Introduction; Data Area Structure; Ir (Internal Relay) Area; Section 3 Memory Areas - Omron C200H Operation Manual

Data Area Structure

3-1

Introduction

Area Acronym
Internal Relay IR
Special Relay SR
Auxiliary Relay AR
Data Memory DM
Holding Relay HR
Timer/Counter TC
Link Relay LR
Temporary Relay TR
Program Memory UM
Work Bits and Words
Flags and Control Bits
3-2

Data Area Structure

16
Details, including the name, acronym, range, and function of each area are
summarized in the following table. All but the last three of these areas are
data areas. Data and memory areas are normally referred to by their acro-
nyms.
Range
Words: 000 to 235
Bits: 00000 to 23515
Words: 236 to 255
Bits: 23600 to 25507
Words: AR 00 to AR 27
Bits: AR 00 to AR 2715
Read/write: DM 0000 to DM 0999
Read only: DM 1000 to DM 1999
Words: HR 00 to HR 99
Bits: HR 0000 to HR 9915
TC 000 to TC 511 (TC numbers used
to access other information)
Words: LR 00 to LR 63
Bits: LR 0000 to 6315
TR 00 to TR 07 (bits only)
UM: Depends on Memory Unit used.
When some bits and words in certain data areas are not being used for their
intended purpose, they can be used in programming as required to control
other bits. Words and bits available for use in this fashion are called work
words and work bits. Most, but not all, unused bits can be used as work bits.
Those that can be used are described area-by-area in the remainder of this
section. Actual application of work bits and work words is described in Sec-
tion 4 Writing and Inputting the Program.
Some data areas contain flags and/or control bits. Flags are bits that are
automatically turned ON and OFF to indicate particular operation status. Al-
though some flags can be turned ON and OFF by the user, most flags are
read only; they cannot be controlled directly.
Control bits are bits turned ON and OFF by the user to control specific as-
pects of operation. Any bit given a name using the word bit rather than the
word flag is a control bit, e.g., Restart bits are control bits.
When designating a data area, the acronym for the area is always required
for any but the IR and SR areas. Although the acronyms for the IR and SR
areas are often given for clarity in text explanations, they are not required,
Function
Used to control I/O points, other bits, timers,
and counters, and to temporarily store data.
Contains system clocks, flags, control bits, and
status information.
Contains flags and bits for special functions.
Retains status during power failure.
Used for internal data storage and manipula-
tion.
Used to store data and to retain the data values
when the power to the PC is turned off.
Used to define timers and counters, and to ac-
cess completion flags, PV, and SV. In general,
when used as a bit operand, a TC number ac-
cesses the completion flag for the timer or
counter defined using the TC number. When
used as a word operand, the TC number ac-
cesses the present value of the timer or count-
er.
Available for use as work bits.
Used to temporarily store and retrieve execu-
tion conditions. These bits can only be used in
the Load and Output instructions. Storing and
retrieving execution conditions is necessary
when programming certain types of branching
ladder diagrams.
Contains the program executed by the CPU.
Section 3-2