Chapter 9—C445 Logic Engine and Expansion I/O
186
Power Xpert C445 Global Motor Management Relay
MN042003EN—January 2019
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RTON—Retentive On-Delay Timer
The RTON function block is a retentive on-delay timer that delays a FALSE to TRUE
transition of IN to OUT by a time defined by PT. Once the timer reaches the PT, the timer
stops running and sets the OUT to TRUE. This behavior is the same as that of the TON
function block, but compared to TON, the RTON function block can retain the state of the
timer when IN transitions from TRUE to FLASE before the timer could complete (ET = PT),
essentially “pausing” the timer. When the IN transitions back to TRUE while the timer is in
the paused state, the timer resumes from its retained state instead of starting from zero.
The timer can be reset by providing a rising edge trigger to the RESET input. In addition to
being retentive, the timer is also persistent through power cycle, meaning that the timer
will retain its state in the event of a power loss to the device.
Parameter
Data type
Description
IN
BOOL
Input trigger to start timer—rising edge
PT
UINT
Preset time (x1ms, x10ms, 100ms, x1s)
RESET
BOOL
Reset timer—rising edge
OUT
BOOL
Timer expired flag—active high
ET
UINT
Elapsed time (x1ms, x10ms, 100ms, x1s)
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