Dm Area; Hr Area; Tc Area - Omron SYSMAC C20P Operation Manual

TC Area

Equal Flag, EQ
Less Than Flag, LE
3–5

DM Area

3–6

HR Area

3–7

TC Area

26
SR 1906 turns ON when the result of a comparison shows two operands to
be equal or when the result of an arithmetic operation is zero.
SR 1907 turns ON when the result of a comparison shows the second of two
4-digit operands to be less than the first.
The DM area is used for internal data storage and manipulation and is acces-
sible only by word. Addresses range from DM 00 through DM 63.
Although composed of 16 bits just like any other word in memory, DM words
cannot be specified by bit for use in instructions with bit-size operands, such
as LD, OUT, AND, and OR.
When the HDM(98) (High-speed Drum Counter) is used the DM area words
32 to 63 are used as the area where the upper and lower limits of the counter
are preset and as such these words cannot be used for any other purposes.
The DM area retains status during power interruptions.
The HR area is used to store and manipulate various kinds of data and can
be accessed either by word or by bit. Word addresses range from HR 0
through HR 9; bit addresses, from HR 000 through HR 915. HR bits can be
used in any order required and can be programmed as often as required.
The HR area retains status when the system operating mode is changed, or
when power is interrupted.
The TC area is used to create and program timers and counters and holds
the Completion Flags, set values (SV), and present values (PV) for all timers
and counters. All of these are accessed through TC numbers ranging from
TC 00 through TC 47. Each TC number is defined as either a timer or
counter using one of the following instructions: TIM, TIMH, CNT or CNTR. No
prefix is required when using a TC number as a definer in a timer or counter
instruction.
Once a TC number has been defined using one of these instructions, it can-
not be redefined elsewhere in the program using the same or a different in-
struction. If the same TC number is defined in more than one of these in-
structions or in the same instruction twice, an error will be generated during
the program check. There are no restrictions on the order in which TC num-
bers can be used.
Once defined, a TC number can be designated as an operand in one or more
instructions other than those listed above. When defined as a timer, a TC
number designated as an operand takes a TIM prefix. The TIM prefix is used
regardless of the timer instruction that was used to define the timer. Once
defined as a counter, the TC number designated as an operand takes a CNT
prefix. 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 the Completion Flag of the timer or
counter. When designated as an operand that requires word data, the TC
number accesses a memory location that holds the PV of the timer or
counter.
Section 3–7