CN209102205U - Shaft vibration sensor protection circuit - Google Patents

Abstract

The utility model relates to a shaft vibration sensor protection circuit, which comprises: a voltage follower circuit, a vibration voltage signal SIG outputs a voltage detection signal SI with enhanced load driving capability through the voltage follower; a reference comparison circuit is used for comparing the vibration voltage signal SIG compares with the reference voltage signal VCC and outputs the comparison voltage signal SV; operational amplifier, the output terminal VOUT of the operational amplifier outputs the signal to be measured, and the voltage detection signal SI is input to the forward input terminal of the operational amplifier, and the output terminal of the operational amplifier is connected to To its reverse input terminal, the voltage signal SV is divided into resistors and divided into the bases of transistors Q1 and Q2, respectively. The emitters of transistors Q1 and Q2 are grounded through resistors respectively; the collectors of transistors Q1 are connected to the operation through resistors. The output end of the amplifier, the collector of the transistor Q2 is connected to the forward input end of the amplifier. The utility model relates to a shaft vibration sensor protection circuit, which can effectively protect the shaft vibration sensor and monitor its state.

Description

Shaft vibration sensor protection circuit

technical field

The utility model relates to a protection circuit, in particular to a circuit for protecting a shaft vibration sensor.

Background technique

Shaft vibration sensor is a non-contact measurement sensor, which measures the vibration displacement or amplitude of the object through the change in the distance between the sensor end and the measured object: when the distance between the measured metal and the probe occurs When it changes, the coil in the sensor probe and the signal processing circuit on the circuit board form an LCR oscillation circuit, thereby generating an oscillating voltage, and this oscillating voltage that varies with distance is converted into a voltage through detection, filtering, linear compensation, amplification and normalization ( Current) changes, and finally completes the conversion of mechanical displacement (gap) into industrial voltage (current).

At present, when the shaft vibration sensor in the domestic market is used in the industrial field, the sensor probe may become loose or deviate from the measured object. At this time, the gap voltage output by the shaft vibration sensor is high, close to the power supply voltage, and the current will follow. close to saturation. If the chips and components inside the circuit board are overloaded for a long time, it will cause damage to the front part of the shaft vibration sensor.

SUMMARY OF THE INVENTION

The purpose of the present invention is to overcome the above deficiencies and provide a shaft vibration sensor protection circuit, which can effectively protect the shaft vibration sensor and monitor its state.

The purpose of this utility model is achieved in this way:

A shaft vibration sensor protection circuit, the circuit includes:

The voltage follower circuit plays the role of impedance matching, and the vibration voltage signal SIG outputs the voltage detection signal SI with enhanced load driving ability through the voltage follower;

a reference comparison circuit for comparing the vibration voltage signal SIG with the reference voltage signal VCC and outputting the comparison voltage signal SV;

Operational amplifier, the output terminal VOUT of the operational amplifier outputs the signal to be tested, the voltage detection signal SI is input to the forward input terminal of the operational amplifier, the output terminal of the operational amplifier is connected to its reverse input terminal, and the voltage signal SV is divided into resistance and voltage division. Then input the bases of the transistor Q1 and the transistor Q2 respectively, the emitters of the transistor Q1 and the transistor Q2 are grounded respectively through the resistor; the collector of the transistor Q1 is connected to the output of the operational amplifier through the resistor, and the collector of the transistor Q2 is connected to the positive terminal of the amplifier. to the input.

The utility model relates to a protection circuit for a shaft vibration sensor. The vibration voltage signal SIG is filtered by an RC filter circuit and then input to a voltage follower circuit.

The utility model relates to a protection circuit for a shaft vibration sensor. The reference comparison circuit includes an operational amplifier U2A, which is input to an inverting input terminal of the operational amplifier U2A based on a voltage signal VCC. The voltage signal SIG is connected to the non-inverting input terminal of the operational amplifier U2A through the resistor, and the input terminal of the operational amplifier U2A outputs the comparison voltage signal SV through the Zener tube and the resistor, and the comparison voltage signal SV is respectively processed by the capacitor and another Zener tube. ground.

The utility model relates to a protection circuit for a shaft vibration sensor. The comparison voltage signal SV outputs the divided voltage to the bases of the transistor Q1 and the transistor Q2 through two sets of resistor divider circuits connected in series.

Compared with the prior art, the beneficial effects of the present utility model are:

After adopting the circuit of the utility model: when the output of the vibration voltage signal SIG (gap voltage) is within the normal linear range of the sensor output, the sensor outputs normally; when the gap voltage output exceeds the sensor output linear range, the sensor output returns to zero, thereby ensuring that the sensor outputs The performance is stable, and at the same time, users can also judge whether the sensor performance is normal on the spot according to this feature, avoiding secondary disassembly and maintenance.

Description of drawings

FIG. 1 is a circuit diagram of a protection circuit of a shaft vibration sensor of the present invention.

Detailed ways

Referring to FIG. 1 , a shaft vibration sensor protection circuit according to the present invention, the circuit includes:

The voltage follower circuit plays the role of impedance matching, and the vibration voltage signal SIG outputs the voltage detection signal SI with enhanced load driving ability through the voltage follower;

a reference comparison circuit for comparing the vibration voltage signal SIG with the reference voltage signal VCC and outputting the comparison voltage signal SV;

Operational amplifier, the output terminal VOUT of the operational amplifier outputs the signal to be tested, the voltage detection signal SI is input to the forward input terminal of the operational amplifier, the output terminal of the operational amplifier is connected to its reverse input terminal, and the voltage signal SV is divided into resistance and voltage division. Then input the bases of the transistor Q1 and the transistor Q2 respectively, the emitters of the transistor Q1 and the transistor Q2 are grounded respectively through the resistor; the collector of the transistor Q1 is connected to the output of the operational amplifier through the resistor, and the collector of the transistor Q2 is connected to the positive terminal of the amplifier. to the input;

The principle of the utility model is that the reference voltage signal VCC is set, and when the reference comparison circuit detects that the vibration voltage signal SIG is greater than the rated voltage value of the reference voltage signal VCC, the transistor Q1 and the transistor Q2 are turned on, thereby turning the operational amplifier The output terminal VOUT outputs the signal to be measured to 0. At this time, the subsequent vibration sensor circuit can know that the front-end sensor deviates from the actual detection position, and effectively prevent excessive voltage from damaging the back-end circuit; when the vibration voltage signal SIG is less than the preset rated value When the voltage value is reached, the transistor Q1 and the transistor Q2 stop working, and the output terminal VOUT of the operational amplifier normally outputs the signal to be measured;

Specifically:

The vibration voltage signal SIG is filtered by the RC filter circuit and then input to the voltage follower circuit;

The reference comparison circuit includes an operational amplifier U2A, which is input to the inverting input terminal of the operational amplifier U2A based on the voltage signal VCC. The inverting phase of the operational amplifier U2A is grounded through a resistor and a capacitor respectively, and the vibration voltage signal SIG is connected to the non-inverting input of the operational amplifier U2A through a resistor. terminal, the input terminal of the operational amplifier U2A outputs a comparison voltage signal SV through a voltage regulator tube and a resistor, and the comparison voltage signal SV is grounded through a capacitor and another voltage regulator tube respectively;

The comparison voltage signal SV outputs the divided voltage to the bases of the triode Q1 and the triode Q2 after passing through the two groups of resistor divider circuits in series;

In addition: it should be noted that the above-mentioned specific embodiment is only an optimized solution of this patent, and any changes or improvements made by those skilled in the art according to the above-mentioned concept are all within the protection scope of this patent.

Claims (4)

1. A shaft vibration sensor protection circuit, characterized in that: the circuit comprises: The voltage follower circuit plays the role of impedance matching, and the vibration voltage signal SIG outputs the voltage follower to the voltage detection signal SI with enhanced load driving ability; a reference comparison circuit for comparing the vibration voltage signal SIG with the reference voltage signal VCC and outputting the comparison voltage signal SV; Operational amplifier, the output terminal VOUT of the operational amplifier outputs the signal to be tested, the voltage detection signal SI is input to the forward input terminal of the operational amplifier, the output terminal of the operational amplifier is connected to its reverse input terminal, and the voltage signal SV is divided into resistance and voltage division. Then input the bases of the transistor Q1 and the transistor Q2 respectively, the emitters of the transistor Q1 and the transistor Q2 are grounded respectively through the resistor; the collector of the transistor Q1 is connected to the output of the operational amplifier through the resistor, and the collector of the transistor Q2 is connected to the positive terminal of the amplifier. to the input. 2 . The protection circuit of a shaft vibration sensor according to claim 1 , wherein the vibration voltage signal SIG is filtered by an RC filter circuit and then input to the voltage follower circuit. 3 . 3. A shaft vibration sensor protection circuit as claimed in claim 1, characterized in that: the reference comparison circuit comprises an operational amplifier U2A, which is input to the inverting input terminal of the operational amplifier U2A based on the voltage signal VCC, and the inverting input terminal of the operational amplifier U2A. The phases are grounded via resistors and capacitors respectively, and the vibration voltage signal SIG is connected to the non-inverting input terminal of the operational amplifier U2A via the resistor. They are grounded through a capacitor and another Zener tube respectively. 4. A shaft vibration sensor protection circuit as claimed in claim 1, characterized in that: the comparison voltage signal SV outputs the divided voltage to the bases of the triode Q1 and the triode Q2 after passing through the two groups of resistor divider circuits connected in series respectively. .