ABB ACS880-01 Series, Firmware Instructions

Page: 77 / 664

Program features 77
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Control of a supply unit (LSU)
General
With drives that consist of a supply unit and one inverter unit, the supply unit can be
controlled through the inverter unit. (In drive systems consisting of multiple inverter
units, this feature is not typically used.) For example, the inverter unit can send a
control word and references to the supply unit, enabling the control of both units from
the interfaces of one control program.
For more information, refer to the firmware manual of the other converter.
Topology
The control units of the supply unit and the inverter unit are connected by fiber optic
cables. With BCU-x2 control units equipped with RDCO modules, CH1 of the inverter
is connected to CH0 of the supply unit.
An example connection with a BCU-based drive system is shown below.
With single drives consisting of separate supply and inverter units, the connection is
factory-wired.
The fiber optic link specifications stated under Specifications of the fiber optic
master/follower link (page 74 ) apply.
Communication
The communication between the converters and the drive consists of data sets of
three 16-bit words each. The inverter unit sends a data set to the supply unit, which
returns the next data set to the inverter unit.
The communication uses data sets 10 and 11, updated at 2 ms intervals. Data sets
10 is sent by the inverter unit to the supply unit, while data set 11 is sent by the supply
unit to the inverter unit. The contents of the data sets are freely configurable, but data
set 10 typically contains the control word, while data set 11 returns the status word.
T = Transmitter; R = Receiver
Inverter unit (INU)
(BCU) Control unit
RDCO
CH1
Supply unit (LSU)
(BCU) Control unit
RDCO
CH0
R T R T