A synchronous trigger circuit and system suitable for dam safety dynamic monitoring network equipment

Abstract

The application discloses a synchronous trigger circuit and system suitable for dam safety dynamic monitoring network equipment, the circuit comprises a current loop communication circuit, a fiber communication circuit and an output port driving bus. The current loop communication circuit can receive the synchronous trigger signal transmitted by the main control device or the upper level network equipment in the form of current loop and / or fiber channel, and simultaneously can forward the received synchronous trigger signal to the next level network equipment in the form of current loop and / or fiber channel; the fiber communication circuit can receive the synchronous trigger signal transmitted by the main control device or the upper level network equipment in the form of fiber, and simultaneously can forward the received synchronous trigger signal to the next level network equipment in the form of fiber and / or current loop channel. The output port driving assembly can transmit the synchronous trigger signal to the local network equipment, and realize the synchronous trigger of the local network equipment and other network equipment in the link. The application supports the mixed form transmission of current loop and fiber, the communication mode is flexible, the signal has strong anti-interference property, and is suitable for long distance transmission.

Description

Technical Field

[0001] This invention relates to a synchronous triggering circuit and system for dynamic monitoring network equipment for dam safety, belonging to the field of automation technology for safety monitoring of water conservancy and hydropower projects. Background Technology

[0002] In special circumstances such as earthquakes and flood discharges, the operational status of different parts of the dam and its surrounding area is not only spatially interconnected but also temporally correlated. The specific locations of the different data acquisition network devices in the dam safety automatic monitoring system are generally distributed across different dam sections, different elevations, and the surrounding area, depending on the actual needs of the project. The distance between these network devices ranges from tens of meters to several kilometers. During special circumstances such as earthquakes and flood discharges, it is crucial for the monitoring network devices distributed across the dam and its surrounding area to rapidly and synchronously begin acquiring dynamic real-time signals from the monitoring instruments and promptly capturing the dam's operational information. This is essential for the scientific analysis and precise control of the dam's safety status.

[0003] To ensure that different automated devices in a system receive a unified trigger signal (command) and synchronously initiate the same or coordinated operation, the main methods include the following four:

[0004] 1) Precise Time Synchronization Trigger Startup: Using this synchronization trigger strategy, the system needs to periodically broadcast time synchronization to each network device via the network, or directly synchronize the time to each network device using a dedicated GPS time synchronization device. Then, each network device automatically starts at the system's preset time and begins the agreed-upon operation (measurement, monitoring, etc.). This strategy is generally suitable for monitoring events with predetermined times, and its synchronization accuracy depends entirely on the synchronization accuracy between the real-time clocks within each network device.

[0005] 2) Sending synchronous trigger start command via network communication interface: When using this synchronous trigger strategy, the synchronous trigger start command is sent by the system host or designated device through the communication port connected to each network device. It is generally issued in the form of a broadcast command. The transmission delay of the command is related to the characteristics of the network itself and the device's parsing speed of the command.

[0006] 3) Synchronous startup by detecting the level of I / O ports interconnected between network devices: When using this synchronous triggering strategy, the controlled device will periodically detect the level of the corresponding I / O port, or further associate the level of the I / O port with the interrupt input of the internal controller in the circuit. Once the level output by the master control device is found to have changed according to the agreement, the execution of the agreed task can be started immediately.

[0007] 4) Synchronous startup is indicated by detecting the on / off state of switch signals interconnected between network devices: When using this synchronous triggering strategy, the processing steps are almost the same as those for synchronous startup by detecting the level of I / O ports interconnected between network devices.

[0008] The shortcomings of the above four methods are analyzed below:

[0009] For strategy 1) based on precise time synchronization triggering, the synchronization accuracy depends entirely on the synchronization accuracy between the real-time clocks inside each network device. This strategy is generally suitable for monitoring events with predetermined occurrence times. For strategy 2) which uses a network interface to send a synchronization trigger command, the delay from when the sending device issues the command to when the receiving device receives and successfully parses the command is determined by factors such as the transmission efficiency of the network itself and the parsing speed of the receiving device. This strategy is often used in situations where the synchronization accuracy requirement is low. For strategy 3) which uses the level of I / O ports interconnected between network devices or strategy 4) which uses the switch signal interconnected between devices for synchronization triggering, the transmission of the synchronization signal can generally only be achieved by direct connection with a metal signal wire. The connection and transmission distance of the signal wire should not be too long, generally within tens of meters. When the length of the signal wire is too long, the synchronization trigger signal will attenuate and is easily affected by external electromagnetic signals. Summary of the Invention

[0010] The purpose of this invention is to overcome the shortcomings of the prior art and provide a synchronous triggering circuit that has strong anti-interference ability, long transmission distance and can quickly send synchronous triggering signals to achieve accurate and fast synchronous triggering of various network devices.

[0011] To achieve the above objectives, the present invention employs the following technical solution: a synchronous triggering circuit, comprising a current loop communication circuit, an optical fiber communication circuit, and an output port drive bus. The current loop communication circuit includes a current loop signal input interface and a current loop signal output interface, and the optical fiber communication circuit includes an optical fiber signal input interface and an optical fiber signal output interface. The output terminal of the current loop signal input interface, the output terminal of the optical fiber signal input interface, the input terminal of the current loop signal output interface, and the input terminal of the optical fiber signal output interface are respectively connected to the output port drive bus.

[0012] After receiving a valid synchronization trigger signal, the current loop signal input interface and / or the optical fiber signal input interface transmit the synchronization trigger signal to the local network device via the output port drive bus. At the same time, the synchronization trigger signal transmitted to the output port drive bus is transmitted to the current loop signal input interface of the next-level current loop communication circuit through the current loop signal output interface, or simultaneously or individually through the optical fiber signal output interface to the optical fiber signal input interface of the next-level optical fiber communication circuit.

[0013] Furthermore, the current loop signal input interface includes an optocoupler, a potential conversion resistor R1, and a first NAND gate;

[0014] The collector of the phototransistor in the optocoupler is connected to the power supply VCC, and the emitter of the phototransistor is connected to ground in series with the potential conversion resistor R1. The two input terminals of the first NAND gate are shorted and electrically connected to the emitter of the phototransistor.

[0015] The light-emitting diode of the optocoupler is used to collect the synchronization trigger signal. When the current loop signal input interface receives a valid synchronization trigger signal, the light-emitting diode is turned on and lit.

[0016] Furthermore, the current loop signal output interface includes a current-limiting resistor R2 and a switching transistor T1 electrically connected to the output port drive bus. When the base of the switching transistor T1 acquires the synchronous trigger signal on the output port drive bus, the switching transistor T1 is turned on, so that the synchronous trigger signal is transmitted to the current loop signal input interface of the next stage current loop communication circuit.

[0017] Furthermore, the fiber optic signal input interface includes a photodetector, a transimpedance amplifier circuit, and a comparator circuit. When the fiber optic signal input interface receives a valid synchronization trigger signal, the photodetector outputs a response current to the transimpedance amplifier circuit. The transimpedance amplifier circuit amplifies the response current and converts it into a voltage signal. The comparator circuit compares the voltage signal with an internal reference voltage and outputs a corresponding valid synchronization trigger signal.

[0018] Furthermore, the optical fiber signal output interface includes a laser tube driving circuit and a laser tube. When the laser tube driving circuit acquires the synchronous trigger signal on the output port driving bus, the laser tube driving circuit drives the laser tube to transmit the synchronous trigger signal through the optical fiber to the optical fiber signal input interface of the next-level optical fiber communication circuit.

[0019] Furthermore, it also includes a third NAND gate and a fourth NAND gate, wherein both inputs of the third NAND gate are connected to the output port drive bus;

[0020] One input of the fourth NAND gate is connected to the output of the third NAND gate, and the other input is connected to the trigger receive enable signal port of the local network device. The output of the fourth NAND gate is connected to the trigger signal receiver of the local network device.

[0021] Furthermore, the local network device is connected to the output port drive bus signal via the second NAND gate. When the local network device is used as a master control device, the synchronization trigger signal issued by the local network device is transmitted to the output port drive bus via the second NAND gate, and then transmitted to the current loop signal output interface and / or the optical fiber signal output interface.

[0022] On the other hand, the present invention also provides a dam safety monitoring system that can simultaneously collect parameters related to dam safety and accurately control the safety status of the dam.

[0023] A dam safety monitoring system includes multiple network monitoring devices distributed at different parts of the dam body for monitoring dam safety-related parameters. Each network monitoring device includes a synchronization triggering circuit as described above. Each network monitoring device is synchronously triggered by the synchronization triggering circuit to synchronously execute agreed monitoring tasks.

[0024] Compared with the prior art, the present invention can achieve at least the following beneficial effects:

[0025] The synchronous triggering circuit provided by this invention includes two communication modes: a current loop communication circuit and an optical fiber communication circuit. It supports hybrid transmission of current loop and optical fiber, offers flexible combination of communication modes, has strong anti-interference capabilities for communication signals, and is suitable for long-distance transmission.

[0026] It is suitable for various signal triggering forms such as level, pulse or edge, and the overall signal delay can be controlled in microseconds or even less. When applied to dam safety monitoring system, it can quickly receive and send synchronous trigger signals for synchronous monitoring (monitoring) of various deterministic or random events, and accurately grasp the safety status of the dam. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of a synchronous triggering circuit provided in an embodiment of the present invention. Detailed Implementation

[0028] The present invention will be further described below with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and should not be used to limit the scope of protection of the present invention.

[0029] In the description of this invention, it should be understood that features specified as "first," "second," etc., may explicitly or implicitly include one or more of those features. In the description of this invention, unless otherwise stated, "multiple" means two or more. The term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone.

[0030] Example 1:

[0031] See Figure 1 This is a synchronous triggering circuit provided in an embodiment of the present invention. It provides interfaces with two different media types: current loop and optical fiber. This circuit is suitable for both the master control device responsible for sending synchronous triggering signals and the triggered network device in a subordinate position. The triggered network device can continue to send the received synchronous triggering signals to the next level network device in the link in the form of current loop and / or optical fiber signals. One output port of the circuit can be connected to a local network device. When the local device acts as the master control device, it can realize the one-to-many transmission and multiple-to-reception of synchronous triggering signals.

[0032] Specifically, the synchronization triggering circuit provided in this embodiment of the invention includes a current loop communication circuit, an optical fiber communication circuit, and an output port drive bus. The current loop communication circuit can receive synchronization triggering signals transmitted in a current loop form from the main control device or the upstream network device, and can also forward the received synchronization triggering signals to the next-level network device in a current loop form. The optical fiber communication circuit can receive synchronization triggering signals transmitted in an optical fiber form from the main control device or the upstream network device, and can also forward the received synchronization triggering signals to the next-level network device in an optical fiber form. The output port drive assembly is communicatively connected to the current loop communication circuit and the optical fiber communication circuit, enabling the transmission of synchronization triggering signals to the local network device, thus achieving synchronization triggering between the local network device and other network devices in the link.

[0033] The current loop communication circuit includes a current loop signal input interface and a current loop signal output interface, and the optical fiber communication circuit includes an optical fiber signal input interface and an optical fiber signal output interface; the output end of the current loop signal input interface, the output end of the optical fiber signal input interface, the input end of the current loop signal output interface, and the input end of the optical fiber signal output interface are respectively connected to the output port drive bus signal.

[0034] In this embodiment of the invention, the synchronization trigger signal is active low or active on the falling edge. When there is no synchronization trigger signal being transmitted or received, the outputs of the circuits connected to the output port drive bus are all in a high-impedance state. Figure 1As shown, the current loop signal input interface includes an optocoupler, a potential conversion resistor R1, and a first NAND gate. The two ends of the LED in the optocoupler serve as the input ports for the current loop signal. When a synchronization trigger signal is input, the LED is turned on and illuminates, emitting light, which triggers the phototransistor in the optocoupler to conduct. The collector of the phototransistor is connected to the power supply VCC, and the emitter of the phototransistor is connected to ground in series with the potential conversion resistor R1. The two input terminals of the first NAND gate are shorted and electrically connected to the emitter of the phototransistor. When the phototransistor is turned on, the potential conversion resistor R1 converts the potential of the phototransistor's emitter to a high level. At this time, the output of the first NAND gate outputs a low level, and the synchronization trigger signal is transmitted to the output port drive bus.

[0035] The fiber optic signal input interface includes a photodetector, a transimpedance amplifier circuit, and a comparator circuit. The synchronization trigger signal transmitted via the fiber optic cable is transmitted in the form of a laser signal. When the laser signal is guided and illuminated by the photodetector, the photodetector outputs a response current to the transimpedance amplifier circuit. The transimpedance amplifier circuit amplifies the response current and converts it into a voltage signal. This voltage signal is then filtered / shaped by the comparator circuit and compared with a reference voltage provided internally to output a corresponding valid synchronization trigger signal.

[0036] If the output port drive bus receives a synchronization trigger signal, and the local network device triggers reception enable, the synchronization trigger signal will be sent to the corresponding trigger signal receiving terminal of the internal control circuit of the local network device, such as an interrupt signal input terminal or other I / O input terminal, through the third NAND gate and the fourth NAND gate. Both inputs of the third NAND gate are connected to the output port drive bus; one input of the fourth NAND gate is connected to the output of the third NAND gate, and the other input is connected to the trigger reception enable signal port of the local network device. The output of the fourth NAND gate is connected to the trigger signal receiving terminal of the local network device. When local reception triggering is disabled (i.e., the trigger reception enable signal is low in the diagram), the output of the fourth NAND gate is in a high-impedance state or a high-level state, and the synchronization trigger signal is prohibited from entering the local network device. The purpose of designing the fourth NAND gate is to control whether external trigger signals are allowed to trigger the local network device according to specific circumstances. If the local network device is not yet ready, or only provides a passageway, triggering to the local device is generally not allowed.

[0037] The local network device is connected to the output port drive bus signal via a second NAND gate. The trigger command issued locally is valid as a high-level signal. When the local network device is used as a master control device, the outputs of the circuits connected to the output port drive bus (including the first NAND gate and the comparator circuit) are all in a high-impedance state. The synchronous trigger signal issued by the local network device is converted into a low-level signal after passing through the second NAND gate. This low-level signal is transmitted to the current loop signal output interface and / or the optical fiber signal output interface via the output port drive bus.

[0038] In one embodiment of the present invention, the current loop signal output interface includes a switching transistor T1, which can be a PNP transistor. The base of the switching transistor T1 is electrically connected to the output port drive bus. The emitter of the switching transistor T1 is connected to the power supply VCC after being connected in series with a resistor R2. The collector of the switching transistor T1 is connected to the current loop signal input interface of the next-stage current loop communication circuit. When the base of the switching transistor T1 acquires the synchronous trigger signal on the output port drive bus, the switching transistor T1 is turned on, and the synchronous trigger signal is transmitted to the current loop signal input interface of the next-stage current loop communication circuit in the form of current.

[0039] In some embodiments of the present invention, the optical fiber signal output interface includes a laser tube driving circuit and a laser tube. When the laser tube driving circuit acquires the synchronous trigger signal on the output port driving bus, the laser tube driving circuit drives the laser tube to transmit the synchronous trigger signal through the optical fiber to the optical fiber signal input interface of the next-level optical fiber communication circuit.

[0040] In summary, the main electronic components used in the embodiments of this invention, such as optocouplers, transimpedance amplifiers, comparator circuits, switching transistor T1, and laser diodes, are all commonly used devices in circuit design. Their maximum signal processing delay is generally in the microsecond range (usually less than 1 microsecond), or even in the nanosecond range. Therefore, the circuit provided in the embodiments of this invention can limit the overall delay to the microsecond range, thereby improving the synchronization triggering accuracy of network devices. Furthermore, the circuit provided in the embodiments of this invention includes a current loop communication circuit and an optical fiber communication circuit, supporting hybrid transmission of current loop and optical fiber, offering flexible communication methods, strong signal anti-interference capabilities, and suitability for long-distance transmission.

[0041] It should be noted that, Figure 1 The synchronous triggering circuit shown can be configured step by step according to the needs of the network device. The specific number and type of interfaces can be increased or decreased according to actual needs.

[0042] Example 2:

[0043] This invention provides a dam safety monitoring system that can simultaneously collect dam safety-related parameters and accurately control the dam's safety status.

[0044] Specifically, the dam safety monitoring system provided in this embodiment of the invention includes multiple network monitoring devices distributed in different parts of the dam body for monitoring dam safety-related parameters. The network monitoring devices include the synchronization triggering circuit described in any one of the embodiments. Each of the network monitoring devices is synchronously triggered through the synchronization triggering circuit to synchronously execute the agreed monitoring tasks.

[0045] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A synchronous trigger circuit, characterized by, The current loop communication circuit includes a current loop signal input interface and a current loop signal output interface, and the fiber communication circuit includes a fiber signal input interface and a fiber signal output interface; the output end of the current loop signal input interface, the output end of the fiber signal input interface, the input end of the current loop signal output interface and the input end of the fiber signal output interface are respectively connected with the output port driving bus; after the current loop signal input interface and / or the fiber signal input interface receive a valid synchronization trigger signal, the synchronization trigger signal is transmitted to the local network device through the output port driving bus; meanwhile, the synchronization trigger signal on the output port driving bus is transmitted to the input interface of the next stage current loop communication circuit through the current loop signal output interface, and is simultaneously or separately transmitted to the fiber signal input interface of the next stage fiber communication circuit through the fiber signal output interface. The third NAND gate and the fourth NAND gate are further included, both input ends of the third NAND gate are connected with the output port driving bus; one input end of the fourth NAND gate is connected with the output end of the third NAND gate, and the other input end is connected with the trigger reception permission signal port of the local network device; the output end of the fourth NAND gate is connected with the trigger signal reception end of the local network device.

2. The synchronous trigger circuit of claim 1, wherein, The current loop signal input interface includes a photoelectric coupler, a potential conversion resistor R1 and a first NAND gate; the collector of the photo-sensitive triode of the photoelectric coupler is connected with a power supply VCC, the emitter of the photo-sensitive triode is connected with the ground through the potential conversion resistor R1 in series, and both input ends of the first NAND gate are connected with the emitter of the photo-sensitive triode after being short-circuited; the light-emitting diode of the photoelectric coupler is used for collecting the synchronization trigger signal, and when the current loop signal input interface receives a valid synchronization trigger signal, the light-emitting diode is turned on to be bright.

3. A synchronous trigger circuit according to claim 1 or 2, characterised in that, The current loop signal output interface includes a current limiting resistor R2 and a switch tube T1 connected with the output port driving bus; when the base of the switch tube T1 collects the synchronization trigger signal on the output port driving bus, the switch tube T1 is turned on to make the synchronization trigger signal transmitted to the current loop signal input interface of the next stage current loop communication circuit.

4. The synchronous trigger circuit of claim 1, wherein, The fiber signal input interface includes a photoelectric detector, a transimpedance amplification circuit and a comparator circuit; when the fiber signal input interface receives a valid synchronization trigger signal, the photoelectric detector outputs a response current to the transimpedance amplification circuit, the transimpedance amplification circuit amplifies the response current and converts it into a voltage signal, and the comparator circuit compares the voltage signal with an internal reference voltage and then outputs a corresponding valid synchronization trigger signal.

5. The synchronous trigger circuit according to claim 1 or 4, characterized in that, The fiber signal output interface comprises a laser tube driving circuit and a laser tube. When the laser tube driving circuit collects a synchronization trigger signal on the output port driving bus, the laser tube driving circuit drives the laser tube to transmit the synchronization trigger signal to a fiber signal input interface of a next stage fiber communication circuit through a fiber.

6. The synchronous trigger circuit of claim 1, wherein, The local network device is connected with the output port driving bus through a second NAND gate. When the local network device is used as a master device, a synchronization trigger signal sent by the local network device is transmitted to the output port driving bus through the second NAND gate, and then transmitted to the current loop signal output interface and / or the fiber signal output interface.

7. A dam safety monitoring system comprising a plurality of network monitoring devices distributed at different locations of a dam body for monitoring parameters related to safety of the dam, characterized in that, The network monitoring devices comprise the synchronization trigger circuit according to any one of claims 1 to 6. The network monitoring devices are synchronously triggered through the synchronization trigger circuit to synchronously perform the agreed monitoring tasks.

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