Omron SYSMAC CV Series Operation Manual page 152

Timer and Counter Instructions
Counters
Set Values
T/C Numbers as Operands
140
Present values (PV) and Completion Flags for TIM and TIMH(015) timers are
refreshed as shown in the following table.
Instruction At execution
TIM PV refreshed and
Completion Flag turned
ON if PV is 0000.
TIMH using Not refreshed
T0000 to T0255
TIMH using PV refreshed and
T0256 to T1023 Completion Flag turned
ON if PV is 0000.
The counter instructions in this section are used to create counter. Most count-
ers require a counter number and a SV, and are connected to multiple instruction
lines which serve as input signals, resets, etc. TCNT(123), an SFC control
instruction, also requires a counter number. Refer to 5-37 SFC Control Instruc-
tions , for details on TCNT(123).
Any one counter number cannot be defined twice, i.e., once it has been used in
any of the counter instructions it cannot be used again unless the two counters
are never active simultaneously. If two counters share a single counter number,
but are not used simultaneously, a duplication error will be generated when the
program is checked, but the counters will operate normally. Once defined, a
counter number can be used as many times as required as an operand in other
instructions to access the present value and Completion Flag of the counter.
A timer or counter SV can be input as a constant or as a word address in a data
area. If an I/O Area word assigned to an Input Unit is designated as the word
address, the Input Unit can be wired so that the SV can be set externally through
thumbwheel switches or similar devices. Timers wired in this way can only be set
externally during RUN or MONITOR mode. All SVs, including those set external-
ly, must be in BCD.
Although set values may be set to 0 for timers and counters, it will disable them,
i.e., turn ON the Completion Flag immediately.
No prefix is required when using a timer or counter number as a definer in a timer
or counter instruction. Once a timer or counter number has been used to create
a timer/counter, it can be prefixed with T or C for use as an operand in various
instructions.
Timer and counter numbers can be designated as operands that require either
bit or word data. When designated as an operand that requires bit data, the timer
or counter number accesses a bit that functions as a Completion Flag that indi-
cates when the timer or counter has completed counting, i.e., the Completion
Flag, which is normally OFF, will turn ON when the timer has timed out or counter
counted out.
When designated as an operand that requires word data, the timer or counter
number accesses a memory location that holds the present value (PV) of the
timer or counter. The PV of a timer or counter can thus be used as an operand in
CMP(020), or any other instruction for which the Timer or Counter Area is al-
lowed.
Note that "T0000" is used to designate both the Completion Flag for the timer
and to designate the PV of the timer. The meaning of the term in context should
be clear, i.e., the first is always a bit operand and the second is always a word
operand. The same is true of all other timer or counter numbers.
Section 5-13
At END(01) Interrupts
PV PV refreshed every
refreshed 80 ms if cycle time
exceeds 80 ms.
Not PV refreshed every
refreshed 10 ms and Completion
Flag turned ON if PV is
0000.
Not Not refreshed
refreshed