BECKHOFF CX9020 - Manual (Page 21)

Mounting and wiring
Power contact PE
Attention
Powerkontakt "PE"
The “PE” power contact must not be used for other potentials. "PE" und "0V" (24V CX­Sys­
tem supply) have to be on the same potential. (connected in the cabinet) Der Powerkontakt
"PE" darf nicht für andere Potentiale verwendet werden. "PE" und "0V" (24V Systemver­
sorgung) müssen auf dem gleichen Potential liegen. (im Schaltschrank verbunden) The
wiring the cabinet has to follow the Norm EN EN 60204­1:2006: Safety of machinery ­ Elec­
trical equipment of machines ­ (PELV = Protective Extra Low Voltage)EN 60204­1:2006
chapter 6.4.1:b): One side of the circuit or a point of the energy source of the circuit must
be connected to protective earth system
Attention
Interrupt power supply / switching off
If the power supply should be disconnected the "0V" must not be disconnected. Always dis­
connect the “24V” wire first. Otherwise there can be electrical current flow via the shield.
Possibly connected devices with own power supply (e.g. panel) must have the same elec­
trical potential for "PE" and "GND" as the CX­unit. Otherwise the CX­unit and/or the con­
nected device can be damaged.
CX9020 21 Version 1.1