With DeviceNet, the control part is transmitted directly.4)
With DeviceNet, the actual value part is transmitted directly.5)
￭
Control word and Status word
The Control word is the principal means for controlling the drive from a fieldbus
system. It is sent by the fieldbus master station to the drive through the adapter
module. The drive switches between its states according to the bit-coded
instructions in the Control word, and returns status information to the master in
the Status word.
For the ABB Drives communication profile, the contents of the Control word and
the Status word are detailed on pages 573 and 574 respectively. The drive states
are presented in the state diagram (page 575).
When a transparent communication profile is selected eg. by parameter group 51
FBA A settings, the control word received from the PLC is available in 6.3 FBA A
transparent control word. The individual bits of the word can then be used for
drive control through bit pointer parameters. The source of the status word, for
example 6.50 User status word 1, can be selected in 50.9 FBA A SW transparent
source.
Debugging the network words
If parameter 50.12 FBA A debug mode is set to Fast, the Control word received
from the fieldbus is shown by parameter 50.13 FBA A control word, and the Status
word transmitted to the fieldbus network by 50.16 FBA A status word. This “raw”
data is very useful to determine if the fieldbus master is transmitting the correct
data before handing control to the fieldbus network.
630 Fieldbus control through a fieldbus adapter
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