Inductive Sensors

Inductive proximity sensor is a non-contact inductive switch (LBS) that switches an electrical signal upon detecting metal within its sensitivity zone (distance up to 15 mm). In industry, this type of detector is utilised in CNC machines, 3D printers, and for automating production and packaging conveyor lines where it is necessary to determine the position of various moving metal objects without direct contact, indirectly determine speed and account with PLCs.

Why buy an inductive sensor from “Specialist”?

We sell high-quality LBS sensors for production. The advantages of non-contact switches for metal object detection from “Specialist”:

1. Diode protection against incorrectly connected polarity
   If incorrectly connected, cheap inductive sensors fail immediately due to overvoltage and overheating, whereas ours have protection.
2. High-quality PVC cable 2 m included
   The two-metre, reliably insulated, and soft 2 and 3-wire signal cable made from tinned copper in PVC with additional external insulation;
3. Stability in industrial conditions
   High vibration resistance and moisture protection of internal components with an IP66 class casing;
4. Precision and interference resistance
   SMT printed circuit board providing sensor accuracy, fast response, and minimising electromagnetic interference — depending on the model, sensors have an optimal frequency from 100 to 600 Hz;
5. Ease of use
   Our catalogue offers a wide selection of cylindrical inductive sensors in sizes M8~M30 with various cord and LED options, a square casing, flat, miniature. Noticeable light indication.

These advantages provide long-term operation and reliability for solving critical tasks in creating an automated system. We have analogues of inductive sensors lj12a3-4-z/by, and lj18a3-8-z/by, which are often used in CNC machines from China. Our limit switches have better construction and an IP66 sealed casing, making them almost fail-proof.

Features and benefits of different series:

• TL — basic and budget option with a threaded cylinder casing having two standard hex nuts.
• TK withstands twice the load current, the cylinder with threading has two additional locking washers for better fixation between the nuts.
• TKX offers a more noticeable 360° light indication, a wire bend protector, and a special hex nut for panel mounting.
• TKI and TKL — designed for convenient installation. This inductive limit switch has a round detachable pin-3 or pin-4 wire connector, straight or angled connection for the 2 m cord (included).

Connecting an inductive sensor

The 24V DC inductive sensor “Specialist” connects to a power supply from 10 to 30 V and has several configurations based on the type of output signal. It should be noted that all limit switches have a discrete ON/OFF output. A three-wire connection is usually used with a PNP or NPN transistor type signal, normally open or closed. The choice depends on both the method of action and the PLC, microcontroller, inverter, or other device that will receive the signal.

Connection diagram of an NPN inductive sensor

Several NPN sensors can be connected in series:

NPN limit switches can also be connected in parallel:

Connection diagram of a PNP inductive sensor

Serial connection of a series of LBS PNP sensors:

Parallel connection of PNP terminators:

How and to which metals do inductive sensors (LBS) react

The magnetic-inductive metal sensor is versatile and detects various metallic objects in its vicinity, but its sensitivity differs between ferrous and non-ferrous alloys. The sensor best detects iron plates. The proximity distance for other metals is adjusted by the distance correction factor Sn.