Ankerui Qingqing
Jiangsu Ankerui Electric Appliance Manufacturing Co., Ltd. Jiangyin, Jiangsu 214405
Abstract : According to the problems existing in the traditional water pump control method, a multi-loop intelligent water pump controller is designed. It has many control methods such as on-site manual control, back-end remote control and also automatic control.
Keyword: Pump Controller Water Supply/Drainage Manual/Level Automatic Control
Abstract : According to the construction and factory water supply and drainage application, the paper puts forward a multi loop smart pump controller, the controller requires control of water supply and drainage equipment can replace the traditional manual control, with the scene in a variety of ways, The background of remote control and automatic control of liquid level, and on / emergence of the pump is running under voltage, over / underload (dry), protective effect of phase failure and external failures, also has the function of communication can pump operation information Uploaded to the industrial automation DCS system and the building of intelligent BA system .
Keywords:water supply and drainage pump controller / manual / automatic control of liquid level
0 Â introduction
In production automation applications and buildings, there are a large number of fans and pumps. For cost considerations, buttons and thermal relays are commonly used as control and protection components. The thermal relay itself has design flaws, poor repeatability, low reliability and hidden protection hazards. The traditional water pump control methods have the disadvantages of complicated control circuit, single function, and difficult maintenance in the later period. Therefore, the traditional water pump control obviously cannot meet the functional requirements of informationization and intelligence. With the development of microcontrollers, the maturity of measurement and protection technology has also changed the application of traditional water pumps, from the button indicator to the current integrated intelligent controller.
1 Function of Intelligent Pump Controller
The functions required by the intelligent controller include: voltage, current, level (switch or analog) measurement functions; over/under voltage, phase sequence, overload, underload (dry run), and fault protection functions; manual/ Liquid level control function; alarm function of water pump operation fault and liquid level abnormality; management function of water pump operation information; communication function with upper computer system.
1 .1 master chip
The MCU chip uses a 32-bit processor MCF51EM256 from Freescale's Coldfire-V1 (with hardware multiply-accumulate MAC unit) architecture core, clock frequency up to 50.33MHz, built-in 256K Flash, 16K RAM, 3-way timer, 3-way SCI communication interface, built-in RTC clock, I2C, SPI, KBI interface and other resources, on-chip integration with programmable delay module PDB and four 16-bit SAR ADC, PDB can directly control the trigger ADC sampling, complete the high precision The voltage and current AC sampling and liquid level measurement can reach a measurement accuracy of 0.5, which has a very high cost performance.
1 . 2 Â Voltage, current, level signal acquisition circuit
Voltage acquisition circuit shown in Figure 1. The three-phase voltages Ua, Ub, Uc adopt the way of resistance depressurization, and add the raised voltage VREF to the sampling signal so that the amplitude of the AC signal is greater than zero, which facilitates AD sampling. At the output of the circuit, a voltage limiting diode is added to the AD input of the MCU chip to limit the input voltage to less than (clamping voltage) 3.3V, which can provide good protection for the AD sampling channel of the MCU chip.
Figure 1 voltage acquisition circuit
     The general acquisition circuit of the liquid level signal is shown in Fig. 2. When the liquid level sensor is a two-wire 4-20mA interface, it requires our controller to output a 24VDC power supply and install the resistors R22 and R45. When the level sensor is a three-wire 4-20mA interface, the sensor power supply is provided by an external switching power supply and resistors R44 and R45 are installed. When the liquid level sensor is 0-10V interface, install resistor R44 (0Ω), R45. Similarly, a protection circuit should also be added at the liquid level acquisition channel.
Figure 2 level signal acquisition circuit
2 traditional water pump control
In the control loop of the traditional water pump, usually the main circuit consists of circuit breakers, contactors and thermal relays; the control loop is generally composed of indicators, meters, control buttons, transfer switches, thermal relays, and time relays. The traditional water pump control method has complex internal wiring, which makes it difficult for the maintenance personnel to debug the equipment and find the wrong wiring, and the functions are generally relatively simple. The intelligent transformation cannot access the system and increases the subsequent equipment investment. Â Â
The intelligent water pump controller integrates the electrical components required for the water pump control, including voltage and current display, multi-function protection relay, hand/automatic transfer switch, start/stop button, water level and status indicator of the water pump equal to one, and cabinet type installation. In the automatic water supply/drainage mode, the two pumps alternately prepare each other. According to the different water levels, the control mode supports the operation of one pump in the middle water level, and the two pumps in the high (low) water level run simultaneously. The current protection supports independent on/off settings to support the standby pump to only alarm without tripping, and to meet the application requirements of fire places such as underground garages and fire hydrants. The secondary wiring diagram of the intelligent pump controller is shown in Figure 3. Compared with the traditional method, it has the advantages of simple wiring, powerful functions, and easy upgrade in the later period.
Figure 3: Intelligent pump controller with a full pressure start level controller control circuit diagram
4 Performance Comparison
The intelligent controller can effectively solve the problems of low safety and reliability of traditional water pump control, large control box size, high energy consumption, low intelligence, and difficult upgrade. The performance of the traditional control box and the intelligent water pump control box is shown in Table 1.
Table 1 Comparison of control performance of traditional control box and intelligent water pump control box
5 Application
Subways, underground stations, or bridge tunnels, due to seepage or rainfall, cause a large amount of accumulated water, seriously affecting the work and people's normal travel, and require regular or irregular pumping and drainage. Requirements: two sewage pumps to achieve the discharge of the pool water treatment; two sewage pumps to work alternately to prevent corrosion stuck; the current work of the sewage pump failure, the standby pump can automatically input; when the collection pool When the water level is running, one pump runs. When the water level is high, the two pumps run simultaneously. When the catchment tank is at a high water level, the water level alarms; it has a low water level, a medium water level, a high water level, an alarm, and a fault indicator. According to the requirements, two water pump level control installation methods are designed, as shown in Figure 4.
Fig. 4 Installation of two pump liquid level controls
6 Conclusion
The water pump control management system, which uses the intelligent water pump controller as the core, replaces the control scheme of the traditional or PLC program, realizes unattended automatic water supply/drainage functions, and has rich protection functions, making the water pump operation safer.
Article Source: "Electrical Applications" No. 2 of 2015
references
[1] GB50015-2003 Design Code for Building Water Supply and Drainage [S]
[2] JGJ16-2008 Civil Building Electrical Design Specification [S]
[3] Du Yiwei, Yan Houwei, Jin Dan. New motor control module technology and application [J]. Construction Electrical, 2011, (06).
[4] Jia Guofang. Research on intelligent monitoring technology of water pump online[J]. Drainage and Irrigation Machinery. 2005(06).
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