Rockwell Automation 1769-BOOLEAN Compact I/O Module Reference Manual - Manual (Page 18)

Publication 1769-RM016A-EN-P - July 2006
18 Module Operation
Output Delay and Duration Operation
Since an output's Boolean expression can change in real time, configuring a
delay and/or duration time when an output is in Boolean control mode could
cause confusion.
The module shall operate in the following manner when output delay and/or
duration times are configured to non-default values (while an output is
configured for Boolean control).
When the Boolean expression controlling an output transitions from FALSE
to TRUE, the output will be directed ON after the delay time has expired only
if:
Case 1
• The output's duration time is not equal to 0. In this case the output
should be directed ON for the length of the duration time regardless of
the state of the output's Boolean expression and then should be directed
OFF regardless of the state of the Boolean expression.
• In Case 1 a “One-shot” type of function has been configured. The
output will be turned ON with a single pulse of configured delay time
and duration time when the output's Boolean expression becomes
TRUE. The length of time the Boolean expression remains TRUE does
not determine whether the “One-shot” pulse occurs. As long as the
duration time of the output has been configured to a value greater than
0, then a “One-shot” ON pulse will occur and the output will remain
ON for the length of the duration time. The output will then turn OFF
regardless of the state of the output's Boolean expression.
• Retriggering of the output is not supported. Any additional transitions
of the output's Boolean expression from FALSE to TRUE after the
initial transition to TRUE are ignored for a length of time equal to the
configured delay time added to the configured duration time. Once the
output's “One-shot” pulse duration is complete, and the output is
turned OFF, a FALSE to TRUE transition of the Boolean expression
will cause another “One-shot” ON pulse to occur.
Case 2
• The output's duration is equal to 0 and the output's Boolean expression
has maintained a state of TRUE for the entire delay time. The output
should then be directed OFF when the output's Boolean expression
becomes FALSE.