Beckhoff CP39 Series, Manual

Page: 36 / 52

Commissioning
CP39xx 36 Version: 3.1
4.3.4 Connecting cables and power supply
NOTE
Incorrect connection procedure
Incorrect procedure when connecting the cables and the power supply can cause hardware damage.
• Follow the documented procedure for connecting the cables and the power supply.
• Always connect all cables first and only then switch on the power supply.
• Please read the documentation for the external devices prior to connecting them.
Connecting cables
Make sure that you first ground the Panel (see Chapter 4.3.1 Grounding the Control Panel [ } 32] ) and then
plug in all data transmission cables.
For a device with a mounting arm adapter, route the cables as shown in chapter 4.3.2 Routing the cables in
the mounting arm adapter [ } 33] and then plug in all data transmission lines.
Check the screw connections between the plugs and sockets.
When connecting the Control Panel to an Industrial PC with UPS output, we recommend using this for the
connection. For CP-Link 4, we recommend connecting the CU880x transmitter boxes to the UPS output of
the PC.
Connecting the power supply
Cables with a maximum cable cross-section of 4 x 0.75 mm
2
can be used for connecting the power supply.
For long supply lines, use 4 x 0.75 mm
2
cables to achieve a low voltage drop on the supply line. There
should be at least 22 V at the voltage connector of the Control Panel, so that the Panel remains switched on
during voltage fluctuations.
Proceed as follows to connect the 24 V
DC
power supply unit:
1. Check the correct voltage of your external power supply.
2. Plug the voltage connector into the voltage socket on the Panel.
3. Screw the voltage connector to the voltage socket. Then check the screw connection.
4. Connect the Panel to your external 24 V power supply.
5. Switch on the 24 V power supply.
6. Calculate the voltage at the power supply plug.
In order to check the voltage at the power supply plug, you must first calculate the voltage drop on the supply
cable. You can orient yourself to the following calculation example:
• CP3924-0000
• Power consumption: 34 W
• Current consumption: 34 W / 22 V = 1.5 A
• Connection with 10 m two-core 0.75 mm
2
cable, although the supply cable length then corresponds to
20 m
• Constant of the specific resistance of pure copper: 0.0178 Ohm * mm
2
/ m
• Resistance of the supply line: 0.0178 Ohm*mm
2
/m * 20 m / 0.75 mm
2
= 0.0178 * 20 / 0.75 = 0.475 Ohm
With the listed data, you can now calculate the voltage drop on the supply line:
• 1.5 A * 0.475 Ohm = 0.7 V
With a CP39xx-0010 with CP-Link 4 and CU8802 transmitter box or PCIe module, the power consumption
increases. In this case, orient yourself to the following example:
• CP3924-0010
• Power consumption: 40 W
• Current consumption: 40 W / 22 V = 1.8 A