ABB ACQ550-U1-011A-6, User Manual

Page: 179 / 314

ACQ550-U1 User’s Manual 179
Embedded fieldbus
Mechanical and electrical installation – EFB
Warning! Connections should be made only while the drive is disconnected from the
power source.
Drive terminals 28
…
32 are for RS485 communications.
• Use Belden 9842 or equivalent. Belden 9842 is a dual twisted, shielded pair cable
with a wave impedance of 120

.
• Use one of these twisted shielded pairs for the RS485 link. Use this pair to
connect all A (-) terminals together and all B (+) terminals together.
• Use one of the wires in the other pair for the reference/common (terminal 31),
leaving one wire unused.
• Do not directly ground the RS485 network at any point. Ground all devices on the
network using their corresponding earthing terminals.
• As always, the grounding wires should not form any closed loops, and all the
devices should be earthed to a common ground.
• Connect the RS485 link in a daisy-chained bus, without dropout lines.
• To reduce noise on the network, terminate the RS485 network using 120

resistors at both ends of the network. Use the DIP switch to connect or disconnect
the termination resistors. See following wiring diagram. The ACQ550 termination
resistor (J-2) are active terminators. This active circuit includes bins (“Pull-up” and
“Pull-down”) resistors.
• Connect the shield at each end of the cable to a drive. On one end, connect the
shield to terminal 28, and on the other end connect to terminal 32. Do not connect
the incoming and outgoing cable shields to the same terminals, as that would
make the shielding continuous.
• For configuration information see the following:
– Communication setup – EFB on page 181 .
– Activate drive control functions – EFB on page 185 .
– The appropriate EFB protocol specific technical data. For example, Modbus
protocol technical data on page 197 .