A detection switch is a switch that is connected to other circuit elements to detect the parameters of a component or circuit (such as current, voltage, etc.). The detection switch has an induction function. The main body is usually a variety of induction switches or close switches, and the external power supply is required to work.

检测开关根据其用途具有各式各样的输出使用方法。

The detection switch has a wide variety of output uses according to its purpose.

1.接点输出式

1. connection output

以微型开关、限位开关、继电器的接点为输出的开关要素，与电磁开关、小型马达、电磁器等连接作为主要目的，可进行数安培电流的开关控制。与电子控制设备连接时，需注意振动时间、最小负荷电流。

With the switch, the limit switch and the relay's connection as the output switch factor, it is connected with the electromagnetic switch, the small motor and the electromagnetic device as the main purpose. The switch control of the ampere current can be carried out. When connecting with electronic control equipment, attention should be paid to vibration time and minimum load current.

2.光电耦合输出式

2. optoelectronic coupling output

检测电路电气绝缘，与接点输出式的使用方法相同。可控制10～50mA电流的开关。

The electrical insulation of the detection circuit is the same as that of the contact output type. The switch of 10 to 50mA current can be controlled.

3.直流3线式

3. DC 3 wire

a.电压输出型

A. voltage output type

如图7所示的输出电路，进行检测时，向负荷输出电压信号。电压输出型主要是以连接由电子计数器、无接点继电器等的晶体管或IC构成的电子控制设备为目的而制造的。

When the output circuit shown in Fig. 7 is detected, the output voltage signal is output to the load. The voltage output type is mainly made up of electronic control equipment consisting of transistors or IC composed of electronic counters, contactless relays, etc.

b.电流输出型

B. current output type

亦可称为开放、集电极输出型。如图8所示，输出晶体管动作时，有吸入电流的NPN型(电流吸收)和吐出电流的PNP型(电流源)。输出晶体管中使用小容量的功率晶体管，则可进行50～200mA电流的开关，并可直接进行电磁继电器、电磁阀、直流电磁器、显示灯等负荷的驱动。

It can also be called open and collector output. As shown in Fig. 8, when the output transistor moves, the NPN type (current absorption) and the PNP type (current source) of the current are absorbed. The power transistors with small capacity in the output transistors can be switched from 50 to 200mA, and can be driven directly by electromagnetic relay, solenoid valve, DC electromagnetic device, display lamp and so on.

4. 直流2线式

4. DC 2 wire

该方式的接近开关有2根导线，因此，使用时对极性予以注意的话，不仅使用方法可与机械式限位开关相同，而且配线简单，但需注意下述状况。

The proximity switch of this method has 2 wires. Therefore, when the use of the polarity is paid attention to, not only the use method can be the same as the mechanical limit switch, but also the wiring is simple, but the following condition should be paid attention to.

(1) 即使开关处于关闭状态，也需向接近开关的检测电路供给电流。为此，负荷中有微量电流流动。该电流称为漏电流。漏电流时，负荷两端产生“漏电流×负荷也是造成使用初期故障的原因。初期故障的发生时间，根据制造方法的不同而不同，不能一概而论，一般多发生在使用开始后的一星期到10天内。

(1) even if the switch is in a closed state, it is necessary to supply the current to the detection circuit of the proximity switch. To this end, there is a micro current flow in the load. The current is called a leakage current. When leakage current is generated, leakage current and load at both ends of the load are also the cause of the initial failure. The occurrence time of the initial failure is different from that of the manufacturing method. It can not be generalized. It usually occurs within a week to 10 days after the start of the operation.

2.偶发故障

2. accidental fault

包括由于半导体部件的不良而引起的故障，电阻、电容的断线、短路、容量不足，电路板的电路断裂、带焊料等的不良现象，但发生率极低。接近开关经常发生故障时，可以考虑为使用环境的问题，请向厂家咨询。

Due to the failure of the semiconductor components, the broken lines, short circuits and capacity of the resistance and capacitance are insufficient, the circuit board's circuit break and the bad phenomena such as solder and so on, but the occurrence rate is very low. When the proximity switch often fails, you can consider the problem of using the environment, please consult the manufacturer.

3.负荷短路与配线错误

3. load short circuit and wiring error

由于配线错误或带电作业引起负荷短路时，导致大电流流向检测开关，输出回路烧毁。作为在检测开关外进行的保护对策，可使用切断快速短路电流的方法，通过熔断器进行保护，不仅可保护负荷短路，还对地线有保护作用。但是，由于开关内的输出晶体管的残余容量小，达不到100[%]的效果。

Due to wiring error or live working short circuit load, leading to large current flow to the detection switch, the output circuit burned. As a protective countermeasure outside the detection switch, the method of cutting fast short circuit current can be used and the fuse is used to protect it. It can not only protect the short circuit of load, but also protect the ground line. However, due to the small residual capacity of the output transistors in the switch, the 100[%] effect is not achieved.

4.干扰波导致的破损

Damage caused by 4. interference waves

由干扰波带来的破损是慢慢形成的，因此在开始使用后的一个月或二三个月后发生破损是极其普通的。因此，在该期间发生破损时，其原因则可判断为干扰波。电感负载开闭时发生的检测开关的瞬间错误动作是由干扰波造成的。

Breakage caused by interference waves is slowly formed, so breakage after one month or two or three months after use is extremely common. Therefore, during the period of damage, the cause can be judged as interference wave. The instantaneous fault action of the detection switch occurred when the inductance load is switched off is caused by the interference wave.