29
AED
CONNECTING INTERFACES AND I/OS
CAN H
CAN L
Master
Node 1
Node X
...
120Ω
120Ω
Bus termination
Bus termination
Fig. 7.4
Possible connection variant
Bus termination (line termination)
The bus termination switch can be used to activate a differential resistance. Bus termina
tion may only be activated at the ends of the bus cable (max. 2 termination resistors are
active).
Important
The termination resistors may only be activated at the end points of the interface cable. If
resistors are also activated in between, this will weaken the signal and anything from
interference to data transmission failure could result.
Bus disconnection
Use the bus disconnection switch to disconnect the AED from the bus. This will not dis
connect the bus cable.
7.1.3
Connection to a PROFIBUS bus system
The PROFIBUS is electrically isolated from the measuring system and the supply voltage.
The transmission method is RS-485, the maximum possible baud rate is 12 Mbits/s. To
set the baud rate, use the PanelX program or a PROFIBUS configuration tool. Before
switching on, set the node address using the two BCD-coded rotary switches S4 and S5
(factory setting 3), see section 4.3 on page 13.
The PROFIBUS connection has four terminals, so that you can route it to the next bus
node. Use shielded, twisted-pair cables as connecting cables.
