Setting reading frequency SCT013 current sensor code using Arduino Uno
you skip reading when the last read is less than 1000/200 = 5ms ago.

unsigned long lastRead;

void loop()
{
   unsigned long currentMillis = millis();
   if(currentMillis - lastRead &gt;= 5){

      double Irms = emon1.calcIrms(1480);  // Calculate Irms only

      Serial.print(Irms*230.0);        // Apparent power
      Serial.print(" ");
      Serial.println(Irms);            // Irms
      lastRead = currentMillis;
    }

}