求翻译：4、仪器使用前，先将调速旋钮置于最小位置，关“振荡开关”和“电源开关”，并向工作室内加入洁净的自来水，水面最少将托盘沉入水中5厘米以上。是什么意思？

4, the instrument before the first speed control knob placed in the minimum position, off "oscillation switch" and "power switch", adding to the work room clean water, the water sinking into the water tray at least more than 5 cm.

Before 4, apparatus used to adjust the speed knob is placed in the small location, " " and " oscillating switch power switch" to work, and indoor joined clean tap water, the water surface at least 5 cm above the tray sinking into the water.

4th, before the instrumentation, will modulate velocity the knob to put in the smallest position first, the pass “vibrates the switch” and “the power switch”, and joins the pure running water to the work room in, water surface most major general the tray sinks to in the water above 5 centimeters.

4, apparatus before use, first speed control knob to the minimum position, turn off "oscillation switch" and "power switch", and to the Studio to join clean tap water, the water tray sank into the water at least 5 cm or more.