ABB TruONE ATS Installation And Operating Instruction page 91

3 4 O X _ 3 0 - 1 6 0 0 r e v. B / 1 S C C 3 0 3 0 1 1 M 0 2 0 1
5.6.3.2 Termination resistor
The modules provide the possibility to in-
sert a 120 Ω termination resistor on the
CAN bus, by setting the DIP-switches
Rterm (1 and 2) on the side of the mod-
ules, in position ON. This option must be
selected before the installation of the
modules. With the Ekip Com DeviceNet -
modules, the dip-switches 3 and 4 of the
Rpol (polarization resistance), are not
used.
ON IA
1 2 3 4
Rterm Rpol
120Ω
on
off
—
Fig. 5.19 Termination resistor; To enable the Rterm, the
dip-switches 1 and 2 must be positioned to ON. This option
must be selected before the installation of the module.
on
off
Information
The termination resistors must never be in-
cluded in the nodes. The inclusion of this ca-
pability could easily lead to a network with im-
proper termination (impedance too high or
too low), potentially causing a failure. For ex-
ample the removal of a node, which includes a
termination resistor, could result in a network
failure.
The termination resistors must not be in-
stalled at the end of a branch (drop line), only
at the two ends of the main backbone (trunk
line).
91