Selecting The Cable; Selecting The Power Unit - Festo CDVI-DN Series Electronic Manual

Valve terminal

Table of Contents

1. Installation

1.4.2 Selecting the cable

1−20

Calculate the necessary cross−sectional area and the

maximum permitted cable length.

Avoid long distances between the power unit and the

valve terminal. Long cables reduce the voltage supplied

by the power unit.

Make sure that cables and sockets suit the ambient condi

tions (e.g. cleaning agents used) and fulfil the required IP

protection class.

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 (Protected Extra Low

Voltage PELV).

Switch power packs are permitted, providing they

guarantee reliable isolation in accordance with EN 60950/

VDE 0805.

Note:

By the use of PELV power units, protection against electric

shock (protection against direct and indirect contact) is guar

anteed in accordance with EN 60204−1/IEC 204. Safety trans

formers with the adjacent symbol must be used for supplying

PELV networks. The valve terminals must be earthed to en

sure that they function correctly (e.g. EMC).

Recommendation:

Use closed−loop controlled power units.

Before selecting the power units, calculate the total

current requirement in accordance with section 1.4.1.

Festo P.BE−CDVI−DN−EN en 0404NH

Table of Contents