Rockwell Automation 1756-SYNCH ControlLogix SynchLink Module User Manual - Manual (Page 44)

Publication 1756-UM521C-EN-P - July 2004
3-16 SynchLink Module Features
Transmitted Direct Words
The SynchLink module can transmit data from the following direct
word sources:
• Output Direct Words (0-3)
• Received Direct Words (0-3)
• Multiplier
In initial configuration, you can choose the Transmitted Direct Words,
but you must use ladder logic to move data to those locations in data
type tags. For more information on the data tags, see Appendix E.
Direct Words
Direct words are data delivered in a single message. These can be
read from the module input tags (i.e. Local.x.I.DirectData[x]) and sent
from the module output tags (i.e. Local.x.O.DirectData[x]). A
SynchLink message can contain a maximum of four direct data words;
each word is 32 bits in length. Direct data can be automatically
forwarded to the next node in the daisy chain or ring configuration.
Multiplier
The Multiplier multiplies one Direct Word on the receive port by the
value in the local tag "Local:x:O.Multiplier" before transmitting it out
the transmit port. This is useful when your application requires fine
adjustments to the direct word between SynchLink nodes.
Although you can configure the multiplier for any of the Direct Words,
it can only be used with one Direct Word at a time.
EXAMPLE
If the Direct Word 0 passes process status on and the
local controller in the downstream chassis identifies
a change in the process, you can use the multiplier
to change the value of the direct word before
passing it on to the next processor.