IC-RAM / A7HGP memory CMOS backup batteryInput points: 16 points.
Voltage: AC200 ~ 240V.
Current: 10mA.
Response time: 25ms.
16 points / a common end..
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 processs of interpretation A78B.
Read only memory. Manufacturers use, content can not be changed, power does not disappear.
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 A78B.
Different series of different models of PLC has different performance, applicable occasions also have different emphasis,
Price also has a greater difference A78B. 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 MITSUBISHI A78B.
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 MITSUBISHI A78B.
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 MITSUBISHI A78B.
Due to the adoption of centralized sampling.
Centralized output mode.
There exist input / output hysteresis phenomena, i.e., the input / output response delay.
8 slot, PID special substrate.
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.
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.
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.
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.
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. A78B.
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.