Figure 24: Two-Levelmaster Rs-485 Bus Of Same Board Type Using Both Communication Contact Pairs; Figure 25: Three-Levelmaster Rs-485 Bus (Same Board Type) - ABB LevelMaster 7100 User Manual

J11
T- T- T+ T+
EARTH
Last sensor on RS-485 bus

Figure 24: Two-LevelMaster RS-485 bus of same board type using both communication contact pairs

Figure 25 displays two additional LevelMasters connected to the first LevelMaster. The first and second LevelMasters are
intermediate units on the bus. The third must be configured to terminate the bus. Communication connections in intermediate
nodes use both pairs on the RS-485 ports.
IMPORTANT NOTES: Connection options depend on the type of wire, gauge, and user preference (see section
4.2, Selecting wire type). Figure 26 shows a two-LevelMaster bus with boards of the same type, where the
communication connection for the additional LevelMaster is through the same connection pair on the RS-485 port
on the first LevelMaster (instead of using both pairs as in shown in Figure 24). While using both pairs is
recommended, this connection also works and is left up to customer preference.
- +
1 POWER
D9
3
New electronic board
J12
(2104836-001)

Figure 25: Three-LevelMaster RS-485 bus (same board type)

(1) To barrier board or,
(2) To flow computer/remote controller
J11
T- T- T+ T+
1
EARTH 3
New electronic board
J12
First sensor on RS-485 bus
LevelMaster 7100 User manual 2105835 Rev AA | 29
- +
POWER
D9
(2104836-001)