Installation manual

Publication 1747-RM001G-EN-P - November 2008
Basic Instructions 2-11
Retentive Timer (RTO)
Use the RTO instruction to turn an output on or off after its timer has been on
for a preset time interval. The RTO instruction is a retentive instruction that
begins to count timebase intervals when rung conditions become true.
The RTO instruction retains its accumulated value when any of the following
occurs.
• Rung conditions become fals.
• You change processor operation from the REM Run or REM Test
mode to the REM Program mode
• The processor loses power (provided that battery backup is maintained)
• A fault occurs
When you return the processor to the REM Run or REM Test mode and/or
rung conditions go true, timing continues from the retained accumulated
value. By retaining its accumulated value, retentive timers measure the
cumulative period during which rung conditions are true.
ATTENTION
The Reset (RES) instruction cannot be used with the
TOF instruction because RES always clears the status
bits as well as the accumulated value. (See 2-20)
TIP
The TOF timer times inside an inactive MCR Pair.
(EN)
(DN)
RTO
RETENTIVE TIMER ON
Timer T4:2
Time Base 0.01
Preset 120
Accum 0
Output Instruction
Fixed SLC
5/01
SLC
5/02
SLC
5/03
SLC
5/04
SLC
5/05
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