Additional voltage supply
The voltage drop in the safe series connection must be checked so that the defined
minimum voltage is still applied to each safety switch. If the defined minimum voltage
is no longer applied to a safety switch, a node for voltage supply must be integrated.
The node for voltage supply must be integrated in the safe series connection in the
direction of the safe evaluation unit, as close as possible to the relevant switch.
Complementary information
Number of safety locking devices in a safe series connection
The maximum number of safety locking devices in a safe series connection
depends on the following factors:
•
Technical implementation of the safe series connection (T-connector, Flexi Loop, or
series connection in the control cabinet)
•
Applied supply voltage
•
Length of cables used
•
Cable cross-section of cables used
•
Load current
•
Node for voltage supply
•
Required performance level
The number of safety locking devices in a safe series connection affects the
response times of the system (
).
4.5
Testing plan
Overview
The manufacturer of the machine and the operating entity must define all required
thorough checks. The definition must be based on the application conditions and the
risk assessment and must be documented in a traceable manner.
Important information
DANGER
Insufficient checks or incorrect repair
Hazard due to lack of effectiveness of the protective device
b
Replace safety switch and actuator if damaged or worn. Never replace individual
parts or assemblies.
b
Check the safety switch at the inspection intervals specified in the national rules
and regulations.
Defining the thorough check
b
When defining the thorough check, please note the following:
°
Define the type and execution of the thorough check.
°
Define the frequency of the thorough check.
°
Notify the machine operators of the thorough check and instruct them
accordingly.
The following thorough checks are often defined in connection with a protective
device:
•
Thorough check during commissioning and modifications
•
Regular thorough check
Minimum requirements for the thorough check
The following checks must be done to ensure permanent and proper function:
PROJECT PLANNING
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8020562/2022-07-07 | SICK
O P E R A T I N G I N S T R U C T I O N S | flexLock
19
Subject to change without notice