Acceleration Sensor Type IEPE Product Description

Acceleration Sensor Type IEPE Product Description

Overview

Internal IEPE IC Piezoelectric acceleration sensor is an emerging international mechatronic measurement sensor. Sensitive parts of the piezoelectric crystal using the positive piezoelectric effect of the output of the high impedance charge, the internal integrated circuit converted to output a low-resistance voltage signal proportional to the amount of mechanical, directly into the readout, display, recording instruments. Because of its small size, rigidity, wide frequency response, high sensitivity, environmental characteristics of a wide range of advantages, energy consumption is very small, easy to use and so on a series of advantages, in the field of vibration and shock has been very widely used.

Piezoelectric sensors with built-in circuitry, in which the impedance conversion circuitry is encapsulated in the rigid housing of the sensor, are compatible with international built-in IEPE (ICP) sensors and constant-current source adapter preamplifiers. In addition to the advantages of ease of use and simplicity of operation, the following advantages are also available:

Low impedance (<100Ω) permits the use of very long cables for signal transmission in harsh environments;

The bias voltage value has a low temperature drift over the operating temperature range as well as a low sensor shock zero drift;

As a two-wire system, it can be adapted to common inexpensive coaxial or twin-wire cables;

The low impedance voltage output (±5V) is compatible with common reading, recording and processing instruments;

Significantly reduces the maintenance requirements of the test system.

1.Circuit Principle

Typical piezoelectric internal circuit acceleration sensor is in the traditional piezoelectric acceleration sensor charge output connected to a field effect tube as the core of the IC circuit, its output and constant current source power supply line is the same line, i.e., in the basis of a DC level superimposed on an AC (vibration) signal, the principle of the figure:

When a measured acceleration by the inertial element force on the piezoelectric element at both ends of the charge generated by the amount of △ Q, such as piezoelectric element of the capacitance of the two ends of the capacitance of the C, then the piezoelectric element at both ends of the open circuit voltage will be generated by an open-circuit voltage of △ V, by the law of static electricity can be obtained from the three quantities of the relationship between the:

△ V = △Q / C

Because the capacitance value is small, so the capacitive resistance is very large, and the voltage △ V and charge △ Q are high impedance signals, when the sensor is an acceleration sensor with built-in circuitry, the high impedance voltage or charge signals can be transformed by the built-in circuitry to obtain the low impedance voltage signals, and the low impedance signal output can be directly entered into the various types of secondary instrumentation for readings or recordings, such as special processing, the built-in circuitry can also be equipped with the gain, filtering and self-calibration functions. If special processing, the built-in circuit can also have gain, filtering and self-calibration functions. The above circuit principle is actually a high-resistance voltage conversion circuit.

Due to the presence of the bias level, the output is a dynamic signal with a DC voltage, i.e., it outputs a high magnitude of about 11±2VDC, and its acceleration signal is an AC signal superimposed on DC, if the user doesn't need this DC, it can be used with a Côté-Coupé capacitor to isolate the DC component. For users with low power requirements, the output amplitude should be reduced.

2.Usage and precautions

The following figure shows the system wiring box, such as the connection of AC coupling capacitors to isolate the DC component, need to be considered with the input impedance of the subsequent instrumentation to form a passive low-pass filter, usually recommended C Ω 10μF, if the input impedance of the subsequent instrumentation is 1MΩ, then the time constant of 10 seconds, will not affect the sensor's low-frequency response.

A. Our 2-wire IEPE products are prohibited to be powered directly by DC power supply, and must be powered by constant current source, otherwise it is easy to damage the internal components and cause no output. Please note.

B. Because the sensor has a built-in circuit, do not allow a high voltage test sensor core and shell insulation resistance between, so that the sensor is very easy to breakdown damage. Users should remember, otherwise the damage will not be replaced. Simple identification method is: use the multimeter's R gear can be tested, forward about tens of KΩ ~ 100KΩ, reverse infinity. Can also detect the bias voltage normal or not to judge the sensor.

C. The voltage sensitivity of the acceleration sensor with built-in circuit is related to the range (measuring range) and can be determined by referring to the following formula:

Range = 5V/sensor sensitivity

For example, if a high sensitivity sensor is selected, the range will be reduced, so please take this into consideration when selecting the sensor to prevent overloading. The sensor itself has a high shock resistance value (without power supply).

D. The matching of current should be considered for long-distance transmission of signals, and the recommended formula for calculating cable length is as follows (for reference):

I = 2πVfC

10⁹

or f = ------------- 2πCV/(I-1)

I - Current supplied by constant current source adapter (A)

f - Operating frequency (Hz)

C - Cable capacitance (F)

V - Maximum peak sensor output voltage (Vp)

Example: 30m cable, 100 pF / m cable capacitance, f = 10k, Vp = 5V, then I = 2mA

E. The company's two-wire IEPE sensor calibration test conditions: 160Hz, 4mA, 10ms^-2, 20±5℃.

Yangzhou Xiyuan Electronic Technology Co.,Ltd.

Building 2,217 kaifa west road,high-tech development zone, yangzhou, jiangsu,China 225128

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Tel: +86 514-82885589

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