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. WWcW_PLCJS_COM－PLC－技.术_网
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. WWW_PL※CJS_COM－PLC－技.术_网
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. ——可——编——程——控－制－器－技——术——门——户
Analog I/O Unit|[PLC] A collective term for Analog Input Unit and Analog Output Unit. WWW_PLCJS@_COM%－PLC－技.术_网
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. WWW_PL※CJS_COM－PLC－技.术_网
Analog Timer Unit|[PLC] A dedicated timer that interfaces through analog signal externally and digital signals internally. WWW.PLCJS.COM——可编程控制器技术门户
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. WWcW_PLCJS_COM－PLC－技.术_网
BCD|[PLC] Short for binary-coded decimal. WWW_PLC※JS_COM－PLC－技.术_网(可编程控※制器技术门户)
BCD calculation|[PLC] An arithmetic calculation that uses numbers expressed in binary-coded decimal. WWW_PLC※JS_COM－PmLC－技.术_网
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. WWW_PLC※JS_COM－PmLC－技.术_网
binary-coded decimal|[PLC] A system used to represent numbers so that each four binary bits is numerically equivalent to one decimal digit. plcjs.技.术_网
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. WWW_P※LCJS_CO※M－PLC－技－.术_网