Power Supply, Potential Groups - Beckhoff BK9105 Documentation

Mounting and wiring
Power contacts
During the design of a Bus Terminal block, the pin assignment of the individual Bus Terminals must
be taken account of, since some types (e.g. analog Bus Terminals or digital 4-channel Bus Termi-
nals) do not or not fully loop through the power contacts. Power Feed Terminals (KL91xx, KL92xx
and EL91xx, EL92xx) interrupt the power contacts and thus represent the start of a new supply rail.
PE power contact
The power contact labelled PE can be used as a protective earth. For safety reasons this contact mates first
when plugging together, and can ground short-circuit currents of up to 125 A.
Risk of damage to the device
Note that, for reasons of electromagnetic compatibility, the PE contacts are capacitatively coupled to the
mounting rail. This may lead to incorrect results during insulation testing or to damage on the terminal (e.g.
disruptive discharge to the PE line during insulation testing of a consumer with a nominal voltage of 230 V).
For insulation testing, disconnect the PE supply line at the Bus Coupler or the Power Feed Terminal! In or-
der to decouple further feed points for testing, these Power Feed Terminals can be released and pulled at
least 10 mm from the group of terminals.
Risk of electric shock!
The PE power contact must not be used for other potentials!
Wiring
Up to eight connections enable the connection of solid or finely stranded cables to the Bus Terminals. The
terminals are implemented in spring force technology. Connect the cables as follows:
1. Open a spring-loaded 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 perma-
nently.
Shielding
Analog sensors and actuators should always be connected with shielded, pair-wise twisted cables.
3.3

Power supply, potential groups

Power supply for the Bus Coupler
The Bus Couplers require a 24 V
spring-loaded terminals labelled 24 V and 0 V. The supply voltage feeds the Bus Coupler electronics and,
over the K-Bus/E-Bus, the Bus Terminals. The power supply for the Bus Coupler electronics and that of the
K-Bus/E-Bus are electrically separated from the potential of the field level.
Power supply for the power contacts
The bottom six connections with spring-loaded terminals can be used to feed the supply for the peripherals.
The spring-loaded terminals are joined in pairs to a power contact. The feed for the power contacts has no
connection to the voltage supply for the Bus Coupler. The design of the feed permits voltages of up to 24 V.
The assignment in pairs and the electrical connection between feed terminal contacts allows the connection
wires to be looped through to various terminal points. The current drawn from the power contacts must not
exceed 10 A for long periods. The current carrying capacity between two spring-loaded terminals is identical
to that of the connecting wires.
16
NOTE
WARNING
supply for their operation. The connection is made by means of the upper
DC
Version: 2.0.0 BK9055 and BK9105