Combustible gas monitoring and alarming system based on ZigBee

Abstract

The invention discloses a combustible gas monitoring and alarming system based on ZigBee, and relates to the technical field of gas monitoring, a gas detection terminal is arranged to detect combustible gas in each storage partition of a target wharf in real time, and a ZigBee router in each storage partition is in communication connection with terminal equipment; a routing table dynamically selects an optimal next-hop node through a periodic routing discovery process, a monitoring acquisition unit of a routing optimization module is set to track routing table updating in real time, an analysis optimization unit analyzes based on a stored routing information table, and a stability evaluation index is calculated, so that the routing table is optimized. The stability degree of the neighbor node of each source node as the optimal node is evaluated, the discovery period of the routing discovery process of each neighbor node by the terminal equipment is intelligently adjusted according to the evaluation result, the problems of excessive unnecessary network bandwidth occupation and system energy consumption increase are reduced, the energy consumption is reduced, and the user experience is improved. And the route sending process of the source node to each neighbor node is more efficient and intelligent.

Description

Technical Field

[0001] The present invention relates to the technical field of gas monitoring, and particularly to a combustible gas monitoring and alarm system based on ZigBee. Background Art

[0002] In the operation scenario of modern liquefied product terminals, safe production is a crucial link. Since the leakage of combustible gas is likely to trigger major safety accidents such as fires and explosions, building an efficient and accurate leakage monitoring and instant alarm system has become a key technical link to avoid accident risks and ensure the safe operation of the terminal. Due to technical defects such as complex wiring, high construction and maintenance costs, and difficult layout adjustment in traditional wired monitoring systems, it is difficult to meet the actual application requirements of the complex and changeable terminal environment and frequent equipment layout adjustments, and significant limitations have been exposed in engineering practice; As a low-power and low-cost short-range wireless communication technology, ZigBee technology has been widely used in the field of wireless sensor networks based on its self-organizing and self-healing network characteristics. A combustible gas monitoring and alarm system built using ZigBee technology can effectively overcome the wiring problems of wired systems, has the technical advantage of flexible deployment, and can better adapt to the complex spatial structure and dynamic operation scenarios of the terminal; However, in the network routing mechanism of the existing combustible gas monitoring and alarm system based on ZigBee technology, in order to ensure the accuracy of the next-hop node information of the source node in the routing table, the existing technical solution is to continuously and real-time monitor all neighbor nodes of the source node. This monitoring process needs to send detection data to each neighbor node in real time to obtain information such as the connection status and link quality of each neighbor node. However, in the actual application environment of the terminal, for neighbor nodes with stable signal transmission and high connection reliability, continuous high-frequency data detection will cause unnecessary network bandwidth occupation and increased system energy consumption; To solve the above problems, the present invention proposes a solution. Summary of the Invention

[0003] The purpose of the present invention is to provide a combustible gas monitoring and alarm system based on ZigBee to solve the problems raised in the above background art.

[0004] The present invention provides a combustible gas monitoring and alarm system based on ZigBee, including: A gas detection terminal for real-time detection of the concentrations of several combustible gases in several storage areas of the target terminal. The gas detection terminal includes several partition detection modules, and one partition detection module corresponds to one storage area of the target terminal; one ZigBee router and several terminal devices are arranged in any one storage area of the target terminal; A monitoring and alarm platform is used to monitor the threshold of the combustible gas concentration in several storage areas of a target terminal and give an alarm. The monitoring and alarm platform includes a data center device; A ZigBee routing device arranged in a storage area maintains a routing table, and the routing table is updated and stored in the partition detection module corresponding to the storage area. The routing table stores several source nodes and their next-hop nodes; The monitoring and acquisition unit is used to collect the updated routing table and transmit it to the analysis and optimization unit for storage as a routing acquisition table of the storage area corresponding to the partition detection module every time an update occurs in the routing table in a partition detection module. The next-hop node of each source node in the routing table is updated through a periodic routing discovery process; The analysis and optimization unit is used to analyze the P1 routing acquisition tables of a storage area after storing each P1 routing acquisition tables of a storage area to determine the next-hop analysis table of several source nodes of the storage area; The analysis and optimization unit is also used to optimize the routing discovery process of the next-hop nodes of all terminal devices and ZigBee routing devices in the storage area according to a preset optimization rule after determining the next-hop analysis table of several source nodes of a storage area.

[0005] Furthermore, several terminal devices arranged in a storage area are communicatively connected to the ZigBee routers arranged in the storage area. A mesh network is constructed among several storage areas by using ZigBee technology, and the mesh network realizes multi-hop transmission of data based on the ZigBee Mesh routing protocol.

[0006] Furthermore, the next-hop node corresponding to any source node is selected from all the neighbor nodes of the source node, where the neighbor node is the direct object of data transmission of the corresponding source node and is selected by the management staff from all the ZigBee routers and terminal devices arranged in all storage areas of the target terminal.

[0007] Furthermore, the discovery period of the routing discovery process of all neighbor nodes of any terminal device or ZigBee router is stored therein.

[0008] Further, a preset upper limit of the alarm concentration of a plurality of combustible gases is stored in the monitoring and alarm platform. After the monitoring and alarm platform receives the concentration detection data of a combustible gas in a storage partition each time, it obtains the detected concentration included therein, compares the detected concentration with the upper limit of the alarm concentration of the combustible gas. If the detected concentration is greater than or equal to the upper limit of the alarm concentration of the combustible gas, an alarm message for the storage partition is generated according to the detected concentration of the combustible gas, and the alarm message is transmitted to the electronic device of the management personnel and simultaneously used to alarm the management personnel in a voice manner.

[0009] Further, the steps for determining the next-hop analysis tables of several source nodes in a storage partition are as follows: S11: Mark all the routing collection tables of the storage partition stored in the analysis and optimization unit in the order of storage as A1, A2,..., Aa, where a≥1; S12: Mark all the terminal devices and ZigBee routing devices arranged in the storage partition as B1, B2,..., Bb, where b≥1; S13: Select B1 as the device to be analyzed, traverse the routing collection tables A1, A2,..., Aa in turn, obtain all the next-hop nodes with the source node being the device to be analyzed and remove duplicates, and mark the remaining next-hop nodes after deduplication as C1, C2,..., Cc, where c≥1; S14: Extract all the routing collection tables with the source node being the device to be analyzed and the next-hop node being C1 from them in the order of the routing collection tables A1, A2,..., Aa, and mark the extracted routing collection tables as D1, D2,..., Dd in the order of extraction, where 1≤d≤a; S15: Calculate the update interval duration E1 of the routing collection tables D1 and D2 according to the time when the routing collection tables D1 and D2 are stored in the analysis and optimization unit. Mark the time when the routing collection table with a smaller subscript, that is, the routing collection table D1, is stored in the analysis and optimization unit as the minuend during the calculation of the update interval duration E1; Similarly, calculate the update interval durations of the routing collection tables D2 and D3, D3 and D4,..., Dd-1 and Dd in turn, and mark them as E2, E3,..., Ed-1; S16: Generate an array of sequences F1, F2,..., Ff related to the device to be analyzed for the next-hop node C1 according to the update interval durations E1, E2,..., Ed-1 according to a preset generation rule, where f≥1; S17: Calculate and obtain the stability evaluation index L1 related to the device to be analyzed for the next-hop node C1 according to a preset calculation rule; S18: Calculate and obtain the stability evaluation indicators of the device to be analyzed with respect to the next-hop nodes C2, C3, ..., Cc in sequence according to S13 to S14, and generate a next-hop analysis table of the device to be analyzed based on them; S19: Select B2, B3, ..., Bb as the devices to be analyzed in sequence according to S12, and generate the next-hop analysis tables of B2, B3, ..., Bb in sequence according to S13 to S18.

[0010] Furthermore, in S16, any one of the sequence arrays F1, F2, ..., Ff consists of several update interval durations with consecutive and identical numerical marking subscripts, and the marking subscripts of the update interval durations increase in sequence from left to right.

[0011] Furthermore, in S17, the calculation rule of the stability evaluation indicator L1 is as follows: S171: Determine whether all the characters constituting the sequence array F1 are 1. Based on the determination result, select to calculate the static duration or interruption duration of the sequence array F1. Similarly, determine whether all the characters constituting the sequence arrays F2, F3, ..., Ff are 1 in sequence, and obtain several static durations and several interruption durations based on the determination results; S172: Process the data of all the static durations obtained in S171 using a discrete point filtering algorithm, and calculate the average value H1 of all the remaining static durations after data processing; S173: Mark all the interruption durations obtained in S171 as I1, I2, ..., Ii in the order of acquisition, where 1 ≤ i < f. Process the interruption durations I1, I2, ..., Ii using a discrete point filtering algorithm, and calculate the average value H2 of all the remaining interruption durations after data processing; S174: Obtain the marking subscripts J1, J2 of the sequence arrays composed of all the characters of the calculated interruption durations I1, I2 in sequence. Obtain the sum of the static durations of all the sequence arrays with marking subscripts greater than J1 and less than J2 in the sequence arrays F1, F2, ..., Ff, and use the sum as the recovery interval duration K1 of the interruption durations I1 and I2. Similarly, obtain the recovery interval durations K2, K3, ..., Ki-1 of the interruption durations I2 and I3, I3 and I4, ..., Ii-1 and Ii in sequence; S175: Use the formula Calculate and obtain the stability evaluation index L1 of the device to be analyzed with respect to the next-hop node C1. In the formula, β1 and β2 are respectively the preset first and second proportion factors, and ɑ1 is the preset dimension balance factor, which is used to adjust the dimensions of different dimensions to the same calculation dimension for numerical calculation. Kk is used to represent each of the recovery interval durations K1, K2,..., Ki, K represents the average value of the recovery interval durations K1, K2,..., Ki-1, and Ki is the sum of the static duration of all sequence arrays with the marked subscript less than J1.

[0012] Further, the steps for the analysis and optimization unit to optimize the discovery period of all terminal devices in the storage partition and all neighbor nodes of ZigBee routing devices after generating the next-hop analysis tables of B1, B2,..., Bb are as follows: S21: Sequentially extract the stability evaluation indexes L1, L2,..., Lc of B1 with respect to the next-hop nodes C1, C2,..., Cc from the next-hop analysis table of B1; S22: Compare the magnitudes of L1 with Lmin and Lmax. If L1 ≥ Lmax, it is determined that the discovery period of B1 with respect to the next-hop node C1 is P2. If L1 ≤ Lmin, it is determined that the discovery period of B1 with respect to the next-hop node C1 is P3. If Lmin < L1 < Lmax, it is determined that the discovery period of B1 with respect to the next-hop node C1 is P4. P2, P3, and P4 are respectively the preset first, second, and third standard discovery periods, and numerically satisfy P2 > P4 > P3. Lmin and Lmax are respectively the preset first and second frequency separation thresholds; S23: Sequentially determine the discovery periods of B1 with respect to the next-hop nodes C2, C3,..., Cc according to S22; Generate the optimized update data of B1 according to the discovery periods of B1 with respect to the next-hop nodes C1, C2,..., Cc, and send the optimized update data to B1; after receiving the optimized update data, B1 updates the discovery periods of the corresponding neighbor nodes stored in B1 according to the discovery periods of all next-hop nodes in the optimized update data; S24: Sequentially generate the optimized update data of B2, B3,..., Bb according to S21 to S23 and send them to the corresponding devices, and the corresponding devices update the discovery periods of the corresponding neighbor nodes stored in them.

[0013] Compared with the prior art, the following beneficial effects are achieved: In the present invention, a gas detection terminal is combined with a variety of combustible gas concentration detection sensors through a partition detection module, enabling real-time detection of combustible gases in each storage partition of the target wharf. The ZigBee Mesh routing protocol is used to construct a mesh network to achieve multi-hop data transmission. The ZigBee routers in each storage partition are communicatively connected to the terminal devices. The routing table is automatically updated based on multiple parameters such as RSSI and LQI through a periodic routing discovery process, dynamically selecting the optimal next-hop node to ensure efficient and stable data transmission. Even if some nodes fail, data can still be transmitted through other paths, improving the reliability and robustness of the network. In the present invention, the monitoring and acquisition unit of the routing optimization module tracks the update of the routing table in real time. The analysis and optimization unit, based on the analysis of the stored routing information table, processes data by calculating stability evaluation indicators and combining a discrete point filtering algorithm, accurately evaluating the stability degree of the neighbor nodes of each source node as the optimal node. According to the evaluation results, the discovery period of the routing discovery process of the terminal device for each neighbor node is intelligently adjusted. In this way, the problems of excessive unnecessary network bandwidth occupation and increased system energy consumption are reduced, the energy consumption is lowered, and the routing sending process of the source node to each neighbor node becomes more efficient and intelligent. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 is a system block diagram of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0015] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0016] Please refer to Figure 1 , this application provides a combustible gas monitoring and alarm system based on ZigBee, including a gas detection terminal, a routing optimization module, and a monitoring and alarm platform; The gas detection terminal is used to detect the concentration of several combustible gases in several storage partitions of the target wharf. In this application, the storage partition refers to the liquefied product storage tank area; The gas detection terminal includes several partition detection modules, and one partition detection module corresponds to one storage partition of the target wharf; In this application, one ZigBee router and several terminal devices are arranged in any storage partition of the target wharf. Among them, the terminal device refers to various gas concentration detection sensors, and various gas concentration detection sensors are used to detect the concentration of the corresponding combustible gas; In this application, the combustible gases detected by the gas concentration detection sensor include hydrogen, carbon monoxide, methane, ethane, propane, butane, ethylene, propylene, butene, acetylene, propyne, butyne, hydrogen sulfide, and phosphine; In this application, several terminal devices arranged in a storage partition are communicatively connected to the ZigBee router arranged in the storage partition to receive and forward the data detected by the corresponding terminal devices; The monitoring and alarm platform is used to monitor the threshold and alarm the combustible gas concentration in several storage partitions of the target terminal. The monitoring and alarm platform includes a data center device. In this application, the data center device is a server; Among them, a mesh network is constructed among the several storage partitions by using ZigBee technology. The mesh network realizes multi-hop transmission of data based on the ZigBee Mesh routing protocol. The corresponding ZigBee router transmits the data detected by the corresponding terminal device to the data center device, and the monitoring and alarm platform analyzes and alarms the received data to realize the monitoring of the combustible gas concentration in the target terminal; In this application, the updated routing table maintained by the ZigBee routing device arranged in a storage partition is stored in the partition detection module corresponding to the storage partition; It should be noted here that when using the ZigBee Mesh routing protocol to construct a mesh network, each ZigBee routing device in the mesh network maintains a routing table, and several source nodes and their next-hop nodes are stored in the routing table; The source node stored in any routing table refers to the terminal device in the storage partition where the ZigBee routing device that maintains the routing table is arranged. At this time, there is the following corresponding relationship: one source node corresponds to one terminal device; The next-hop node corresponding to any source node is to select a neighbor node from all the neighbor nodes of the source node as its next-hop node, where the neighbor nodes are selected by the management personnel from all the ZigBee routers and terminal devices arranged in all the storage partitions of the target terminal according to whether the distance between the source node and them is within the effective transmission range of the wireless signal, and then several ZigBee routers and terminal devices are selected from all the ZigBee routers and terminal devices as its neighbor nodes; It should be noted here that the neighbor node is the direct object of the data transmission corresponding to the source node. The source node can send the detected or received data to the neighbor node, and the neighbor node further forwards it, and finally realizes the transmission of the data from the source node to the destination node; In this application, the destination node to which the data detected or received by any source node is finally transmitted is the same, which is the data center device; In this application, all neighbor nodes of any terminal device or ZigBee router are stored therein. In this application, the next-hop node of each source node in the routing table is automatically updated through a periodic routing discovery process. The content of the routing discovery process is as follows: The next-hop node of any source node is that the source node sends a probe data frame (such as a beacon frame or a specific link state probe frame in the ZigBee standard) to all its neighbor nodes through its discovery period. During the sending process of the probe data frame, each neighbor node is evaluated in real time based on several monitoring parameters, and the next-hop node of the source node is periodically selected. The source node and its next-hop node are transmitted to the corresponding ZigBee routing device, and the ZigBee routing device updates the routing table therein. The monitoring parameters include received signal strength indication (RSSI), link quality indication (LQI), packet reception rate (PRR), response time of each neighbor node to the probe data frame, and packet loss rate. Among them, the discovery period of the routing discovery process of the next-hop node of any source node in the initial routing table is real-time, that is, the probe data frame is sent to all its neighbor nodes in real time for any source node. All neighbor nodes of any terminal device or ZigBee router store the discovery period of the routing discovery process. The partition detection module collects in real time the concentration detection data of several combustible gases in the corresponding storage partition and transmits it to the monitoring and alarm platform. One piece of the concentration detection data contains the detected concentration of the corresponding combustible gas. The monitoring and alarm platform stores the preset upper limit of the alarm concentration of several combustible gases. The setting of the upper limit of the alarm concentration of one combustible gas is determined based on the lower explosion limit of the combustible gas, generally between 25% and 50% of the lower explosion limit. In this application, the management personnel set the concentration upper limit of the corresponding combustible gas according to the type of the combustible gas and the environment of the target terminal. After the monitoring and alarm platform receives the concentration detection data of one combustible gas in one storage partition each time, it obtains the detected concentration contained therein, compares the detected concentration with the upper limit of the alarm concentration of the combustible gas. If the detected concentration is greater than or equal to the upper limit of the alarm concentration of the combustible gas, an alarm message for the storage partition is generated according to the detected concentration of the combustible gas, and the alarm message is transmitted to the electronic device of the management personnel and used to alarm the management personnel synchronously in a voice manner. The electronic devices include but are not limited to computers, smart phones, tablet computers, etc. If the detected concentration is less than the upper limit of the alarm concentration of the combustible gas, no processing is performed. A routing optimization module is used to analyze and optimize the routing discovery process of the next-hop node of each source node in the routing table updated and stored in several partition detection modules. The routing optimization module includes a monitoring and acquisition unit and an analysis and optimization unit; For any one partition detection module, every time the monitoring and acquisition unit monitors that the routing table in the partition detection module is updated once, it collects the updated routing table once, and transmits the collected routing table to the analysis and optimization unit for storage as the routing acquisition table of the storage partition corresponding to the partition detection module; In this application, every time the next-hop node of a source node is updated once, it means that the corresponding routing table has been updated once; For any one storage partition, when the storage quantity of the routing acquisition table of the storage partition in the analysis and optimization unit reaches P1, the analysis and optimization unit analyzes all the routing acquisition tables of the storage partition, and updates the discovery period of the routing discovery process of several source nodes in the storage partition based on the analysis result. P1 is a preset standard analysis threshold, and the value of P1 is set regularly by the management personnel according to the warehousing operations and monitoring tasks of the target wharf. The analysis steps are as follows: S11: Mark all the routing acquisition tables of the storage partition stored in the analysis and optimization unit in the order of storage as A1, A2,..., Aa in turn, where a≥1; S12: Mark all the terminal devices and ZigBee routing devices arranged in the storage partition as B1, B2,..., Bb in turn, where b≥1; S13: Select B1 as the device to be analyzed, traverse the routing acquisition tables A1, A2,..., Aa in turn, obtain all the next-hop nodes whose source node is the device to be analyzed, remove duplicates from the obtained all next-hop nodes, and mark the remaining all next-hop nodes after deduplication as C1, C2,..., Cc in turn, where c≥1; S14: Extract all the routing acquisition tables whose source node is the device to be analyzed and the next-hop node is C1 from the routing acquisition tables A1, A2,..., Aa in order, and mark all the extracted routing acquisition tables as D1, D2,..., Dd in the order of extraction, where 1≤d≤a; S15: According to the time when the routing acquisition tables D1 and D2 are stored in the analysis and optimization unit, calculate and obtain the update interval duration E1 between the routing acquisition tables D1 and D2. During the calculation of the update interval duration E1, mark the time when the routing acquisition table with a smaller subscript, that is, the routing acquisition table D1, is stored in the analysis and optimization unit as the minuend; Similarly, calculate and obtain the update interval durations between the routing acquisition tables D2 and D3, D3 and D4,..., Dd-1 and Dd in turn, and mark them as E2, E3,..., Ed-1; S16: Generate sequence arrays F1, F2, …, Ff (f ≥ 1) related to the device to be analyzed for the next-hop node C1 according to the update interval durations E1, E2, …, Ed-1 according to a preset generation rule. The generation rule is as follows: S161: Concatenate the update interval durations E1, E2, …, Ed-1 in ascending order of the marker subscripts to obtain a concatenated sequence; S162: Cut the concatenated sequence from left to right to obtain sequence arrays F1, F2, …, Ff (f ≥ 1) related to the device to be analyzed for the next-hop node C1; In any one of the sequence arrays F1, F2, …, Ff, it consists of several update interval durations with consecutive and identical marker subscripts, and the marker subscripts of the update interval durations increase sequentially from left to right; In any two sequence arrays with consecutive marker subscripts in the sequence arrays F1, F2, …, Ff, the following is satisfied: the value after adding 1 to the marker subscript of the rightmost update interval duration in the sequence array with a smaller marker subscript is numerically consistent with the marker subscript of the leftmost update interval duration in the sequence array with a larger marker subscript; It should be noted here that if there is an update interval duration, and the update interval durations corresponding to the marker subscripts whose values are consistent with the combination of adding 1 and subtracting 1 to the marker subscript of the update interval duration are all different from the update interval duration, then the interval duration is also used as a group of sequence arrays, and the number of characters in the sequence array is 1; S17: Calculate and obtain the stability evaluation index L1 related to the device to be analyzed for the next-hop node C1 according to a preset calculation rule. The calculation rule is as follows: S171: Determine whether all characters constituting the sequence array F1 are 1. Based on the determination result, select to calculate the static duration or interruption duration of the sequence array F1. The determination content is as follows: If all characters constituting the sequence array F1 are 1, convert all characters constituting the sequence array F1 into integers and perform numerical addition, and use the added result as the static duration of the sequence array F1. Otherwise, convert all characters constituting the sequence array F1 into integers and perform numerical addition, and use the added result as the interruption duration of the sequence array F1; Similarly, determine whether all characters constituting the sequence arrays F2, F3, …, Ff are 1 in turn. Based on the determination result, obtain several static durations and several interruption durations; S172: Process the data of several static durations obtained from the sequence arrays F1, F2, …, Ff in S171 using a discrete point filtering algorithm, and calculate the average value H1 of all remaining static durations after data processing; S173: Mark all the interruption durations obtained from the sequence arrays F1, F2, ..., Ff in S171 as I1, I2, ..., Ii in the order of acquisition, where 1 ≤ i < f. Use the discrete point filtering algorithm to process the data of the interruption durations I1, I2, ..., Ii, and calculate the average value H2 of all the remaining interruption durations after data processing; S174: Sequentially obtain the marker subscripts J1, J2 of the sequence arrays composed of all the characters of the calculated interruption durations I1, I2. Obtain the sum of the static durations of all the sequence arrays with marker subscripts greater than J1 and less than J2 in the sequence arrays F1, F2, ..., Ff, and use the sum as the recovery interval duration K1 between the interruption durations I1 and I2. Similarly, sequentially obtain the recovery interval durations K2, K3, ..., Ki-1 between the interruption durations I2 and I3, I3 and I4, ..., Ii-1 and Ii; S175: Use the formula to calculate and obtain the stability evaluation index L1 of the device to be analyzed with respect to the next-hop node C1. In the formula, β1 and β2 are the preset first and second proportion factors respectively, and ɑ1 is the preset dimension balance factor, which is used to adjust the dimensions of different dimensions to the same calculation dimension for numerical calculation. Kk is used to represent each of the recovery interval durations K1, K2, ..., Ki, K represents the average value of the recovery interval durations K1, K2, ..., Ki-1, and Ki is the sum of the static durations of all the sequence arrays with marker subscripts less than J1. It should be noted here that the stability evaluation index L1 is artificially defined to measure the stability degree of the next-hop node C1 as the optimal node; In this application, the discrete point filtering algorithm is the Z-score filtering algorithm; S18: Sequentially calculate and obtain the stability evaluation indexes of the device to be analyzed with respect to the next-hop nodes C2, C3, ..., Cc according to S13 to S14, and generate the next-hop analysis table of the device to be analyzed based on them; S19: Sequentially select B2, B3, ..., Bb as the devices to be analyzed according to S12, and sequentially generate the next-hop analysis tables of B2, B3, ..., Bb according to S13 to S18; After generating the next-hop analysis tables of B1, B2, ..., Bb, the analysis and optimization unit optimizes the discovery periods of all the terminal devices in the storage partition and all the neighbor nodes of the ZigBee routing devices according to the preset optimization rules. The optimization steps are as follows: S21: Sequentially extract the stability evaluation indexes L1, L2, ..., Lc of B1 with respect to the next-hop nodes C1, C2, ..., Cc from the next-hop analysis table of B1; S22: Compare the magnitudes of L1, Lmin, and Lmax. If L1 ≥ Lmax, then determine that the discovery period of B1 with respect to the next-hop node C1 is P2. If L1 ≤ Lmin, then determine that the discovery period of B1 with respect to the next-hop node C1 is P3. If Lmin < L1 < Lmax, then determine that the discovery period of B1 with respect to the next-hop node C1 is P4. P2, P3, and P4 are the preset first, second, and third standard discovery periods in sequence, and numerically satisfy P2 > P4 > P3. Lmin and Lmax are the preset first and second frequency separation thresholds respectively. In this application, the value of P3 is 1 s, which is real-time; S23: Sequentially determine the discovery periods of B1 with respect to the next-hop nodes C2, C3,..., Cc according to S22; Generate the optimized update data of B1 according to the discovery periods of B1 with respect to the next-hop nodes C1, C2,..., Cc, and send the optimized update data to B1; After B1 receives the optimized update data, update the discovery periods of the corresponding neighbor nodes stored in B1 according to the discovery periods of all the next-hop nodes in the optimized update data; S24: Sequentially generate the optimized update data of B2, B3,..., Bb according to S21 to S23 and send them to the corresponding devices, and the corresponding devices update the discovery periods of the neighbor nodes stored therein; Some of the data in the above formula are numerically calculated after removing their dimensions, and the content not described in detail in this specification belongs to the prior art well-known to those skilled in the art.

[0017] The above embodiments are only used to illustrate the technical method of the present invention and not to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical method of the present invention can be modified or equivalently replaced without departing from the spirit and scope of the technical method of the present invention.

Claims

1. A combustible gas monitoring and alarm system based on ZigBee, characterized in that, Including: A gas detection terminal for real-time detection of the concentrations of several combustible gases in several storage areas of a target terminal. The gas detection terminal includes several partition detection modules, and one partition detection module corresponds to one storage area of the target terminal; one ZigBee router and several terminal devices are arranged in any one storage area of the target terminal; A monitoring and alarm platform for threshold monitoring and alarm of the combustible gas concentrations in several storage areas of the target terminal. The monitoring and alarm platform includes a data center device; A ZigBee routing device arranged in one storage area maintains a routing table, and the routing table is updated and stored in the partition detection module corresponding to the storage area. The routing table stores several source nodes and their next-hop nodes; A monitoring and acquisition unit is used to collect the updated routing table and transmit it to the analysis and optimization unit for storage as a routing acquisition table of the storage area corresponding to the partition detection module every time the routing table in a partition detection module is updated once. The next-hop node of each source node in the routing table is updated through a periodic routing discovery process; An analysis and optimization unit is used to analyze the P1 routing acquisition tables of a storage area and determine the next-hop analysis table of several source nodes of the storage area after storing P1 routing acquisition tables of each storage area; The analysis and optimization unit is also used to optimize the routing discovery process of the next-hop nodes of all terminal devices and ZigBee routing devices in the storage area according to a preset optimization rule after determining the next-hop analysis table of several source nodes of each storage area; 2. The ZigBee-based combustible gas monitoring and alarm system according to claim 1, wherein Several terminal devices arranged in one storage area are communicatively connected to the ZigBee router arranged in the storage area. A mesh network is constructed among several storage areas by using ZigBee technology, and the mesh network realizes multi-hop transmission of data based on the ZigBee Mesh routing protocol; 3. The ZigBee-based combustible gas monitoring and alarm system according to claim 1, wherein, The next-hop node corresponding to any one source node is selected from all neighbor nodes of the source node, where the neighbor node is the direct object of data transmission corresponding to the source node and is selected by the management personnel from all ZigBee routers and terminal devices arranged in all storage areas of the target terminal; 4. The ZigBee-based combustible gas monitoring and alarm system according to claim 3, characterized in that The discovery period of the routing discovery process of all neighbor nodes of any one terminal device or ZigBee router is stored therein; 5. The ZigBee-based combustible gas monitoring and alarm system according to claim 1, characterized in that The monitoring and alarm platform stores the upper limit of the alarm concentration of several preset combustible gases. After receiving the concentration detection data of a combustible gas in a storage area each time, the detected concentration included therein is obtained, and the detected concentration is compared with the upper limit of the alarm concentration of the combustible gas. If the detected concentration is greater than or equal to the upper limit of the alarm concentration of the combustible gas, an alarm message of the storage area is generated according to the detected concentration of the combustible gas, and the alarm message is transmitted to the electronic device of the management personnel and an alarm is given to the management personnel in a voice manner synchronously; 6. The ZigBee-based combustible gas monitoring and alarming system according to claim 1, characterized in that, The steps for determining the next-hop analysis table of several source nodes of a storage area are as follows: S11: Mark all the routing collection tables of the storage partition stored in the analysis and optimization unit as A1, A2, ..., Aa in the order of storage, where a ≥ 1; S12: Mark all the terminal devices and ZigBee routing devices deployed in the storage partition as B1, B2, ..., Bb respectively, where b ≥ 1; S13: Select B1 as the device to be analyzed, traverse the routing collection tables A1, A2, ..., Aa in sequence, obtain all the next-hop nodes with the source node being the device to be analyzed and remove duplicates, and mark the remaining next-hop nodes after deduplication as C1, C2, ..., Cc respectively, where c ≥ 1; S14: Extract in sequence from the routing collection tables A1, A2, ..., Aa all the routing collection tables with the source node being the device to be analyzed and the next-hop node being C1, and mark the extracted routing collection tables as D1, D2, ..., Dd in the order of extraction, where 1 ≤ d ≤ a; S15: Calculate the update interval duration E1 between the routing collection tables D1 and D2 according to the moments when the routing collection tables D1 and D2 are stored in the analysis and optimization unit. Mark the moment when the routing collection table with a smaller subscript, i.e., the routing collection table D1, is stored in the analysis and optimization unit as the minuend during the calculation of the update interval duration E1. Similarly, calculate the update interval durations between the routing collection tables D2 and D3, D3 and D4, ..., Dd - 1 and Dd in sequence, and mark them as E2, E3, ..., Ed - 1 respectively; S16: Generate sequence arrays F1, F2, ..., Ff related to the next-hop node C1 of the device to be analyzed according to the update interval durations E1, E2, ..., Ed - 1 according to the preset generation rules, where f ≥ 1; S17: Calculate the stability evaluation index L1 related to the next-hop node C1 of the device to be analyzed according to the preset calculation rules; S18: Calculate the stability evaluation indexes related to the next-hop nodes C2, C3, ..., Cc of the device to be analyzed in sequence according to S13 to S14 and generate the next-hop analysis table of the device to be analyzed based on them; S19: Select B2, B3, ..., Bb as the devices to be analyzed in sequence according to S12, and generate the next-hop analysis tables of B2, B3, ..., Bb in sequence according to S13 to S18.

7. The ZigBee-based combustible gas monitoring and alarm system according to claim 6, wherein S16, In any one of the sequence arrays F1, F2, ..., Ff, it consists of several update interval durations with consecutive and identical marked subscripts, and the marked subscripts of the update interval durations increase in order from left to right.

8. The ZigBee-based flammable gas monitoring and alarm system according to claim 6, wherein S17, The calculation rules of the stability evaluation index L1 are as follows: S171: Determine whether all the characters constituting the sequence array F1 are 1. Based on the determination result, select to calculate the static duration or interruption duration of the sequence array F1. Similarly, determine whether all the characters constituting the sequence arrays F2, F3, ..., Ff are 1 in sequence. Based on the determination results, obtain several static durations and several interruption durations; S172: Process the static duration obtained in S171 using a discrete point filtering algorithm, and calculate the average value H1 of all the remaining static duration after data processing; S173: Mark the interruption durations obtained in S171 as I1, I2, …, Ii in the order of acquisition, where 1 ≤ i < f. Process the interruption durations I1, I2, …, Ii using a discrete point filtering algorithm, and calculate the average value H2 of all the remaining interruption durations after data processing; S174: Sequentially obtain the marker subscripts J1 and J2 of the sequence arrays composed of all characters of the calculated interruption durations I1 and I2. Obtain the sum of the static durations of all sequence arrays with marker subscripts greater than J1 and less than J2 in the sequence arrays F1, F2, …, Ff, and use the sum as the recovery interval duration K1 between the interruption durations I1 and I2. Similarly, sequentially obtain the recovery interval durations K2, K3, …, Ki - 1 between the interruption durations I2 and I3, I3 and I4, …, Ii - 1 and Ii; S175: Use the formula to calculate and obtain the stability evaluation index L1 of the device to be analyzed with respect to the next-hop node C1. In the formula, β1 and β2 are respectively the preset first and second proportion factors, ɑ1 is the preset dimension balance factor used to adjust the dimensions of different dimensions to the same calculation dimension for numerical calculation. Kk is used to represent each of the recovery interval durations K1, K2, ..., Ki. K represents the average value of the recovery interval durations K1, K2, ..., Ki-1. Ki is the sum of the static duration of all sequence arrays with the marked subscript less than J1.

9. The ZigBee-based combustible gas monitoring and alarming system according to claim 8, characterized in that, The steps for the analysis and optimization unit to optimize the discovery periods of all terminal devices in the storage partition and all neighbor nodes of the ZigBee routing devices after generating the next - hop analysis tables of B1, B2, …, Bb are as follows: S21: Sequentially extract the stability evaluation indicators L1, L2, …, Lc of B1 related to the next - hop nodes C1, C2, …, Cc from the next - hop analysis table of B1; S22: Compare the magnitudes of L1 with Lmin and Lmax. If L1 ≥ Lmax, then determine that the discovery period of B1 related to the next - hop node C1 is P2. If L1 ≤ Lmin, then determine that the discovery period of B1 related to the next - hop node C1 is P3. If Lmin < L1 < Lmax, then determine that the discovery period of B1 related to the next - hop node C1 is P4. P2, P3, and P4 are the preset first, second, and third standard discovery periods in sequence, and numerically satisfy P2 > P4 > P3. Lmin and Lmax are the preset first and second frequency separation thresholds respectively; S23: Determine the discovery periods of B1 related to the next - hop nodes C2, C3, …, Cc in sequence according to S22; Generate the optimized update data of B1 according to the discovery periods of B1 related to the next - hop nodes C1, C2, …, Cc, and send the optimized update data to B1. After receiving the optimized update data, B1 updates the discovery periods of the corresponding neighbor nodes stored in B1 according to the discovery periods of all the next - hop nodes in the optimized update data; S24: Sequentially generate the optimized update data of B2, B3, …, Bb according to S21 to S23 and send them to the corresponding devices, and let the corresponding devices update the discovery periods of the corresponding neighbor nodes stored in them.

Images