Environment / Scraper control system

Conceptual formulation: There were 2 circular and 2 long basins to be controlled during the final purification in the plant. The circular and long scrapers are to push the floating sludge from the basins into the pumping ducts. Attention had to be given to the fact that during this process the long scrapers move in opposite directions. The sludge level is to be displayed decentrally. The duct pumps are to be controlled according to sewage levels. The filling of the ducts is to first take place when the circular scraper is on level with the intake fitting and when the long scraper is in the end position. All single ducts are to be pumped into a collecting duct. The collecting duct is to be emptied depending on the time of year.

Implementation: Each scraper and the pumping house was equipped with a PS 4-201-MM1-control system from Moeller GmbH. Each control system functions decentrally alone as master. These control systems were connected via the Moeller K-Bus, in order to implement the interdependence i.e the movement in opposite directions of the long scraper and the data transfer of the sludge level amounts. The pump house PLC functions as a distributor. This means that it collects all of the data and transfers it further to the other PLC's and to the higher level lead system.

Environment / Raw sewage

Conceptual formulation: The raw sewage trucks enter the purication plant and confirm their identify with a barcode-card at the gate. The system checks the card for authorization and upon verifcation opens the gate. The raw sewage is released into a collecting basin. There it is checked for redox levels, salt content, weight, etc. When the levels are within the acceptable limits the raw sewage is released into the plant and the data is transferred to be processed and saved.
The personnel is to enter all of the current levels into a database. The personnel is to also assign a barcode and required authorizations to companies and enter the data into the database. All entries are entered into user friendly masks. All important values are to be saved and called up as a graph. The entire plant is to be displayed in the system.

Implementation: A Simatic S7-300 with a CPU 315-DP was used. This communicates with a S7-400 via profibus FMS that was already available.The barcodes were read into the software by the barcode reader from Deltalogic GmbH via a RS-232 interface from the CP-340 component.
The program WIN-CC, version 4.0 from Siemens AG, was used to display the intake of raw sewage. The company data, target values, and authorizations were processed with MSAccess. The entry masks were developed in MS-Visual-Basic.