Mounting and wiring
BK11x0, BK1250
41
Version: 4.1
Power contacts
On the right hand face of the Bus Coupler there are three 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.
Fig. 30:
Potential diagram EKxxxx
5.6
Ethernet cable
Transmission standards
10Base5
The transmission medium for 10Base5 consists of a thick coaxial cable ("yellow cable") with a max.
transmission speed of 10 Mbaud arranged in a line topology with branches (drops) each of which is
connected to one network device. Because all the devices are in this case connected to a common
transmission medium, it is inevitable that collisions occur often in 10Base5.
10Base2
10Base2 (Cheaper net) is a further development of 10Base5, and has the advantage that the coaxial cable is
cheaper and, being more flexible, is easier to lay. It is possible for several devices to be connected to one
10Base2 cable. It is frequent for branches from a 10Base5 backbone to be implemented in 10Base2.
