ACQ550-U1 User’s Manual 231
Fieldbus adapter
• The serial communication channel is defined as the source for controlling 
commands from EXT1 (set using parameters 1001 EXT1 COMMANDS and 1102 
EXT1/EXT2 SEL).
• The external plug-in fieldbus adapter is activated:
– Parameter 9802 
COMM PROT SEL = 4 (EXT FBA).
– The external plug-in fieldbus adapter is configured to use the drive profile 
mode or drive profile objects.
The content of the 
CONTROL WORD depends on the protocol/profile used. See the 
user’s manual provided with the FBA module and/or section ABB Drives profile 
technical data on page 240.
Status Word
The 
STATUS WORD is a 16-bit word containing status information, sent by the drive to 
the fieldbus controller. The content of the 
STATUS WORD depends on the protocol/
profile used. See the user’s manual provided with the FBA module and/or section 
ABB Drives profile technical data on page 240.
Reference
The contents of each 
REFERENCE  word:
• can be used, as speed or frequency reference
• is a 16-bit word comprised of a sign bit and a 15-bit integer 
• Negative references (indicating reversed rotation direction) are indicated by the 
two’s complement of the corresponding positive reference value.
The use of a second reference (REF2) is supported only when a protocol is 
configured for the ABB Drives profile.
Reference scaling is fieldbus type specific. See the user’s manual provided with the 
FBA module and/or the following sections as appropriate:
• Reference scaling on page 244 (ABB Drives profile technical data)
• Reference scaling on page 248 (Generic profile technical data).
Actual Values
Actual Values are 16-bit words containing information on selected operations of the 
drive. Drive Actual Values (for example, Group 10: START/STOP/DIR parameters) 
can be mapped to Input Words using Group 51: EXT COMM MODULE parameters 
(protocol-dependent, but typically parameters 5104…5126). 
Planning
Network planning should address the following questions:
• What types and quantities of devices must be connected to the network?
• What control information must be sent down to the drives?
• What feedback information must be sent from the drives to the controlling 
system?