address|[PLC] The location in memory where data is stored. For data areas, an address consists of a two-letter data area designation and a number that designate the word and/or bit location. For the UM area, an address designates the instruction location (UM area); for the FM area, the block location (FM area), etc.
allocation|[PLC] The process by which the PC assigns certain bits or words in memory for various functions. This includes pairing I/O bits to I/O points on Units.
Analog Input Unit|[PLC] A Special I/O Unit that converts external analog input signals to digital input signals for the PC. The analog signals can be voltages or amperages.
Analog I/O Unit|[PLC] A collective term for Analog Input Unit and Analog Output Unit.
Analog Output Unit|[PLC] A Special I/O Unit that converts digital output signals from the PC to analog output signals for field devices. The analog signals can be voltages or amperages.
Analog Timer Unit|[PLC] A dedicated timer that interfaces through analog signal externally and digital signals internally. 字串2
AND|[PLC] 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.
BCD|[PLC] Short for binary-coded decimal.
BCD calculation|[PLC] An arithmetic calculation that uses numbers expressed in binary-coded decimal.
binary|[PLC] A number system where all numbers are expressed to the base 2. Although in a PC all data is ultimately stored in binary form, binary is used to refer to data that is numerically equivalent to the binary value. It is not used to refer to binary-coded decimal. Each four binary bits is equivalent to one hexadecimal digit.
binary-coded decimal|[PLC] A system used to represent numbers so that each four binary bits is numerically equivalent to one decimal digit.
bit|[PLC] The smallest unit of storage in a PC. The status of a bit is either ON or OFF. Four bits equal one digit; sixteen bits, one word. Different bits are allocated to special purposes, such as holding the status input from external devices, while other bits are available for general use in programming.
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bit address|[PLC] The location in memory where a bit of data is stored. A bit address must specify (sometimes by default) the data area and word that is being addressed as well as the number of the bit.
bit designator|[PLC] An operand that is used to designate the bit or bits of a word to be used by an instruction.
bit number|[PLC] 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.
buffer|[PLC] A temporary storage space for data in a computerized device.
bus bar|[PLC] The line leading down the left and sometimes right side of a ladder diagram. Instruction execution follows down the bus bar, which is the starting point for all instruction lines.
call|[PLC] A process by which instruction execution shifts from the main program to a subroutine. The subroutine may be called by an instruction or by an interrupt.
carry flag|[PLC] 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 operation.
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clock pulse|[PLC] A pulse available at a certain bit in memory for use in timing operations. Various clock pulses are available with different pulse widths.
clock pulse bit|[PLC] A bit in memory that supplies a pulse that can be used to time operations. Various clock pulse bit are available with different pulse widths.
condition|[PLC] An ‘instruction’ placed along an instruction line to determine how terminal instruction on the right side are to be executed. Each condition is assigned to a bit in memory that determines its status. The status of the bit assigned to each condition determines, in turn, the execution condition for each instruction up to a terminal instruction on the right side of the ladder diagram.
constant|[PLC] An operand for which the actual numeric value is input directly and in place of a data memory address would hold the value to be used.
control bit|[PLC] A bit in a memory area that is set either from the program or from a Programming Device to achieve a specific purpose, e.g., a Restart bit is turned ON and OFF to restart a Unit.
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Control System|[PLC] 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 system.
controlled system|[PLC] The devices that are being controlled by a PC System.
control signal|[PLC] A signal sent from the PC to affect the operation of the controlled system.
counter|[PLC] Either a dedicated number 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 TC 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|[PLC] An acronym for central processing unit. In a PC System, the CPU executes the program, processes I/O signals, communicates with external devices, etc.
CPU Unit|[PLC] The CPU Unit contains the CPU and provides a certain number of I/O points.
data area|[PLC] An area in the PC’s memory that is designed to hold a specific type of data, e.g., the SR area is designed to hold flags and control bits. Memory areas that hold programs are not considered data areas.
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data area boundary|[PLC] The highest address available in a data area. When designating an operand that requires multiple words, it is necessary that the highest address in the data area is not exceeded.
debug|[PLC] A process by which a draft program is corrected until it operates as intended. Debugging includes both removal of syntax errors as well as fine-tuning of timing and coordination of control operations.
decimal|[PLC] A number system where all numbers are expressed to the base 10. Although in a PC all data is ultimately stored in binary form, four binary bits are often used to represent one decimal digit, a system called binary-coded decimal.
decrement|[PLC] Decreasing a numeric value by 1.
default|[PLC] A value assumed and automatically set by the PC when a specific value is not input by the user.
definer|[PLC] A number used as an operand for an instruction but that serves to define the instruction itself rather that the data on which the instruction is to operate. Definers include jump numbers, subroutine numbers, etc.
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delay|[PLC] In tracing, a value that specifies where tracing to begin in relationship to the trigger. A delay can be either positive or negative, i.e., can designate an offset on either side of the trigger.
destination|[PLC] The location where data of some sort in an instruction is to be placed as opposed to the location from which data is to be taken for use in the instruction. The location from which data is to be taken is called the source.
differentiation instruction|[PLC] An instruction used to ensure that the operand bit is never turned ON for more than one scan after the execution condition goes either from OFF to ON for a Differentiate Up instruction or from ON to OFF for a Differentiate Down instruction.
digit|[PLC] A unit of storage in memory that consists of four bits.
digit designator|[PLC] An operand that is used to designate the digit or digits of a word to be used by an instruction.
distributed control|[PLC] An automation concept in which control of each portion of an automated system is located near the devices actually being controlled, i.e., control is decentralized and ‘distributed’ over the system. Distributed control is a concept basic to PC Systems.
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DM area|[PLC] A data area used to hold word data. A word in the DM area cannot be accessed by bit.
download|[PLC] The process of transferring a program or data from a higher-level computer to a lower-level computer or PC.
electrical noise|[PLC] Electrical ‘static’ that can disturb electronic communications. The ‘snow’ that can appear on a TV screen is an example of the effects of electrical noise.
error code|[PLC] A numeric code output to indicate the existence of and something about the nature of an error. Some error codes are generated by the system; other are defined in the program by the operator.
exection condition|[PLC] The ON or OFF status under which an instruction is executed. The execution condition is determined by the logical combination of conditions on the same instruction line and up to the instruction being executed.
execution time|[PLC] The time required for the CPU to execute either an individual instruction or an entire program.
Expansion I/O Unit|[PLC] An Expansion I/O Unit is connected to increase the number of I/O points available. 字串3
extended counter|[PLC] A counter created in a program that count higher that any of the standard counters provided by the individual instructions.
extented timer|[PLC] A timer created in a program that times longer that any of the standard timers provided by the individual instructions.
Factory Intelligent Terminal|[PLC] A Programming Device provided with advanced programming and debugging capabilities to facilitate PC operation. The Factory Intelligent Terminal also provides various interfaces for external devices, such as floppy disk drives.
fatal error|[PLC] An error that will stop PC operation and require correction before operation can be continued.
FIT|[PLC] Short for Factory Intelligent Terminal.
flag|[PLC] A dedicated bit in memory that is set by the system to indicate some type of operating status. Some flags, such as the carry flag, can also be set by the operator or program.
flicker bit|[PLC] A bit that is programmed to turn ON and OFF at a specific interval.
force reset|[PLC] The process of artificially turning OFF a bit from a Programming Device. Bits are usually turned OFF as a result of program execution.
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force set|[PLC] The process of artificially turning ON a bit from a Programming Device. Bits are usually turned ON as a result of program execution.
function code|[PLC] A two-digit number used to input an instruction into the PC.
GPC|[PLC] Short for Graphic Programming Console.
Graphic Programming Console|[PLC] A Programming Device provided with advanced programming and debugging capabilities to facilitate PC operation. A Graphic Programming Console is provided with a large display onto which ladder-diagram programs can be written directly in ladder-diagram symbols for input into the PC without conversion to mnemonic form.
hardware error|[PLC] An error originating in the hardware structure of the PC, as opposed to a software error, which ordinates in software (i.e., programs).
hexadecimal|[PLC] A number system where all numbers are expressed to the base 16. Although in a PC all data is ultimately stored in binary form, displays on and inputs through Programming Devices are often expressed in hexadecimal to facilitate operation. Each four binary bits is numerically equivalent to one hexadecimal digit. 字串7
Host Link System|[PLC] One or more host computers connected to one or more PCs through Host Link Units so that the host computer can be used to transfer data to and receive data from the PC(s). Host Link Systems enable centralized management and control of a PC System.
Host Link Unit|[PLC] An interface used to connect a PC to a host computer in a Host Link System.
host computer|[PLC] A computer that is used to transfer data or programs to or receive data or programs from a PC in a Host Link System. The host computer is used for data management and overall system control. Host computers are generally small personal or business computers.
HR area|[PLC] A data area used to store and manipulate data and to preserve data when power to the PC is turned OFF.
I/O capacity|[PLC] The number of inputs and outputs that a PC is able to handle. This number ranges from around one-hundred for smaller PCs to two-thousand for the largest ones.
I/O devices|[PLC] The devices to which terminals on I/O Units, Special I/O Units, or Intelligent I/O Units are connected. I/O devices may be either part of the Control System, if they function to help control other devices, or they may be part of the controlled system. 字串4
I/O Link|[PLC] Created in an Optical Remote I/O System to enable input/output of one or two IR words directly between PCs. The words are input/output between the PC controlling the Master and a PC connected to the Remote I/O System through an I/O Link Unit or an I/O Link Rack.
I/O Link Unit|[PLC] A Unit used with certain PCs to create an I/O Link in an Optical Remote I/O System.
I/O point|[PLC] The place at which an input signal enters the PC System or an output signal leaves the PC System. In physical terms, an I/O point corresponds to terminals or connector pins on a Unit; in terms of programming, an I/O point corresponds to an I/O bit in the IR area.
I/O response time|[PLC] The time required for an output signal to be sent from the PC in response to and input signal received from an external device.
I/O Unit|[PLC] The most basic type of Unit mounted to a backplane to create a Rack. I/O Units include Input Units and Output Units, each of which is available in a range of specifications. I/O Units do not include Special I/O Units, Link Units, etc.
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I/O word|[PLC] A word in the IR area that is allocated to a Unit in the PC System.
increment|[PLC] Increasing a numeric value by 1.
initialization error|[PLC] An error that occurs either in hardware or software before the PC System has actually begun operation, i.e., during initialization.
initialize|[PLC] Part of the startup process whereby some memory areas are cleared, system setup is checked, and default values are set.
input|[PLC] The signal coming from an external device into the PC. Input often is usedabstractly or collectively to refer to incoming signals.
input bit|[PLC] A bit in the IR area that is allocated to hold the status of an input.
input device|[PLC] An external device that sends signal(s) into the PC System.
input point|[PLC] The point at which an input enters the PC System. An input point physically corresponds to terminals or connector pin(s).
input signal|[PLC] A change in the status of a connection entering the PC. Generally an input signal is said to exist when, for example, a connection point goes from low to high voltage or from a nonconductive to a conductive state. 字串6
instruction|[PLC] A direction given in the program that tells the PC an action to be carried out and the data to be used in carrying out the action. Instructions can simply turn a bit ON or OFF, or they can perform much more complex actions, such as converting and/or transferring large blocks of data.
instruction block|[PLC] A group of instructions that is logically related in a ladder-diagram program. Although any logically related group of instructions could be called an instruction block, the term is generally used to refer to blocks of instructions called logic blocks that require logic block instructions to relate them to other instructions or logic blocks.
instruction execution time|[PLC] The time required to execution an instruction. The execution time for any one instruction can vary with the execution condition for the instruction and the operands used in it.
instruction line|[PLC] A group of conditions that lie together on the same horizontal line of a ladder diagram. Instruction lines can branch apart or join together to form instruction blocks.
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interface|[PLC] An interface is the conceptual boundary between systems or devices and usually involves changes in the way the communicated data is represented. Interface devices perform operations as changing the coding, format, or speed of the data.
interlock|[PLC] A programming method used to treat a number of instructions as a group so that the entire group can be reset together when individual execution is not required. An interlocked program section is executed normally for an ON execution condition and partially reset for an OFF execution condition.
inverse condition|[PLC] A condition that produces an ON execution condition when the bit assigned to it is OFF and an OFF execution condition when the bit assigned to it is ON.
IR area|[PLC] A data area whose principal function is to hold the status of inputs coming into the system and outputs that are to be set out of the system. Bits and words in the IR are that are used this way are called I/O bits and I/O words. The remaining bits in the IR area are work bits.
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jump|[PLC] A type of programming where execution moves directly from one point in a program to a separate point in the program without sequentially executing the instruction in between. Jumps are usually conditional on an execution condition.
jump number|[PLC] A definer used with a jump that defines the points from which and to which a jump is to be made.
ladder diagram|[PLC] (program)A form of program arising out of relay-based control systems that uses circuit-type diagrams to represent the logic flow of programming instructions. The appearance of the program suggests a ladder, and thus the name.
ladder diagram symbol|[PLC] A symbol used in a ladder-diagram program.
ladder instruction|[PLC] An instruction that represents the ‘rung’ portion of a ladder-diagram program. The other instructions in a ladder diagram fall along the right side of the diagram and are called terminal instructions.
leftmost|[PLC] (bit/word) The highest numbered bits of a group of bits, generally of an entire word, or the highest numbered words of a group of words. These bits/words are often called most significant bits/words.
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link|[PLC] A hardware or software connection formed between two Units. “Link” can refer either to a part of the physical connection between two Units or a software connection created to data existing at another location (I/O Links).
load|[PLC] The processes of copying data either from an external device or from a storage area to an active portion of the system such as a display buffer. Also, an output device connected to the PC is called a load.
logic block|[PLC] A group of instructions that is logically related in a ladder-diagram program and that requires logic block instructions to relate it to other instructions or logic blocks.
logic block instruction|[PLC] An instruction used to locally combine the execution condition resulting from a logic block with a current execution condition. The current execution condition could be the result of a single condition or of another logic block. AND Load and OR Load are the two logic block instructions.
LR area|[PLC] A data area that is used in a PC Link System so that data can be transferred between two or more PCs. If a PC Link System is not used, the LR area is available for use as work bits. 字串7
Master|[PLC] Short for Remote I/O Master Unit.
main program|[PLC] All of a program except for the subroutines.
memory area|[PLC] Any of the areas in the PC used to hold data or programs.
mnemonic code|[PLC] A form of a ladder-diagram program that consists of a sequential list of the instructions without using a ladder diagram. Mnemonic code is required to input a program into a PC when using a Programming Console.
MONITOR mode|[PLC] A mode of PC operation in which normal program execution is possible but in which modification of data held in memory is still possible. Used for monitoring or debugging the PC.
NC input|[PLC] An input that is normally closed, i.e., the input signal is considered to be present when the circuit connected to the input opens.
nest|[PLC] Programming one jump within another jump, programming a call to a subroutine from within another subroutine, etc.
NO input|[PLC] An input that is normally open, i.e., the input signal is considered to be present when the circuit connected to the input closes.
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noise interference|[PLC] Disturbances in signals caused by electrical noise.
nonfatal error|[PLC] A hardware or software error that produces a warning but does not stop the PC from operating.
normal condition|[PLC] A condition that produces an ON execution condition when the bit assigned to it is ON and an OFF execution condition when the bit assigned to it is OFF.
NOT|[PLC] A logic operation which inverts the status of the operand. For example, AND NOT indicates an AND with the opposite of the actual status of the operand bit.
OFF|[PLC] The status of an input or output when a signal is said not to be present. The OFF state is generally low voltage or non-conductivity, but can be defined as the opposite of either.
OFF delay|[PLC] The delay produced between the time turning OFF a signal is initiated (e.g., by an input device or PC) and the time the signal reaches a state readable as an OFF signal (i.e., as no signal) by a receiving party (e.g., output device or PC).
ON|[PLC] The status of an input or output when a signal is said to be present. The ON state is generally high voltage or conductivity, but can be defined as the opposite of either.
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ON delay|[PLC] The delay produced between the time a signal is initiated (e.g., by an input device or PC) and the the time the signal reaches a state readable as an ON signal by a receiving party (e.g., output device or PC).
one-shot bit|[PLC] A bit that is turned ON or OFF for a specified interval of time longer than one scan.
operand|[PLC] A bit(s) or word(s) designated as the data to be used for an instruction. An operand can be input as a constant expressing the actual numeric value to be used or as an address to express the location in memory of the data to be used.
operand bit|[PLC] A bit designated as an operand for an instruction.
operand word|[PLC] A word designated as an operand for an instruction.
operating error|[PLC] An error that occurs during actual PC operation as opposed to an initialization error, which occurs before actual operations can begin.
