The expression automation parts usually describes an inductive proximity sensor or metal sensor – the inductive sensor is considered the most commonly utilised sensor in automation. You will find, however, other sensing technologies which use the term ‘proximity’ in describing the sensing mode. Some examples are diffuse or proximity photoelectric sensors that utilize the reflectivity in the object to modify states and ultrasonic sensors that utilize high-frequency soundwaves to detect objects. Every one of these sensors detect objects that are in close proximity towards the sensor without making physical contact.
One of the most overlooked or forgotten proximity sensors on the market today is definitely the capacitive sensor. Why? Perhaps it is because these people have a bad reputation dating back to whenever they were first released years back, as they were more vulnerable to noise than most sensors. With advancements in technology, this has stopped being the case.
Capacitive sensors are versatile in solving numerous applications and will 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 be short and conical shaped, similar to the shielded version from the 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 have a large spherical field that allows them to be used in level detection applications. Since capacitive sensors can detect virtually anything, they can detect levels of liquids including water, oil, glue and the like, plus they can detect levels of solids like plastic granules, soap powder, dexqpky68 and all sorts of things else. Levels could be detected either directly where the sensor touches the medium or indirectly the location where the sensor senses the medium through a nonmetallic container wall.
With improvements in capacitive technology, sensors happen to be designed that can 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 also can reliably actuate when sensing aggressive acids like hydrochloric, sulfuric and hydrofluoric acids. Additionally, these sensors can detect liquids through glass or plastic walls approximately 10 mm thick, are unaffected by moisture and require a minimum of cleaning during these applications.
The sensing distance of fanuc pcb depends upon several factors including the sensing face area – the greater the better. The following factor may be the material property of the object to get sensed or its dielectric strength: the better the dielectric constant, the greater the sensing distance. Finally, the actual size of the target affects the sensing range. Equally as having an inductive sensor, the prospective will ideally be similar to or larger in size in comparison to the sensor.
Most capacitive sensors use a potentiometer to allow adjustment of the sensitivity from the sensor to reliably detect the target. The maximum quoted sensing distance of any capacitive sensor is founded 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 useful for these applications for maximum system reliability. Capacitive sensors are ideal for detecting nonmetallic objects at close ranges, usually below 30 mm and for detecting hidden or inaccessible materials or features.