• Autonics Automation India Private Limited

Capacitive Proximity Sensor

Autonics has a wide variety of capacitive proximity sensors, named as CR series. These can be used to detect all types of materials both metals and non-metals like iron, plastic, water, stone, wood, powder, paper, glass, etc. These work on the capacitive principles and hence the name. When any object comes near the sensing facer, the capacitance of the surroundings varies and is detected. Known for long life cycle and high reliability, the sensitivity can be adjusted by a potentiometer on the capacitive sensor. Also the sensitivity adjustment is used to restrict the area of sensing so that unwanted objects will not be detected. Autonics has proximity sensors in M18 and M30 sizes. The M18 housings are available with a sensing range of 8 mm, and M30 of 15 mm. Both AC 2-wire and DC 3-wire versions are available; both PNP and NPN outputs are available in DC capacitive type. The sensor works on 12-24 V DC for DC type and 100-240 V AC for AC type. These have switching frequency of 50 Hz for DC type and 20 Hz for AC type. The output current can be up to a maximum of 200 mA. The red LED on the sensor provides information about the On/Off condition. The sensor is surge- and reverse polarity-protected, and IP66 class, with 2 mtr in-built cable. The capacitive sensors can be used along with Autonics make sensor controllers PA10-U for developing different types of logics. Typical applications are to detect liquid level inside the bottle from outside. Two capacitive sensors, one at the top and one at the bottom of a tank will provide level limit control, so that the switching On/Off of the solenoid valve is possible to control the liquid level. Another application is in packaging machines where it is used to detect the absence of the cap of bottles moving on a conveyor. Capacitive sensors are widely used for detection of milk inside the packs; coal in the coal industry; and non hazardous and non corrosive powders in different chemical industries. The advantage of the capacitive type over the inductive type sensor is that it can detect any material coming within its sensing range.