time 92 Command generation unit 93 Period management unit 94 Wireless data transmitter (master station)
95 Wireless data receiver (master station)
96 Reception Data Analysis Unit 122 Command Processing Completion Time 124 Transmission Allowable Time Reassignment Time 175 Emergency Communication Time 176 Emergency Communication Start Time

Claims (27)

A wireless communication system comprising a master station and a plurality of slave stations under the master station,
The master station sets a transmission permissible time that allows data transmission to each slave station within a certain communication cycle, and sets command data that is an instruction command for each slave station and the permissible transmission time. Notify each slave station,
Each of the slave stations performs processing on the command data to generate response data, and based on the data amount of the response data and the transmission rate between the own station and the master station, the allowable transmission time When it is determined whether or not the response data can be transmitted, and when it is determined that the response data cannot be transmitted within the allowable transmission time, the response data is discarded and transmission of the response data is stopped. A wireless communication system. A wireless communication system comprising a master station and a plurality of slave stations under the master station,
The master station sets a transmission permissible time that allows data transmission to each slave station within a certain communication cycle, and sets command data that is an instruction command for each slave station and the permissible transmission time. Notify each slave station,
Each of the slave stations performs processing on the command data to generate response data, and based on the data amount of the response data and the transmission rate between the own station and the master station, the allowable transmission time When the response data is determined to be transmitted or not and it is determined that the response data cannot be transmitted within the allowable transmission time, the response data is retained as remaining data, and the data of the remaining data A wireless communication system, wherein a transmission impossible notification storing the amount and priority as remaining data information is transmitted to the master station within the allowable transmission time. A wireless communication system comprising a master station and a plurality of slave stations under the master station,
The master station sets a transmission permissible time that allows data transmission to each slave station within a certain communication cycle, and sets command data that is an instruction command for each slave station and the permissible transmission time. Notify each slave station,
Each of the slave stations performs processing on the command data to generate response data, and based on the data amount of the response data and the transmission rate between the own station and the master station, the allowable transmission time When the response data can be transmitted within the allowable transmission time, it is determined that transmission of the response data within the allowable transmission time is impossible. The remaining data is divided into divided response data and remaining data that cannot be transmitted, and the remaining data is retained as the remaining data information. The divided response data and the remaining data information The wireless communication system characterized by transmitting the division response data notification storing the information to the master station within the allowable transmission time. The master station transmits NACK data indicating non-reception confirmation to the slave station when the response data from the slave station cannot be normally received within the transmission allowable time set for the slave station. And
When each of the slave stations receives NACK data from the master station, it re-determines whether the response data can be transmitted within the allowable transmission time, and can transmit the response data within the allowable transmission time. The wireless communication system according to any one of claims 1 to 3, wherein the response data is retransmitted to the master station when it is determined that the response data is present. The master station holds the number of times the NACK data is transmitted for each slave station as the number of retransmission occurrences for each slave station, and for each slave station holding the remaining data, A transmission permissible time reassignment time for assigning a reassignment transmission permissible time that allows transmission of data is provided in the communication period, and based on the data amount and priority of the remaining data, and the number of occurrences of retransmission, Set different reassignment transmission allowable time for each slave station,
5. The wireless communication system according to claim 4, wherein each of the slave stations transmits the remaining data within the allowable reassignment transmission time allocated to the local station.   The master station provides an emergency communication time within the communication cycle for detecting that an event that requires an emergency stop has occurred in the master station or each of the slave stations, and sets the emergency communication time as the command data The wireless communication system according to claim 1, wherein the wireless communication system is notified to each of the slave stations. Each slave station sends an emergency notification within the emergency communication time when an event that requires an emergency stop occurs in its own station,
The wireless communication system according to claim 6, wherein the master station performs an emergency stop of the local station and each of the slave stations based on the emergency notification.   The master station performs an emergency stop of the own station and each of the slave stations when a radio wave having a predetermined radio field strength or higher is received from outside the system at the frequency used by the local station within the emergency communication time. The wireless communication system according to claim 6 or 7, wherein   Each of the slave stations receives a radio wave having a predetermined radio field strength or higher from the outside of the system at the frequency used by the local station within the emergency communication time, and the other slave stations under the master station The wireless communication system according to any one of claims 6 to 8, wherein an emergency stop of the local station is performed when the emergency notification is received. A wireless communication system comprising a master station and a plurality of slave stations under the master station,
The master station sets a transmission permissible time that allows data transmission to each slave station within a certain communication cycle, and sets command data that is an instruction command for each slave station and the permissible transmission time. Notify each slave station,
Each slave station is
A slave station side wireless data receiving unit for receiving slave station side received data including the command data;
A command processing unit that performs processing on the command data to generate response data;
A transmission determination unit that determines whether the response data can be transmitted within the allowable transmission time based on a data amount of the response data and a transmission speed between the local station and the master station;
A slave station side wireless data transmitter for transmitting slave station side transmission data including the response data to the master station;
With
The transmission determination unit
When it is determined that transmission of the response data is impossible within the allowable transmission time, the response data is discarded and transmission of the response data is stopped. A wireless communication system comprising a master station and a plurality of slave stations under the master station,
The master station sets a transmission permissible time that allows data transmission to each slave station within a certain communication cycle, and sets command data that is an instruction command for each slave station and the permissible transmission time. Notify each slave station,
Each slave station is
A slave station side wireless data receiving unit for receiving slave station side received data including the command data;
A command processing unit that performs processing on the command data to generate response data;
A transmission determination unit that determines whether the response data can be transmitted within the allowable transmission time based on a data amount of the response data and a transmission speed between the local station and the master station;
A slave station side wireless data transmitter for transmitting slave station side transmission data including the response data to the master station;
With
The transmission determination unit
When it is determined that transmission of the response data is impossible within the allowable transmission time, the response data is retained as remaining data, and the data amount and priority of the remaining data are stored as remaining data information Generate disabling notifications,
The said radio | wireless communications system characterized by the above-mentioned radio | wireless data transmission part of the said sub_station | mobile_unit transmitting the said transmission impossible notification to the said master station within the said transmission permissible time. A wireless communication system comprising a master station and a plurality of slave stations under the master station,
The master station sets a transmission permissible time that allows data transmission to each slave station within a certain communication cycle, and sets command data that is an instruction command for each slave station and the permissible transmission time. Notify each slave station,
Each slave station is
A slave station side wireless data receiving unit for receiving slave station side received data including the command data;
A command processing unit that performs processing on the command data to generate response data;
A transmission determination unit that determines whether the response data can be transmitted within the allowable transmission time based on a data amount of the response data and a transmission speed between the local station and the master station;
A slave station side wireless data transmitter for transmitting slave station side transmission data including the response data to the master station;
With
The transmission determination unit
When it is determined that transmission of the response data is impossible within the allowable transmission time, the response data is divided into response data having a data amount that can be transmitted within the communication period and remaining data having a data amount that cannot be transmitted. And holding the remaining data divided into the data amount and priority of the remaining data as remaining data information, generating a divided response data notification storing the divided response data and the remaining data information,
The slave station-side radio data transmitter transmits the division response data notification to the master station within the allowable transmission time. The master station is
A command generation unit for generating the command data;
A master station side wireless data receiving unit that receives master station side received data including the response data from each of the slave stations;
A period management unit that sets the transmission permissible time and generates a transmission permissible time notification that notifies the transmission permissible time to each of the slave stations;
A master station-side radio data transmitter that transmits the command data and the master station-side transmission data including the transmission allowable time notification to each of the slave stations;
With
The master station side radio data receiving unit transmits NACK data indicating a non-reception confirmation when the response data from the slave station cannot be normally received within the transmission allowable time set for the slave station. Send the request to the master station side wireless data transmitter,
In response to the NACK data transmission request, the master station side wireless data transmission unit generates NACK data and transmits the NACK data to each of the slave stations.
When the NACK data is received, the command processing unit re-determines whether the response data can be transmitted within the allowable transmission time, and determines that the response data can be transmitted within the allowable transmission time. In this case, the wireless communication system according to any one of claims 10 to 12, wherein the response data is retransmitted to the master station. The master station is
A received data analysis unit that analyzes the received data on the master station side and transmits the remaining data information to the cycle management unit when the received data on the master station side is the division response data notification or the transmission impossible notification; Prepared,
The cycle management unit
The number of transmissions of the NACK data for each of the slave stations is held as the number of retransmission occurrences for each of the slave stations, and the remaining data is allowed to be transmitted to each of the slave stations holding the remaining data Based on the amount and priority of the remaining data stored in the remaining data information and the number of retransmission occurrences, a transmission allowable time reassigning time for allocating the reassigned transmission allowable time to be assigned is provided in the communication cycle. And setting a different allowable re-transmission transmission time for each slave station,
The transmission determination unit
The wireless communication system according to claim 13, wherein the remaining data is transmitted within the re-assignment transmission allowable time assigned to the own station.   The cycle management unit provides an emergency communication time within the communication cycle for detecting that an event requiring an emergency stop has occurred in the master station or each of the slave stations, and sets the emergency communication time to the command The wireless communication system according to claim 10, wherein the wireless communication system is added to data and notified to each of the slave stations. The command processing unit generates an emergency notification and transmits the emergency notification within the emergency communication time when an event that requires an emergency stop has occurred in the local station,
The command generation unit stops command generation processing based on the emergency notification,
The wireless communication system according to claim 15, wherein the cycle management unit issues an emergency stop instruction to each of the slave stations based on the emergency notification. The master station side wireless data receiving unit generates an emergency notification when receiving a radio wave having a radio field strength equal to or higher than a predefined radio frequency at a frequency used by the local station within the emergency communication time,
The command generation unit stops command generation processing based on the emergency notification,
The cycle management unit generates an emergency stop instruction for each slave station based on the emergency notification,
The radio communication system according to claim 15 or 16, wherein the command processing unit stops command processing based on the emergency stop instruction. The slave station side wireless data receiving unit receives a radio wave having a predetermined radio field strength or higher from the outside of the system at the frequency used by the local station within the emergency communication time, and other subordinates of the master station When receiving the emergency notification from the slave station of, generate an emergency radio wave reception notification,
The transmission determination unit generates an emergency stop instruction for the command processing unit based on the emergency radio wave reception notification,
The wireless communication system according to any one of claims 15 to 17, wherein the command processing unit stops command processing based on the emergency stop instruction. A wireless communication system for transmitting and receiving data between a master station and a plurality of slave stations under the master station,
A first step of setting a transmission permissible time within which the master station allows the response data to be transmitted to the slave stations within a certain communication cycle;
A second step in which the master station transmits command data, which is an instruction command for each slave station, and the allowable transmission time to each slave station;
Processing for the command data is performed to generate response data. Based on the data amount of the response data and the transmission speed between the own station and the master station, each slave station is within the allowable transmission time. A third step of determining whether or not to transmit the response data in
A fourth step of discarding the response data and stopping the transmission of the response data when the slave station determines that the response data cannot be transmitted within the allowable transmission time;
A wireless communication method comprising: A wireless communication system for transmitting and receiving data between a master station and a plurality of slave stations under the master station,
A first step of setting a transmission allowable time within which the master station allows data transmission to each of the slave stations within a certain communication cycle;
A second step in which the master station transmits command data, which is an instruction command for each slave station, and the allowable transmission time to each slave station;
Processing for the command data is performed to generate response data. Based on the data amount of the response data and the transmission speed between the own station and the master station, each slave station is within the allowable transmission time. A third step of determining whether or not to transmit the response data in
When the slave station determines that transmission of the response data is impossible within the allowable transmission time, the response data is retained as remaining data, and the data amount and priority of the remaining data are stored in the remaining data information the transmission impossible notification that contains a fourth step of transmitting to the master station in the transmission allowable time as,
A wireless communication method comprising: A wireless communication system for transmitting and receiving data between a master station and a plurality of slave stations under the master station,
A first step of setting a transmission allowable time within which the master station allows data transmission to each of the slave stations within a certain communication cycle;
A second step in which the master station transmits command data, which is an instruction command for each slave station, and the allowable transmission time to each slave station;
Processing for the command data is performed to generate response data. Based on the data amount of the response data and the transmission speed between the own station and the master station, each slave station is within the allowable transmission time. A third step of determining whether or not to transmit the response data in
When each of the slave stations determines that the response data cannot be transmitted within the allowable transmission time, the response data cannot be transmitted with the divided response data having a data amount that can be transmitted within the allowable transmission time. Divided response data in which the remaining data is held by dividing the remaining data into a remaining amount of data, and the remaining response data and the remaining data information are stored with the remaining data amount and priority as remaining data information A fourth step of transmitting a notification to the master station within the allowable transmission time;
A wireless communication method comprising: In the first step, a transmission allowable time reassignment time for assigning a reassignment transmission allowable time allowing the transmission of the remaining data to each of the slave stations in which the parent station holds the remaining data, Within the communication cycle,
When the master station fails to normally receive the response data from the slave station within the transmission allowable time set for each slave station, NACK data indicating non-reception confirmation is transmitted to the slave station. And a fifth step
When each of the slave stations receives NACK data from the master station, it is determined again whether the response data can be transmitted within the allowable transmission time, and the response data can be transmitted within the allowable transmission time. A sixth step of retransmitting the response data to the master station,
The wireless communication method according to any one of claims 19 to 21, further comprising: A seventh step of holding the number of times the master station has transmitted the NACK data for each slave station as the number of retransmission occurrences for each slave station;
An eighth step in which the master station sets the reassignment allowable transmission time different for each of the slave stations based on the amount and priority of the remaining data and the number of retransmission occurrences;
A ninth step in which each of the slave stations transmits the remaining data within the reassignment allowable transmission time allocated to the local station;
The wireless communication method according to claim 22, further comprising: In the first step, an emergency communication time for detecting that an event that requires an emergency stop of the master station or each of the slave stations has occurred in the communication cycle is provided in the communication cycle,
The wireless communication method according to any one of claims 19 to 23, wherein, in the second step, the emergency communication time is added to the command data and notified to each of the slave stations. A tenth step of transmitting an emergency notification within the emergency communication time when an event that requires an emergency stop at each of the slave stations occurs;
An eleventh step in which the master station performs an emergency stop of its own station and each of the slave stations based on the emergency notification;
The wireless communication method according to claim 24, further comprising:   A twelfth step of performing an emergency stop of the own station and each of the slave stations when the master station receives from the outside of the system radio waves having a radio field strength equal to or higher than a predetermined frequency at a frequency used by the own station within the emergency communication time; The wireless communication method according to claim 24 or 25, further comprising:   When each of the slave stations receives a radio wave having a radio field strength equal to or higher than a predefined radio frequency at a frequency used by the local station within the emergency communication time, and from the other slave stations under the master station The radio communication method according to any one of claims 24 to 26, further comprising a thirteenth step of executing an emergency stop of the own station when an emergency notification is received.

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