Inductive sensor: principle of operation and device

The inductive sensor is a very common device that is part of the bottom equipment in automated production control systems. The devices are widely used in machine building, textile, food and other industries. The most effective devices are used in machine tools as limit switches, as well as in automatic lines.

In this case, inductive sensors only react to metals, remaining insensitive to other materials. This property allows increasing the protection of devices from interference by introducing into their sensitivity zone various lubricants, emulsions and other substances that will not cause a false alarm.

The objects affected by the inductive position sensor are various metal parts: cams, sliders, gear teeth. In many cases, a plate attached to the equipment parts can be used.

According to statistics, of all the position sensors in use, more than 90 percent are inductive devices. This can be explained by their excellent performance, low cost and at the same time high reliability, which can not be said for other devices.

The non-contact switch (inductive sensor) operates according to the following principles. The generator included in the device produces an electromagnetic field that interacts with the object. The required duration of the control signal and hysteresis during switching is provided by the trigger. The amplifier allows you to increase the signal amplitude to the desired value.

Located in the sensor, the light indicator provides quick tuning, monitoring of operation and shows the status of the switch. To protect against penetration of water and solid particles into the device, a compound is used. The body of the product allows you to mount an inductive proximity sensor and protect the device from mechanical influences. It is made of polyamide or brass, completing hardware components.

During the operation of the device, when the voltage is applied to the inductor of the generator, an alternating magnetic field is created, which is located in front of the active surface of the switch. When an object of sensitivity enters the zone of influence, the quality of the circuit and the amplitude of the oscillations decrease. As a result, the trigger triggers and the switch output state changes.

The inductive sensor has some application features. It can recognize different groups of metals, due to the absence of wear and mechanical impact is a durable device. The devices are equipped with short-circuit and overload protection mechanisms.

They are resistant to high pressure, are admitted in various versions for use at high temperatures (up to 150 ^° C) and low (-60 ^° C) temperatures. The inductive sensor is resistant to active chemical media, it can have an analog or discrete output to determine the position relative to the device of the target object.