Omron CPM1A operation manual Acp, Ascii, Autoexec.Bat, Bcd

	Glossary
*DM	Indirectly addressed DM area. See indirect address and DM area.
1:1 PC Link	A link created between two PCs to create common data in their LR areas.
ACP	See add count input.
add count input	An input signal used to increment a counter when the signal changes from OFF
	to ON.
address	A number used to identify the location of data or programming instructions in
	memory.
AND	A logic operation whereby the result is true if and only if both premises are true.
	In ladder-diagram programming the premises are usually ON/OFF states of bits
	or the logical combination of such states called execution conditions.
area	See data area and memory area.
area prefix	A one or two letter prefix used to identify a memory area in the PC. All memory
	areas except the IR and SR areas require prefixes to identify addresses in them.
arithmetic shift	A shift operation wherein the carry flag is included in the shift.
ASCII	Short for American Standard Code for Information Interchange. ASCII is used to
	code characters for output to printers and other external devices.
AR Area	A PC data area allocated to flags and control bits.
AUTOEXEC.BAT	An MS-DOS file containing commands automatically executed at startup.
back-up	A copy made of existing data to ensure that the data will not be lost even if the
	original data is corrupted or erased.
basic instruction	A fundamental instruction used in a ladder diagram. See advanced instruction.
baud rate	The data transmission speed between two devices in a system measured in bits
	per second.
BCD	See binary-coded decimal.
BCD calculation	An arithmetic calculation that uses numbers expressed in binary-coded deci-
	mal.
binary	A number system where all numbers are expressed in base 2, i.e., numbers are
	written using only 0’s and 1’s. Each group of four binary bits is equivalent to one
	hexadecimal digit. Binary data in memory is thus often expressed in hexadeci-
	mal for convenience.
binary calculation	An arithmetic calculation that uses numbers expressed in binary.
binary-coded decimal	A system used to represent numbers so that every four binary bits is numerically
	equivalent to one decimal digit.
bit	The smallest piece of information that can be represented on a computer. A bit
	has the value of either zero or one, corresponding to the electrical signals ON
	and OFF. A bit represents one binary digit. Some bits at particular addresses are
	allocated to special purposes, such as holding the status of input from external
	devices, while other bits are available for general use in programming.
bit address	The location in memory where a bit of data is stored. A bit address specifies the
	data area and word that is being addressed as well as the number of the bit
	within the word.

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