Refer to the attached example. In order to understand the interface of the controller with the transformer, the following information needs to be considered:

• Based on the fact that we consider a digital controller, a clock signal is required. The frequency of the clock signal can be set up by the user with the help of the dedicated user dialogue of the clock element.
• The voltage controller within the example is a simple proportional-integral controller.
• The key function for this controller is the event function, see also the following description, where the function will trigger each time when the "trigger" variable changes from negative to positive values:

1. syntax: event(condition, trigger, 'name=xxx dtime=...')
2. function: emits event named xxx if trigger signal changes sign from - to +
3. function triggers only if condition is true (=1);

• The output of the controller is the variable nntap_int of the transformer. In contradiction to the "nntap" variable which you can access via the transformer input dialogue this internal variable could have any non-integer values. The interfacing to the desired transformer is realized by the event object which is stored inside the corresponding DSL controller element. It could be accessed by using the Events button of the DSL model user dialogue. Note, that the event name has to be the same as in the related DSL model script. The required link to the transformer is realized by the element target.