Omron CPM1A Operation Manual page 181

bit designator
bit number
bit-control instruction
block
building-block PC
bus
bus bar
byte
call
Carry Flag
central processing unit
CH
channel
character code
checksum
clock pulse
clock pulse bit
common data
communications cable
comparison instruction
160
Glossary
An operand that is used to designate the bit or bits of a word to be used by an
instruction.
A number that indicates the location of a bit within a word. Bit 00 is the rightmost
(least-significant) bit; bit 15 is the leftmost (most-significant) bit.
An instruction that is used to control the status of an individual bit as opposed to
the status of an entire word.
See logic block and instruction block.
A PC that is constructed from individual components, or "building blocks." With
building-block PCs, there is no one Unit that is independently identifiable as a
PC. The PC is rather a functional assembly of Units.
A communications path used to pass data between any of the Units connected
to it.
The line leading down the left and sometimes right side of a ladder diagram.
Instruction execution proceeds down the bus bar, which is the starting point for
all instruction lines.
A unit of data equivalent to 8 bits, i.e., half a word.
A process by which instruction execution shifts from the main program to a sub-
routine. The subroutine may be called by an instruction or by an interrupt.
A flag that is used with arithmetic operations to hold a carry from an addition or
multiplication operation, or to indicate that the result is negative in a subtraction
operation. The carry flag is also used with certain types of shift operations.
A device that is capable of storing programs and data, and executing the instruc-
tions contained in the programs. In a PC System, the central processing unit
executes the program, processes I/O signals, communicates with external
devices, etc.
See word.
See word.
A numeric (usually binary) code used to represent an alphanumeric character.
A sum transmitted with a data pack in communications. The checksum can be
recalculated from the received data to confirm that the data in the transmission
has not been corrupted.
A pulse available at specific bits in memory for use in timing operations. Various
clock pulses are available with different pulse widths, and therefore different fre-
quencies.
A bit in memory that supplies a pulse that can be used to time operations. Vari-
ous clock pulse bits are available with different pulse widths, and therefore differ-
ent frequencies.
Data that is stored in a memory of a PC and which is shared by other PCs in the
same the same system. Each PC has a specified section(s) of the area allocated
to it. Each PC writes to the section(s) allocated to it and reads the sections allo-
cated to the other PCs with which it shares the common data.
Cable used to transfer data between components of a control system and con-
forming to the RS-232C or RS-422 standards.
An instruction used to compare data at different locations in memory to deter-
mine the relationship between the data.