140
If
the execution condition remains ON long enough
for TIM to time down to zero,
the Completion Flag for the TC number used will turn ON and will remain ON
until TIM is reset (i.e., until its execution condition is goes OFF).
The
following figure illustrates the relationship between the execution condition
for TIM and the Completion Flag assigned to it.
Execution
condition
Completion Flag
ON
OFF
ON
OFF
SV SV
Precautions Timers
in interlocked program sections are reset when the execution condition
for
IL(02) is OFF
. Power interruptions also reset timers. If a timer that is not reset
under these conditions is desired, SR area clock pulse bits can be counted to
produce timers using CNT. Refer to 5-14-4 COUNTER – CNT for details.
Program
execution will continue even if a non-BCD SV is used, but timing will not
be accurate.
The
SV of the timers can be set in the range #0000 to #9999 (BCD). If the SV for a
timer
is set to #0000 or #0001, it will operate in the following way
. If the
SV is set
to
#0000, when the timer input
goes from OFF to ON, the Completion Flag will
turn
ON. If the SV is set to #0001, because the timer accuracy is 0 to –0.1 s, the
actual time will be a value between 0 and 0.1 s, and the Completion Flag may
turn
ON as soon as the timer input goes from OFF to ON. With other values also,
allow for a timer accuracy of 0 to –0.1 s when setting the SV.
Flags ER:
SV is not in BCD.
Indirectly
addressed DM word
is non-existent. (Content of
∗
DM word is
not BCD, or the DM area boundary has been exceeded.)
Examples All
of the following examples use OUT in diagrams that would generally be used
to control output bits in the IR area. There is no reason, however
, why these dia
-
grams cannot be modified to control execution of other instructions.
The
following example shows two timers, one set with a constant and one set via
input
word 005. Here,
00200 will be turned ON after 00000 goes ON and stays
ON
for at least 15
seconds. When 00000 goes OFF
, the timer will be reset and
00200
will be turned OFF
. When 00001 goes ON, TIM 001 is started from the SV
provided through IR word 005. Bit 00201 is also turned ON when 00001 goes
ON.
When the SV in 005 has expired, 00201 is turned OFF
. This bit will also be
turned
OFF when TIM 001 is reset, regardless of whether or not SV has expired.
00000
TIM 000
00001
TIM 001
00200
00201
015.0 s
TIM 000
#0150
TIM 001
IR 005
IR 005
Address Instruction Operands
00000 LD 00000
00001 TIM 000
# 0150
00002 LD TIM 000
00003 OUT 00200
00004 LD 00001
00005 TIM 001
005
00006 AND NOT TIM 001
00007 OUT 00200
Example 1:
Basic Application
Timer and Counter Instructions Section 5-14
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