GPRS DTU Ambient Temperature Remote Monitoring System

Case background

At present, no matter in people's daily life, or in industrial industries such as energy and chemical industry, the monitoring of ambient temperature has become an indispensable work. In some fields with higher requirements for ambient temperature, the monitoring of ambient temperature Monitoring is the top priority. Traditional temperature monitoring needs to be monitored by manpower and simple temperature detection equipment. With the development and progress of science and technology, in industry and in industries with strict requirements on ambient temperature, the above work alone has not kept up. On the development steps, a lot of manpower and material resources will be wasted. With the development of communication technology, a wireless data transformation system based on GPRS communication technology can not only monitor the ambient temperature in real time but also realize unattended monitoring in ambient temperature monitoring. This remote monitoring system is perfectly suitable for similar temperature monitoring, etc. Various industrial environments, it is playing an increasingly important role.

Overall structure of the system

The ambient temperature monitoring system is mainly composed of data collection end point, monitoring center and data transmission network. The system adopts GPRS as the communication network, which has the characteristics of no need to set up communication lines, flexible and convenient networking, and high resource utilization.

The system mechanism block diagram is as follows:

Data collection end point

Data collection end point collects temperature and other related data through end point sensor equipment such as temperature sensor, and sends data to the monitoring center through the GPRS module. The collected end point is composed of temperature sensor, DTU and RTU. The temperature data collected by the temperature sensor is obtained by the RTU. Perform data processing, transmit it to the monitoring center server through DTU, and display, query and save the data in real time.

Acquisition end point hardware equipment

The temperature sensor adopts high-precision DS18B20 temperature sensor, the measurement temperature range is -55-125 degrees, and the accuracy can reach +/-0.0625 degrees. It adopts stainless steel sheath encapsulation, waterproof, anti-corrosion, high temperature resistance, anti-interference, suitable for various harsh environments temperature detection.

The remote measurement and control end point adopts wireless monitoring and alarm GPRS RTU, which is based on the mobile GPRS network platform, embedded with industrial-grade GPRS wireless module, has 4 external information monitoring and alarm functions, connects temperature sensors, and monitors equipment or ambient temperature information at any time. After it changes or exceeds the warning range, send alarm information to the remote server or up to 5 moderator mobile phones to protect the safety of personnel, equipment and property.

Features

◆ Small size, easy to install;

◆ Wide voltage supply range: 5V-30V;

◆ 4 analog inputs, acquisition accuracy: 12bit, default 4-20mA input, (optional 0-5V, 0-30V input), support access to most sensors.

◆ It can be configured to exceed the upper and lower limits of alarm, recovery alarm, repeated alarm, etc., and the alarm content can be modified arbitrarily;

◆ Support up to 5 moderators, send an alarm text message to the moderator when an alarm occurs;

◆ With RS232, RS485 dual serial port;

◆ Serial port transmission supports a variety of protocols, our company's custom protocols and Modbus protocols (ASCII, RTU, Modbus TCP) are perfectly supported;

◆ The data transmission adopts the GPRS module to realize the functions:

◇ GPRS disconnection automatic reconnection;

◇ Up to 6 central servers can be connected at the same time as needed;

◇ Support fixed IP, domain name resolution and APN private network addressing;

◇ Support TCP, UDP, PPP, ICMP, DNS, FTP and other protocols;

◇ The number of nodes supported is theoretically unlimited as long as the server resources allow;

◇ Reduce the cost of wiring and the trouble of construction;

◇ Support SMS data transmission, SMS parameter configuration function;

◇ Support phone and SMS wake-up function;

◆ Support special software for local and remote parameter configuration and maintenance;

◆ Support local and remote firmware upgrade;

The DTU module adopts JY-MD GPRS DTU, which realizes transparent conversion with TCP/UDP protocol through RS232 or RS485 interface based on GPRS network platform. The user uses the AT command interface based on serial communication and is connected to the Internet, which greatly simplifies the user development process.

System software design

The system software consists of the acquisition end point software and the client side software of the monitoring center. The acquisition end point software processes the temperature and other parameters collected by the RTU, and sends it to the monitoring center server through the GPRS DTU. The server software can display the real-time monitoring of the parameters. Data storage, history query and other operations.

Acquisition end point software

The end point is connected to the GPRS DTU through the RS232 serial port, and is controlled by the AT command. The establishment and release of the communication link are controlled by the monitoring center. If the DTU wants to establish a connection with the background, it must tell the Internet Protocol Address or domain name of the receiving end of the DTU. Otherwise dtu doesn't know who to connect with. After the mobile phone logs into the gprs network, the mobile phone will temporarily assign an Internet Protocol Address of the mobile content to the mobile phone, which is different from the address on the Internet. If the Internet Protocol Address is told to dtu, dtu cannot establish a connection with him. However, if you buy a mobile custom APN node sim card and put it in dtu and mobile phone respectively, you can establish direct communication between dtu and mobile phone.

The configuration software is as follows

Communication connection between GPRS DTU and monitoring center

1. Real-time online (maintaining real-time communication with the central end) The power consumption is the largest.

2. The lower computer is triggered by data (the DTU remains in standby state, detects the serial port signal, and then performs GPRS dialing to establish a connection with the center when the serial port has data). This mode is relatively power-saving (but if the lower computer sends data more frequently, it is more powerful than the first one. The first mode may also consume more power)

3. Center call mode (call online by phone or text message, DTU also maintains standby state) This mode is relatively power-saving (but if the host computer calls more frequently, it may consume more power than the first mode)

4. The device is completely shut down, and the lower computer controls the dtu power supply; when the lower computer needs to send data, it will supply power to the dtu. This mode consumes the least power. The defect is that the center cannot actively send data.

Monitoring Center Software

The software display interface is as follows

Real-time display of data and history query can be displayed through the software interface.

Conclusion：

The wireless remote temperature monitoring system based on GPRS DTU has good stability and high accuracy of measured data. The end point of the equipment can also be connected to various sensor devices such as voltage, humidity, pressure, tension, etc., as well as data transmission monitoring in various wide-area environments. Work has an increasing role in unattended industrial environments.