Omron SYSMAC C Series User Manual page 43

Note:
Forced timer set
To force set a timer, put the PC in MONITOR mode and press
The display shows the first timer, Timer 00, and its preset time if the timer
is not currently running. Then, to clear the set time for one scan time,
press
Due to the short cycle period, however, you will not be able to see this
clearing actually take place. If the timer is currently operating, depressing
MONTR
displays the current value of the timer. If the timer has completely gone
through its timing period, you will see this value.
Depressing
RESET
restarts the timing operation from the set time.
Special auxiliary relays 1808 to 1907 cannot be forcibly set or reset.
These relays serve as flags that are internally "raised" and "lowered" (set
and reset) to enable monitoring of PC operation. If an attempt is made to
set or reset one of these relays, you'll hear a beep and no key input will be
accepted by the programming console.
Changing set value of timer or counter
It's also possible to change the set value of a timer/counter during
program execution. This is used for such purposes as slowing down or
speeding up an assembly line operation without having to stop the
program.
This operation can only be done in MONITOR mode. To reset the value of
a timer, first key in