Turn on and cut function details: The table shows the turn on and cut situations as pointer moves deasil, and the function is opposite while the pointer moves widdershins.

表中描述的开是表示：仪表压力指针位于小刻度值时所具有的开，压力指针从小刻度值开始顺时针动时的开状态，当压力指针逆时针转动时，实现的开相反。