Rockwell Automation 1756-SYNCH ControlLogix SynchLink Module User Manual - Manual (Page 45)

Publication 1756-UM521C-EN-P - July 2004
SynchLink Module Features 3-17
The multiplier can only transmit the same word it received (i.e. this
feature does not allow your module to receive direct word 0 and
transmit it as direct word 1). The multiplier output is limited to 16 bits;
any value generated by the multipler larger than 65535 is truncated to
16 bits, and a multiplier overflow error (described below) is reported
by the Synchlink module. Make sure any data that is passed onto the
Output word is less than 65535 else you receive incorrect output data.
Mutiplier Overflow
The Multiplier Overflow bit is a data tag ( Local.x.I.SynchLinkMultiplier
Overflow) that exceeds the maximum multiplier value of 65535. This value is
reported back to you through the input data tags.
The Transmitted Direct Words are configured on the following screen:
IMPORTANT
The Multiplier on Transmitted Direct Words truncates
values after the decimal point and can give
misleading results under some circumstances. For
example, using a multiplier of 0.95 with a value of 20
yields a result of 18 instead of the expected 19. The
reason for this error is that 0.95 is represented by a
floating point value (~0.949999). The result of
18.9998 is truncated to 18 instead of rounded to 19.
We recommend you verify your results when using
the multiplier function.
IMPORTANT
If you want to pass a Multiplier Overflow value
(received from an upstream node) to a third node
downstream but not locally change the direct word
data transmitted to the downstream node, you must
use a Multiplier value = 1.
Transmitted Direct Words