Rockwell Automation 1336T Function Block Prog. Manual, Series A/B - Manual (Page 40)

2–6 System Component Detail
1336 FORCE — 5.9 August 1995
For example, if you want to use the output, or result, of an ADD2
function block as an input to a SCALE function block, you can create
a link between the two function blocks as shown here.
Input Output ADD2 SCALE Input Output
Link between nodes
You can also create a function block that is linked to a linear
parameter, such as the velocity feedback parameter. In addition, if
you have two function blocks that both use the drive’s velocity
feedback parameter, you can link their input parameters together so
that both function blocks receive the same input data.
When you link two function blocks, the information about the link
(source reference number) is stored with the function block that
receives the information (destination) and not with the function
block that provides the information (source). In the example above,
the information about the link is stored at the input to the SCALE
function block.
Link Operation During Execution
During execution, the drive processes the function block links one
function block at a time. If two function block inputs are both linked
to the same linear drive parameter, the drive transfers the data from
the required parameter twice. Because the drive parameters are
updated every one to two milliseconds, the values for the same drive
parameter may be different during the same pass through the
application.
In the following example, the LIMIT and MULTIPLY function blocks
both receive input from the same drive parameter. However, they
may receive a different value from the drive parameter during the
same pass through the application.
LIMIT
MULTIPLY
Velocity Feedback
from the drive
Input
Input
Event 1
Event 24