4.3.6 Muting
Overview
Mut
ing temporarily bypasses the protection of the safety light curtain so that material
can be conveyed 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 indepen‐
dent 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
•
Mut
ing 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 output 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
Mut
ing 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
T
he 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 pro‐
cessing 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
4 P
ROJECT PLANNING
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O P E R A T I N G I N S T R U C T I O N S | deTec4 Ex II 3GD 8023872/18YZ/2021-01-14 | SICK
Subject to change without notice
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