Case introduction: Our company has undertaken an automatic control system for sewage treatment in a certain factory. The system control is implemented in three layers: the basic control layer, the on-site control layer, and the remote monitoring control layer. The central control system mainly adopts Siemens S7-1500 series PLC, Siemens switch, 12 inch intelligent touch screen and other components.

Basic control: Basic control has the highest control priority, and when the control mode is in manual operation, PLC control is blocked. On site equipment can be manually operated and inspected on the control cabinet. The control cabinet provides basic control, and in the event of a PLC system malfunction, local manual operation can still be used to start/stop the controlled equipment.

On site control layer: When the equipment is in the debugging and commissioning stage or the fault maintenance stage, the equipment can be started/stopped on the on-site operation box to achieve close observation of the equipment's operating status, without the need to run to the control room to start the equipment.

Remote monitoring and control layer: Send instructions on the upper computer or use the logic control function of PLC based on instrument data to provide equipment start stop and key equipment linkage, chain control, etc.

Single action control: In the control terminal screen, single action control can be selected to directly control the start and stop of each water pump and controlled equipment unit.

Linkage control: Linkage control can also be selected on the control terminal to enter automatic control mode based on parameters measured by sensors and pre-set modes. For example, the liquid level gauge controls the start/stop of the sewage pump; Automatically control the operating status of the Roots blower based on the parameters measured by the DO online instrument; The operation timing of each process link can be set according to the requirements of the process, etc.

The upper computer configuration adopts Siemens Botu WINCC configuration software, which can monitor the operating status of process equipment, collect and monitor process parameters, remotely control relevant equipment, and set operating parameters. Implement functions such as report printing and accident alarm printing.

Case details: