The Control Word And The Status Word; References; Fieldbus Reference Selection; Reference Handling - ABB ACS800 Firmware Manual

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The Control Word and the Status Word

The Control Word (CW) is the principal means of controlling the drive from a fieldbus
system. It is effective when the active control location (EXT1 or EXT2, see
parameters 10.01 and 10.02) is set to COMM.CW, or if Par. 10.07 is set to 1 (with
Generic Drive communication profile only).
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.
See section
of the Control Word and the Status Word.

References

References (REF) are 16-bit signed integers. A negative reference (indicating
reversed direction of rotation) is formed by calculating the two's complement from
the corresponding positive reference value.

Fieldbus reference selection

Fieldbus reference (called COMM. REF in signal selection contexts) is selected by
setting a Reference selection parameter – 11.03 or 11.06 – to COMM. REFx or FAST
COMM. (With Generic Drive communication profile, fieldbus reference is also
selected when Par. 10.08 is set to 1.)
COMM. REF1 (in 11.03) or COMM. REF2 (in 11.06)
The fieldbus reference is forwarded.
FAST COMM
The fieldbus reference is forwarded. The reference is read every 2 milliseconds if
either of the following conditions is met:
• Control location is EXT1, Par. 99.04 MOTOR CTRL MODE is DTC
• Control location is EXT2, Par. 99.04 MOTOR CTRL MODE is DTC and a torque
reference is used.
In any other event, the fieldbus reference is read every 6 milliseconds.

Reference handling

The control of rotation direction is configured for each control location (EXT1 and
EXT2) using the parameters in group 10. Fieldbus references are bipolar, that is they
can be negative or positive. The following diagrams illustrate how group 10
parameters and the sign of the fieldbus reference interact to produce the reference
REF1/REF2.
Notes:
• With the ABB Drives communication profile, 100% reference is defined with
parameters
Fieldbus control
Communication profiles
11.05 (REF1) and
on page 249 for information on the composition
11.08 (REF2).