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IPC
FEC®
FEC_ FCXX_ HE12 Version 1.2 as of 03.07.2000
Switched mode power supplies with reliable
isolation as per EN 60950 / VDE 0805 are
permitted.
The PS1 PSE3 power supply meet the above
requirements. The 24 V DC sensor supply pro-
vided in the FC21 and FC23 products meets the
above requirement for reliable mains voltage
isolation and can therefore be used for supp-
lying the digital inputs, provided that potential
isolation from the internal system voltage is
not required for providing interference immu-
nity, for example.
Power supplies with basic isolation and 2.5 kV
of dielectric strength are permitted for supp-
lying the power to the digital transistor out-
puts (24 V DC nominal).
The power relays that are used allow mains
voltages of overload category II to be switched
directly, and the isolation strength between
the contacts and the coil is greater than 4 kV.
The solid-state relays that are used allow AC
voltages in overload category I to be switched.
Interference immunity:
Only shielded cable should be used for TP and
cross-over cables. TP cables of type S/STP are
suitable. The shields should be connected to
an interference-free earth at both ends, over a
large area and with low impedance.