As the name Schreiber FlexControl implies, the Schreiber process control system is very flexible, yet simple to operate. With the FlexControl, there are 5 standard levels of control. The Scheiber concept is to select the least complex and least expensive level of control that will produce the degree of treatment required for each facility by the NPDES permit. Keep it simple wheneever possible!
Level 1 is the least complex, while level 5, the most complex, produces the highest degree of treatment. For those installations where only a simple "DO mode" type process control is required, the SFP level 1 would be specified. If the permit severely limits the amount of Phosphorous in the effluent, then a level 5 SFP control would be a wise choice.
Regardless of the level selected, once the system is in place and operating, the PLC collects the monitoring signals, does all of the necessary computing/evaluating and sends the controlling signals to operate the plant automatically. Fail-safe back up systems are incorporated into the SFP to handle PLC outages and other emergency-type situations, and the process is easily upgradable.