There are various sensors used in LCA such as: micro switches that make physical contacts with work (MISUMI P/N MZW822, MZQ1, etc.); non contacting photo sensors (beam sensor: PEX11, photo-micro sensor: FPM24, etc.); and proximity sensor (PGXL8, etc.). Sensors must have environmentally extremely reliable outputs since the outputs determine the outcome of the control sequences to follow. Typical sensors and performances are introduced below. Select according to application specific needs.

(1) Characteristic comparisons of detection sensors

Switch type Micro switch Limit switch Proximity sensor Photo sensor Photo sensor Item Detection method Contacting Non-contacting Non-contacting Non-contacting Detection principle Mechanical switch Magnetic field detection Through beam Reflective Detection accuracy Detection distance Response time Life Noise immunity Environmental immunity (dust, water, etc.)

(2) Outline of various sensors

Contacting sensors (micro switches/limit switches) are disadvantaged in response time and operational life, but are often used where their superior noise immunity and actuation reliability are needed. Also, they are constructed to withstand many environmental adversities such as external forces, water, oil, dust, and wide temperature variations.
The proximity sensors that operate on magnetic field detection principle have sensing distance limitations. It is recommended to use within 70% of the maximum detection distance specification considering environmental temperature variations.

Photo sensors can be categorized into three groups based on the type of light receptor elements used.

	・	Opposing through beam type
	・	Reflex reflector through beam type Two part construction with a reflector plate and a emitter/receptor element.
	・	Reflective type Single unit type containing emitter and receptor.

The through beam type is actuated when an object block the beam. The reflective type is actuated by a reflection from an object.