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.
612 Fieldbus control through a fieldbus adapter
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