The XC600CX controller family is designed to easily control compressors and blowers simultaneously, both in a normal and a complex compound system. The compressors can be staged, screw, Scroll™ or Stream™. There is also the possibility of controlling two suction circuits with common condensing. The neutral zone control logic depends on the temperature or pressure in the suction line for the compressors and in the hot gas line for the blowers. By means of an optimised rotation algorithm, the operating hours of the loads can be kept at an equilibrium in order to equalise the wear of the loads. Each load of the controller has its potential-free protective contact, the activation of which immediately switches off the output of the load. For optimal safety of the entire system, the controller has 2 additional potential-free digital inputs for the high and low pressure switches, which immediately switch off the entire interconnected system in an emergency.