Omron SYSMAC CJ - REFERENCE MANUAL 08-2008 Reference Manual page 305

Timer and Counter Instructions
Note
Example
Timers will be reset or paused in the following cases. (When a TTIM(087)/
TTIMX(555) timer is reset, its PV is reset to 0000 and its Completion Flag is
turned OFF.)
Condition
Operating mode changed from RUN or
MONITOR mode to PROGRAM mode or
1
vice versa.
Power supply interrupted and reset
Execution of CNR(545)/CNRX(547), the
RESET TIMER/COUNTER instructions
Operation in interlocked program section
(IL(002)–ILC(003))
Operation in jumped program section
(JMP(004)–JME(005))
1. If the IOM Hold Bit (A50012) has been turned ON, the status of timer Com-
pletion Flags and PVs will be maintained when the operating mode is
changed.
2. If the IOM Hold Bit (A50012) has been turned ON and the status of the IOM
Hold Bit itself is protected in the PLC Setup, the status of timer Completion
Flags and PVs will be maintained even when the power is interrupted.
3. The PV will be set to the SV when TTIM(087)/TTIMX(555) is executed.
When TTIM(087)/TTIMX(555) is in a program section between IL(002) and
ILC(003) and the program section is interlocked, the PV will retain its previous
value (it will not be reset). Be sure to take this fact into account when
TTIM(087)/TTIMX(555) is programmed between IL(002) and ILC(003).
When an operating TTIM(087)/TTIMX(555) timer is in a program section
between JMP(004) and JME(005) and the program section is jumped, the PV
will retain its previous value. Be sure to take this fact into account when
TTIM(087)/TTIMX(555) is programmed between JMP(004) and JME(005).
When a TTIM(087)/TTIMX(555) timer is forced set, its Completion Flag will be
turned ON and its PV will be reset to 0000. When a TTIM(087)/TTIMX(555)
timer is forced reset, its Completion Flag will be turned OFF and its PV will be
reset to 0000. The forced set and forced reset operations take priority over the
status of the timer and reset inputs.
The timer's PV is refreshed only when TTIM(087)/TTIMX(555) is executed, so
the timer will not operate properly when the cycle time exceeds 100 ms
because the timer increments in 100-ms units.
The timer's Completion Flag is refreshed only when TTIM(087)/TTIMX(555) is
executed, so a delay of up to one cycle may be required for the Completion
Flag to be turned ON after the timer times out.
Typical timers such as TIM/TIMX(550) are decrementing counters and the PV
shows the time remaining until the timer times out. The PV of TTIM(087)/
TTIMX(555) shows how much time has elapsed, so the PV can be used
unchanged in many calculations and display outputs.
When timer input CIO 000000 is ON in the following example, the timer PV
will begin counting up from 0. Timer Completion Flag T0001 will be turned ON
when the PV reaches the SV.
If the reset input is turned ON, the timer PV will be reset to 0000 and the Com-
pletion Flag (T0001) will be turned OFF. (Usually the reset input is turned ON
to reset the timer and then the timer input is turned ON to start timing.)
PV
0000 OFF
2
0000 OFF
BCD: 9999 OFF
3
Binary: FFFF
Retains previ- Retains previous status.
ous status.
Retains previ- Retains previous status.
ous status.
Section 3-6
Completion Flag
265