Glossary
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Completion Flag A flag used with a timer or counter that turns ON when the timer has timed out
or the counter has reached its set value.
condition A symbol placed on an instruction line to indicate an instruction that controls
the execution condition for the terminal instruction. Each condition is assigned
a bit in memory that determines its status. The status of the bit assigned to
each condition determines the next execution condition. Conditions corre-
spond to LOAD, LOAD NOT, AND, AND NOT, OR, or OR NOT instructions.
CONFIG.SYS An MS DOS file containing environment settings for a personal computer.
constant An input for an operand in which the actual numeric value is specified. Con-
stants can be input for certain operands in place of memory area addresses.
Some operands must be input as constants.
control bit A bit in a memory area that is set either through the program or via a Pro-
gramming Device to achieve a specific purpose, e.g., a Restart Bit is turned
ON and OFF to restart a Unit.
control data An operand that specifies how an instruction is to be executed. The control
data may specify the part of a word is to be used as the operand, it may spec-
ify the destination for a data transfer instructions, it may specify the size of a
data table used in an instruction, etc.
control signal A signal sent from the PC to effect the operation of the controlled system.
Control System All of the hardware and software components used to control other devices. A
Control System includes the PC System, the PC programs, and all I/O
devices that are used to control or obtain feedback from the controlled sys-
tem.
controlled system The devices that are being controlled by a PC System.
count pulse The signal counted by a counter.
counter A dedicated group of digits or words in memory used to count the number of
times a specific process has occurred, or a location in memory accessed
through a TIM/CNT bit and used to count the number of times the status of a
bit or an execution condition has changed from OFF to ON.
CPU Unit See central processing unit.
CTS An acronym for clear-to-send, a signal used in communications between elec-
tronic devices to indicate that the receiver is ready to accept incoming data.
CX-Programmer Windows-based Support Software for programming SYSMAC PCs.
CX-Protocol Windows-based Support Software for the protocol macro function of SYS-
MAC PCs.
CY See Carry Flag.
cycle One unit of processing performed by the CPU Unit, including ladder program
execution, peripheral servicing, I/O refreshing, etc.
cycle time The time required to complete one cycle of CPU Unit processing.
cyclic interrupt See scheduled interrupt.
data area An area in the PC’s memory that is designed to hold a specific type of data.
data area boundary The highest address available within a data area. When designating an oper-
and that requires multiple words, it is necessary to ensure that the highest
address in the data area is not exceeded.
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