Appendix A – Fieldbus control
428
switches between its states according to the bit-coded instructions of the Control
Word.
The Status Word (SW) is a word containing status information, sent by the drive to
the fieldbus controller.
Actual values
Actual values (ACT) are 16/32-bit words containing information on selected
operations of the drive.
FBA communication profile
The FBA communication profile is a state machine model which describes the
general states and state transitions of the drive. The State diagram on page 429
presents the most important states (including the FBA profile state names). The FBA
Control Word (2.12 FBA MAIN CW, page 95) commands the transitions between
these states and the FBA Status Word (2.13 FBA MAIN SW, page 98) indicates the
status of the drive.
Fieldbus adapter module profile (selected by adapter module parameter) defines
how the control word and status word are transmitted in a system which consists of
fieldbus controller, fieldbus adapter module and drive. With transparent modes,
control word and status word are transmitted without any conversion between the
fieldbus controller and the drive. With other profiles (eg, PROFIdrive for FPBA-01,
AC/DC drive for FDNA-01, DS-402 for FCAN-01 and ABB Drives profile for all
fieldbus adapter modules) fieldbus adapter module converts the fieldbus-specific
control word to the FBA communication profile and status word from FBA
communication profile to the fieldbus-specific status word.
For descriptions of other profiles, see the User’s Manual of the appropriate fieldbus
adapter module.
Fieldbus references
References (FBA REF) are 16/32-bit signed integers. A negative reference is formed
by calculating the two’s complement from the corresponding positive reference
value. The contents of each reference word can be used as speed, torque, position,
synchron or profile velocity reference.
When torque or speed reference scaling is selected (by parameter 50.04 FBA REF1
MODESEL / 50.05 FBA REF2 MODESEL), the fieldbus references are 32-bit
integers. The value consists of a 16-bit integer value and a 16-bit fractional value.
The speed/torque reference scaling is as follows:
Reference Scaling Notes
Torque reference FBA REF / 65536
(value in %)
Final reference is limited by parameters 20.06 MAXIMUM
TORQUE and 20.07 MINIMUM TORQUE.
Speed reference FBA REF / 65536
(value in rpm)
Final reference is limited by parameters 20.01 MAXIMUM
SPEED, 20.02 MINIMUM SPEED and 24.12 SPEED
REFMIN ABS.
Position reference
See parameter group 60 (page 219)
Velocity reference