A difficulty arises when the point and instrument are not at the same level. 當測點和儀器不在同一水平面上時，工作就會遇到困難。
The gas thermometers with capillaries facilitate separation of the display unit from the measuring point. 帶有毛細管的氣體溫度計把顯示單元和測量點分開了。
Owing to the high cost of wiring, most process plants have hundreds or even thousands of discrete measurement points that are not connected to the control system. 由於配線的成本很高，許多過程工廠擁有數百或數千離散測量點，與控制系統相連接。
