2 slots.
Can be installed in the power supply unit for A series units installed QnA/.
When the programmer input programinto the user program memory,
Then CPU according to the function of the system (the system program memory to explain the compiler),
Translate the user program into PLC internally recognized by the user to compile the program A3UCPU Hardware Manual A3UCPU User's Manual.
Relay output interface circuit of PLC
Working process: when the internal circuit output digital signal 1,
There is a current flowing through, the relay coil has a current, and then the normally open contact is closed,
Provide load current and voltage A3UCPU
When the internal circuit outputs a digital signal 0, there is no current flowing through it,
The relay coil does not have a current, and the normally open contact is broken off,
A current or voltage that is disconnected from the load A3UCPU Hardware Manual A3UCPU User's Manual.
It is through the output interface circuit to the internal digital circuit into a signal to make the load action or not action.
I/O points is an important indicator of PLC.
Reasonable selection of I/O points can not only satisfy the control requirements of the system,
And the total investment of the system is the lowest A3UCPU Hardware Manual A3UCPU User's Manual.
The input and output points and types of PLC should be determined according to the analog quantity and switch quantity of the controlled object,
Generally an input / output element to take up an input / output point.
Taking into account the future adjustment and expansion,
In general should be estimated on the total number of points plus the amount of spare 20%~30%.
The following describes the centralized control system I/O points of the estimate. 5 slots.
No need to install power.
For QnA/A series.
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.
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 / ouutput hysteresis phenomena, i A3UCPU Hardware Manual A3UCPU User's Manual. e., the input / output response delay.
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 A3UCPU Hardware Manual A3UCPU User's Manual.
Read only memory. Manufacturers use, content can not be changed, power does not disappear.