ABB AC 800M User Manual page 68

Bus connector
transmit signals. The Sub-D plug, connected to the Sub-D connector of the device,
needs only the receive and transmit signals for the communication transmission.
The connector shown below include a terminating resistor that can be turned on and
off.
This type of connector can be used equally well at the beginning, end or middle of a
PROFIBUS segment. The terminating resistor must be turned on in the connector
for the first / last device on the bus segment. It must be turned off for the devices in
the middle.
Figure 23. PROFIBUS connector
One connector with a PG socket should be used in the most accessible spot (at the
beginning or end) for each line on every segment. This connector makes it
possible to attach a diagnostic device for service access.
Be sure that the connector type used is suitable for the selected transmission rate.
68
Section 3 Fieldbus Topologies
3BDS009029R5001 B