Power supply, potential groups

Bus Coupler power supply

The Bus Couplers require a 24 VDC supply for their operation. The connection is made by means of the upper spring-loaded terminals labelled 24 V and 0 V. The supply voltage is used by the Bus Coupler electronics and for direct voltage generation for the E-bus. The voltage generation for the E-bus takes place in a DC/DC converter without electrical isolation.

Note

E-bus power supply

The EK18xx units supply the E-bus with max. 1000 mA E-bus current.
Power feed terminals are to be inserted if the added terminals require more current!

Input for power contacts

The connections with spring-loaded terminals can be used for the peripheral supply. The spring-loaded terminals are linked with 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 current load via the power contacts may not permanently exceed 10 A; the supply line must therefore be protected by a 10 A fuse (slow-blow).

Power contacts

On the right hand face of the Bus Coupler there are two spring contacts for the power contact connections. The spring contacts are hidden in slots so that they can not be accidentally touched. By attaching a Bus Terminal the blade contacts on the left hand side of the Bus Terminal are connected to the spring contacts. The tongue and groove guides on the top and bottom of the Bus Coupler and of the Bus Terminals guarantees that the power contacts mate securely.

The current load of the power contacts may not permanently exceed 10 A.

Electrical isolation

The bus couplers operate by means of three independent potential groups. The supply voltage feeds the E-bus electronics in the bus coupler and the E-bus itself, which are electrically isolated. The supply voltage is also used to generate the operating voltage for the fieldbus.

Note: All the Bus Terminals are electrically isolated from the E-bus. The E-bus is thus electrically isolated from everything else.

Power supply, potential groups 1:
Potential connection diagram (example EK1814)

GND concept

Power supply, potential groups 2:
GND concept EK18xx

Fuse protection

Coupler supply, fuse 1:

depending on the required current consumption and hence the configured terminals typ. max 500 mA

Power supply, potential groups 3:

Calculating the fuse protection

For dimensioning the fuse protection for the system voltage note the calculation of current consumption in the technical data!

Power contacts, fuse 2:

permitted max. 10 A (slow-blow)

Coupler electronics and power contacts can be supplied together from the same source; the fusing must then be dimensioned accordingly to max. 10 A.