POSYC 4301/4302/4303 series industrial PCs
Installation, use and maintenance manual - EN
Rev. 1.02
29
Through appropriate repeater devices (maximum 9) it is possible to extend the connection and connect up to
126 devices.
Example of Profibus wiring
Termination resistors configuration
For correct operation it is necessary to use a suitable cable, terminating it appropriately. The
termination consists in connecting at the beginning and at the end of the section of resistors
with a defined ohmic value (see figure below); for the beginning and end of the section, the
master and the most remote slave are considered respectively (called 1 and 4 in the figure
below). The length of the cable connecting the intermediate line (called 2 and 3 in the figure
below) must be as short as possible (in any case below 1mt), otherwise the signal quality
will be lost.
It is good practice to connect the shield of the cable used at both ends to the ground; the
failure to connect the screen to the ground (disconnected from both ends) nullifies the func-
tion of the screen itself.
