Three-phase electric signal data acquisition system based on LPC2103

The scheme adopts LPC2103 as the core design of the three-phase electric signal data acquisition system. The Hall sensor is used to accurately and safely obtain the voltage and current signals. The data storage is combined with the SD card storage mode and the serial port transmission data to the upper computer storage mode. , increased the application flexibility of the data acquisition system, and gave a detailed software and hardware development process. Through the calibration of the test software, the data acquisition results are accurate and effective, which proves that the three-phase electrical signal data acquisition system designed in the scheme can lay a good foundation for the research on the operation state monitoring of the hydraulic power system based on motor drag. Data platform.

0 Preface

Hydraulic equipment driven by three-phase asynchronous motors has been widely used in production practice due to its many advantages in operation, and more research has been carried out on the safe and stable operation of hydraulic systems. Among the various characteristic signals that can reflect the operating state of such equipment, the three-phase electrical signal of the motor can fully reflect its hydraulic fault and motor fault [1], and the three-phase electrical signal has the characteristics of stability and being less susceptible to interference. Therefore, according to the needs of the application, the three-phase electric signal data acquisition system with high portability and practicability is developed, and the functions of real-time accurate acquisition and storage of the three-phase electric signals in the operation of the hydraulic equipment are completed, and the hydraulic system based on the motor drive is realized. Equipment condition monitoring and troubleshooting are all important and meaningful.

1 system hardware development

According to the application environment of the three-phase electric signal data acquisition system, the hardware part of the data acquisition system developed in this paper consists of four modules: analog signal acquisition, conditioning unit, data acquisition and processing unit and data storage data communication. The principle of the system is shown in Figure 1.

1.1 main control chip unit

The master chip is the core part of the entire data acquisition system. According to the design requirements of the application, when selecting the main control chip, there are mainly the following aspects:

(1) Small in size and rich in internal resources to reduce external expansion and reduce the volume of hardware modules of the data acquisition system;

(2) It has a higher calculation rate and improves the accuracy of real-time data;

(3) Low power consumption and high cost performance.

To sum up the above problems, the design chooses LPC2103 as the main control chip, and the minimum system is shown in Figure 2.

The LPC2103 uses an external crystal oscillator consisting of CX1, CX2 and 11.0592MHz crystal oscillators, which are then supplied to the internal working clock of the chip through an internal PLL and 4 times the frequency. CX3, CX4 and Y2 are real-time clock crystal parts [2-3].

1.2 Signal acquisition unit

In the digital mining system developed by this design, the signal acquisition includes two parts of three-phase voltage and three-phase current, and the related hardware design is carried out according to the characteristics of the two signals.

1.2.1 Three-phase voltage acquisition

The three-phase asynchronous motor that drives the hydraulic equipment has a rated operating voltage of 380 V. The AD chip used in this design is a 10-bit A/D module built into the LPC2103. It requires an input analog signal with a voltage range of 0 to 3.3 V. Therefore, under the premise of accurate measurement, taking into account the convenience of use, design implementation cycle and economic issues, the three-phase voltage is obtained by resistor divider, and the schematic is shown in Figure 3.