Mitsubishi Electric L02SCPU User's Manual And Reference page 306

(7) Precautions for using timers
(a) Use of the same timer
Do not use the OUT T or OUT ST instruction that describes the same timer more than once within one
scan. If used, the current timer value will be updated by each OUT T or OUT ST instruction execution,
resulting in incorrect time measurement.
(b) When the timer is not executed in every scan
Current values are not updated for every scan, resulting in incorrect time measurement. While a coil of a timer
is on, do not make the OUT T or OUT ST instruction jumped to any other part with another instruction such
as CJ.
For subroutine programs where a timer is provided and a coil is on, use the timer once in each scan.
(c) Programs that cannot use timers
Timers cannot be used in interrupt programs and fixed scan execution programs.
(d) When the set value is 0:
The contact turns on when the OUT T or OUT ST instruction is executed.
(e) Timer setting value and timer limit setting
Set the timer to meet the following condition:
Timer setting value
If the values are set to become "Timer setting value < Scan time + Timer Limit Setting", the coil and the contact
might be simultaneously turned on depending on the timing on which the coil is turned on.
If the setting does not meet the above condition, make the value of the timer limit setting smaller to meet the
condition.
304
Scan time
K2
(SD526,SD527)
T0
Timer limit setting