NRF2401 wireless communication module design based on the remote control out of aluminum handle

 

    (1 Guizhou Branch of China Aluminum smelters, Guiyang 550058; 2 North China University; 3 China Unicom Ltd.) Abstract: Chip RF Transceiver nRF2401 features and characteristics of several currently used kind of short-range wireless communications technology for a comparative analysis. Elaborated nRF2401's role in the remote control handle its hardware and software design ideas, and gives some microcontroller C code.

 

Keywords: Wireless communication; nRF2401; Application

 

Introduction

 

In the past, tending the workshop on the aluminum control box to control the time, we use a hoist cable box through the way to achieve. Wired transmission speed, data flow, and reliability. But in the field operations, the crane and the equipment often carried around, up and down, rotate, move, etc., so that other devices hanging between the junction box and cables can easily be Jiaoduan, which gives the production brought great inconvenience. This article discusses a way to wirelessly control instead of a wired control, thereby improving this situation.

 

    Currently, short-range wireless communication and practical technologies are: infrared technology, Bluetooth technology, 802. Llb technology and micro-power short-range wireless communications technology.

 

    Infrared communications technology since the data transfer process between the two communicating devices can not have obstacles, and can not move while transmission and is therefore not suitable for use in complex industrial field use. Bluetooth technology, effective transmission distance is less than 10 m, more suitable for mouse, keyboard and other equipment. 802. Llb technical standard is a wireless LAN with international standards, mainly used to build large-scale wireless networks, equipment is relatively expensive. Micro-power short-range wireless communication typically use digital signal single-chip RF transceiver chip, coupled with a microcontroller and a few external components can constitute a special or general purpose wireless communication module. The power is small, simple and rapid development has been widely used. This article describes a nRF2401 Single Chip RF Transceiver that the use of micro-power wireless communication technology. Table 1 shows that the comparison between several communication technologies.

 

1 nRF2401 power station purposes and characteristics Introduction

 

    Norway Nodic nRF2401 chip produced 2.4

 

2 System Design

 

    Wireless communication system is the control system of aluminum electrolytic a subsystem of aluminum systems for workers in a timely manner to facilitate operations and records and displays data and design, system block diagram shown in Figure 2. NRF2401 wireless communication system includes a remote control module and the nRF2401 handle two parts of aluminum. Both in the hardware design is basically the same, the software design and function as the main communication vary difference.

 

    Wireless communication system using a common hardware STC89LE58RD + low-power microcontroller as the master chip, nRF2401 transceiver module is. nRF2401 chip microcontroller with hardware connection circuit shown in Figure 3. By adjusting PWR_UP, CE and CS values ​​of the nRF2401 three pins in four different operating modes, the configuration of its four operating modes as shown in Table 2.

 

    In order to obtain a suitable distance of the transceiver, inductance and capacitance parameters should be adjusted, but also in the production of PCB can be increased when the length of the antenna, here we use a single whip antenna. In order to improve the stability of the system, you should use a high Q and high precision SMD wirewound inductors, high stability crystal, high stability chip capacitors. nRF2401 transceiver mode has ShockBurstTM transceiver mode and direct mode transceiver are two specific choice of which mode transceiver can be configured in the program status word, channel 1 configured maximum length of the valid data 256-ADDR_W-CRC, frequency of 2 400 + RF_CH × 1 MHZ,

 

    In ShockBurst rM transceiver mode, nRF2401 use the on-chip FIFO stack area, the data from the microcontroller into low-speed to high-speed (1 Mb / s) emission data, so you can try to energy conservation, and the use of low-speed microcontroller can achieve very a high transmission data rate. nRF2401 internal CRC (cyclic redundancy check) error correction hardware and protocol can be 100% RF test automatically when the transmitted data with header and the CRC code word processing, data is received automatically remove the header and the CRC code. Each chip can be set by software up to 40 bit address, but only received the same address with the machine only when receiving data.

 

3 remote control handle functional design

 

    After the above analysis, the remote control of the aluminum handle specific design solution is to handle and display function wireless remote control used in combination.

 

    Wireless remote control handle has two rows of the display, the first row shows the slot number and slot indicate the amount of the second row shows the amount of aluminum slot time. Work to carry out the remote control handle aluminum electrolyzer working slot number issued PLC, PLC returns the amount of aluminum electrolytic cell to pre-remote control handle, remote control handle out of the slot and the amount of aluminum through the LED display. Meanwhile remote control handle up and down through the Query button, the query slot and single-slot capacity indication. Preparation work, press the start button on remote controller, PLC control lifted out of aluminum began to work, and the actual amount of time for the issue of aluminum remote control handle, shown in the first two rows of the display.

 

    Remote control handle design mode switch can be used in the aluminum GHz wireless RF transceiver chip, the operating frequency of 2.4 ~ 2.5 GHz, in the global wireless market unimpeded. nRF2401 supports multi-point communication, the maximum transfer rate of more than 1 Mb / s, the working voltage of 1.9 ~ 3.6 V, with 125 channels, multi-frequency and frequency hopping to meet the needs of a large main working parameters can be passed by the user according to the chip status word requires its own configuration. SOC design using the method, only a small number of external components can be composed of RF transceiver circuitry. nRF2401 no complex communication protocols, it is completely transparent to the user, the same product can communicate freely between users without the need for wireless communication theory and a deeper understanding of the working mechanism.

 

    Chip built-in frequency synthesizer, a power amplifier, a crystal oscillator and a modulator other functional modules. Phi DuoCeiver rM surgery which it can use the same antenna, two different channels simultaneously received data. Meanwhile chip power consumption is very low, in order to -5 dBm launch power, operating current of only 10.5 mA, working current accepted only 18 mA, a variety of low-power operating modes, energy-saving design is more convenient. So nRF2401 is the industry's smallest and least power consumption, minimal external components RF system-on-chip low-cost one.

 

    nRF2401 using 5 mm x5 mm 24-pin QFN package pinout shown in Figure 1 (top view) shows. Status and debug state transition. Meanwhile remote controller and PLC systems handshake also available through a button or open the key to control.

 

4 Software Design

 

    In accordance with the system hardware design, software design ideas are: system power initialization, for nRF2401 configuration (initialization), then the system enters the receiving or sending cycle. Program flow chart shown in Figure 4. There are 144 nRF2401 status word, of which the first 24 reserved for test, the system defaults to 8E081CH, can not be written to. So just on the back of 120 bytes can be configured. Status Word and function as shown in Table 3.

 

    Since the microcontroller and nRF2401 take the I / O directly connected, so when you use the software to simulate the initialization nRF2401 SPI interface written to the status word. In the program initially defined: sbitPWR_UP = P3 ^ 4; sbit CE = P2 "0: sbit CS = P2" 1; sbitDRl = P2 ^ 2; sbit DATA = P2 "3: sbit CLKl = P2 ^ 4.

 

5 Conclusion

 

    Introduced a wireless communication system in electrolytic aluminum system has been applied. Chip RF Transceiver nRF2401 use as a communications chip, to achieve the functions of the remote control, so that the improved system has a remote control function to facilitate equipment maintenance and other work, reducing the workload of workers, improve production efficiency. NRF2401 chip microcontroller and wireless data transmission system consisting of low cost, small size, flexible, low power consumption, the county has good versatility and reliability, the system can be generalized to other monitoring and industrial control systems.