Summary of GPRS DTU related problems (New)

1. What does GPRS DTU mean

GPRS DTU is a wireless data terminal of Internet of things, which provides users with wireless long-distance data transmission function by using public operator network It adopts high-performance industrial 8 / 16 / 32-bit communication processor and industrial wireless module, takes the embedded real-time operating system as the software support platform, and provides RS232 and RS485 (or RS422) interfaces, which can be directly connected to the serial port equipment to realize the transparent data transmission function.

2. What are the functions of GPRS DTU

The most important function is the transparent transmission of data, which realizes the remote data acquisition, transmission and control together with RTU, PLC, sensors and other equipment.

3. Common networking modes of GPRS DTU

Scheme 1: the central server adopts the fixed IP address of the public network, and jy-dtu-g and jy-dtu-c series GPRS DTU directly access the Internet host through the IP address.

Scheme 2: the central server adopts dynamic public network IP + dynamic domain name resolution software such as ADSL. Jy-dtu-g and jy-dtu-c series GPRS-DTU resolve the IP address of the central server through DNS to complete two-way communication. This method can greatly save the cost of public network fixed IP, but the stability is subject to the stability of DNS server, so we should find a reliable DNS service provider. This scheme is suitable for small-scale applications.

Scheme 3: the central server adopts dynamic public network IP such as ADSL, IP resolution server software + GSM modem, gr100 series GPRS-DTU dial-up and send information to the IP resolution server. The IP resolution server completes two-way UDP communication by sending the information back to the host IP address. This method can greatly save the cost of fixed IP in the public network. This scheme is more stable than scheme 2, does not need a stable DNS service provider, and has higher security and stability. If dynamic public network IP such as ADSL is adopted, customers are recommended to use this scheme.

Scheme 4: the center adopts jy-dtu-g and jy-dtu-c series GPRS-DTU or gprs modem, and the whole network adopts mobile APN private network fixed IP. In this scheme, customers first apply for APN private network service with mobile. Mobile assigns a special APN to customers, and ordinary users are not allowed to apply for the APN. The SIM card used for GPRS private network only opens this special APN, and the use of other APNs is limited. After obtaining the APN, assign mobile internal fixed IP to all monitoring points and centers. However, compared with scheme 2, this scheme does not need DNS resolution. It has mobile intranet fixed IP, reduces intermediate links and enhances stability; All data are transmitted in the APN intranet of mobile gprs without going through the public network, and the security is enhanced. This scheme does not need to bear the monthly rent of the special line. It is cost-effective and recommended.

Scheme 5: the center adopts APN dedicated line, and all points adopt intranet fixed IP. In this scheme, the customer center is connected to the GPRS network of the mobile company through a 2m APN special line, the private fixed IP address is used for wide area connection between the interconnection routers of both parties, and the GRE tunnel is used between GGSN and the interconnection router of the mobile company. Assign a special APN to customers, and ordinary users shall not apply for the APN. The SIM card used for GPRS private network only opens this special APN, and the use of other APNs is limited. After obtaining the APN, assign mobile internal fixed IP to all monitoring points and centers. End to end encryption is adopted between mobile terminal and server platform to avoid possible leakage of information in the whole transmission process. Both parties adopt firewall for isolation, and filter IP address and port on the firewall. The security and stability of this scheme are greatly improved compared with the previous schemes, and it is suitable for the application environment with high security requirements, more data points and high timeliness requirements. The best networking mode when funds allow.

4. What are the application fields of GPRS DTU?

Power monitoring, oilfield monitoring, remote meter reading, street lamp monitoring, environmental monitoring, meteorological monitoring, water conservancy monitoring, heat network monitoring, electricity meter monitoring, machine room monitoring, traffic indication, coal monitoring, earthquake monitoring, vehicle guidance, water supply monitoring, expressway monitoring, real-time noise monitoring, monitoring of key pollution sources of environmental protection, real-time transmission monitoring of water supply pipe network Automatic remote control system of power distribution network.

5. What product is SMS DTU?

Short message DTU is based on mobile phone network and transmits data in the form of short message, which can realize reliable transmission in places covered by GSM network; The setting of the computer in the system center is flexible, and it can even be received directly by personal mobile phone without computer, which is suitable for applications that need to receive data anytime and anywhere; User interface RS232 / RS485 dual serial port.

6. What is the actual GPRS data transmission rate of DTU?

Maximum downlink transmission rate: 85.6 Kbps, maximum uplink transmission rate: 42.8 Kbps.

7. How to connect GPRS DTU to configuration software

In the configuration software, DTU product drivers from many manufacturers have been integrated. In the process of user development, you can first use wired research and development, and then develop all functions on the configuration software. You can change from wired mode to wireless mode with a simple modification. There are helpful instructions in the configuration software.

8. Is GPRS DTU a GPRS receiver

Strictly speaking, not a receiver. GPRS can communicate in two directions. The principle of logging in GPRS with mobile phone is the same. The essence of communication is to establish a socket connection with the central software, and then send and receive data.

9. How many ways can GPRS DTU communicate with the center in practical application?

◆ real time online (real-time communication with the central end) this way, the power consumption of each DTU will be different, but it is undoubtedly the largest power consumption.

◆ data trigger of the lower computer (DTU keeps in standby mode, detects serial port signal, and establishes connection with the center by GPRS dialing when there is data on the serial port). This mode is relatively power-saving (but if the lower computer sends data more frequently, it may consume more power than the first mode)

◆ center call mode (call online through telephone or SMS, and DTU remains in standby mode). This mode is relatively power-saving (but it may consume more power than the first mode if the upper computer calls more frequently)

◆ the equipment 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 has the lowest power consumption, and the defect is that the center cannot send data actively.

10. What's the matter with GPRS DTU serial communication mode

GPRS DTU provides serial communication interfaces, including RS232, RS485, RS422, etc., which are common serial communication methods. Moreover, GPRS DTU mostly designs the serial port data as "transparent conversion", that is to say, GPRS DTU can convert the original data on the serial port into TCP / IP data packets for transmission without changing the original data communication content. Therefore, GPRS DTU can be connected with various user equipment using serial communication, and there is no need to change the user equipment.

11. Can GPRS DTU transmit video now?

GPRS is poor, and it will be stuck. Can't do real-time monitoring. But you can make do with low requirements. 3G DTU can be used.

12. What is GPRS DTU heartbeat packet

Heartbeat is a symbol that GPRS DTU remains permanently online. In fact, the heartbeat time of GPRS DTU is a link maintenance parameter, that is, the time interval of heartbeat packet transmission. DTU periodically sends heartbeat packets in fixed format to DSC (Data Service Center). After DSC receives heartbeat packets, it will give DTU confirmation information, so as to maintain the link connection between DTU and DSC and maintain the link survival, Ensure that DTU is always online.

13. Response problem of GRPS DTU heartbeat packet

Heartbeat packets generally have only one byte, which is used to maintain the connection (generally, there is no data transmission and reception for 15 minutes, and the IP will be recovered and redistributed by the operator). As for how to deal with it, it depends on what your center needs to do. Generally speaking, it is useless to update the last communication time of the connection.

14. What is the main working principle of GPRS data transmission module?

GPRS data transmission module is the main application part of GPRS DTU. It is an industrial wireless data transmission equipment. It provides users with the function of transparent TCP wireless long-distance data transmission or transparent UDP wireless long-distance data transmission through mobile GPRS network.

15. How to solve the problem of public IP in GPRS DTU test

Use Telecom broadband to access the Internet, obtain a temporary IP address, obtain the local public network IP, use a TCP server software as the server side, open a port, and the operating system firewall opens an exception port for this port.

16. Why does GPRS DTU use the SIM card of private APN access point much slower than that of public access point?

The SIM card of the private APN access point is first connected to the public network base station to access the APN. Because there is an additional layer of authentication and exchange process, the time will be slower than the original, which is up to tens of seconds slower.

17. Can GPRS DTU data center only use wireless network card to access the Internet?

Dynamic domain name resolution or fixed IP can be done after the data center has public IP.

There are many public dialing networks that need ADSL domain name resolution.

18. Transmission problem of GPRS DTU

GPRS DTU is automatically connected, permanently online, and transparently transmits data point-to-point.

19. If GPRS is used for networking, do you use GPRS DTU or GPRS module? Which development cycle is short.

The development cycle with DTU is shorter than that of modules