Festo ASI−EVA−4E Serie Instrucciones Para El Usuario página 19

3.5 Connecting the AS−Interface bus
Please note
The sensor power supply for the inputs is provided via
the AS−Interface bus.
Warning
Use only power units which guarantee reliable isolation
of the operating voltages as per IEC 742/EN 60742/
VDE 0551 with at least 4 kV isolation resistance (Pro
tected Extra Low Voltage PELV). Switch power packs are
permitted, providing they guarantee reliable isolation in
accordance with EN 60950/VDE 0805.
By the use of PELV power units, protection against electric
shock (protection against direct and indirect contact) is
guaranteed in accordance with EN 60204−1 / IEC 204.
Safety transformers with the adjacent symbol must be
used for supplying PELV networks. The valve terminals
must be earthed to ensure that they function correctly
(e.g. EMC).
Recommendation: Use the Festo AS−Interface combi power
unit type ASI−CNT−115/230 VAC−B.
Festo ASI−EVA−4E... 0401b English 19