Detail from the wiring diagram of a wastewater treatment plant (WWTP)
Moduls of a PLC
- The central control of operation sequencing takes place with the help of a switchgear cabinet, which has an programmable logic control (PLC). By changeable operating parameters the personnel of the sewage purification plant can consider different operational situations and can select for example between a single-stage and a multi-stage operation.
- The partial or also entire operation of the plant can be fully automatic implemented.
- The individual limit values, e.g. for the oxygen or the period of time of the nitrification and denitrification phases, are adjusted at the operating panel of the PLC, e.g. a SIMATIC panel by Siemens.
- The visualisation and archiving of the individual characteristic values can be realized with a screen writer, e.g. the (paperless) Memograph by Endress+Hauser.