The word automation supplier usually describes an inductive proximity sensor or metal sensor – the inductive sensor is considered the most commonly utilised sensor in automation. You can find, however, other sensing technologies which use the term ‘proximity’ in describing the sensing mode. Such as diffuse or proximity photoelectric sensors that use the reflectivity in the object to alter states and ultrasonic sensors designed to use high-frequency soundwaves to detect objects. All of these sensors detect objects which can be in close proximity for the sensor without making physical contact.
One of the most overlooked or forgotten proximity sensors that you can buy is definitely the capacitive sensor. Why? Perhaps this is due to these people have a bad reputation dating back to to when they were first released years ago, because they were more vulnerable to noise than most sensors. With advancements in technology, this is no longer the truth.
Capacitive sensors are versatile in solving numerous applications and might detect various kinds of objects for example glass, wood, paper, plastics and ceramics. ‘Object detection’ capacitive sensors can be identified by the flush mounting or shielded face from the sensor. Shielding causes the electrostatic field being short and conical shaped, similar to the shielded version of your proximity sensor.
Just because there are non-flush or unshielded inductive sensors, in addition there are non-flush capacitive sensors, as well as the mounting and housing looks exactly the same. The non-flush capacitive sensors possess a large spherical field that enables them to be used in level detection applications. Since capacitive sensors can detect virtually anything, they could detect degrees of liquids including water, oil, glue or anything else, and they also can detect levels of solids like plastic granules, soap powder, dexqpky68 and almost everything else. Levels can be detected either directly where the sensor touches the medium or indirectly where the sensor senses the medium by way of a nonmetallic container wall.
With improvements in capacitive technology, sensors have been designed that will compensate for foaming, material build-up and filming of water-based highly conductive liquids. These ‘smart’ capacitive sensors are based on the conductivity of liquids, and they can reliably actuate when sensing aggressive acids such as hydrochloric, sulfuric and hydrofluoric acids. Moreover, these sensors can detect liquids through glass or plastic walls approximately 10 mm thick, are unaffected by moisture and require virtually no cleaning in these applications.
The sensing distance of fanuc parts depends on several factors for example the sensing face area – the larger the better. The subsequent factor will be the material property in the object to become sensed or its dielectric strength: the better the dielectric constant, the greater the sensing distance. Finally, how big the prospective affects the sensing range. Just like having an inductive sensor, the marked will ideally be equivalent to or larger in dimensions than the sensor.
Most capacitive sensors have a potentiometer to permit adjustment from the sensitivity from the sensor to reliably detect the marked. The utmost quoted sensing distance of any capacitive sensor is based on metallic target, and consequently you will discover a reduction factor for nonmetal targets.
Although capacitive sensors can detect metal, inductive sensors ought to be utilized for these applications for maximum system reliability. Capacitive sensors are ideal for detecting nonmetallic objects at close ranges, usually under 30 mm and for detecting hidden or inaccessible materials or features.