The phrase automation parts usually refers to an inductive proximity sensor or metal sensor – the inductive sensor is the most commonly utilised sensor in automation. You will find, however, other sensing technologies designed to use the phrase ‘proximity’ in describing the sensing mode. Some examples are diffuse or proximity photoelectric sensors that use the reflectivity from the object to modify states and ultrasonic sensors that use high-frequency soundwaves to detect objects. Most of these sensors detect objects that are in close proximity to the sensor without making physical contact.
Probably the most overlooked or forgotten proximity sensors currently available is definitely the capacitive sensor. Why? Perhaps this is due to these people have a bad reputation dating back to to once they were first released in the past, while they were more vunerable to noise than most sensors. With advancements in technology, this is not really the way it is.
Capacitive sensors are versatile in solving numerous applications and can detect various kinds of objects including glass, wood, paper, plastics and ceramics. ‘Object detection’ capacitive sensors are often recognized by the flush mounting or shielded face of the sensor. Shielding causes the electrostatic field to get short and conical shaped, much like the shielded version in the proximity sensor.
Just as there are non-flush or unshielded inductive sensors, in addition 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 levels of liquids including water, oil, glue and so on, and so they can detect degrees of solids like plastic granules, soap powder, dexqpky68 and almost anything else. Levels might be detected either directly where the 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 water-based highly conductive liquids. These ‘smart’ capacitive sensors are based on the conductivity of liquids, and so they 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 up to 10 mm thick, are unaffected by moisture and require little or no cleaning over these applications.
The sensing distance of fanuc module depends on several factors such as the sensing face area – the greater the better. Another factor may be the material property of your object being sensed or its dielectric strength: the higher the dielectric constant, the higher the sensing distance. Finally, the size of the prospective affects the sensing range. Just as having an inductive sensor, the prospective will ideally be comparable to or larger in size than the sensor.
Most capacitive sensors use a potentiometer to enable adjustment from the sensitivity from the sensor to reliably detect the marked. The maximum quoted sensing distance of your capacitive sensor will depend on metallic target, and thus you will find a reduction factor for nonmetal targets.
Although capacitive sensors can detect metal, inductive sensors should be utilized for these applications for optimum system reliability. Capacitive sensors are fantastic for detecting nonmetallic objects at close ranges, usually lower than 30 mm and for detecting hidden or inaccessible materials or features.