The term automation supplier usually refers to an inductive proximity sensor or metal sensor – the inductive sensor is regarded as the commonly utilised sensor in automation. There are actually, however, other sensing technologies that use the phrase ‘proximity’ in describing the sensing mode. Such as diffuse or proximity photoelectric sensors designed to use the reflectivity in the object to modify states and ultrasonic sensors that utilize high-frequency soundwaves to detect objects. All of these sensors detect objects that happen to be in close proximity to the sensor without making physical contact.
One of the most overlooked or forgotten proximity sensors currently available may be the capacitive sensor. Why? Perhaps this is due to there is a bad reputation dating back to when they were first released years ago, as they were more vunerable to noise than most sensors. With advancements in technology, this has stopped being the case.
Capacitive sensors are versatile in solving numerous applications and might detect various types of objects for example glass, wood, paper, plastics and ceramics. ‘Object detection’ capacitive sensors are easily identified by the flush mounting or shielded face of the sensor. Shielding causes the electrostatic field to become short and conical shaped, just like the shielded version of your proximity sensor.
Just since there are non-flush or unshielded inductive sensors, additionally, there are non-flush capacitive sensors, as well as the mounting and housing looks the same. The non-flush capacitive sensors have a large spherical field that enables them to be used in level detection applications. Since capacitive sensors can detect virtually anything, they could detect quantities of liquids including water, oil, glue and so on, plus they can detect levels of solids like plastic granules, soap powder, dexqpky68 and almost everything else. Levels can be detected either directly where sensor touches the medium or indirectly in which the sensor senses the medium through a nonmetallic container wall.
With improvements in capacitive technology, sensors happen to be designed that will make amends for foaming, material build-up and filming of water-based highly conductive liquids. These ‘smart’ capacitive sensors are derived from the conductivity of liquids, and they also can reliably actuate when sensing aggressive acids such as hydrochloric, sulfuric and hydrofluoric acids. Furthermore, these sensors can detect liquids through glass or plastic walls around 10 mm thick, are unaffected by moisture and require little if any cleaning within these applications.
The sensing distance of fanuc parts is determined by several factors including the sensing face area – the greater the better. Another factor is definitely the material property of the object being sensed or its dielectric strength: the larger the dielectric constant, the greater the sensing distance. Finally, the size of the marked affects the sensing range. In the same way having an inductive sensor, the target will ideally be equivalent to or larger in proportions compared to the sensor.
Most capacitive sensors use a potentiometer to allow adjustment from the sensitivity from the sensor to reliably detect the objective. The highest quoted sensing distance of any capacitive sensor is founded on a metal target, and consequently you will discover a reduction factor for nonmetal targets.
Although capacitive sensors can detect metal, inductive sensors must be used for these applications for optimum 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.