GPRS RTU rural drinking water application scheme

Abstract: in the middle of a county in Gansu Province, there is drought and little rain, lack of water resources, and the contradiction between supply and demand is very prominent. At the same time, the regional and temporal and spatial distribution of water resources is quite different, and the problem of rural drinking water is particularly serious Especially the problem of drinking water safety. This scheme is designed for the automatic control network in the rural drinking water safety project in the east of a county in the capital of Gansu Province,

Process introduction: the clean water tank in the water purification plant is connected with the water distribution pump room to realize the joint dispatching of production and operation of the water plant. The water transmission and distribution project is equipped with water transmission main pipes and branch pipes to control subordinate towns and villages, and controlled by high-level water tanks. Realize 24-hour continuous constant pressure water supply. After pressurization, the thousand water pipes are sent to the high-level pool in the area. Floating ball valve is installed in each high-level water tank Its function is to automatically close the water inlet when the water level in the pool rises to the limited water level of the float valve. The remote transmission of control signal adopts GPRS technology of mobile communication network The automatic control actuator is "GPRS DTU" "GPRS DTU" shall be connected to the nearest power supply when there is power supply. If there is no power supply nearby or the power supply is insufficient, solar energy and battery shall be used for power supply.

The project adopts the principle of the combination of PLC centralized control in the main control room and RTU data acquisition in the field control cabinet. Monitoring content: two clean water tanks and one water storage tank are added in the water purification plant, and the water level of the tank needs to be monitored; Monitoring contents of water plant pump house: 3 water distribution pumps, 2 water intake pumps, 1 backwash pump and 1 drainage pump. Main pipe in water distribution network: 1 # midway booster pump (3 sets), 2 # midway booster pumps (sets). There are 23 high-level pools and 2 front pools, and the water level of the pool needs to be monitored; Forebay monitoring water flow

Branch main pipe of a town: midway booster pump (2 sets), 5 high-level water tanks and 1 forebay. The monitoring content is the same as above.

Branch pipes in a town: midway booster pumps (2 sets), 9 high-level pools and 1 forebay. The monitoring contents are the same as above.

Branch pipes in a town: 4 high-level water pools to monitor the water level of each pool;

1、 Networking Scheme

The PLC control system of this project should adapt to the characteristics of rural water network construction The control strategy must face the remote control application of different objects in large-span scattered places, and realize various on-site data transmission and processing, remote control, remote maintenance and other problems in large-scale distributed applications. The core of t-process technology is to realize the collection and remote transmission of various data packets, so as to facilitate real-time monitoring in the monitoring and dispatching center.

1. GPRS wireless communication scheme

GPRS is the English abbreviation of general packet radio service. It is a new network service developed on the basis of the existing GSM system. Building a basic GPRS data monitoring system requires: data acquisition and control unit (RTU), GPRS terminal communication unit, SIM card supporting GPRS service, and LN_ Ternet connected data center (computer).

The data of the pump station is collected and monitored by the on-site PLC, and other data collection parts on the site are collected by RTU and transmitted to the monitoring center by GPRS. The remote control cabinet does not need any other devices except system power supply and GPRS RTU and DTU.

PLC control cabinet is equipped with GPRS wireless communication module According to the field water level data collected by GPRS wireless network, the control of the pump station is completed.

2. Composition of the programme system

1) Field control, acquisition point: the field monitoring point collects relevant information by RTU, and the information is sent to GPRS wireless network through GPRS DTU terminal PLC + GPRS mode can receive the data from the monitoring center to control the start and stop of the water pump.

2) Monitoring center: private network connection scheme: the server adopts DDN special line provided by provincial mobile communication company to connect with GPRS network. You can also apply for LP through fixed public network.

3) GPRS IGSM mobile data transmission network: the data collected by RTU is transmitted through China GPRS wireless data network and finally transmitted to the monitoring center

4) Monitoring system software: real-time collection of relevant data of on-site control points, with remote diagnosis, testing and supervision functions, to meet the data collection and control between various industry dispatching or control centers and many remote stations. For example, Kingview, etc

2、 Networking of automatic control part of the project

1. Monitoring principle

The PLC control cabinet only functions when the "manual and automatic" change-over switch of the field control cabinet is in "automatic" and is mainly used to control the automatic start and stop of the pump. The booster pump is equipped with multiple high-level water tanks, and the control mode adopts the water level of the high-level water tank at this level

Control: when the water level of any pool in the high-level pool is lower than the set water level, start the water distribution; Water pump: when the water level of all pools in the high-level pool reaches the set water level, the water distribution pump shall be stopped. Other pumps: start the water intake pump when the water level in the pool is lower than the set water level; Stop the water intake pump when the water level in the pool reaches the set water level.

2. Each network node of the T-Pass automatic control part

1) Water plant and monitoring center. Server1 is the server of the monitoring center, which is equipped with monitoring software, real-time database to manage all data on site, UPS power supply and wall mounted LCD; Server2 is the video monitoring server: client1client2 is two clients. The distance between PLCs in the water plant is relatively close Ethernet communication is adopted to read data from each other. The monitoring contents of the subsystem are as follows: water level data of clean water tank, water level data of reservoir and the status of each pump. The water distribution pump unit adopts the water level control of this level high-level tank.

2) Main pipe in water distribution network. The high-level pool and forebay control the booster pump according to the water level data. 1 # midway booster pump, 2 midway booster pumps with multiple high-level pools The control mode adopts the water level control of the high-level pool at this level. The monitoring content of each water pump is the same as above

3) A town branch pipe. Content: pressure pump. Head pond. Water level and flow, and control the booster pump according to the water level data. The booster pump is equipped with multiple high-level water tanks, and the control mode adopts the water level control of the high-level water tank at this level. The monitoring content of each water pump is the same as above

4) A town branch pipe. Middle tank, high-level tank, front pump. Water level and flow data, and control the booster pump according to the water level data. The booster pump is equipped with multiple high-level water tanks. The control mode is to control the water level of the high-level water tank at this level. The monitoring content of each pump is the same as above

5) A town is divided into high-level water tanks, and the water level of each water tank needs to be monitored: the booster pump is controlled according to the water level data, and the control mode adopts the water level control of the high-level water tank at the same level.