BECKHOFF CX51x0 - Manual (Page 33)

Mounting and wiring
The terminals are implemented in spring force technology. Connect the cables as follows:
1. Open a spring­loaded terminal by slightly pushing with a screwdriver or a rod into the square opening
above the terminal.
2. The wire can now be inserted into the round terminal opening without any force.
3. The terminal closes automatically when the pressure is released, holding the wire safely and
permanently.
Wire cross section 0,5 ... 2.5 mm 2 AWG 20 … AWG 14
Strip length 8 ... 9 mm 8.38 mm
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”.
UL requirements
WARNING
Loss of UL Listing
In order to comply with UL requirements, the CX controllers must not be connected to un­
limited voltage sources!
In order to comply with UL requirements, the CX controllers may only be connected to sup­
ply voltages (24 V DC) that originate from:
a) an isolated source that is protected with a fuse (compliant with UL248) of 4 A max., or
b) a voltage source that is compliant with NEC class 2.
An NEC class 2 voltage source must not be connected in series or parallel with another
NEC class 2 voltage source! These UL requirements apply to all supply voltages for CX
controllers!
PE power contacts
Attention
Power contact “PE”
The “PE” power contact must not be used for other potentials. “PE" and “0V" (24 V system
supply) must have the same potential (connected in the control cabinet). The cabling in the
control cabinet must comply with EN 60204­1:2006 PELV ­ Protective Extra­Low Voltage.
EN 60204­1:2006 section 6.4.1:b): One side of the circuit or one point of the energy source
for this circuit must be connected the protective earth conductor system.
Attention
Interruption of the power supply / switching off
The device may not be switched off by disconnecting the ground. The 24 V line must al­
ways be disconnected first, since otherwise current may continue to flow via the shielding,
depending on the device. Any devices with independent power supply that may be con­
nected (e.g. a Panel) must have the same potential as the CX system for “PE" and
“GND" (no potential difference). A potential difference may result in damage to the con­
troller and the periphery.
CX51x0 33 Version 1.0