The present invention provides a solution for optimizing the transport capacity of an elevator system. In response to the persistence command, a transaction with an instance store can be initiated. The performance of this type of a circuit is very temperature dependent but it can be compensated for temperature related changes in the output or load RMS voltage by means of preventing variations in the trigger angle the circuit is running at. A first comparison is made between a first link utilization parameter and first and second link utilization threshold parameters.