Introduction to Industrial Automation

Figure 2.31  Magnetic proximity switch based on magnetoresistive detection.

Position control

Object counting

Pulses generation synchronized

with the rotation of the shaft

Slot type proximity switch for

monitoring of production continuity

Detection of faulty

objects for rejection

Controlling fill level

of granular solids

Figure 2.32  Typical applications of proximity switch usage.

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Hardware Components for Automation and Process Control 

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typical applications of proximity switches are the precise position detection of a moving object in a 

machine tool; the number of produced objects as they are traveling on a conveyor belt; and the pulse 

generation for synchronizing purposes, which are also performed by suitable proximity switches. A 

slot type proximity switch can monitor reliably the continuity of production of lightly connected 

objects. As an example, the utilization of a proximity switch could also check the presence of the clo-

sures on boxes, in order to reject the faulty boxes from the production line. Furthermore, capacitive 

proximity switches can be used in specific applications, as in the case of level detection of a granular 

solid in a tank. The market offers a wide range of proximity sensors to meet different types of appli-

cations and many others. Finally, it should be noted that the lack of physical contact with the target 

object and the absence of mechanical parts increase the life of a proximity sensor and make it more 

reliable in comparison to other mechanical proximity sensors, such as “limit switches”.