Rockwell Automation 1769-BOOLEAN Compact I/O Module Reference Manual - Manual (Page 19)

Publication 1769-RM016A-EN-P - July 2006
Module Operation 19
• In Case 2 the output will follow the state of the Boolean expression as
long as the configured delay time has expired and the Boolean
expression has maintained a TRUE state. When an output's Boolean
expression transitions from FALSE to TRUE, the output will be turned
ON only if the Boolean expression has maintained a state of TRUE for
the entire length of the delay time. If the output's Boolean expression
transitions to FALSE before the configured delay time expires, then the
delay time should be terminated and the output should not be turned
ON. If the output's Boolean expression has maintained a TRUE state
for the full length of the delay time, the output will be turned ON and
will remain ON until the Boolean expression becomes FALSE.
• If an output's Boolean expression is configured with both the delay and
duration times set to 0, then the output simply follows the state of the
Boolean expression, ON when the expression is TRUE and OFF when
it is FALSE.
Boolean Control Mode
Examples The following examples illustrate the module's operation when an output is
configured in Boolean control mode. Examples 1…5 show module output
operation for Case 1 where the configured duration time is greater than 0.
Examples 6 and 7 show module operation for Case 2 where the configured
duration time is equal to 0.
Example 1: Duration > 0, Delay > TRUE Time
In this example, the output is configured with a duration time greater than 0, a
delay time greater than 0, and the configured delay time is longer than the time
that the Boolean expression remains TRUE.
Since the configured duration time is greater than 0, a “One-shot” pulse
occurs on the output. The pulse starts an amount of time after the FALSE to
TRUE transition of the Boolean expression equal to the configured delay time.
The “One-shot” pulse lasts as long as the configured duration time even
though the Boolean expression transitions to FALSE. The second “One-shot”
pulse occurs on the output since there was a FALSE to TRUE transition in the
Boolean expression after the first “One-shot” pulse is completed.