Wiring
Operating Manual PSS u2 EF 2DO R 8A
1003625-EN-03
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7
Wiring
7.1
General wiring guidelines
Please note:
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If short circuits occur between the cable from the output to the load and a supply line, it
will no longer be possible to switch off the load. Possible remedies:
– Exclude the error by using separate multicore cable for supply voltages
– Use dual actuators, e.g. two contactors in series.
– Use an additional shutdown device such as a main contactor
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Use appropriate wiring to exclude short circuits between the outputs.
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The actuators may be connected using unshielded cables.
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To prevent contact welding, a fuse should be connected before the output contacts (see
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It is essential to consider the relay's service life graphs to prevent contact welding (see
).
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The safety system must be used only in enclosed spaces.
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For applications in accordance with SIL CL 2 and SIL CL 3 relay outputs must be 2-chan-
nel. Only the relay contact of the same module may be used.
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With inductive loads, sufficient fuse protection must be provided on all output contacts.
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If voltages higher than 50 VAC or 120 VDC are connected to the relay contacts, please
note the following:
– Specific accident prevention regulations apply.
– These voltages must only be applied at the upper terminals (Ox3), to guarantee pro-
tection against contact when removing the terminal blocks.
7.1.1
Connection mechanism for terminal blocks
Procedure:
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Use a flat head screwdriver.
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Strip the wire back 9 mm.
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Feed the stripped cable as far as it will go into the opening for the spring-loaded terminal.
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Check that the cable is firmly seated.
Please note:
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The minimum cable cross section for field connection terminals on the terminal blocks is
0.15 mm
2
(AWG26).
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The maximum cable cross section for field connection terminals on the terminal blocks is
1.5 mm
2
with ferrules (AWG14)
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Use copper wiring.
