ACS550 User’s Manual 181
Fieldbus Adapter
Control Interface
In general, the basic control interface between the fieldbus system and the drive
consists of:
• Output Words:
– CONTROL WORD
– REFERENCE (speed or frequency)
– Others: The drive supports a maximum of 15 output words. Protocols limits
may further restrict the total.
• Input Words:
– STATUS WORD
– Actual Value (speed or frequency)
– Others: The drive supports a maximum of 15 input words. Protocols limits may
further restrict the total.
Note! The words “output” and “input” are used as seen from the fieldbus controller
point of view. For example an output describes data flow from the fieldbus controller
to the drive and appears as an input from the drive point of view.
The meanings of the controller interface words are not restricted by the ACS550.
However, the profile used may set particular meanings.
Control Word
The CONTROL WORD is the principal means for controlling the drive from a fieldbus
system. The fieldbus controller sends the
CONTROL WORD to the drive. The drive
switches between states according to the bit-coded instructions in the
CONTROL
WORD. Using the CONTROL WORD requires that:
• The drive is in remote (REM) control.
• The serial communication channel is defined as the source for controlling
commands from EXT1 (set using parameters 1001 EXT1 COMMANDS and 1102
EXT1/EXT2 SEL).
• The external plug-in fieldbus adapter is activated:
Fieldbus
Fieldbus Controller
Control Word (CW)
References
Status Word (SW)
Actual Values
Parameter R/W Requests/Responses
Process I/O
Service
Messages
(Acyclic)
(cyclic)
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