Fieldbus control
148
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 is set to FIELDBUS.
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 Communication profiles on page 149 for information on the composition
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.
Reference handling
The control of rotation direction is configured using the parameters in group 10.
Fieldbus references are bipolar, i.e. they can be negative or positive.
Notes:
• 100% reference is defined by parameter 11.05
• External reference scaling parameter 11.04 is also in effect.
Actual Values
Actual Values (ACT) are 16-bit words containing information on selected operations
of the drive. The functions to be monitored are selected with the parameters in group
92. The scaling of the integers sent to the master as Actual Values depends on the
selected function; please refer to chapter Actual signals and parameters.
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