How can i calculate the correct value of the RMS in simulink?

Hej, I have a buck circuit in simulink and i am using the voltmeter and the ampmeter block to get the current. I also collect the RMS and the minimum value. However,

When i display the values of both the RMS and the minimum value it keeps changing even though i did not modify anything in the circuit. I tried using a function block instead and modify the sampling time but it also did not work. What i want is the claculation of the RMS and Min at steady state (it should be a constant value). So how can I do a calculation of the RMS and Min at steady state correctly?