求翻译：例3： 主机低位放置时，若出液面低于体腔0.5米，于使腔内实际压力为10KPa，则设定压力为10 KPa+5KPa=15 KPa。当灌注泵运行至腔内显示压力为15 KPa时，腔内实际压力为15 KPa-5 KPa=10 KPa.是什么意思？

Example 3: Host low placed, if the body cavity of 0.5 m below the surface, the actual pressure in the cavity for the 10KPa, then the set pressure of 10 KPa +5 KPa = 15 KPa. When the infusion pump to the chamber pressure of 15 KPa show, the actual cavity pressure is 15 KPa-5 KPa = 10 KPa.