BECKHOFF CX2020 - Manual (Page 26)

Mounting and wiring
Wire size width 0.5 ... 2.5 mm 2 AWG 20 .. AWG 14
Wire stripping length 8 ... 9 mm 0.33 inch
LED
If the power supply unit is connected correctly and the power supply is switched on, the two upper LEDs in
the terminal prism are green. The left LED (Us) indicates the CPU supply. The right LED (Up) indicates the
terminal supply. The other LEDs indicate the Terminal Bus status. A detailed description of the LEDs can be
found in section “LED troubleshooting”.
PE power contacts
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.
CX2020, CX2030, CX2040 26 Version 1.2