Industrial Communication Guide

Distinction between simple and smart sensors A “simple sensor” generates an analog measurement signal from a physical quantity. This signal then has to be prepared by a converter so that it can then be further processed by a control computer. A “smart sensor” or “intelligent sensor” has the advantage that in addition to recording the measured quantity, it can also prepare and process the latter according to predefined functions and then output this as digital information. This intelligence allows it to communicate directly with the control computer.

How a simple sensor works In the picture you can see a simple conveyor belt above which a sensor has been mounted in the form of a retroreflective sensor. This uses reflection to detect whether a workpiece is located at the relevant point on the conveyor belt or not. If there is no workpiece under the light barrier, the light is not reflect- ed and the sensor delivers the value “no workpiece present” as the electrical signal. If a workpiece does pass under the light barrier, the light is reflected on the top of the workpiece and the sensor supplies “workpiece present” as the electrical signal.

Control computer

Physical quantity

Analog signal

Digital signal

Simple sensor

Converter (I/O system)

Smart Sensor

Control computer

Physical quantity

Analog signal

Digital signal

Simple sensor

Converter

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