Circuit for processing key phase signal in rotary machine vibration analysis
Technical Field
The invention relates to the field of rotary machine vibration monitoring signal processing, in particular to a circuit for processing a key phase signal in rotary machine vibration analysis.
Background
The key phase device is an indispensable part in the processing of a vibration monitoring signal of a rotating machine, the key phase device mainly serves as a phase reference and an initial time scale of data acquisition, and two modes, namely an eddy current mode and a photoelectric mode, are commonly adopted in the engineering field, wherein the principle of the photoelectric mode is that a reflective label is attached to the surface of a rotating shaft, infrared light emitted by a photoelectric sensor irradiates on the reflective label by utilizing the rotation of the rotating shaft for one circle, and the change of the luminous flux causes the change of the output level state of the photoelectric sensor; the principle of the eddy current method is that an eddy current sensor is arranged near a rotating shaft with a certain gap, the rotating shaft rotates for one circle, and the sensor outputs a pulse signal with a direct current component.
Most of key phase signals in prior art adopt fixed level in processing, and multiple comparative levels are set for switch selection according to the difference of the amplitude and polarity of the pulsating signal of the eddy current key phase device and the superposed direct current level, so that the key phase signal is very inconvenient to apply, cannot be automatically identified and processed, cannot adapt to occasions with any polarity, and has a too narrow dynamic range.
Disclosure of Invention
The purpose of the invention is as follows: the invention aims to provide a circuit for processing a key phase signal in rotary mechanical vibration analysis, which can adapt to any polarity in the occasions using an eddy current sensor and an optoelectronic key phase device as the key phase device and has wide dynamic range.
The technical scheme is as follows: the invention relates to a circuit for processing key phase signals in rotary machine vibration analysis, which comprises an average level detection circuit, a filtering amplification circuit, a hysteresis comparator and a shaping circuit, wherein one end of the average level detection circuit is connected with a signal input end, and the other end of the average level detection circuit is connected with an input end of the filtering amplification circuit; the output end of the filtering amplification circuit is connected with the positive input end of the hysteresis comparator; the input end of the negative pole of the hysteresis comparator is connected with a signal input end, and the output end of the hysteresis comparator is connected with the shaping circuit.
Preferably, the average level detection circuit comprises a positive average level detection circuit and a negative average level detection circuit which are connected in parallel, wherein the positive average level detection circuit comprises a diode with a positive electrode connected with the signal input end, a resistor connected with the diode in series and a grounded capacitor; the negative average level detection circuit comprises a diode with a negative electrode connected with the signal input end, a resistor connected with the diode in series and a grounded capacitor.
Preferably, the filtering and amplifying circuit includes a low-pass filter and a non-inverting amplifier, and the low-pass filter is connected to a non-inverting input terminal of an operational amplifier in the non-inverting amplifier.
Preferably, a current limiting resistor is arranged in a circuit of the hysteresis comparator inverting input end connected with the signal input end.
Preferably, the shaping circuit is an inverter circuit.
The technical principle is as follows: the key phase signal is divided into two paths after entering the circuit, one path enters the average level detection circuit, the average component in the key phase signal is detected, then the key phase signal passes through the filter amplification circuit and enters the hysteresis comparator, the key phase signal in the other path is compared, and the bipolar pulse signal output after comparison is converted into unipolar pulse, namely the key phase pulse signal through the shaping circuit.
Has the advantages that: according to the invention, the input key phase signals with any polarity can be converted into unipolar pulse signals at last, so that the signals monitored by the vibration of the rotary machine can be analyzed conveniently, the state of the equipment can be judged in time, and meanwhile, even the key phase signals with smaller amplitude can be accurately judged through the amplifying circuit.
Drawings
FIG. 1 is a circuit diagram of the present invention;
FIG. 2 is a schematic diagram of a negative polarity-superimposed negative DC input key phase signal according to the present invention;
fig. 3 is a schematic diagram of the key phase signal input by the present invention being a positive polarity superimposed with a negative dc.
Detailed Description
As shown in fig. 1, a circuit diagram of the present invention includes an average level detection circuit 1, a filtering amplification circuit 2, a hysteresis comparator 3 and a shaping circuit 4, wherein a key phase signal is input from a KP terminal, the input key phase signal is divided into two paths, one path directly enters an inverting input terminal of the hysteresis comparator through a current limiting resistor R2 of 2k Ω, the other path enters the average level detection circuit 1, the average level detection circuit 1 includes a forward average level detection circuit and a negative average level detection circuit connected in parallel, the forward average level detection circuit includes a diode D1 with a model number of 1N4148 and a positive electrode connected to a signal input terminal, a capacitor C1 of 2 μ F and a resistor R3 of 1M Ω, and detects a forward average level in the key phase signal; the negative average detection circuit comprises a diode D2 with the same model number of 1N4148 and the negative electrode connected with the signal input end, a capacitor C2 with the voltage of 2 muF and a resistor R4 with the voltage of 1 Momega, and detects the negative average level in the key phase signal; the average level component detected by the average level detection circuit 1 enters a non-inverting amplifier composed of an operational amplifier U1A, a resistor R6 of 100k Ω and a resistor R7 of 10k Ω after being filtered by a filter composed of a resistor R5 of 47k Ω and a capacitor C3 of 100nF, the amplified average level component is input to a non-inverting input terminal of a hysteresis comparator composed of an operational amplifier U1B and a feedback resistor JR11 of 100k Ω through a current limiting resistor JR9, when the amplitude of a key phase signal directly entering the non-inverting input terminal of the hysteresis comparator is larger than that entering the non-inverting input terminal of the hysteresis comparator, the U1B outputs a level of-12V, otherwise, the bipolar negative pulse signal output by the U1B is shaped by a NOT circuit U2A and converted into a unipolar positive pulse with a steeper edge, namely a key phase pulse signal.
As shown in fig. 2, when the key phase signal input at the KP terminal is negative polarity-superimposed negative dc, the invention detects that the average value of the negative dc is lower than the negative ripple signal, and after the comparison processing of U1B, the invention can output a regular square wave signal at the output end of U2A; as shown in fig. 3, when the key phase signal input at the KP terminal is a positive polarity-superimposed negative dc, the invention detects the average value of the negative dc, the level of which is higher than that of the negative ripple signal, and after the comparison processing of U1B, the invention can also output a regular square wave signal at the output terminal of U2A; similarly, the processing process of the signals of the positive polarity pulse superposition positive direct current level and the negative polarity pulse superposition positive direct current level is completely the same, and finally, square wave signals can be obtained, so that the state of the equipment can be analyzed conveniently.