The phrase automation parts usually means an inductive proximity sensor or metal sensor – the inductive sensor is easily the most commonly utilised sensor in automation. You can find, however, other sensing technologies which use the term ‘proximity’ in describing the sensing mode. These include 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. Every one of these sensors detect objects that are in close proximity on the sensor without making physical contact.
Probably the most overlooked or forgotten proximity sensors that you can buy may be the capacitive sensor. Why? Perhaps it is because these people have a bad reputation going back to when they were first released years ago, as they were more prone to noise than most sensors. With advancements in technology, this is not the case.
Capacitive sensors are versatile in solving numerous applications and may detect various types of objects such as glass, wood, paper, plastics and ceramics. ‘Object detection’ capacitive sensors are typically recognized by the flush mounting or shielded face of your sensor. Shielding causes the electrostatic field to get short and conical shaped, just like the shielded version from the proximity sensor.
Just as there are non-flush or unshielded inductive sensors, there are non-flush capacitive sensors, as well as the mounting and housing looks exactly the same. The non-flush capacitive sensors use a large spherical field that enables them to be used in level detection applications. Since capacitive sensors can detect virtually anything, they are able to detect amounts of liquids including water, oil, glue or anything else, and so they can detect amounts of solids like plastic granules, soap powder, dexqpky68 and almost anything else. Levels might be detected either directly where sensor touches the medium or indirectly where the sensor senses the medium using a nonmetallic container wall.
With improvements in capacitive technology, sensors happen to be designed that can make up for foaming, material build-up and filming of water-based highly conductive liquids. These ‘smart’ capacitive sensors derive from the conductivity of liquids, and so they can reliably actuate when sensing aggressive acids for example hydrochloric, sulfuric and hydrofluoric acids. Furthermore, these sensors can detect liquids through glass or plastic walls approximately 10 mm thick, are unaffected by moisture and require little if any cleaning during these applications.
The sensing distance of fanuc parts is dependent upon several factors such as the sensing face area – the greater the better. Another factor is the material property of your object being sensed or its dielectric strength: the better the dielectric constant, the higher the sensing distance. Finally, the actual size of the prospective affects the sensing range. Equally as by having an inductive sensor, the prospective will ideally be equivalent to or larger in dimensions compared to the sensor.
Most capacitive sensors possess a potentiometer to enable adjustment from the sensitivity of your sensor to reliably detect the marked. The most quoted sensing distance of a 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 fantastic for detecting nonmetallic objects at close ranges, usually below 30 mm and then for detecting hidden or inaccessible materials or features.