Input and output points: 1024 points.
Input / output data points: 1024 points.
Program capacity: 14K.
Basic command processing speed (LD command) s:0.20.
Integral type: the PLC components are installed together or a few pieces of printed circuit board,
And together with the power supply installed in the casing to form a single overall called the host or the basic unit, small, ultra small PLC using this structure A3NCPUP21 Programming Manual A3NCPUP21
Modular: PLC is the basic components of a separate module.
Medium and large PLC used this way. Easy maintenance.
Each scanning process. Focus on the input signal sampling. Focus on the output signal to refresh.
Input refresh process. When the input port is closed,
Program in the implementation phase, the input end of a new state, the new state can not be read A3NCPUP21 Programming Manual.
Only when the program is scanned, the new state is read.
A scan cycle is divided into the input sample, the program execution, the output refresh.
The contents of the component image register are changed with the change of the execution of the program.
The length of the scan cycle is determined by the three.
CPU the speed of executing instructions A3NCPUP21 Programming Manual.
Time of instruction.
Instruction count.
Due to the adoption of centralized sampling.
Centralized output mode.
There exist input / output hysteresis phenomena, i.e., the input / output response delay.
User program storage capacity: it is a measure of how much the user application can store the number of indicators.
Usually in words or K words as units. 16 bit binary number is a word,
Every 1024 words are 1K words. PLC to store instructions and data in words.
General logical operation instructions each account for 1 words. Timer / counter,
Shift instruction accounted for 2 words. Data operation instructions for 2~4. For common cathode input module (2 line type).Input unit (upper / lower limit LS signal) (NSD servo system)
Each scanning process. Focus on the input signal sampling. Focus on the output signal to refresh.
Input refresh process. When the input port is closed,
Program in the implementation phase, the input end of a new state, the new state can not be read.
Only when the program is scanned, the new state is read.
A scan cycle is divided into the input sample, the program execution, the output refresh.
The contents of the component image register are changed with the change of the execution of the program.
The length of the scan cycle is determined by the three.
CPU the speed of executing instructions.
Time of instruction.
Instruction count.
Due to the adoption of centralized sampling.
Centralized output mode.
There exist input / output hysteresis phenomena, i.e., the input / output response delay.
PLC selection with the development of PLC technology, more and more types of PLC products,
Function is becoming more and more perfect, and its application is more and more extensive.
Different series of different models of PLC has different performance, applicable occasions also have different emphasis,
Price also has a greater difference. Therefore PLC selection,
Under the premise of meeting the control requirements,
Should consider the best performance to price ratio, a reasonable choice of PLC A3NCPUP21 Manual .
System program memory for storing system program,
Including management procedures, monitoring procedures, as well as the user program tto do the compiler to compile the process of interpretation A3NCPUP21 Manual .
Read only memory. Manufacturers use, content can not be changed, power does not disappear.