A method and system for monitoring marine fiber optic sensing devices

Abstract

This invention discloses a monitoring method and system for marine fiber optic sensing devices. The method includes: S1, connecting various fiber optic sensing devices, a monitoring circuit board, and a host computer, and then setting monitoring parameters using monitoring software on the host computer; S2, receiving communication signals transmitted from various fiber optic sensing devices using the communication unit in the monitoring circuit board, processing and identifying the received communication signals, and then transmitting them to the monitoring software on the host computer; S3, displaying the received identification and processing results on the monitoring software on the host computer. This invention uses the monitoring circuit board to uniformly monitor various optoelectronic devices, simplifying their external communication interfaces and summarizing data parameters. It enables real-time monitoring of the operating status of each optoelectronic device, providing rapid fault location and emergency fault handling, and ensuring sufficient support for rapid maintenance, thereby better guaranteeing the normal operation of fiber optic sensing devices for marine sonar and underwater acoustic communication.

Description

Technical Field

[0001] This invention relates to the field of marine equipment monitoring technology, and in particular to a method and system for monitoring marine fiber optic sensing equipment. Background Technology

[0002] Currently, fiber optic sensing equipment used in marine sonar and underwater acoustic communication contains a variety of optoelectronic devices, such as modulated narrow linewidth light sources, optical amplifiers, and optical attenuators. Monitoring these important optoelectronic devices can provide real-time feedback on the working status of the fiber optic sensing equipment, thereby ensuring the normal operation and rapid maintenance of the fiber optic sensing equipment.

[0003] Each optoelectronic device has its own monitoring interface and protocol. Fiber optic sensing equipment consists of multiple and various types of optoelectronic devices. Without a unified monitoring system, it is impossible to monitor all these optoelectronic devices simultaneously.

[0004] Therefore, researching a monitoring method and system capable of simultaneously monitoring multiple optoelectronic devices in fiber optic sensing equipment is a technical problem that needs to be solved by those in this field. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention provides a method and system for monitoring marine fiber optic sensing devices.

[0006] This invention provides a method for monitoring marine fiber optic sensing equipment, the method comprising the following steps:

[0007] S1. Connect each fiber optic sensing device to the monitoring circuit board, connect the monitoring circuit board to the host computer, and then use the monitoring software in the host computer to set the monitoring parameters.

[0008] S2. Monitor each fiber optic sensing device based on the monitoring circuit board card, and use the communication unit in the monitoring circuit board card to receive the communication signals transmitted by each fiber optic sensing device. Then, identify and process the received communication signals and transmit them to the host computer.

[0009] S3. The monitoring software in the host computer displays the received identification and processing results.

[0010] Preferably, the specific implementation of the identification and processing of the received communication signal in step S2 includes:

[0011] S21. Determine whether the communication signal received by the communication unit in the monitoring circuit board is the correct communication protocol; if yes, proceed to step S22; otherwise, return an error code.

[0012] S22. Based on the preset command recognition byte, determine and identify the fiber optic sensing module corresponding to the communication signal. If it is a transparent transmission protocol, proceed to step S23; if it is a full parameter return command, proceed to step S24; if it is a light source modulation amplitude command, proceed to step S25.

[0013] S23. The monitoring circuit board card directly transmits the transparent transmission protocol to the monitoring software in the host computer.

[0014] S24. The monitoring circuit board sorts the data of the communication signal and transmits it to the monitoring software in the host computer.

[0015] S25. The monitoring circuit board selects the corresponding light source modulation channel according to the command identification number and channel number in the communication signal, and performs read, write or storage operations according to the operation mode parameters. Among them: the read operation refers to reading the parameters of the corresponding light source modulation channel stored in the EEPROM and sending them out; the write operation refers to changing the modulation parameters of the corresponding light source modulation channel; the storage operation refers to storing the modulation amplitude parameters in the received communication signal in the EEPROM.

[0016] Preferably, in step S21, the method of frame header, frame tail and check bit is used to determine whether the communication signal received by the communication unit in the monitoring circuit board is a correct communication protocol.

[0017] Preferably, in step S24, the order in which the monitoring circuit board sorts the data of the communication signal is as follows: light source data, optical amplifier data, and optical attenuator data.

[0018] This invention also provides a marine fiber optic sensing device monitoring system, which uses the aforementioned marine fiber optic sensing device monitoring method. The system includes a host computer and several fiber optic sensing devices, as well as monitoring circuit boards connected to the host computer and the fiber optic sensing devices respectively. The host computer has monitoring software connected to the monitoring circuit boards. The monitoring software is used to set and read monitoring parameters, control the operation of each fiber optic sensing device based on the data from the monitoring circuit boards, and display the communication signals transmitted by the monitoring circuit boards. The monitoring circuit boards include a data processing unit, a storage unit, a communication unit, and a power supply unit. The data processing unit receives and processes the communication signals transmitted by each fiber optic sensing device. The storage unit stores the communication signals processed by the data processing unit. The communication unit enables data interaction between the monitoring circuit boards and each fiber optic sensing device, and between the monitoring circuit boards and the host computer. The power supply unit supplies power to each fiber optic sensing device.

[0019] Preferably, the data processing unit includes a modulation unit for phase modulation of a modulated narrow linewidth light source and a level conversion unit for level conversion of communication signals.

[0020] Preferably, the communication unit uses RS485 mode or / and RS232 mode for communication.

[0021] Preferably, the electrical interface connecting the monitoring circuit board to each optoelectronic device is J30J-9TJNP5-J, and the electrical interface connecting the monitoring circuit board to the host computer is J30J-15TJNP5-J.

[0022] Preferably, the power supply unit includes a first power supply unit for controlling the power supply on / off of the modulated narrow linewidth light source, a second power supply unit for controlling the power supply on / off of the optical amplifier, and a third power supply unit for controlling the power supply on / off of the optical attenuator.

[0023] Preferably, the first power supply unit, the second power supply unit, and the third power supply unit are each composed of two pairs of input power supplies, namely a 12V power supply and a 5V power supply.

[0024] Compared with existing technologies, this invention proposes a monitoring method and system for marine fiber optic sensing equipment. This method unifies the monitoring of multiple types of optoelectronic devices in fiber optic sensing equipment used for marine sonar and underwater acoustic communication, simplifying external communication interfaces and summarizing data parameters. It can monitor the working status of each optoelectronic device in real time, provide rapid fault location and emergency fault handling, and provide sufficient guarantee for rapid maintenance, thereby better ensuring the normal operation of fiber optic sensing equipment for marine sonar and underwater acoustic communication. Attached Figure Description

[0025] Figure 1 This is a flowchart of a monitoring method for marine fiber optic sensing equipment according to the present invention.

[0026] Figure 2 This is a structural block diagram of a marine fiber optic sensing device monitoring system according to the present invention.

[0027] Figure 3 The upper computer monitoring software in this invention can modulate a narrow linewidth light source interface;

[0028] Figure 4 This is the optical amplifier interface of the monitoring software in this invention;

[0029] Figure 5 This is the optical attenuator interface of the monitoring software in this invention;

[0030] Figure 6 This is a schematic diagram of the different input power supply interfaces in this embodiment. Detailed Implementation

[0031] To better understand the above-mentioned objectives, features, and advantages of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that, unless otherwise specified, the embodiments and features described in these embodiments can be combined with each other.

[0032] like Figure 1 As shown, Figure 1 The specific process of a monitoring method for marine fiber optic sensing equipment is shown.

[0033] In one embodiment, a method for monitoring a marine fiber optic sensing device includes the following steps:

[0034] S1. Connect each fiber optic sensing device to the monitoring circuit board, connect the monitoring circuit board to the host computer, and then use the monitoring software in the host computer to set the monitoring parameters.

[0035] S2. Monitor each fiber optic sensing device based on the monitoring circuit board card, and use the communication unit in the monitoring circuit board card to receive the communication signals transmitted by each fiber optic sensing device. Then, identify and process the received communication signals and transmit them to the host computer.

[0036] In this step, the specific implementation method of the monitoring circuit board card identifying and processing the received communication signals includes:

[0037] S21. Determine whether the communication signal received by the communication unit in the monitoring circuit board is the correct communication protocol; if yes, proceed to step S22; otherwise, return an error code.

[0038] S22. Based on the preset command identification bytes, the fiber optic sensing module corresponding to the communication signal is judged and identified. If it is a transparent transmission protocol, proceed to step S23; if it is a full parameter return command, proceed to step S24; if it is a light source modulation amplitude command, proceed to step S25. Specifically, each fiber optic sensing device is equipped with a corresponding fiber optic sensing module. The preset command identification bytes include a command identification number and a channel number. The type of the corresponding photoelectric sensing device is identified by the command identification number, and the specific photoelectric sensing device corresponding to the type is identified by the channel number.

[0039] S23. The monitoring circuit board card directly transmits the transparent transmission protocol to the monitoring software in the host computer.

[0040] S24. The monitoring circuit board sorts the data of the communication signal and transmits it to the monitoring software in the host computer.

[0041] S25. The monitoring circuit board selects the corresponding light source modulation channel according to the command identification number and channel number in the communication signal, and performs read, write or storage operations according to the operation mode parameters. Among them: the read operation refers to reading the parameters of the corresponding light source modulation channel stored in the EEPROM and sending them out; the write operation refers to changing the modulation parameters of the corresponding light source modulation channel; the storage operation refers to storing the modulation amplitude parameters in the received communication signal in the EEPROM.

[0042] S3. The host computer monitoring software displays the received identification and processing results.

[0043] In this embodiment, the monitoring circuit board card is used to uniformly monitor multiple types of optoelectronic devices in the fiber optic sensing equipment used for marine sonar and underwater acoustic communication. This simplifies the external communication interface, summarizes data parameters, and enables real-time monitoring of the working status of each optoelectronic device. It can provide rapid fault location and emergency fault handling, providing sufficient guarantee for rapid maintenance, thereby better ensuring the normal operation of the fiber optic sensing equipment for marine sonar and underwater acoustic communication.

[0044] In one embodiment, the monitoring circuit board sorts the communication signal data in the following order: light source data, optical amplifier data, and optical attenuator data.

[0045] like Figure 2 As shown, this embodiment also provides a marine fiber optic sensing device monitoring system, which uses the above-described marine fiber optic sensing device monitoring method. It includes a host computer and several fiber optic sensing devices, as well as monitoring circuit boards connected to the host computer and the fiber optic sensing devices respectively. The host computer has monitoring software connected to the monitoring circuit boards. The monitoring software is used to set and read monitoring parameters, control the operation of each fiber optic sensing device based on the data from the monitoring circuit boards, and display the communication signals transmitted by the monitoring circuit boards. The monitoring circuit boards include a data processing unit, a storage unit, a communication unit, and a power supply unit. The data processing unit receives and processes the communication signals transmitted by each fiber optic sensing device. The storage unit stores the communication signals processed by the data processing unit. The communication unit enables data interaction between the monitoring circuit boards and each fiber optic sensing device, and between the monitoring circuit boards and the host computer. The power supply unit supplies power to each fiber optic sensing device.

[0046] The data processing unit includes a modulation unit for phase modulation of a modulated narrow linewidth light source and a level conversion unit for level conversion.

[0047] The communication unit uses RS485 mode and / or RS232 mode for communication.

[0048] The electrical interface connecting the monitoring circuit board to each optoelectronic device is J30J-9TJNP5-J, and the electrical interface connecting the monitoring circuit board to the host computer is J30J-15TJNP5-J.

[0049] The power supply unit includes a first power supply unit for controlling the power supply on / off of the modulated narrow linewidth light source, a second power supply unit for controlling the power supply on / off of the optical amplifier, and a third power supply unit for controlling the power supply on / off of the optical attenuator.

[0050] Each of the first, second, and third power supply units consists of two pairs of input power supplies, namely a 12V power supply and a 5V power supply. It should be noted that the power supply interfaces for both pairs of input power supplies are pairs of through-hole pads, wherein the through-hole diameter of the 12V power supply interface is 1.0mm, and the through-hole pad diameter is 1.5mm. Figure 6 As shown in Figure a; the through-hole diameter of the 5V power supply interface is 2.0mm, and the pad diameter is 3.5mm, as follows. Figure 6 As shown in b.

[0051] In this embodiment, the monitoring circuit board includes eight light source communication modulation and power supply circuits, namely light source communication modulation and power supply circuit 1, light source communication modulation and power supply circuit 2, light source communication modulation and power supply circuit 3, light source communication modulation and power supply circuit 4, light source communication modulation and power supply circuit 5, light source communication modulation and power supply circuit 6, light source communication modulation and power supply circuit 7, and light source communication modulation and power supply circuit 8; and eight optical amplifier communication power supply circuits, namely optical amplifier communication power supply circuit 9, optical amplifier communication power supply circuit 10, optical amplifier communication power supply circuit 11, optical amplifier communication power supply circuit 12, optical amplifier communication power supply circuit 13, and optical amplifier communication power supply circuit 14. The system includes: an optical amplifier communication power supply circuit 14, an optical amplifier communication power supply circuit 15, an optical amplifier communication power supply circuit 16, four optical attenuator communication power supply circuits (17, 18, 19, and 20), one FPGA core chip 25, one EEPROM storage chip 26, four fast level conversion circuits (21, 22, 23, and 24), one external communication circuit 27, and an input power supply circuit 29. The host computer monitoring software 34 runs on the host computer and includes three main interfaces: a light source monitoring interface, an optical amplifier monitoring interface, and an optical attenuator monitoring interface. Figure 3 As shown in Figures 4 and 5. The monitoring circuit board and the host computer running the monitoring software can be connected via communication cable 35.

[0052] In this embodiment, the eight light source communication modulation power supply circuits are identical. This invention uses light source communication modulation power supply circuit 1 as an example. Light source communication modulation power supply circuit 1 includes three functional parts: communication, modulation, and power supply. The communication circuit uses RS232 circuitry, employing a MAX3232 chip. The modulation circuit is a 12-bit digital-to-analog converter chip AD5444, which converts the digital cosine signal into an analog cosine signal. Then, the AD5444's current analog signal is converted into a voltage analog signal by an OPA429 amplifier, which further amplifies the analog cosine signal. The maximum analog signal amplitude can reach 10V. The power supply circuit is a P-channel MOSFET, controlled by FPGA pins to control the switching on and off of the MOSFET, thereby controlling the power supply to the light source.

[0053] In this embodiment, the eight optical amplifier communication power supply circuits are identical. Taking the optical amplifier communication power supply circuit 9 as an example, the optical amplifier communication power supply circuit 9 includes two functions: communication and power supply. The communication circuit is an RS232 communication circuit, using a MAX3232 chip circuit as the communication circuit. The power supply circuit is a P-channel MOSFET, and the FPGA pin controls the on / off state of the MOSFET, thereby controlling the on / off state of power supply to the optical amplifier.

[0054] In this embodiment, the communication power supply circuits of the four optical attenuators are the same circuit. Taking the optical attenuator communication power supply circuit 17 as an example, the optical attenuator communication power supply circuit 17 includes two functions: communication and power supply. The communication circuit is an RS232 communication circuit, which uses a MAX3232 chip circuit as the communication circuit. The power supply circuit is a P-channel MOSFET, which is controlled by the FPGA pin to control the on and off of the MOSFET, thereby controlling the on and off of the power supply to the optical attenuator.

[0055] In this embodiment, the four fast level conversion circuits are identical, with fast level conversion circuit 21 being used as an example. Fast level conversion circuit 21 employs a single-channel level conversion chip SN74LVC1T45, which has two setting modes: input and output. Its direction can be controlled via FPGA pins; a high level indicates output, and a low level indicates input. This allows it to be used as a clock input or output, or as a pulse modulation signal input and output.

[0056] In this embodiment, the external communication circuit 27 includes two communication modes: RS485 and RS232. The RS485 communication uses a MAX3485 chip, while the RS232 communication uses a MAX3232 chip. Data exchange can be performed using either communication mode according to the host computer configuration.

[0057] In this embodiment, the internal program logic of the FPGA core chip 25 of the monitoring circuit board is implemented as follows:

[0058] Based on the communication signal received by the external communication circuit 27 from the module located in the photoelectric sensing device, the correct communication protocol is determined by the frame header, frame tail and check bit. Then, the communication signal is identified according to the preset command identification byte to determine which photoelectric sensing device's communication module corresponds to the communication signal. Specifically, the preset command identification byte includes a command identification number and a channel number. The type of the corresponding photoelectric sensing device is identified by the command identification number, and the specific photoelectric sensing device corresponding to the type is identified by the channel number.

[0059] The remaining data segments in the communication protocol are the corresponding transparent transmission protocols for light sources, optical amplifiers, or optical attenuators. The internal program logic of the FPGA core chip 25 will send the transparent transmission protocol segments to the corresponding optoelectronic devices according to the command identification number and channel number.

[0060] In addition, there are two special command identifiers: the full parameter return command and the light source modulation amplitude command.

[0061] The full-parameter return command does not have any extra data segments.

[0062] The command specifies the light source modulation amplitude, and the remaining data segments contain the operation mode parameters and modulation amplitude parameters.

[0063] The communication signals sent from the internal program logic of the FPGA core chip 25 to the external communication circuit 27 are based entirely on the received signals for identification and transmission, wherein:

[0064] For example, in the case of a full parameter return command, the internal program logic of the FPGA core chip 25 will sort and send the temperature, fault code and special parameters of all modules. The sorting method is: first the light source data, then the optical amplifier data, and finally the optical attenuator data.

[0065] For example, when a command is given to the light source modulation amplitude, the internal program logic of the FPGA core chip 25 will select the corresponding light source modulation channel according to the command identification number and channel number, and then perform a read operation, a write operation or a storage operation according to the operation mode parameters. The read operation is to read the parameters of the corresponding light source modulation channel stored in the EEPROM and then send them out. The write operation is to change the modulation parameters of the light source modulation channel. The storage operation is to store the modulation amplitude parameters in the received communication protocol in the EEPROM.

[0066] If it is a transparent transmission protocol, the internal program logic of the FPGA core chip 25 will not modify the received optoelectronic device protocol and will directly send it to the host computer monitoring software through the external communication circuit 27.

[0067] In this embodiment, the monitoring software 34 of the host computer is a monitoring software running on the host computer, which includes three main interfaces: a modulated narrow linewidth light source monitoring interface, an optical amplifier monitoring interface, and an optical attenuator monitoring interface.

[0068] like Figure 3 As shown, the monitoring interface for modulated narrow linewidth light sources includes three sections: light source parameter settings, modulation parameter settings, and light source parameter reading and display.

[0069] The light source parameter setting section includes settings for the drive current of 8 light sources, thereby changing the output power of the corresponding light source. The drive current can be read or written to each of the 8 light sources separately.

[0070] The modulation parameter setting section contains the modulation parameter settings for 8 light sources, thereby changing the corresponding modulation amplitude. The modulation amplitude of each of the 8 light sources can be read, written, or stored separately.

[0071] The light source parameter display panel includes the temperature, output power, and fault information for eight light sources. It also automatically cuts off the power to the corresponding light source based on the fault parameters.

[0072] like Figure 4 As shown, the optical amplifier monitoring interface consists of two columns: optical amplifier parameter settings and optical amplifier parameter reading and display.

[0073] The optical amplifier parameter setting section includes setting the current for 8 optical amplifiers, thereby changing the output power of the corresponding optical amplifier. The current setting can be read or written to each of the 8 optical amplifiers.

[0074] The optical amplifier parameter display panel includes the temperature, actual power, actual operating current, and fault display for eight optical amplifiers. It also automatically cuts off the power to the corresponding optical amplifier based on the fault parameters.

[0075] like Figure 5As shown, the optical attenuator monitoring interface contains four columns with the same function, namely optical attenuator 1, optical attenuator 2, optical attenuator 3 and optical attenuator 4. This embodiment uses the optical attenuator 1 column for implementation.

[0076] The optical attenuator module displays the reading and writing settings for the 8-channel optical attenuation values, as well as the input power, output power, and module temperature.

[0077] In this embodiment, the monitoring software 34 of the host computer connects and communicates through the connection button in the upper right corner of the interface, the storage button sets whether to store the optoelectronic device parameters, and the exit button exits the running state and closes the software.

[0078] The above provides a detailed description of a marine fiber optic sensing device monitoring method and system provided by the present invention. Specific examples have been used to illustrate the principles and implementation methods of the invention; the descriptions of the embodiments are merely for the purpose of helping to understand the core ideas of the invention. It should be noted that those skilled in the art can make various improvements and modifications to the invention without departing from its principles, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

Claims

1. A monitoring method for marine fiber optic sensing equipment, characterized in that, The method includes the following steps: S1. Connect each fiber optic sensing device to the monitoring circuit board, connect the monitoring circuit board to the host computer, and then use the monitoring software in the host computer to set the monitoring parameters. S2. Monitor each fiber optic sensing device based on the monitoring circuit board card, and use the communication unit in the monitoring circuit board card to receive the communication signals transmitted by each fiber optic sensing device. Then, identify and process the received communication signals and transmit them to the host computer. S3. The monitoring software in the host computer displays the received identification and processing results; The specific implementation methods for identifying and processing the received communication signals in step S2 include: S21. Determine whether the communication signal received by the communication unit in the monitoring circuit board is the correct communication protocol; if yes, proceed to step S22; otherwise, return an error code. S22. Based on the preset command recognition byte, determine and identify the fiber optic sensing module corresponding to the communication signal. If it is a transparent transmission protocol, proceed to step S23; if it is a full parameter return command, proceed to step S24; if it is a light source modulation amplitude command, proceed to step S25. S23. The monitoring circuit board card directly transmits the transparent transmission protocol to the monitoring software in the host computer. S24. The monitoring circuit board sorts the data of the communication signal and transmits it to the monitoring software in the host computer. S25. The monitoring circuit board selects the corresponding light source modulation channel according to the command identification number and channel number in the communication signal, and performs read, write or storage operations according to the operation mode parameters. Among them: the read operation refers to reading the parameters of the corresponding light source modulation channel stored in the EEPROM and sending them out; the write operation refers to changing the modulation parameters of the corresponding light source modulation channel; the storage operation refers to storing the modulation amplitude parameters in the received communication signal in the EEPROM.

2. The marine fiber optic sensing device monitoring method as described in claim 1, characterized in that, In step S21, the method of frame header, frame tail and check bit is used to determine whether the communication signal received by the communication unit in the monitoring circuit board is the correct communication protocol.

3. The marine fiber optic sensing device monitoring method as described in claim 2, characterized in that, In step S24, the monitoring circuit board sorts the data of the communication signal in the following order: light source data, optical amplifier data, and optical attenuator data.

4. A marine fiber optic sensing equipment monitoring system, characterized in that, The monitoring method for marine fiber optic sensing devices according to any one of claims 1-3 includes a host computer and several fiber optic sensing devices, as well as monitoring circuit boards connected to the host computer and the fiber optic sensing devices respectively. The host computer has monitoring software connected to the monitoring circuit boards. The monitoring software is used to set and read monitoring parameters, control the operation of each fiber optic sensing device according to the data of the monitoring circuit boards, and display the communication signals transmitted by the monitoring circuit boards. The monitoring circuit boards include a data processing unit, a storage unit, a communication unit, and a power supply unit. The data processing unit is used to receive and process the communication signals transmitted by each fiber optic sensing device. The storage unit is used to store the communication signals processed by the data processing unit. The communication unit is used to enable data interaction between the monitoring circuit boards and each fiber optic sensing device, and between the monitoring circuit boards and the host computer. The power supply unit is used to supply power to each fiber optic sensing device.

5. The marine fiber optic sensing equipment monitoring system as described in claim 4, characterized in that, The data processing unit includes a modulation unit for phase modulation of a modulated narrow linewidth light source and a level conversion unit for level conversion of communication signals.

6. The marine fiber optic sensing equipment monitoring system as described in claim 5, characterized in that, The communication unit uses RS485 mode and / or RS232 mode for communication.

7. The marine fiber optic sensing equipment monitoring system as described in claim 6, characterized in that, The electrical interface connecting the monitoring circuit board to each optoelectronic device is J30J-9TJNP5-J, and the electrical interface connecting the monitoring circuit board to the host computer is J30J-15TJNP5-J.

8. The marine fiber optic sensing equipment monitoring system as described in claim 7, characterized in that, The power supply unit includes a first power supply unit for controlling the power supply on / off of the modulated narrow linewidth light source, a second power supply unit for controlling the power supply on / off of the optical amplifier, and a third power supply unit for controlling the power supply on / off of the optical attenuator.

9. The marine fiber optic sensing equipment monitoring system as described in claim 8, characterized in that, The first power supply unit, the second power supply unit, and the third power supply unit are each composed of two pairs of input power supplies, namely a 12V power supply and a 5V power supply.

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