A kind of multi-channel electromagnetic valve current harvester and acquisition method
Technical field
The present invention relates to wheel box control, particularly relate to multi-channel electromagnetic valve current harvester and acquisition method.
Background technology
In automatic gear-box control, the control of solenoid valve is more and more important, and the quality of its control directly has influence on the comfortableness taken and the life-span of basic machine.So need in the calibration process of Control Software, monitor the working condition of solenoid valve in real time, adjust control variable, to obtain best control strategy.Solenoid valve is an inductive load, and PWM (width modulation) control technology is generally selected in its control for use, to the requirement of sampling than higher.General sample circuit is difficult to satisfy the high negative pressure that produces when electric current that the circuit high speed changes and solenoid valve turn-off to be impacted, and because the abominable electromagnetic environment in the car, also difficultly carries out in real time, communicates by letter reliably with host computer.When needs are sampled to the multichannel current signal simultaneously, can produce the sampling asynchronous, data distortion.
Summary of the invention
The invention discloses a kind of multi-channel electromagnetic valve current harvester.Concrete technical scheme is as follows.
A kind of multi-channel electromagnetic valve current harvester is by Chip Microcomputer A/D processing module, CAN communication module, the compunication module, the amplifying circuit module, the sampling resistor module, the external circuitry module is formed, wherein sampling resistor is a precision resistance, be connected in the electromagnetic valve circuit that needs to measure, when electric current flows through sampling resistor, can produce small pressure drop at the sampling resistor two ends, after the processing and amplifying, the result is sent into Chip Microcomputer A/D processing module in this pressure drop input amplifying circuit module.
The amplifying circuit module comprises first order operational amplifier, regulates resistance, second level operational amplifier, filter resistance and filter capacitor, the sampling resistor two ends are connected respectively in the first order operational amplifier, first order operational amplifier extracts the small pressure drop at sampling resistor two ends, and after overregulating resistance adjustment enlargement factor, send into second level operational amplifier, filter resistance and filter capacitor carry out filtering to the signal that amplified, and at last the result are sent into Chip Microcomputer A/D processing module.The signal that Chip Microcomputer A/the D processing module is handled well is sent into host computer by the CAN communication module.
Wherein first order operational amplifier is a differential amplifier, and second level operational amplifier is the configuration amplifier.
The invention also discloses and adopt above-mentioned multi-channel electromagnetic valve current device to carry out current acquisition method.
Utilize above-mentioned multi-channel electromagnetic valve current harvester, can realize the signals collecting of high-speed real-time, can adapt to fast-changing voltage and high negative, regulate current amplification factor and filtering frequency range easily, reduce the electric current that the inductance characteristic of solenoid valve brings effectively and change fluctuation, data in real time can be uploaded to host computer and carry out the synchronization monitoring analysis, be convenient to analysis data.Have anti-high negative voltage, the enlargement factor adjustment is flexible, and communication speed is fast, advantage of high sampling precision.
Description of drawings
Fig. 1: basic functional block diagram;
Fig. 2: current sample amplifying circuit;
Fig. 3: capture program process flow diagram.
Embodiment
Below in conjunction with accompanying drawing the present invention is carried out concrete description.
Multi-channel electromagnetic valve current harvester shown in Figure 1, by Chip Microcomputer A/D processing module 1, CAN communication module 2, compunication module 3, amplifying circuit module 4, sampling resistor module 5, external circuitry module 6 is formed.
Shown in Figure 2 is the current sample amplifying circuit, as the powerful precision resistance R of little resistance of sampling resistor
SENBe connected in the electromagnetic valve circuit that needs to measure R
SENTwo ends are connected respectively among the first order operational amplifier OP1, when electric current flows through R
SENThe time, can be at R
SENTwo ends produce small pressure drop, and first order differential operational amplifier OP1 sends into second level operational amplifier, resistance R after adjusting enlargement factor with the small pressure drop extraction at resistance two ends and through resistance R x
FAnd capacitor C
FThe signal that amplified is carried out filtering, at last the result is sent into Chip Microcomputer A/D processing module 1.The signal that communication module 2 is good with acquisition process is sent into host computer by CAN communication.
In solenoid control, the controlled device solenoid valve is an inductive load, so change at electric current, can produce when particularly opening and turn-offing and hinder the moment high negative pressure that electric current changes, therefore having added continuous current circuit-diode D in circuit adopts and discharges this wherein high-energy of moment, but can exert an influence even defective chip to device, also can influence the accuracy of acquired signal, therefore first order operational amplifier OP1 chooses the chip of negative pressure resistant, the circuit of the assurance first order is not subjected to the influence of negative pressure like this, and the second level can be carried out signal Processing safely accurately because the isolation of the first order has been arranged.