Rockwell Automation DeviceLogix System User Manual - Manual (Page 40)

40 Publication RA-UM003B-EN-P - February 2010
Chapter 2 Navigate the Function Block Editor Interface
The valid data ranges are as follows.
Pulse Timer
The Pulse Timer generates a TRUE value on its output for a fixed
amount of time. The duration of the TRUE pulse is determined by the
preset value along with the time base of the timer. When the input to
the timer changes from FALSE to TRUE, it sets the output to TRUE and
starts the accumulator counting. It then increments the accumulator
each time the time base number of milliseconds has expired. When
the accumulator reaches the preset value, the timer resets the output
to FALSE.
In the Pulse Timer, the input acts only as a trigger to start the
accumulator counting. Once the accumulator starts timing, it continues
to rise regardless of the state of the input. As long as the output is
TRUE and the accumulator is counting, additional triggers of the input
do not affect the state of the output or the count of the accumulator.
Once the accumulator reaches the preset value and the timer resets
the output to FALSE, the Pulse Timer can again trigger the process by
sensing a FALSE to TRUE transition on the input pin. Even if the input
remains on the entire time the accumulator is counting, when the
accumulator reaches the preset value, the timer resets the output to
FALSE.
At any point during the operation of the timer, if it detects a TRUE
level on the reset input, it will disable the timer and set the output to
FALSE. The timer must again be triggered by a FALSE to TRUE
transition on the input. This means that if the input is TRUE and the
timer is reset, the timer will remain inactive. Even if the reset changes
back to FALSE while the input is TRUE, the timer remains inactive. In
order to start a new pulse operation, the input must change to FALSE
and then back to TRUE.
Parameters Data Range
PRE 0 ~ 65535
ACC 0 ~ 65535
Time Base 0 (1 ms), 1 (10 ms)