End - End(01); No Operation - Nop(00); 5-11 Timer And Counter Instructions - Omron SYSMAC C20P Operation Manual

Timer and Counter Instructions
5–9 End – END(01)
Description
Flags
5–10 No Operation – NOP(00)
Description
Flags
5–11 Timer and Counter Instructions
56
Ladder Symbol
END(01) is required as the last instruction in any program. No instruction
written after END(01) will be executed. END(01) can be placed anywhere in
the program to execute all instructions up to that point, as is sometimes done
to debug a program, but it must be removed to execute the remainder of the
program.
If there is no END(01) in the program, no instructions will be executed and
the error message "NO END INST" will appear.
END(01) turns OFF ER, CY, GR, EQ, and LE.
NOP(00) is not generally required in programming and there is no ladder
symbol for it. When NOP(00) is found in a program, nothing is executed and
the next instruction is moved to. When memory is cleared prior to program-
ming, NOP(00) is written at all addresses. NOP(00) can be input through the
00 function code.
There are no flags affected by NOP(00).
TIM and TIMH are decrementing ON-delay timer instructions which require a
TC number and a set value (SV).
CNT is a decrementing counter instruction and CNTR is a reversible counter
instruction. Both require a TC number and a SV. Both are also connected to
multiple instruction lines which serve as an input signal(s) and a reset.
Any one TC number cannot be defined twice, i.e., once it has been used as
the definer in any of the timer or counter instructions it cannot be used again.
Once defined, TC numbers can be used as many times as required as oper-
ands in instructions other than timer and counter instructions.
TC numbers run from 00 through 47. No prefix is required when using a TC
number as a definer in a timer or counter instruction. Once defined as a tim-
er, a TC number can be prefixed with TIM for use as an operand in certain
instructions. The TIM prefix is used regardless of the timer instruction that
was used to define the timer. Once defined as a counter, a TC number can
be prefixed with CNT for use as an operand in certain instructions. The CNT
is also used regardless of the counter instruction that was used to define the
counter.
TC numbers can be designated for operands that require bit data or for oper-
ands that require word data. When designated as an operand that requires
bit data, the TC number accesses a bit that functions as a "Completion Flag"
that indicates when the time/count has expired, i.e., the bit, which is normally
OFF, will turn ON when the designated SV has expired. When designated as
an operand that requires word data, the TC number accesses a memory lo-
cation 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(20) or any other
instruction for which the TC area is allowed by designating the TC number
Section 5–11
END(01)