Input points: 16 points.
Voltage: DC12/24V.
Current: 4/10mA.
Response time: 10ms.
32 points / a common end.
Negative utility.
20 point terminal station.
System program memory for storing system program,
Including management procedures, monitoring procedures, as well as the user program to do the compiler to compile the process of interpretation A171SHCPUN Programming Manual .
Read only memory. Manufacturers use, content can not be changed, power does not disappear A171SHCPUN
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 A171SHCPUN Programming Manual . Therefore PLC selection,
Under the premise of meeting the control requirements,
Should consider the best performance to price ratio, a reasonable choice of PLC.
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 A171SHCPUN 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.
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. SI/QSI/H-PCF/ wide H-PCF optical cable double loop PC (control station / common station) / remote I/O network (remote master station).
Switch volume control is designed to,
According to the current input combination of the switch quantity and the history of the input sequence,
So that PLC generates the corresponding switching output,
In order to make the system work in a certain order.
So, sometimes also known as the order control.
And sequential control is divided into manual, semi-automatic or automatic.
And the control principle is decentralized, centralized and hybrid control three.
The length of time required to execute the instruction, the length of the user''s program, the type of instruction, and the speed of the CPU execution are very significant,
Generally, a scanning process, the fault diagnosis time,
Communication time, input sampling and output refresh time is less,
The execution time is accounted for the vast majority of.
The response time of PLC is the interval between the time of the change of the external output signal of the PLC aand the time of the change of the external output signal which is controlled by it,
Lag time, this is the time constant of the input circuit,
The time constant of the output circuit, the arrangement of the user statement and the usse of the instruction,
The cycle scan mode of PLC and the way of PLC to refresh the I/O and so on A171SHCPUN Manual A171SHCPUN Manual.
This phenomenon is called the I/O delay time effect.