Optical Slave Rack|[PLC] A Slave Rack connected through an Optical Remote I/O Slave Unit.
OR|[PLC] A logic operation whereby the result is true if either one or both of the premises is true. In ladder-diagram programming the premises are usually ON/OFF states of bits or the logical combination of such states called execution conditions.
output|[PLC] The signal sent from the PC to an external device. Output often is used abstractly or collectively to refer to outgoing signals.
output bit|[PLC] A bit in the IR area that is allocated to hold the status to be sent to an output device.
output device|[PLC] An external device that receives a signal(s) from the PC System.
output point|[PLC] The point at which an output leaves the PC System. An output point physically corresponds to terminals or connector pin(s).
output signal|[PLC] A change in the status of a connection leaving the PC. Generally an output 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9
overseeing|[PLC] Part of the processing performed by the CPU that includes general tasks required to operate the PC.
overwrite|[PLC] Changing the content of a memory location so that the previous content is lost.
PC|[PLC] An acronym for Programmable Controller.
PC System|[PLC] All of the Units connected to the CPU Unit up to, but not including the I/O devices. The limits of the PC System on the upper end is the PC and the program in its CPU and on the lower end, I/O Units, an I/O Link Unit, etc.
PCB|[PLC] An acronym for printed circuit board.
Peripheral Device|[PLC] Devices connected to a PC System to aid in system operation. Peripheral devices include printers, programming devices, external storage media, etc.
present value|[PLC] The current time left on a timer or the current count of a counter. Present value is abbreviated PV.
printed circuit board|[PLC] A board onto which electrical circuits are printed for mounting into a computer or electrical device.
program|[PLC] The list of instructions that tells the PC the sequence of control actions to be carried out. 字串4
Programmable Controller|[PLC] A computerized device that can accept inputs from external devices and generate outputs to external devices according to a program held in memory. Programmable Controllers are used to automate control of external devices.
programmed alarm|[PLC] An alarm given as a result of execution of an instruction designed to generate the alarm in the program as opposed to one generated by the system.
programmed error|[PLC] An error arising as a result of execution of an instruction designed to generate the error in the program as opposed to one generated by the system.
programmed message|[PLC] A message generated as a result of execution of an instruction designed to generate the message in the program as opposed to one generated by the system.
Programming Console|[PLC] The simplest form or Programming Device available for a PC. Programming Consoles are available both as hand-held models and as CPU-mounting models.
Programming Device|[PLC] A peripheral device used to input a program into a PC or to alter or monitor a program already held in the PC. There are dedicated programming devices, such as Programming Consoles, and there are non-dedicated devices, such as a host computer.
字串6
PROGRAM mode|[PLC] A mode of operation that allows for inputting and debugging programs but that does not permit normal execution of the program.
PROM Writer|[PLC] A Peripheral Device used to write programs and other data into a ROM for permanent storage and application.
prompt|[PLC] A message or symbol that appears on a display to request input from the operator.
PV|[PLC] Short for present value.
refresh|[PLC] The process of updating output status sent to external devices so that it agrees with the status of output bits held in memory and of updating input bits in memory so that they agree with the status of inputs from external devices.
relay-based control|[PLC] The forerunner of PCs. In relay-based control, groups of relays are wired to each other to form control circuits. In a PC, these are replaced by programmable circuits.
Remote I/O Master Unit|[PLC] The Unit in a Remote I/O System through which signals are sent to all other Remote I/O Units. The Remote I/O Master Unit is mounted either to a C200H, C500, C1000H, or C2000H CPU Rack or an Expansion I/O Rack connected to the CPU Rack. Remote I/O Master Unit is generally abbreviated to simply “Master.”
字串2
Remote I/O Slave Unit|[PLC] A Unit mounted to a C200H, C500, C1000H, or C2000H Backplane to form a Slave Rack. Remote I/O Slave Unit is generally abbreviated to simply “Slave.”
Remote I/O System|[PLC] A C200H, C500, C1000H, or C2000H system in which remote I/O points are controlled through a Master mounted to a CPU Rack or an Expansion I/O Rack connected to the CPU Rack. K-type PCs can be connected to Remote I/O Systems through I/O Link Units.
Remote I/O Unit|[PLC] Any of the Units in a Remote I/O System. Remote I/O Units include Masters, Slaves, Optical I/O Units, I/O Link Units, and Remote Terminals.
reset|[PLC] The process of turning a bit or signal OFF or of changing the present value of a timer or counter to its set value or to zero.
return|[PLC] The process by which instruction execution shifts from a subroutine back to the point from which the subroutine was called. A return is automatic upon completion of the subroutine and the return is always to .
reversible counter|[PLC] A counter that can be both incremented and decrement depending on a specified condition(s).
字串3
reversible shift register|[PLC] A shift register that can shift data in either direction depending on a specified condition(s).
right-hand instruction|[PLC] Another term for terminal instruction.
rightmost|[PLC] (bit/word)The lowest numbered bits of a group of bits, generally of an entire word, or the lowest numbered words of a group of words. These bits/words are often called least significant bits/words.
RUN mode|[PLC] The operating mode used by the PC for normal control operations.
scan|[PLC] The process used to execute a ladder-diagram program. The program is examined sequentially from start to finish and each instruction is executed in turn based on execution conditions.
scan time|[PLC] The time required for a single scan of the ladder-diagram program.
self diagnosis|[PLC] A process whereby the system checks its own operation and generates a warning or error if an abnormality is discovered.
self-maintaining bit|[PLC] A bit that is programmed to maintain either an OFF or ON status until set or reset by a specific condition(s) different from the one that originally caused the bit to turn OFF or ON. 字串4
servicing|[PLC] The process whereby the PC provides data to or receives data from external devices or remote I/O or otherwise handles data transactions for Link Systems.
set|[PLC] The process of turning a bit or signal ON.
set value|[PLC] The count from which a counter starts counting down (or, in the case of a reversible counter, the maximum count) or the time from which a timer starts timing. Set value is abbreviated SV.
shift register|[PLC] One or more words in which data is shifted in bit, digit, or word units a specified number of units to the right or left.
Slave|[PLC] Short for Remote I/O Slave Unit.
Slave Rack|[PLC] A C200H, C500, C1000H, or C2000H Rack containing a Remote I/O Slave Unit and controlled through a Remote I/O Master Unit. Slave Racks are generally located away from the CPU Rack.
software error|[PLC] An error that occurs in the execution of a program.
software protects|[PLC] A software means of protecting data from being changed as opposed to a physical switch or other hardware setting.
字串6
source|[PLC] The location from which data is taken for use in an instruction as opposed to the location to which the result of an instruction is to be written. The location to which the result of an instruction is to be written is called the destination.
SR area|[PLC] A data area in a PC used mainly for flags, control bits, and other information provided about PC operation. The status of only certain SR bits may be controlled by the operator, i.e., most SR bits can only be read.
subroutine|[PLC] A group of instructions placed after the main program and executed only if called from the main program or activated by an interrupt.
subroutine number|[PLC] A definer used to identify the subroutine that a subroutine call or interrupt activates.
SV|[PLC] Short for set value.
switching capacity|[PLC] The voltage/current that a relay can switch on and off.
syntax error|[PLC] An error in the way in which a program is written. Syntax errors can include ‘spelling’ mistakes (i.e., a function code that does not exit), mistakes in specifying operands within acceptable parameters (e.g., specifying unwritable SR bits as a destination), and mistakes in actual application of instructions (e.g., a call to a subroutine that does not exist).
字串2
system error|[PLC] An error generated by the system as opposed to one resulting from execution of an instruction designed to generate an error.
system error message|[PLC] An error message generated by the system as opposed to one resulting from execution of an instruction designed to generate a message.
TC area|[PLC] A data area that can be used only for timers and counters. Each bit in the TC area serves as the access point for the SV, PV, and Completion flag for the timer or counter defined with that bit.
TC number|[PLC] A definer that corresponds to a bit in the TC area and used to define the bit as either a timer or a counter.
terminal instruction|[PLC] An instruction placed on the right side of a ladder diagram that uses the final execution condition on an instruction line(s).
timer|[PLC] A location in memory accessed through a TC bit and used to time down from the timer’s set value. Timers are turned ON and reset according to their execution conditions.
TM area|[PLC] A memory area used to store the results of a trace.
字串7
transmission distance|[PLC] The distance that a signal can be transmitted.
TR area|[PLC] A data area used to store execution conditions so that they can be reloaded later for use with other instructions.
transfer|[PLC] The process of moving data from one location to another within the PC or between the PC and external devices. When data is transferred, generally a copy of the data is sent to the destination, i.e., the content of the source of the transfer is not changed.
UM area|[PLC] The memory area used to hold the active program, i.e., the program that is being currently executed.
Unit|[PLC] In OMRON PC terminology, the word Unit is capitalized to indicate any product sold for a PC System. Though most of the names of these products end with the word Unit, not all do, e.g., a Remote Terminal is referred to in a collective sense as a Unit. Context generally makes any limitations of this word clear.
unit number|[PLC] A number assigned to some Link Units and Special I/O Units to assign words and sometimes other operating parameters to it.
字串7
watchdog timer|[PLC] A timer within the system that ensures that the scan time stays within specified limits. When limits are reached, either warnings are given or PC operation is stopped depending on the particular limit that is reached. Although a default value of 130 ms is automatically set for the basic time limit, this value can be extended by the program.
Wired Slave Rack|[PLC] A Slave Rack connected through a Wired Remote I/O Slave Unit.
word|[PLC] A unit of storage in memory that consists of 16 bits. All data areas consists of words. Some data areas can be accessed by words; others, by either words or bits.
word address|[PLC] The location in memory where a word of data is stored. A word address must specify (sometimes by default) the data area and the number of the word that is being addressed.
work bit|[PLC] A bit in a work word.
work word|[PLC] A word that can be used for data calculation or other manipulation in programming, i.e., a ‘work space’ in memory. A large portion of the IR area is always reserved for work words. Parts of other areas not required for special purposes may also be used as work words, e.g., I/O words not allocated to I/O Units.
字串8
