APL-100限位開關就是用以限定機械設備的運動極限位置的電氣開關。限位開關有接觸式的和非接觸式的。接觸式的比較直觀，機械設備的運動部件上，安裝上行程開關，與其相對運動的固定點上安裝極限位置的擋塊，或者是相反安裝位置。當行程開關的機械觸頭碰上擋塊時，切斷了（或改變了）控制電路，機械就停止運行或改變運行。由于機械的慣性動這種行程開關有一定的“超行程”以保護開關不受損壞。非接觸式的形式很多，常見的有干簧管、光電式、感應式等，這幾種形式在電梯中都能夠見到。
M2：2-SPDT
M3：3-SPDT
M4：4-SPDT
M5：2-DPDT
MG2：2SPDT鍍金觸點
ML2：2SPDT-40℃
MZ：直行程
PP：P+F(NAMUR)
   (Exia Ⅱ CT6）
PA：電感接近（2or3）
QA：磁感接近（2or3）
F：4-20mA閥位反饋
K：0-1K阻值輸出
W：2.4Ghz無線通訊

APL-100限位開關APL-100行程開關APL-100回迅器APL-100閥位顯示APL-100氣動附件作為工業自動化控制系統中的重要執行機構，可遠距離集中控制能滿足計算機程控的需要；如今在石油化工、燃氣設備、核工業、電力裝備、環保水處理、暖通空調、鋼 鐵冶金、工業窯爐、罐裝設備、釀酒設備、干燥設備、真空設備、表面處理、生物制藥、食品機械、紡織印染、造紙等行業中得到廣泛的使用，也是國防建設、科技 建設的首選產品。
The function of APL-100 limit switch is to realize sequence control, positioning control and position status detection. Used to control the travel and limit protection of mechanical equipment. Structure: composed of operation head, contact system and housing.
APL-100 limit switch is an electrical switch used to limit the movement limit position of mechanical equipment. There are contact and non-contact limit switches. The contact type is more intuitive. The moving parts of the mechanical equipment are equipped with a travel switch, and the stop point of the relative movement is installed with a limit stop, or the opposite installation position. When the mechanical contact of the travel switch hits the stop, the control circuit is cut off (or changed), and the machine stops or changes its operation. Due to the mechanical inertia, this travel switch has a certain "over travel" to protect the switch from damage. There are many forms of non-contact type, the common ones are reed switch, photoelectric type, induction type, etc. These types can be seen in the elevator.
APL-100 limit switch APL-100 travel switch APL-100 echo device APL-100 valve position display APL-100 pneumatic accessories as an important actuator in industrial automation control system, can be centralized control from a long distance can meet the computer program control Need; now in petrochemical industry, gas equipment, nuclear industry, power equipment, environmental protection water treatment, HVAC, iron and steel metallurgy, industrial kilns, canning equipment, brewing equipment, drying equipment, vacuum equipment, surface treatment, biopharmaceutical It is widely used in food machinery, textile printing and dyeing, paper making and other industries, and is also the first choice for national defense construction and technology construction.