4.3.6
Muting
Overview
Muting temporarily bypasses the protective action of the safety light curtain so that
material can be transported to or from a machine or system. As a result, the work
process remains uninterrupted. The function can be configured during commissioning.
The distinction between people and materials is made by 2 signals that are independ‐
ent of each other. Based on the logical evaluation of these signals, the protective device
is bypassed if a valid muting condition is present. As soon as something other than
material enters the hazardous area, the work process is interrupted.
Prerequisites
•
Muting may only be activated during the period in which the material to be trans‐
ported (e.g. on a pallet) is blocking access to the hazardous area
•
Muting must be automatic, i.e., not manual
•
Muting must not depend on a single electrical signal
•
Muting must be triggered by at least 2 signals wired independently of each other
(e.g. by muting sensors)
•
Muting must not depend entirely on software signals (e.g. from a PLC)
•
Muting must be reversed after the material has passed through in order that the
protective device becomes effective again
•
The material to be transported must be detected above a certain length, i.e., an
interruption of the muting signals must not last longer than 500 ms
•
Attach muting sensors as appropriate to prevent muting from being triggered by
someone unintentionally
4.3.6.1
Muting sensors
Overview
Muting sensors detect material and supply the signals required by an evaluation unit for
the logical linking.
Muting signals can be generated in the following ways:
•
Optical sensors
•
Inductive sensors
•
Mechanical switches
•
Controller signals
Arranging muting sensors
The following is to be observed in the arrangement of muting sensors:
•
Muting sensors must be arranged so that only the material is detected and not the
means of transport or conveyor (vehicle or pallet)
•
Muting sensors must be arranged so that material can pass the ESPE unimpeded,
although persons are safely detected by the ESPE
•
Muting sensors must be arranged so that they detect the material with a minimum
distance in front of the ESPE. The minimum distance ensures the required proc‐
essing time until muting is activated.
•
If a muting connector is not used and both muting signals are on the extension
connection, the muting sensors must be arranged so that the signals arrive at the
device at different times
PROJECT PLANNING
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8021645/1EB0/2022-04-28 | SICK
O P E R A T I N G I N S T R U C T I O N S | deTec4
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Subject to change without notice
