Sensor comprehensive experimental box

The BG-SJ sensor experimental box is suitable for teaching experiments in courses such as "Automatic Detection Technology", "Sensor Principles and Technology", "Industrial Automation Control", "Non electric Measurement Technology", "Optoelectronic Conversion Technology" in universities, vocational schools, and teacher training institutions.

BG-SJ typeSensor comprehensive experimental boxIntegrating sensors, detection objects, signal processing circuits, excitation sources, and display instruments. The fully transparent teaching sensor has a clear structure and principle, and the entire instrument is compact in structure, easy to operate, functionally efficient, and cost-effective. It is an ideal experimental instrument for understanding and mastering the basic principles and characteristics of sensors.

BG-SJ typeSensor comprehensive experimental boxCompared with the existing 998B experimental instrument, the strain sensor adopts a double hole cantilever beam standard force sensor, which overcomes the disadvantages of low experimental accuracy and poor stability caused by the use of a simple strain beam in the 998B experimental instrument, making the experiment more accurate and stable. At the same time, it has many advantages such as lightweight and flexible, easy to carry, and convenient to store.

Construction:

The sensor experimental box consists of three parts: the sensor installation platform, the signal source/data acquisition/display instrument, and the signal processing circuit

1、 Sensor installation section:

1. Parallel vibration beam: The parallel vibration beam is a cantilever structure, with one end fixed and the other end free. The free end is equipped with a vibration disk and a magnetic steel located in the excitation coil. Various sensors are installed on the vibration disk, and static and dynamic characteristic experiments of the sensors can be completed using a measuring rod and excitation signals.

2. Two sets of electric heaters: composed of electric heating wires, can achieve a temperature rise of about 30 ℃ higher than the ambient temperature during heating.

3. A set of speed measuring motors: consisting of a high-speed axial flow fan with adjustable noise reduction, combined with photoelectric, fiber optic, and eddy current sensors for speed measurement experiments.

4. Photoelectric converter: composed of infrared emitting and receiving tubes.

5. Sensor configuration: Sensor configuration and structure: Industrial sensor requirements, split structure.

Resistance strain sensor: composed of BHF type strain gauges, 6 working gauges and 2 compensating gauges.

Hall sensor: composed of HZ type linear semiconductor Hall chip and magnetic steel produced by JVC company, with a signal linear range of ± ≥ 3mm.

Capacitive sensor: a differential variable area capacitive sensor composed of two sets of fixed plates and one set of moving plates, with a linear range of ≥ ± 3mm.

Inductive sensor (differential transformer) sensor: a transparent hollow coil wound from one primary and two secondary coils, with a soft magnetic ferrite core and a measurement range of ≥ 10mm.

Inductive sensor (self sensing) sensor: a transparent hollow coil made up of one primary and two secondary coils, with a soft magnetic ferrite core and a measurement range.

Eddy current displacement sensor: composed of a flat coil wound with multiple enameled wires and a metal eddy current sheet. DC resistance: 1 Ω -2 Ω, range: ≥ 3mm.

Piezoelectric accelerometer: composed of PZT -5 dual piezoelectric chip and metal mass block. f≥10KHZ、Q≥20pc/g。

Magnetic electric sensor: composed of coils wound with multiple enameled wires and magnetic steel, DC resistance: 30 Ω -40 Ω, sensitivity: 0.5V/M/S.

Thermocouple sensor: DC resistance: composed of two copper constantan thermocouples (division mark T) connected in series, with the free end being the ambient temperature.

Photoelectric sensor: Reflective infrared photoelectric switch.

Fiber optic sensor: a light guided sensor composed of a semi-circular multi-mode fiber optic probe and infrared emission and reception circuits, with a linear range of ≥ 2mm.

Pressure sensor: MPX type diffusion silicon piezoresistive pressure sensor from the United States.

P-N junction temperature sensor: a temperature sensor made using the excellent temperature voltage characteristics of semiconductor P-N junction.

Gas sensor: Sensitivity: 50-5000ppm. Medium CH4 (alcohol)

Humidity sensor: polymer film material: Rh: 10% -95%.

Pyroelectric infrared sensor: Far infrared type.

Photoresistor: CDS material: Resistance: several ohms to several thousand ohms.

Silicon solar cell: Si solar type.

Photodiode: Infrared type.

Phototransistor: Infrared type.

Laser graphic control sensor: Laser power: 650nm/200mw.

Laser source: semiconductor laser.

Laser colors: red, green.

It has the following control methods: numerical control, voice control (signal modulation), and program control.

2、 Signal source/data acquisition/display section:

1. Two sets of display instruments

Digital voltage/frequency meter: 3-digit display, voltage range 0-2V, 0-20V, frequency range 3Hz-2KHz, 10Hz-20KHz, sensitivity ≥ 50mV.

2. Two sets of oscillators:

　　（1）Audio oscillator: 0.4KHz10KHz output continuously adjustable, V-P-P =20V， 180 °, 0 ° inverted output, maximum power output current at Lv terminal 0.5A.

　　（2）Low frequency oscillator: 1-30HZ output continuously adjustable, V-P-P=20V， The maximum output current is 0.5A, and the Li terminal can be used as a current amplifier.

3. Two sets of stabilized power supplies: (A) DC ± 15V power supply, mainly providing the working power supply of the whole machine and the heating power supply for temperature experiments, with a maximum excitation current of 1.5A. (B) ± 2V - ± 10V adjustable output DC stabilized power supply with five levels, with a maximum output current of 1.5A. It mainly provides the DC excitation source for sensors.

4. Computer data collection and software:

Data acquisition card: 12 bit A/D conversion, sampling speed of 1.25-100000 times/second, controllable sampling speed, divided into single sampling, timed sampling, and continuous sampling (low-frequency slow scan oscilloscope function), standard RS-232/USB interface.

Processing software: With a good computer display interface and convenient practical processing software, it can select and edit experimental projects, collect and process data, analyze and compare graphics, and print files.

3、 Signal processing circuit section:

(1) Bridge balance network: used to form a test bridge, providing bridge sockets, standard resistors, and AC/DC adjustable balance potentiometers.

(2) Differential amplifier: with a passband of 010KHz, it can be connected to an AC/DC amplifier with a gain of 1100 times the same phase and opposite phase.

(3) Capacitor converter (amplifier): a signal processing circuit composed of a high-frequency oscillator, amplifier, and double T-bridge.

(4) Voltage amplifier: a in-phase input amplifier with a gain of approximately 5 times, with a passband of 070KHz.

(5) Phase shifter: gain of 1, phase shift range ≥ ± 40 ° (related to fi).

(6) Phase sensitive detector: a detection circuit composed of a shaping circuit and an electronic switch. The detectable voltage frequency is 0-10KHz, and the maximum allowable input voltage is 10Vp-p.

(7) Charge amplifier: a capacitive feedback amplifier used to amplify/convert the charge output signal of piezoelectric sensors.

(8) Low pass filter: composed of a 50Hz notch filter and an RC filter, with a transition frequency of around 35Hz.

(9) Eddy current converter: It consists of a frequency conversion and amplitude modulation conversion circuit, a detector, and a follower. The sensor is an inductive element in the oscillation circuit. Output voltage ≥ | 8 | V (probe away from the measured object).

(10) Triple point linear correction sensor conditioning circuit: This circuit should have a significant and effective triple point linearization correction for nonlinear signals. The voltage range of the inflection point should reach 2V, 5V, and 8V.

(11) AC frequency conversion circuit: AC 36V low-voltage safe single-phase power supply, load using corresponding incandescent lamps and motors, frequency adjustable range 20Hz-200Hz.