It often happens, when protecting a structure, that the potential of the object is different on location. So, in order to solve this, it is possible to place more reference cells and have the Amstel rectifier regulate on the average potential in the limits of its maximum and minimal values.

To save time and operation cost it is the best solution to control the rectifiers by GSM in combination with the Amstel in the Cloud, in order to have synchronized timer operation.  

Amstel 2 to 4 for ICCP on ships with separated LB and SB Cathodic Protection. The problem that occur frequently in harbours is that the systems fail when a single rectifier is used.