Passive camera water meter reading system based on M-bus

Abstract

The utility model discloses an M-bus-based passive camera water meter reading system which comprises a plurality of wired camera water meter terminals and a concentrator, the concentrator and the wired camera water meter terminals are connected through a bus M-Bus, and the bus comprises an M-Bus + and an M-Bus-; the concentrator activates the wired camera shooting water meter terminal in a time-sharing mode, and the wired camera shooting water meter terminal judges the working mode at the moment according to the lead code and the matching address. The method has the advantages that the power consumption on the M-Bus is reduced, and the on-load number of the M-Bus is increased. The concentrator supplies power to the wired camera water meter for a short time through a bus, and time-sharing data collection of the water meter is achieved in cooperation with algorithms such as system circuit design, communication and dormancy.

Description

Technical Field

[0001] The utility model is a passive camera water meter reading system based on M-bus, belonging to the technical field of M-Bus camera water meters. Background Art

[0002] At present, wired camera meters generally adopt passive mode, and generally have two communication modes: M-Bus bus and RS485 bus. The concentrator is connected to the camera meter through the M-Bus bus. Its advantage is that there are only two connecting wires. The M-Bus bus can be used as a communication connection method and a power supply method for the camera water meter. The disadvantage is that the power supply capacity of the M-Bus bus is limited and cannot support multiple camera water meters to take pictures at the same time. The concentrator is connected to the camera meter through the RS485 bus. There are 4 connecting wires, 2 communication connecting wires and 2 power supply connecting wires. Because the power supply is connected separately, the advantage of connecting through the RS485 bus is that it can support multiple camera water meters to work at the same time. The disadvantage is that there are many connecting wires and the on-site construction is difficult. At the same time, compared with the RS485 bus, the M-Bus bus has good anti-interference performance and supports long-distance transmission, which can reach more than 1,000 meters. In addition, the M-Bus protocol also supports the function of multiple meters in one, that is, one M-Bus bus can connect multiple water, electricity and gas meters, which is convenient for centralized management and processing of data. The RS485 protocol uses differential signal transmission, which has strong anti-interference performance, but the transmission distance is short.

[0003] In special environments, using the M-Bus bus has certain advantages, but because the camera water meter consumes a lot of power when taking pictures, the output load of the M-Bus chip cannot meet the load capacity requirements of the camera meter. How to use the M-Bus bus to provide load for the camera meter, reduce the power consumption of the terminal node, reduce the bus load current fluctuation during communication, and increase the number of bus-loaded cameras has become a difficult problem in the application of M-Bus bus camera water meters. Utility Model Content

[0004] The technical problem to be solved by the utility model is to provide a passive camera water meter reading system based on M-bus in view of the above shortcomings, reduce the power consumption on the M-Bus bus, and increase the bus load capacity. The concentrator supplies power to the wired camera water meter for a short time through the bus, and cooperates with the system circuit design, communication, sleep and other algorithms to realize the time-sharing data collection of the water meter. The power consumption of the camera water meter terminal determines the number of camera water meters mounted under the same bus load capacity, as well as the service life of the concentrator in the case of a battery-powered concentrator. This system reduces the power consumption of the entire system by reducing the standby power consumption of the camera water meter terminal and activating the data collection in time-sharing manner, which greatly increases the bus load capacity and extends the service life of the meter reading system under the same energy.

[0005] In order to solve the above technical problems, the utility model adopts the following technical solutions:

[0006] The passive camera water meter reading system based on M-bus includes several wired camera water meter terminals and a concentrator. The concentrator and the wired camera water meter terminals are connected through a bus M-Bus, and the bus includes M-Bus+ and M-Bus-. The concentrator activates the wired camera water meter terminals by time-sharing, and the wired camera water meter terminals determine the working mode at this time according to the leading code and the matching address.

[0007] The wired camera water meter terminal is connected to two lines of the concentrator in parallel. Both the wired camera water meter terminal and the concentrator include a single chip microcomputer, an M-Bus communication circuit, and a power supply circuit.

[0008] Furthermore, the power supply circuit of the wired camera water meter terminal includes a chip U4, and the model of the chip U4 is TSS721A.

[0009] Furthermore, pin 1 of the chip U4 is connected to one end of a resistor R6, pin 16 of the chip U4 is connected to one end of a resistor R5, and the other ends of the resistor R6 and the other ends of the resistor R5 are connected to two ends of the TVS tube TVS1.

[0010] Furthermore, two ends of the TVS tube TVS1 are connected to M+ and M- ends, and the M+ and M- ends are connected to buses M-Bus+ and M-Bus-, which are connected to the concentrator bus through wiring terminals.

[0011] Furthermore, pin 6 of the chip U4 is connected to one end of a capacitor C17, the other end of the capacitor C17 is grounded, pin 14 of the chip U4 is connected to one end of a resistor R12, the other end of the resistor R12 is grounded, and pin 3 of the chip U4 is connected to one end of a capacitor C18, the other end of the capacitor C18 is grounded.

[0012] Furthermore, pin 4 of the chip U4 is connected to one end of a resistor R13, and the other end of the resistor R13 is grounded, pin 8 of the chip U4 is connected to one end of a resistor R11 and connected to the single-chip microcomputer, pin 12 of the chip U4 is connected to one end of a resistor R10 and connected to the single-chip microcomputer, pin 5 of the chip U4 is connected to one end of a resistor R9 and connected to the single-chip microcomputer, pin 10 of the chip U4 is connected to one end of a resistor R8, and the other end of the resistor R11, the other end of the resistor R10, the other end of the resistor R9 and the other end of the resistor R8 are grounded.

[0013] Furthermore, the power supply circuit of the wired camera meter also includes a chip U6, pin 4 of the chip U6 is connected to the single-chip microcomputer, pin 5 of the chip U6 is connected to one end of a capacitor C20 and pin 2 of the chip U4, and the other end of the capacitor C20 is grounded.

[0014] Furthermore, pin 3 of the chip U6 is connected to one end of a capacitor C21, one end of a resistor R14 and one end of a resistor R15, and the other end of the resistor R15 is grounded, pin 6 of the chip U6 is connected to one end of an inductor L2, one end of a capacitor C19 and one end of a diode D1, and the other end of the diode D1 is grounded, the other end of the capacitor C19 is connected to pin 1 of the chip U6, the other end of the inductor L2 is connected to one end of a capacitor C22, the other end of the resistor R14 and the other end of the capacitor C21, and is connected to the CM_VCC end, the CM_VCC end is connected to the input pin of the voltage regulator chip, and the other end of the capacitor C22 is grounded.

[0015] The utility model adopts the above technical solution, and compared with the prior art, has the following technical effects:

[0016] Reduce the power consumption on the M-Bus and increase the number of bus loads. The concentrator provides short-term power to the wired camera water meter through the bus, and cooperates with the system circuit design, communication, sleep and other algorithms to realize the time-sharing data collection of the water meter. The power consumption of the camera water meter terminal determines the number of camera water meters mounted under the same bus load capacity, as well as the service life of the concentrator in the case of a battery-powered concentrator. This system reduces the power consumption of the entire system by reducing the standby power consumption of the camera water meter terminal and activating the data collection in time, which greatly increases the number of bus loads and extends the service life of the meter reading system under the same energy. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the specific implementation of the utility model or the technical solution in the prior art, the following is a brief introduction to the drawings required for the specific implementation or the prior art description. In all the drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, each element or part is not necessarily drawn according to the actual scale.

[0018] Figure 1 Provide wiring diagram for concentrator and wired camera meter system;

[0019] Figure 2 This is the schematic diagram of the M-Bus to serial port circuit at the camera meter end;

[0020] Figure 3 This is the schematic diagram of the power supply circuit for the camera at the camera meter end. DETAILED DESCRIPTION

[0021] Embodiment 1, as Figure 1 As shown, the passive camera water meter reading system based on M-bus includes several wired camera water meter terminals and a concentrator. The concentrator and the camera water meter terminals are connected through the bus M-Bus. The bus includes M-Bus+ and M-Bus-, and does not distinguish between polarities.

[0022] The wired camera water meter terminal is connected to two lines of the concentrator one by one in parallel. The wired camera meter and the concentrator both include a single chip microcomputer, an M-Bus communication circuit, and a power supply circuit.

[0023] The concentrator activates the wired camera water meter terminal by time-sharing, and the wired camera water meter terminal determines the working mode at this time according to the preamble code and the matching address. When the preamble code is received, the wired camera water meter switches from the low-power standby mode to the ready state. In the ready state, the camera water meter will determine whether the address matches. If the address matches, the camera meter enters the working mode. If the address does not match, the camera meter immediately enters the low-power sleep state. When the preamble code is not received, the wired camera water meter will no longer perform address matching and directly enter the low-power standby mode. In the ready state, the time for the single-chip microcomputer to judge the address is in microseconds, so the wired camera meter is in the low-power sleep mode most of the time. The power consumption of the concentrator and the camera meter will be reduced from milliampere level to microampere level when entering the low-power mode, so the power consumption of the system is greatly reduced.

[0024] like Figure 2 and Figure 3 As shown, the power supply circuit of the wired camera meter end includes a chip U4, the model of the chip U4 is TSS721A, the pin 1 of the chip U4 is connected to one end of the resistor R6, the pin 16 of the chip U4 is connected to one end of the resistor R5, the other end of the resistor R6 and the other end of the resistor R5 are connected to the two ends of the TVS tube TVS1, the two ends of the TVS tube TVS1 are connected to the M+ end and the M- end, the M+ end and the M- end are connected to the bus M-Bus+, M-Bus- are connected to the concentrator bus through the wiring terminal.

[0025] Pin 6 of the chip U4 is connected to one end of a capacitor C17, and the other end of the capacitor C17 is grounded, pin 14 of the chip U4 is connected to one end of a resistor R12, and the other end of the resistor R12 is grounded, pin 3 of the chip U4 is connected to one end of a capacitor C18, and the other end of the capacitor C18 is grounded, pin 4 of the chip U4 is connected to one end of a resistor R13, and the other end of the resistor R13 is grounded, pin 8 of the chip U4 is connected to one end of a resistor R11 and connected to a single-chip microcomputer, pin 12 of the chip U4 is connected to one end of a resistor R10 and connected to a single-chip microcomputer, pin 5 of the chip U4 is connected to one end of a resistor R9 and connected to a single-chip microcomputer, pin 10 of the chip U4 is connected to one end of a resistor R8, and the other end of the resistor R11, the other end of the resistor R10, the other end of the resistor R9 and the other end of the resistor R8 are grounded.

[0026] Pin 11 of the chip U4 is connected to a VCC power supply for connecting to a power supply pin of a single-chip microcomputer, and pins 8, 12 and 5 of the chip U4 are connected to the single-chip microcomputer.

[0027] The power supply circuit of the wired camera meter also includes a chip U6, wherein pin 4 of the chip U6 is connected to the single-chip microcomputer, pin 5 of the chip U6 is connected to one end of a capacitor C20 and pin 2 of the chip U4, the other end of the capacitor C20 is grounded, pin 3 of the chip U6 is connected to one end of a capacitor C21, one end of a resistor R14 and one end of a resistor R15, the other end of the resistor R15 is grounded, pin 6 of the chip U6 is connected to one end of an inductor L2, one end of a capacitor C19 and one end of a diode D1, the other end of the diode D1 is grounded, the other end of the capacitor C19 is connected to pin 1 of the chip U6, the other end of the inductor L2 is connected to one end of a capacitor C22, the other end of the resistor R14 and the other end of the capacitor C21, and is connected to the CM_VCC end, the CM_VCC end is connected to the input pin of the voltage regulator chip, and the other end of the capacitor C22 is grounded.

[0028] Figure 2 and Figure 3 The schematic diagram of the power management design for the camera meter is shown in the figure. The power supply of the microcontroller uses the output power supply VCC of TSS721, while the power supply of the camera uses a bus step-down solution. M_VB is the voltage after internal rectification of the TSS721 chip, which is used as the input voltage of the step-down chip ME3116. In this way, the power supply from the M-Bus can be obtained without distinguishing polarity. In addition, the power supply of the camera can be controlled by the CLT_CM enable terminal, so that CM_VCC is only turned on when the camera is taking pictures. Combined with the system time-sharing meter reading, it is ensured that only one camera of the camera meter is working on the bus. Because the camera meter does not communicate when taking pictures, the power supply of the camera does not affect the communication. During communication, the bus only powers the microcontroller, and the power consumption is about a few milliamperes. Similarly, only one microcontroller of the camera meter is working, and the others are in low-power sleep mode, so the power consumption on the bus is very small and does not affect the M-Bus communication.

[0029] Concentrator-side process:

[0030] 1. The battery-powered concentrator is initially in a low-power sleep mode. The concentrator periodically wakes up in the sleep mode to determine whether meter reading is required. If required, it enters the working mode and enters process 2; if not, it enters process 7.

[0031] 2. After the concentrator enters the working mode, the microcontroller controls the power supply circuit to supply power to the M-Bus. The concentrator reads the address of the camera meter that needs to be read from the memory, takes the address of the first camera meter and enters process 3.

[0032] 3. The concentrator sends a hexadecimal leading code, such as 0xFE, 0xFE, 0xFE, to the camera meter at the above address. The concentrator sends a meter reading instruction to the camera meter. The instruction adopts the camera meter extended 188 protocol. The address field in the instruction is the above address. This address is used to determine whether the camera meter matches the address and then decides whether to switch to working mode or sleep mode. After the concentrator sends the meter reading instruction, it enters process 4.

[0033] 4. The concentrator waits for a response from the camera table at the address above. If a response is received, it proceeds to process 5. If no response is received within the timeout period, it records an exception and proceeds to process 6.

[0034] 5. At this time, the concentrator and the camera meter confirm the establishment of a communication connection. The concentrator waits for the camera meter to complete taking pictures. The concentrator sends a data read instruction. At this time, the instruction does not carry a leading code. After the data read service is completed, enter process 6.

[0035] 6. Get the address of the next camera meter and repeat steps 3-5 until the last meter is read. Go to step 7.

[0036] 7. The concentrator enters low-power sleep mode.

[0037] Wired camera meter end process:

[0038] 1. The camera meter is in a power-off state at the beginning and does not work. When the concentrator supplies power to the bus, the camera meter starts to work. If the camera meter receives data, it enters process 2; if it does not receive data, it enters process 7.

[0039] 2. The camera meter receives the data and determines whether it is the leading code 0xFE, 0xFE, 0xFE. If it is, it enters process 3; if not, it enters process 7.

[0040] 3. The camera meter switches from low power mode to ready state. The camera meter determines whether the subsequent instruction address matches its own. If it matches, it enters process 4. If it does not match, it enters process 6.

[0041] 4. The camera meter switches from the ready state to the working mode. The camera meter responds to the concentrator according to the camera meter extended 188 protocol format, confirms the establishment of the communication connection, and enters process 5.

[0042] 5. The camera meter starts taking pictures, and controls CLT_CM to turn on the camera power CM_VCC. After the camera meter finishes taking pictures, controls CLT_CM to turn off the camera power CM_VCC. Enter process 6.

[0043] 6. The camera meter waits for the concentrator to read the data instruction, and records the time each time the communication is completed. If no data is received within the timeout period, it enters process 7.

[0044] 7. The camera meter enters low power standby mode.

[0045] The concentrator and camera meter system according to the above process realizes time-sharing meter reading for several wired camera meters, ensuring that only one camera meter is in working mode and the other camera meters are in low-power standby mode. In low-power standby mode, the power consumption of the camera meter is only at the microampere level, which greatly reduces the power consumption of the system during meter reading, thereby increasing the upper limit of the system bus load capacity, while reducing the bus load current fluctuation during communication and increasing system stability.

[0046] The description of the present invention is given for the purpose of illustration and description, and is not intended to be exhaustive or to limit the present invention to the disclosed form. Many modifications and variations will be apparent to those of ordinary skill in the art. The embodiments are selected and described in order to better illustrate the principles and practical applications of the present invention and to enable those of ordinary skill in the art to understand the present invention and thereby design various embodiments with various modifications suitable for specific uses.

Claims

1. The passive camera water meter reading system based on M-bus is characterized by: It includes several wired camera water meter terminals and concentrators. The concentrator and the wired camera water meter terminals are connected through a bus M-Bus, and the bus includes M-Bus+ and M-Bus-. The concentrator activates the wired camera water meter terminals by time-sharing, and the wired camera water meter terminals determine the working mode at this time according to the leading code and the matching address. The wired camera water meter terminal is connected to two lines of the concentrator in parallel. Both the wired camera water meter terminal and the concentrator include a single chip microcomputer, an M-Bus communication circuit, and a power supply circuit.

2. The passive camera water meter reading system based on M-bus as claimed in claim 1, characterized in that: The power supply circuit of the wired camera water meter terminal includes a chip U4, and the model of the chip U4 is TSS721A.

3. The passive camera water meter reading system based on M-bus as claimed in claim 2, characterized in that: Pin 1 of the chip U4 is connected to one end of a resistor R6, pin 16 of the chip U4 is connected to one end of a resistor R5, and the other ends of the resistor R6 and the other ends of the resistor R5 are connected to two ends of a TVS tube TVS1.

4. The passive camera water meter reading system based on M-bus as claimed in claim 3, characterized in that: The two ends of the TVS tube TVS1 are connected to an M+ end and an M- end, and the M+ end and the M- end are connected to a bus M-Bus+ and M-Bus- and are connected to a concentrator bus through a wiring terminal.

5. The passive camera water meter reading system based on M-bus as claimed in claim 2, characterized in that: Pin 6 of the chip U4 is connected to one end of a capacitor C17, and the other end of the capacitor C17 is grounded. Pin 14 of the chip U4 is connected to one end of a resistor R12, and the other end of the resistor R12 is grounded. Pin 3 of the chip U4 is connected to one end of a capacitor C18, and the other end of the capacitor C18 is grounded.

6. The passive camera water meter reading system based on M-bus as claimed in claim 2, characterized in that: Pin 4 of the chip U4 is connected to one end of a resistor R13, and the other end of the resistor R13 is grounded, pin 8 of the chip U4 is connected to one end of a resistor R11 and is connected to the single-chip microcomputer, pin 12 of the chip U4 is connected to one end of a resistor R10 and is connected to the single-chip microcomputer, pin 5 of the chip U4 is connected to one end of a resistor R9 and is connected to the single-chip microcomputer, pin 10 of the chip U4 is connected to one end of a resistor R8, and the other ends of the resistors R11, R10, R9 and R8 are grounded.

7. The passive camera water meter reading system based on M-bus as claimed in claim 2, characterized in that: The power supply circuit of the wired camera water meter terminal also includes a chip U6, wherein the 4th pin of the chip U6 is connected to the single-chip microcomputer, the 5th pin of the chip U6 is connected to one end of the capacitor C20 and the 2nd pin of the chip U4, and the other end of the capacitor C20 is grounded.

8. The passive camera water meter reading system based on M-bus as claimed in claim 7, characterized in that: Pin 3 of the chip U6 is connected to one end of capacitor C21, one end of resistor R14 and one end of resistor R15, and the other end of resistor R15 is grounded. Pin 6 of the chip U6 is connected to one end of inductor L2, one end of capacitor C19 and one end of diode D1, and the other end of diode D1 is grounded. The other end of capacitor C19 is connected to pin 1 of chip U6. The other end of inductor L2 is connected to one end of capacitor C22, the other end of resistor R14 and the other end of capacitor C21, and is connected to CM_VCC. CM_VCC is connected to the input pin of the voltage regulator chip, and the other end of capacitor C22 is grounded.

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