Abstract: According to the design requirements of temperature control systems, a temperature control system design scheme based on ZigBee and GPRS is proposed, and the hardware and software designs of the temperature control system are provided. The combination of ZigBee and GPRS wireless communication methods can achieve information transmission, which not only greatly reduces the number of devices in the system, but also makes the system placement flexible. Tests have shown that the system is easy to operate, stable and reliable in operation, fast and efficient. The system design has met the requirements of the design goals and has broad application prospects.

Introduction

Traditional temperature control systems typically use wired signal transmission, which incurs high wiring costs and inconvenience in maintenance. UAD149A0001 technology, as an emerging wireless communication technology with short distance, low complexity, low power consumption, and low cost, has been widely applied; GPRS is a new packet data bearer service developed on the existing GSM system, which is particularly suitable for intermittent, sudden or frequent, small amount of data transmission, as well as occasional large data transmission. This feature is suitable for most mobile internet applications. Introducing ZigBee and GPRS into temperature control systems and combining the two wireless communication methods to achieve information transmission will help solve the problem of relatively lagging informationization and automation in temperature control systems.

Introduction to ZigBee Technology and GPRS Technology

1.1 ZigBee Technology Introduction

UAD149A0001 is an emerging wireless communication technology with short distance, low complexity, low power consumption, and low cost. Based on the IEEE802.15.4 standard, it defines the content of mutual compatibility between devices produced by different manufacturers. It can organize several small sensors for communication, which only require a small amount of energy to transmit data through multi hop methods. It has been widely used in many fields, such as the collection and transmission of small data volume information such as temperature, humidity, lighting, and gas concentration.

The main characteristics of ZigBee:

(1) Low power consumption

This is a significant advantage of ZigBee technology. Due to its low power consumption during information transmission and reception, and the use of sleep mechanism in the MAC layer, the channel access delay is short, making ZigBee nodes very energy-efficient. The battery life of the node can reach six months to two years.

(2) Low cost

Due to the simplicity of the ZigBee protocol stack compared to Bluetooth and Wi Fi, the requirements for communication control devices are reduced, which can lower device costs. In addition, the ZigBee protocol is free of patent fees, which can reduce software usage costs. Low cost is also a significant advantage of ZigBee.

(3) Large network capacity

A star structured ZigBee network can accommodate up to 254 slave devices and one master device, making networking very flexible.

(4) Safe and reliable

In the MAC layer, a secure confirmation data transmission mode is adopted, and each sent data packet must wait for the receiver’s confirmation message. It provides a data packet security check function based on cyclic redundancy check (CRC), supports authentication and authentication, and the system is safe and reliable.

(5) Low latency

The communication delay and activation delay from sleep state of ZigBee are both very short, with a typical device search delay of 30ms, sleep activation delay of 15ms, and active device channel access delay of 15ms.

(6) Low speed rate

ZigBee has lower data transmission rates in different operating frequency bands.

The data transmission rate in the 868MHz frequency band is 20kbps, and the data transmission rate in the 915MHz frequency band is 40kbps. The data transmission rate in the 2.4GHz frequency band is 250kbps.

1.2 Introduction to GPRS Technology

GPRS is the English abbreviation for General Packet Radio Service, which is a packet switching system. The GPRS logical structure is shown in Figure 1. The basic function of GPRS is to transmit packet services between mobile terminals and routers in standard data communication networks. The GPRS network structure is based on the GSM system, and the voice part still uses the basic processing unit of the original GSM, while the data part adds some new data processing units and interfaces. In order to achieve data bearer, the GPRS system has introduced several new network units, such as packet processing unit (PCU), GPRS service support unit (SGSN), GPRS gateway support unit (GGSN), as well as other auxiliary units for data service management and application, such as DNS and DHCP servers, network time protocol server (NTP), billing gateway CG, etc.