FOXBORO CM902WX USA

FOXBORO CM902WX USA Description:

Characterization

PLC function instruction end high - voltage inverter PID closed-loop control

The requirements of closed-loop control of frequency converter put forward by users on site are as follows: frequency converter can automatically adjust the speed of frequency conversion pump according to the change of water consumption of the user system, ending the constant pressure water supply of pipe network;Together with the LCD can be set pressure target value.

According to the user's requirements, the PLC is equipped with special modules fx2n-4ad and fx2n-2da.Fx2n-4ad is an imitation input module with four input channels and a maximum resolution of 12 bits. The imitation input is planned to be -10v ~ 10V or 4 ~ 20mA.Fx2n-2da is a simulated output module, with 2 output channels and a maximum resolution of 12 bits. The output value of the simulated value is planned as -10v to 10V and maybe 4 to 20 mA.In this way, through reading instructions (FROM) and writing instructions (TO), as well as PID closed-loop control function instructions carried by PLC, it can end the PID closed-loop control of pipe network water pressure at the user's site.

The detailed programming process is as follows :PLC reading instruction (FROM) reads the response value of the user's water pressure, and the response value is stored in the D12 data address of the PID instruction with the moving instruction (MOV);The user's water pressure setting value is stored in the D10 data address in the PID command with the move command (MOV);D200 ~ D222 saves working parameters of PID;D14 is the operation value output of PID instruction. The PID closed-loop operation result D14 is written into the simulated output module through the writing instruction (TO) of PLC, and then converted into the simulated signal of -10v ~ 10V or 4 ~ 20mA into the high-voltage inverter controller for frequency setting.

The water supply network of the sewage treatment plant of pangang is huge, and the water pressure of the pipe network is slow to change the speed of the pump. Therefore, the calculation speed of PID should not be too fast, that is, the proportional dispatching should not be too fast. Otherwise, if the water pressure of the pipe network is suddenly changed too much, the frequency converter's dispatching simply constitutes a long time of vibration.According to this situation, as shown in figure 3, you can participate in the PLC control program PID distance accounting time (T0) and PID operation dead zone (M0), so that the PID accounting speed scheduling can be consistent with the pipe pressure change speed, to avoid the pipe pressure shock.

Conclusion

High voltage frequency converter bypass cabinet bypass logic control with PLC to automatically through work in pangang's sewage treatment plant of light high voltage frequency converter to simulate fault description, high voltage inverter automatic bypass cabinet in the transfer from variable frequency power frequency, frequency shift frequency of mutual switch is very convenient, can end within 10 s, greatly advance the reliability of the pump.The field PID closed-loop control effect is very ambitious, the water pressure is not firm very small, not firm beyond 0.1kg, frequency converter can sensitive regulation speed, the water pressure control in the setting and planning, the regulation speed will not occur any vibration.Through the serial port rs-232 communication between PLC and the controller of high voltage inverter, the system pipe pressure and various state quantities of PLC can be supervised on the LCD screen of high voltage inverter.

Packing and delivery items

Packing: Brand new and original in box

Lead time: 2-3 days against the payment

Terms of payment: Telegram transfer

Warranty: 1 year

Minimum order: 1

Contact Details

Email: sales6@cambia.cn

Mobile: +86 18030270289

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