2
2-4
User manual IC220SDL953 - September 2011
GFK-2731
Requirements for con-
trolled devices/actuators
The error detection of the module varies depending on the parameterization. This results
in specific requirements for the actuators.
– If the outputs are parameterized with test pulses, the output circuits are tested by test
pulses at regular intervals. These test pulses are visible at the output and can trigger
undesirable reactions with quick responding actuators.
Switching off the test pulses affects the error detection of the module. Please observe
the achievable safety integrity level, which is specified in "Connection examples for
The failure detection time is 20 ms.
– Only use appropriately qualified actuators.
– Use reliable components. These include, for example:
– Use relays or contactors with positively driven N/C contacts to safely monitor the state
(pick-up, drop-out).
– Please observe any special environmental requirements in your application when
selecting the controlled devices.
– Please note applicable C standards in your application (e.g., EN 1010), in which, for
example, the number of controlled devices required to achieve a particular category is
specified.
WARNING: Unintentional machine startup
If the process does not tolerate this behavior, actuators with sufficient inertia must
be used.
In general, the load must not be so dynamic that it causes dangerous states within
1 ms.
Quick actuators, which offer a safety-related response to pulses in under 1 ms, may
not generally
be used.
Please refer to "Single-channel assignment of safe outputs" on page 6-5 and "Two-
channel assignment of safe outputs" on page 6-8 for additional information.
– Control contactors according to EN 60947-4-1
– Power contactors
– Relays with positively driven contacts according to DIN EN 50205
