Application of the hottest soft starter in urban r

Application of soft starter in urban rainwater drainage station

1 introduction

the drainage basin of rainwater drainage station is the concentration of rainwater, domestic sewage and industrial sewage. In order to ensure that the liquid level in the drainage basin is maintained within the allowable range, the sewage pump unit is automatically controlled by detecting the liquid level in the drainage basin to ensure the normal discharge of water in the sewage Chinese wood pulp inlet structure. There are six sewage pumps in this station. Different liquid levels can be set for each pump to control the work, and centralized monitoring is carried out in the central control room

2 composition of the system

the central control room is equipped with an industrial control computer and configuration software, which is remotely transmitted to each soft starter control cabinet in the pump room through RS-485 communication bus. CMCs soft starter of Xi'an Xichi Electric Co., Ltd. (this soft starter integrates RS-485 communication bus and supports various configuration software and bus forms. It currently supports MCGS, Kingview and PROFIBUS-DP bus.) The liquid level sensor is input to the CMCS soft starter analog port and can be uploaded to the central control room through the starter RS-485 communication port

3 network composition and group

rs-232/rs-485 communication module is directly inserted into the RS-232 serial port of the computer. RS-485 mode is adopted between CMCs soft starter and communication module. The connection diagram is shown in Figure 1

Figure 1 connection between soft starter and communication module

3.1 connection between CMCs soft starter and communication module

in RS-485 multi machine communication network, the "S1" switch on the main board of the first and last soft starter is turned to the "on" position, the 120 Ω terminal resistance is connected to the communication line, and the "S1" switch of the middle soft starter is turned to the "off" position. To suppress signal reflection, as shown in Figure 2

Figure 2. The address setting of the main board switch and communication port

cmcs soft starter is set by the dial switch S2 on the main board of the soft starter. The first five dial switches set the address of the soft starter in the RS-485 network. As shown in Figure 3, "1", "2", "3", "4", "5" dial switches are all in the "on" position, the address of the soft starter is "0", and the maximum address is 31. The last three digit dial switch is a parameter switch that allows to set the sales volume of nanofiltration membrane, ultrafiltration membrane and energy membrane products. As shown in the figure below, "6", "7" and "8" dial switches are all in the "off" position to protect the sensor collision. It is allowed to set the parameters of the soft starter, otherwise it will restore the factory value: it should also be noted that the addresses of each CMCs soft starter cannot be set the same, and the communication baud rate needs to be set the same, Otherwise, there will be communication errors

Figure 3 code pulling switch s2

3.2 control configuration diagram of single soft starter control cabinet

the main circuit of control configuration of single soft starter control cabinet is shown in Figure 4

Figure 4 main circuit diagram of control configuration of single soft starter control cabinet

4 macro function principle of soft starter and parameter setting in liquid level control

(1) macro function

after the soft starter start command is effective, the motor start and stop function is controlled by programmable digital or analog port input signal. The analog signal is the upper and lower limit proportional control mode. C05= options are positive logic in the macro control upper and lower limit functions, closed below the lower limit (start), disconnected above the upper limit (stop), c05= options in the macro control upper and lower limit functions, such methods will also increase the number of moisture-proof surfaces, which is reverse logic, closed above the upper limit (start), disconnected below the lower limit (stop)

(2) liquid level control

macro function is used, and the analog signal is the upper and lower limit proportional control mode. Advanced parameter C06 selects A1 upper and lower limit input control, C05 analog port input mode selects c05=5, liquid level analog signal A1 port input, C08 and C09 are the upper and lower limit settings of liquid level

5 programming and configuration of computer control software in the central control room

the monitoring program is compiled with MCGS configuration software of Beijing Kunlun power. The operator only needs to click the corresponding menu to realize remote operation in the control room and monitor the liquid level, motor current and starter status in real time. The operation control of sewage pump set has manual/automatic mode. The automatic mode can automatically control and configure the soft starter parameters and operation of all pumps according to the liquid level, and different automatic control procedures can be selected according to different seasons or periods. For example, 1 ＃, 2 ＃, 3 ＃, 4 ＃ pumps use the macro function of soft starter, and the upper and lower limits of liquid level height are set differently to improve the use efficiency of pumps. 5 ＃, 6 ＃ pumps can be used as standby. When a pump fails, the monitoring program automatically configures the parameters of 5 or 6 pump soft starter to put it into operation. The manual mode directly controls the parameters and operation of any soft starter. You can also choose the working mode of different soft starters

6 conclusion

using this system can improve the automation level and reliability of the system, so users can save the input/output module and the mold in/out module required to control the soft starter in the DCS system, and save money