Introduction; Overview - Siemens S7-1500F Manual

1 Introduction

Introduction
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1.1

Overview

Inductive sensors are suitable for detecting metallic objects without contact. They
build up a magnetic field, which is influenced by the metal objects that are
electrically conductive. This field change is detected by the sensor and it switches
the output.
In addition, there are other inductive, clocking sensors. These receive a pulsating
clocking signal as input, which they forward in the "attenuated state". In this case,
an attenuated state means that they have detected an electrically conductive
material and are activated or excited.
Figure 1-1 Clock signals at the input and output of a clocking sensor
Clock input
Sensor output
When correctly configured such inductive and clocking sensors are protected
against cross-circuits by the clocking property and are therefore suitable for safety
functions up to SIL 3 or PL e with only a single sensor.
However, the performance level PL e is not achieved for a safety function with a
fail-safe input module. This is due to the fact that the settings necessary to operate
this sensor on the F-DI module limit the ISO 13849-1 category to Category 3 and
the maximum performance level to PL d.
The typical field of application for such sensors is positioning processes. As an
example, the following graphic shows a possible area of application for such a
positioning function. A conveyor belt transports cartons that are to be sorted into
different trolleys. To ensure that the cartons are only pushed off the conveyor belt
when a collecting trolley is definitely available, the presence of the collecting
trolleys is detected by inductive sensors.
Inductive clocking sensor
Entry ID: 109818998, V1.0,
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Unattenuated state
05/2023
Attenuated state
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