Ideal operational amplifier
The Op-Amp block models an ideal operational amplifier (op-amp). If the voltage at the positive pin is denoted by Vp, and the voltage at the negative pin by Vm, then an ideal op-amp behavior is defined by Vp = Vm. In other words, the op-amp gain is assumed to be infinite. By implication, the current from the Vp to the Vm terminal is zero.
The Op-Amp block has no parameters.
You can initialize the Current into output node variable prior to simulation. For more information, see About Variable Initialization.