Control through the embedded fieldbus interface 337
Control word and Status word
The Fieldbus control word (CW) is a 16-bit or 32-bit packed boolean word. It 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. In the embedded fieldbus
communication, the CW is written to drive parameter 02.36 EFB main cw from where
it can be used in the control of the drive. The Fieldbus CW is either written to the drive
Control word as it is, or the data is converted. See section About the EFB
communication profiles on page 338.
The Fieldbus status word (SW) is a 16-bit or 32- bit packed boolean word. It contains
status information from the drive to the fieldbus controller. In the embedded fieldbus
communication, the SW is read from drive parameter 02.37 EFB main sw. The Drive
status word is either written to the fieldbus SW as it is or the data is converted. See
section About the EFB communication profiles on page 338.
References
Fieldbus references (REF1 and REF2) are 16-bit or 32-bit signed integers. The
contents of each reference word can be used as the speed, frequency, or process
reference. In the embedded fieldbus communication, the REF1 and REF2 are written
to 02.38 EFB main ref1 and 02.39 EFB main ref2 from where you can use them in the
control of the drive. The references are either written to the drive references as they
are, or the values are scaled. See section About the EFB communication profiles on
page 338.
Actual values
Fieldbus actual signals (ACT1 and ACT2) are 16-bit or 32-bit signed integers. They
convey selected drive parameter values from the drive to the master. The drive
values are either written to the fieldbus actual values as they are, or the values are
scaled. See section About the EFB communication profiles on page 338.
Data inputs/outputs
Data input/output (I/O) are 16-bit or 32-bit words containing selected drive parameter
values. Parameters 58.35 Data I/O 1 … 58.58 Data I/O 24 define the addresses from
which the master either reads data (input) or to which it writes data (output).
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