Design And Implementation Of A Multichannel Acquisition And Editing Controller Based On FPGA

In order to monitor,process,and analyze the dynamic parameters of the test aircraft in large-scale aerospace engineering experiments,necessary preparations are required.The research task of this topic originates from the pre research task of "a balloon flying test" conducted by an aerospace research institute.A multi-channel acquisition and encoding and timing control device based on FPGA was designed,which can collect and encode voltage signals of different ranges,while receiving digital signals from the camera.The unified packaging and encoding are transmitted to the memory through the LVDS long line,and the data is also read back to the acquisition and encoding device through the LVDS interface;Able to accept airship instructions and control external equipment;After encoding and device processing,the collected data is transmitted to the ground measurement and control station through an Ethernet interface,and then uploaded to the upper computer for further data processing and analysis.Analyze the functional requirements in the development task book,and design the acquisition and editing device scheme.The overall structure adopts a cascade structure,with the main control card,power supply card,and acquisition card inserted and cascaded through the inter board connectors.This article introduces the communication mode of the key hardware between the acquisition and editing device and the ground measurement and control station,using the FPGA+PHY method,and communicating through the Gigabit Ethernet interface.It also introduces the RGMII management configuration interface and transceiver control design in detail.Communication with memory is through the LVDS interface,and drivers are added at the sending end to enhance the circuit driving ability and solve the signal attenuation problem.The receiver adds an equalizer to enhance the high-frequency component of the signal and restore data information.Analog signals enter the signal conditioning filter circuit to ensure signal quality before entering the analog-to-digital converter.After passing through the conditioning circuit,the signal enters the linear optocoupler for isolation to prevent the analog-to-digital converter from switching states that may interfere with the signal to be collected.At the same time,isolation measures are taken to reduce signal oscillations and reduce layering values,thereby improving acquisition accuracy.The software logic introduces the UDP protocol.The logic design of parameter writing to EEPROM is introduced.In order to achieve long-distance transmission,the LVDS link adopts8B/10 B coding and maintains DC balance.Maintain link stability and improve transmission reliability.AD acquisition uses a ROM address lookup table to quickly switch acquisition channels for more accurate A/D conversion.The airship command is sent from the airship terminal to the acquisition and editing controller through an RS485 signal.The acquisition and editing controller responds and completes the control of initiating explosive devices and electromagnetic valves through a control relay.Through unit testing,equipment joint testing,and a large number of environmental tests,the acquisition and editing device can complete 11 channels of common ground acquisition and 5 channels of isolated acquisition,with an acquisition accuracy of less than 5 ‰.It can receive asynchronous camera digital signals and achieve zero error transmission through2-way LVDS.The acquisition and editing device can also receive and respond to various ground commands,complete real-time monitoring,acquisition,and storage status tasks,meeting design requirements.