Fieldbus control interface
The communication between a fieldbus system and the drive consists of 16-bit input
and output data words (with the ABB drives profile) and 32-bit input and output words
(with the DCU profile).
Control word and Status word
The Control word (CW) is the principal means of controlling the drive from a fieldbus
system. The Control word is sent by the fieldbus controller to the drive. The drive
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.
References
References (REF) are 16-bit signed integers. A negative reference (eg reverse
direction of rotation) is formed by calculating the two's complement from the
corresponding positive reference value. The contents of each reference word can be
used as the speed, frequency, torque or process reference.
Actual values
Actual values (ACT) are 16-bit words containing selected values of the drive.
Fieldbus control with embedded fieldbus 307