Aerotank Mixer for Biological Wastewater Treatment Plant
Software and hardware complex for an automated process control system for biological wastewater treatment of Kaustik OJSC, Sterlitamak
The process control system of biochemical wastewater treatment - the aero-mixer - is a software and hardware complex in which the tasks of monitoring and controlling the technological process and the condition of the equipment are solved at the following levels:
• at the level of primary controls and controls (local devices, sensors, transducers, actuators);
• at the level of the controller of technological objects Modicon Premium;
• at the level of the automated workplace of the operator.
The controller of technological objects implements the functions:
1. Collection of information on measured and monitored parameters and equipment condition (sensor polling)
2. Equipment control;
3. Primary information processing:
• control of reliability;
• comparison with settings;
• word formation of events (state, accident, precaviation).
Video frame of the general technological scheme of biological treatment facilities
The following functions are implemented at the operator station level:
1. Display all current information.
2. Registration of information in the event log.
3. Control of technological parameters and equipment condition:
change of color and parameter when it exceeds the permissible limits (pre-emergency condition, accident);
• change of equipment color depending on its state (in operation, stopped, accident);
• change of settings on measured and monitored parameters;
• sound alarm.
4. Management of technological equipment.
5. Compiling reports and summaries, the ability to present data in graphical form.
6. Permanent recording of all events in the archive with the possibility of subsequent viewing.
7. Display of complex diagnostics.
The operator station is a software and hardware complex.
The hardware consists of a personal computer, a hardware key for working with the Citect v. Software package. 7.0 (USB port).
The software runs on Windows XP SP2, and consists of an OPC-server OFS (for communication with a Modicon Premium controller) and an application written using the SCADA Citect v tool package. 7.0.
PTK performs continuous diagnostics of input / output channels, controller status, data transfer channel and operator station.
Diagnosing I / O channels includes:
• detection of an analog sensor open circuit with a 4-20 mA signal;
• detection of the disconnection of the power supply circuit of a discrete sensor;
• diagnostics of parameters beyond the limits.
Diagnosing the status of the controller includes determining by the built-in means a failure of a typical replacement module.
Diagnosis of data transmission channels includes:
• diagnostics of the connection status;
• detection of link breakage.
Diagnostics of the operator’s station are carried out by the built-in tools of the Windows XP operating system.