B&B Electronics GW-7553 - Manual - Manual (Page 11)

In order to minimize the reflection effect of signal transmission, both ends (first
node and last node) of a PROFIBUS segment needs to be equipped with an
active terminal resistor as shown in figure 6. A standard PROFIBUS connector
is usually already equipped with a terminal resistor. The user therefore only has
to switch on the resistor of the devices stationed at the ends of a segment as
shown in figure 7.
Figure 6 PROFIBUS connection
Terminator Switch
Terminator OFF
Terminator ON
Figure 7 PROFIBUS connector
GW-7553 PROFIBUS/Modbus TCP Gateway User Manual (Version 1.00, Dec/2008) PAGE: 11