A kind of data acquisition system (DAS) based on vibrating string type sensor
Technical field
The utility model relates to a kind of data acquisition system (DAS) based on vibrating string type sensor, and particularly a kind of prolongable strain data acquisition system based on vibrating string type sensor belongs to civil structure health monitoring technical field.
Background technology
The health monitoring of structure is in order to ensure from the construction stage to the completion of works and even the security and the reliability of the structure in the whole cycle in serviceable life.Vibrating string type sensor is able to widespread use in the long-term health monitoring of structure.
A lot of large structures have all been installed vibrating string type sensor, and through the strain value of reading strain instrument apparatus measurement structure body, but present device has following deficiency:
1. a common device has only a sensor interface, can only carry out data acquisition to a measuring point, and industry spot often need be monitored a plurality of (tens or even up to a hundred) point, just need multiple arrangement be operated separately; Independently of one another between multiple arrangement;
2. one-way communication, conventional device only possesses the one-way communication function of image data mostly, can't when test needs, carry out the adjusting of working time, can't when the system works space, auto sleep reduce power consumption.
The utility model content
The purpose of the utility model is in order to overcome the defective of above-mentioned prior art, can to carry out long-term health monitoring to structure, proposed a kind of data acquisition system (DAS) based on vibrating string type sensor more convenient, energy-conservationly.
The purpose of the utility model realizes by the following technical programs.
A kind of data acquisition system (DAS) based on vibrating string type sensor of the utility model comprises host computer, usb protocol and CAN protocol conversion gateway, one or more than one data acquisition module, externally fed power supply, sensor;
Each data acquisition module include processor and processor peripheral circuit, power source conversion and mu balanced circuit, battery flowmeter charge circle, CAN bus interface circuit, RS485 bus interface circuit, swash frequency circuit, the vibrating string type sensor of pick up frequency circuit (frequency signal amplifies and filtering shaping circuit), constant current source exciting circuit, temperature signal collection circuit, data storage circuitry, or more than one sensor interface circuit and or more than one band thermistor;
Sensor interface circuitry links to each other with vibrating string type sensor through four signal wires of band shielding, is respectively applied for the temperature signal that swashs frequently, picks up frequently, the exciting current signal is provided and obtains the voltage form of sensor output to sensor;
Swash amplitude that frequency circuit produces processor and carry out power amplification for the road pulse signal of+5V; And the signal after the power amplification produced the multichannel driving pulse through switch driver, the amplitude that 400Hz to 6000Hz is provided via sensor interface circuitry to sensor again for+5V pumping signal;
Pick up frequency circuit (frequency signal amplifies and filtering shaping circuit) and obtain the resonance frequency signal (natural frequency of string wire) of sensor output through sensor interface circuitry; Amplify and the shaping processing through high-pass filtering, LPF, signal, and the signal after will handling is sent into processor;
The constant current source exciting circuit provides exciting current to each sensor through sensor interface circuitry under the control of processor, regulate the size of exciting current through the resistance that changes pull-up resistor in the constant current source exciting circuit;
Temperature signal collection circuit obtains the voltage signal of the sign sensor temperature of each sensor output through sensor interface circuitry; And this voltage signal amplified and Filtering Processing, thereby being carried out analog to digital conversion, the analogue collection module that voltage signal processed is sent into processor make processor obtain the temperature signal of each sensor;
The data-carrier store circuit is a volatile memory, links to each other with processor with address bus through data bus, is used for the data that interim storage of processor receives;
The processor of each data acquisition module all is connected on the CAN bus by the CAN bus interface circuit and connects with the interactive mode that realizes a plurality of data acquisition modules, constitutes an interactive data acquisition system, thereby realizes the expanding function of multimode; The CAN bus links to each other with host computer with the CAN protocol conversion gateway via usb protocol again; The data upload of processor collection in each acquisition module is carried out subsequent treatment to host computer, receive the sharp frequency time interval, adjusting sample frequency, dormancy and other control instructions relevant that host computer sends the set handling device simultaneously with system;
Power source conversion and mu balanced circuit be input as externally fed power supply (6-24VDC), power source conversion and mu balanced circuit be output as processor and peripheral circuit, battery flowmeter charge circle, CAN bus interface circuit, RS485 bus interface circuit, swash frequency circuit, pick up frequency circuit, constant current source exciting circuit, temperature signal collection circuit and data storage circuitry provides power supply;
Battery flowmeter charge circle is used to detect the output voltage values of power source conversion and mu balanced circuit; And testing result sent into processor; Processor is delivered to host computer through CAN bus interface circuit and usb protocol and CAN protocol conversion gateway with testing result again, by the supply voltage of the real-time video data acquisition module of host computer;
Each module has also been reserved the RS485 interface circuit in order to the later stage expansion, and processor is through RS485 bus interface circuit and outside RS485 bus communication;
Said host computer is the desktop computer or the notebook computer of band USB interface.
A kind of data acquisition system (DAS) of the utility model based on vibrating string type sensor, its course of work is:
1) processor of data acquisition module receives the steering order that host computer sends through usb protocol and CAN protocol conversion gateway via the CAN bus interface circuit;
2) processor is based on the control instruction of host computer transmission; Swash the working time interval of frequency circuit through control bus and address bus adjustment; And start sharp frequency circuit and pick up frequency circuit, adjust the sample frequency of temperature signal collection circuit simultaneously, and start the A/D collection of processor;
3) resonance frequency signal (natural frequency of string wire) of the sensor of each data acquisition module output after picking up frequency circuit amplification, filtering and shaping, obtains the pulse signal of fixed frequency and amplitude, and it is sent into processor; Simultaneously, the temperature signal of the voltage form of sensor output, through sending into processor after amplification and the Filtering Processing, processor carries out the A/D conversion through the integrated ADC module in inside;
4) processor through control bus judge pick up accomplish frequently after, the A/D Acquisition Circuit is accomplished after the sampling simultaneously, reads the data value after resonance frequency value and the temperature signal A/D conversion through data bus;
5) processor carries out the FIR Filtering Processing with frequency values and temperature value, and deposits the data value after the Filtering Processing in the data-carrier store circuit on the one hand, on the other hand via sending host computer to through usb protocol and CAN protocol conversion gateway behind the CAN bus interface circuit;
6) if receive the dormancy instruction that host computer transmits, processor then control data acquisition module gets into low-power consumption mode.
When monitoring on-the-spot needed monitoring point more for a long time, then need a plurality of data acquisition modules, thereby constitute an interactive data acquisition system.Each acquisition module is relatively independent to carry out data acquisition, and data are passed to host computer by the CAN bus.
Beneficial effect
The utility model is simple in structure, cost is low, convenient in application; Can carry out module and expand, simultaneously tens even up to a hundred put to monitor and unify and control; When system needs, can swash the frequency time interval to twice of each acquisition module and change; When certain module work space, can let this module get into low-power consumption mode.
Description of drawings
Fig. 1 is the structural representation of the utility model.
Embodiment
Below in conjunction with accompanying drawing and embodiment the utility model is further specified.
Embodiment
A kind of data acquisition system (DAS) based on vibrating string type sensor; As shown in Figure 1; This system is widenable to a plurality of data acquisition modules, and data acquisition system (DAS) comprises host computer, usb protocol and CAN protocol conversion gateway, one or more than one data acquisition module, externally fed power supply, sensor;
Each data acquisition module include processor and processor peripheral circuit, power source conversion and mu balanced circuit, battery flowmeter charge circle, CAN bus interface circuit, RS485 bus interface circuit, swash frequency circuit, the vibrating string type sensor of pick up frequency circuit (frequency signal amplifies and filtering shaping circuit), constant current source exciting circuit, temperature signal collection circuit, data storage circuitry, or more than one sensor interface circuit and or more than one band thermistor;
Sensor interface circuitry links to each other with vibrating string type sensor through four signal wires of band shielding, is respectively applied for the temperature signal that swashs frequently, picks up frequently, the exciting current signal is provided and obtains the voltage form of sensor output to sensor;
Swash amplitude that frequency circuit produces processor and carry out power amplification for the road pulse signal of+5V; And the signal after the power amplification produced the multichannel driving pulse through switch driver, the amplitude that 400Hz to 6000Hz is provided via sensor interface circuitry to sensor again for+5V pumping signal;
Pick up frequency circuit (frequency signal amplifies and filtering shaping circuit) and obtain the resonance frequency signal (natural frequency of string wire) of sensor output through sensor interface circuitry; Amplify and the shaping processing through high-pass filtering, LPF, signal, and the signal after will handling is sent into processor;
The constant current source exciting circuit provides exciting current to each sensor through sensor interface circuitry under the control of processor, regulate the size of exciting current through the resistance that changes pull-up resistor in the constant current source exciting circuit;
Temperature signal collection circuit obtains the voltage signal of the sign sensor temperature of each sensor output through sensor interface circuitry; And this voltage signal amplified and Filtering Processing, thereby being carried out analog to digital conversion, the analogue collection module that voltage signal processed is sent into processor make processor obtain the temperature signal of each sensor;
The data-carrier store circuit is a volatile memory, links to each other with processor with address bus through data bus, is used for the data that interim storage of processor receives;
The processor of each data acquisition module all is connected on the CAN bus by the CAN bus interface circuit and connects with the interactive mode that realizes a plurality of data acquisition modules, constitutes an interactive data acquisition system, thereby realizes the expanding function of multimode; The CAN bus links to each other with host computer with the CAN protocol conversion gateway via usb protocol again; The data upload of processor collection in each acquisition module is carried out subsequent treatment to host computer, receive the sharp frequency time interval, adjusting sample frequency, dormancy and other control instructions relevant that host computer sends the set handling device simultaneously with system;
Power source conversion and mu balanced circuit be input as externally fed power supply (6-24VDC), power source conversion and mu balanced circuit be output as processor and peripheral circuit, battery flowmeter charge circle, CAN bus interface circuit, RS485 bus interface circuit, swash frequency circuit, pick up frequency circuit, constant current source exciting circuit, temperature signal collection circuit and data storage circuitry provides power supply;
Battery flowmeter charge circle is used to detect the output voltage values of power source conversion and mu balanced circuit; And testing result sent into processor; Processor is delivered to host computer through CAN bus interface circuit and usb protocol and CAN protocol conversion gateway with testing result again, by the supply voltage of the real-time video data acquisition module of host computer;
Each module has also been reserved the RS485 interface circuit in order to the later stage expansion;
Above-mentioned host computer is the desktop computer of band USB interface;
Above-mentioned processor model is PIC33FJ64GP706;
The master chip of above-mentioned CAN bus interface circuit is CTM8251;
The constant current source model is REF191 in the above-mentioned constant current source exciting circuit;
The course of work of above-mentioned vibrating string type sensor data acquisition system (DAS) is:
1) processor of data acquisition module receives the steering order that host computer sends through usb protocol and CAN protocol conversion gateway via the CAN bus interface circuit;
2) processor is based on the control instruction of host computer transmission; Swash the working time interval of frequency circuit through control bus and address bus adjustment; And start sharp frequency circuit and pick up frequency circuit, adjust the sample frequency of temperature signal collection circuit simultaneously, and start the A/D collection of processor;
3) resonance frequency signal (natural frequency of string wire) of the sensor of each data acquisition module output after picking up frequency circuit amplification, filtering and shaping, obtains the pulse signal of fixed frequency and amplitude, and it is sent into processor; Simultaneously, the temperature signal of the voltage form of sensor output, through sending into processor after amplification and the Filtering Processing, processor carries out the A/D conversion through the integrated ADC module in inside;
4) processor through control bus judge pick up accomplish frequently after, the A/D Acquisition Circuit is accomplished after the sampling simultaneously, reads the data value after resonance frequency value and the temperature signal A/D conversion through data bus;
5) processor carries out the FIR Filtering Processing with frequency values and temperature value, and deposits the data value after the Filtering Processing in the data-carrier store circuit on the one hand, on the other hand via sending host computer to through usb protocol and CAN protocol conversion gateway behind the CAN bus interface circuit;
6) if receive the dormancy instruction that host computer transmits, processor then control data acquisition module gets into low-power consumption mode.
More when the on-the-spot needed monitoring point of monitoring, then need a plurality of data acquisition modules, thereby constitute an interactive data acquisition system.Each acquisition module is relatively independent to carry out data acquisition, and data are passed to host computer by the CAN bus.
The above is the preferred embodiment of the utility model, and the utility model should not be confined to the disclosed content of this embodiment and accompanying drawing.Everyly do not break away from the equivalence of accomplishing under the spirit disclosed in the utility model or revise, all fall into the scope of the utility model protection.