The application of Yitian domestic PLC in the measurement and control system of PH value in sewage treatment plant

I. Introduction

Equipment process flow is: primary filtration (3 minutes, can be set) - filtration (6-12 hours, can be set) - water (3 minutes) - gas red (5 minutes, can be set) - gas water ( 8 minutes, can be set) - water (4 minutes, can be set) - back to the initial filter

In the automatic state, if there is a call after the power failure, the system will first close all the valves and then cycle according to the system flow.

Second, the system composition

The sewage treatment electric control system adopts the centralized control method, adopts Yitian programmable controller, and the system runs stably and reliably. The electronic control system is divided into main electric control cabinets and HMI man-machine operation, operation buttons, solenoid valves, trunking and wire and cable. The operation of the device is performed on the touch screen on the operation handle. The touch screen has a Chinese operation interface of the device, information such as startup operation, parameter setting, current operation status, and fault information.

The man-machine interface adopts K-TP170micro of Siemens company, the programmable controller is used for Yi Tian system PLC, (ETMX-MSDH32DC-T+ ETEM-DH16+ETEM-AH6-V)

Three-color indicators are installed on the man-machine interface console. When the indicators are on, the meanings are as follows:

Red ----------- device is faulty

Yellow ----------- The device is at the origin

Green ----------- The device is in operation

When there is a fault, the buzzer on the operation console will show intermittent alarms.

In the event of an emergency, the "system emergency stop" button on the operating handle can be pressed.

Third, the program control part

Turn on the pump

Open flocculation pump

Turn on the fan

Turn on the mixer

Start automatically

Filtering time or system pressure exceeds the upper limit

Recoil signal

Start filter conditions

Initial filtration time

Filter time

Air time

Fourth, summary

Yitian PLC, its PLC's excellent performance and stability, good performance in frequent motion control, provides a better cost-effective, greatly saving the cost for the user.