Rockwell Automation 2755 Enhanced Decoder Series B - Manual (Page 122)

8–9 Configuration: Extended Match Table and Counters
Publication 2755-833
Output Duration
!
ATTENTION: Outputs that are addressed from
multiple Extended Match Code Table entries (or from
both Primary and Extended Match Code Table entries)
and have overlapping durations will activate as shown
below. Failure to consider this fact could lead to
unexpected discrete output behavior.
The settings in the Primary Match Code Table determine the duration
of all outputs initiated by the Extended Match Codes.
For example, assume output 1 is set to activate for 100 ms on a
match to 1234 in the Primary Match Code Table, and to activate on a
match to 1345 in the Extended Match Code Table. The duration of
the Extended Match Code Table activation will be 100 ms (as
established in the Primary Match Code Table). If the decoder reads
1234, followed 75 ms later by 1345, the resulting timing will be the
175 ms. The following illustration will help explain why.
Read 1234
Output Timing of
1234 Alone
Output Timing of
1345 Alone Read 1345
Output Timing of
12341345
Milliseconds
0 25 50 75 100 125 150 175 200
Combined
Result