Beckhoff EtherCAT EP3752-0000, Documentation

Page: 16 / 58

Mounting and cabling
EP3752-0000 16 Version: 1.4
4.2 Supply voltages
WARNING
Power supply from SELV/PELV power supply unit!
SELV/PELV circuits (Safety Extra Low Voltage, Protective Extra Low Voltage) according to
IEC 61010-2-201 must be used to supply this device.
Notes:
• SELV/PELV circuits may give rise to further requirements from standards such as IEC 60204-1 et al, for
example with regard to cable spacing and insulation.
• A SELV (Safety Extra Low Voltage) supply provides safe electrical isolation and limitation of the voltage
without a connection to the protective conductor,
a PELV (Protective Extra Low Voltage) supply also requires a safe connection to the protective conduc-
tor.
CAUTION
Observe the UL requirements
• When operating under UL conditions, observe the warnings in the chapter UL Requirements [ } 21] .
The EtherCAT Box has one input for two supply voltages:
• Control voltage U
S
The following sub-functions are supplied from the control voltage U
S
:
◦ the fieldbus
◦ the processor logic
◦ typically the inputs and the sensors if the EtherCAT Box has inputs.
• Peripheral voltage U
P
For EtherCAT Box modules with digital outputs the digital outputs are typically supplied from the
peripheral voltage U
P
. U
P
can be supplied separately. If U
P
is switched off, the fieldbus function, the
function of the inputs and the supply of the sensors are maintained.
The exact assignment of U
S
and U
P
can be found in the pin assignment of the I/O connections.
Redirection of the supply voltages
The power IN and OUT connections are bridged in the module. Hence, the supply voltages U
s
and U
p
can be
passed from EtherCAT Box to EtherCAT Box in a simple manner.
NOTE
Note the maximum current!
Ensure that the permitted current for the connectors is not exceeded when routing the supply voltages U
S
and U
P
:
M8 connector: max. 4 A
7/8" connector: max 16 A
NOTE
Unintentional cancellation of the electrical isolation of GND
S
and GND
P
possible.
In some types of EtherCAT Box modules the ground potentials GND
S
and GND
P
are connected.
• If several EtherCAT Box modules are supplied with the same electrically isolated voltages, check
whether there is an EtherCAT Box among them in which the ground potentials are connected.