ABB SREA-50 Guide D'installation Et De Mise En Route page 8

8 Quick installation and start-up guide – SREA-50
Connection procedure
1. Connect SREA-50 to the inverter:
•
Connect the A- terminal of SREA-50 to the negative signal
connector (X4:2) of the inverter.
•
Similarly, connect the B+ terminal to the positive signal
connector (X4:1).
•
For signal ground, connect the COM terminal to X4:3.
•
Ground the cable shield(s) at one end only, for example, to
the PE busbar near the X4 connector of the inverter.
2. Wire any additional inverters so that the bus forms a daisy
chain topology as shown in the diagram above. Between the
units on the bus, ground the cable shield(s) at one end only.
3. Terminate the bus at each end. Whenever SREA-50 is at one
end of the bus, connect one of the 120 ohm resistors included
between its A- and B+ terminals. Whenever an inverter is
located at the end of the bus, activate its internal termination
by setting switch S1:2 to ON.
Note: The termination circuit built in the inverter is active and
requires that the inverter is powered. If the inverter is not
powered at all times, use an external 120 ohm resistor
(connected between X4:1 and X4:2) instead and make sure
that internal termination is disabled (S1:2 is set to OFF).