A Proprietary technology, developed by CAS, allows the automatic control of CP installations via macro cell currents measured during the operation of CP. Macro cell currents are measured with macro-cell sensors (CorSensys AG, CH) as shown on the picture above left. 
Negative macro cell currents are anodic and indicate corrosion, positive currents are cathodic and indicate full corrosion protection.  In the picture above right, the macro cell currents measured within a research project (KKS-St. Marx) before and after implementing automatic control.  Except during depolarization measurements, during which the protection current is turned off and except for one short period, anodic macro cell currents are completely eliminated.
The automatic closed loop control regulates the applied voltage such that macro cell currents remain in the range of 0,0 - 0,1 µA/cm2.