Operating Instructions

•
Swit
ch-on commands that put the machine in a dangerous state may only be
activated when the OSSDs of the safety locking device are in the ON state.
•
Closing or locking the protective device must not trigger the automated starting
of a hazardous machine function. This must occur by means of a separate start
command.
•
The safety switch tests the OSSDs at regular intervals. To do this, the safety switch
switches each OSSD briefly (for max. 300 µs) to the OFF state and checks whether
this channel is voltage-free during this time. Make sure that the machine’s control
does not react to these test pulses and the machine does not switch off.
4.4.1 Safe series connection
Overview
Sever
al safety switches can be connected in series in a safe series connection. The
connected devices act like a single device. The type of safe series connection depends
on the safety switch variant selected.
The following options are available:
•
Safe series connection with Flexi Loop (with diagnostics)
In a series connection with Flexi Loop, the safety switches are connected to
F
lexi L
oop nodes. Each Flexi Loop node evaluates a safety switch and sends the
information to the Flexi Soft safety controller.
•
Safe ser
ies connection with T-connector (without diagnostics)
In a series connection with T-connectors, several safety switches are connected
via T-c
onnectors and connected to the safe evaluation unit.
•
Safe ser
ies connection in control cabinet (with diagnostics)
In a series connection in the control cabinet, the safety switches are led to the
contr
ol cabinet individually. The OSSDs of the safety switches are connected in
series there and evaluated by the evaluation unit. The Aux outputs can be individu‐
ally connected to the programmable logic controller (PLC).
Safe series connection with T-connectors or in the control cabinet
1 1 1 1 1 2
OSSD1
OSSD2
OSSD1
OSSD2
OSSD1
OSSD2
OSSD1
OSSD2
OSSD1
OSSD2
Figure 7: Switching with 5 safety switches connected in series
1
Safety switch
2
Safe evaluation unit
The voltage drop in the series connection must be checked so that the defined mini‐
mum volta
ge is still applied to the last safety switch.
For connection cables with a length of 2 m and a cable cross-section of 0.25 mm², the
maximum number of safety switches connected in series depends on the voltage as
follows:
4 PROJECT PLANNING
16
O P E R A T I N G I N S T R U C T I O N S | flexLock 8020562/2021-04-30 | SICK
Subject to change without notice
Review version 2021-04-30