         Serial.println(argument);
       }
     }
-    else if(command=="e") { // set effect color
+    // set effect color
+    // "e:[000-255].[000-255].[000-255];"
+    else if(command=="e") {
       if(argument.length()==11) {
-        // argument likes "255.255.255"
         e_color_r = constrainValue(argument.substring(0,3).toInt());
         e_color_g = constrainValue(argument.substring(4,7).toInt());
         e_color_b = constrainValue(argument.substring(8,11).toInt());

  if (0<Serial.available()) {
    String command = Serial.readStringUntil(':');
    String argument = Serial.readStringUntil(';');
    
    if(command=="i") { // set instrument color
      Serial.println(command);
      if(argument.length()==11) {
        // argument likes "255.255.255"
        i_color_r = constrainValue(argument.substring(0,3).toInt());
        i_color_g = constrainValue(argument.substring(4,7).toInt());
        i_color_b = constrainValue(argument.substring(8,11).toInt());

      Serial.println(slit_position);
      updateLED();
    }
    // set brightness min value
    // "b:[0.0-1.0];"
    else if(command=="b") {
      // TODO argument check
      // argument is float
      brightness_min = argument.toFloat();
