According to the control requirements of the system, using the appropriate design method to design MITSUBISHI PLC program.
Write one by one to achieve the control function or the sub task of the program,
Gradually improve the functions specified by the system.
MITSUBISHI PLC initialization procedure. After MITSUBISHI PLC on power, the general need to do some of the initial operation,
In order to start making necessary preparations, to avoid the wrong operation of the system.
The main contents of the initialization program are: to some data area, counter and so on,
For some initial state display, etc.. "
Coaxial data link anomaly station.
Extension sub station.
Redundant operation switch of master station. Input points: 16 points.
Voltage: DC100/110/125V.
Current: 2mA.
Response time: 20ms.
8 points / a common end.
Positive / negative sharing.
20 point terminal station.
Each scanning process. Focus on the input signal sampling AD57 MITSUBISHI. Focus on the output signal to refresh.
Input refresh process
AD57 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 AD57 MITSUBISHI.
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 AD57 MITSUBISHI.
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.
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.
Read only memory. Manufacturers use, content can not be changed, power does not disappear. Input and output points: 480 points.
Program capacity: 7K step.
Basic command processing speed: 4.4 ~ 5.6us.
Power supply: input DC5V output 2A DC24V/.
Modular: PLC is the basic components of a separate module.
Medium and large PLC used this way. Easy maintenance.
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.
User program storage capacitty: it is a measure of how much the user application can store the number of indicators AD57.
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 llogical operation instructions each account for 1 words AD57. Timer / counter,
Shift instruction accounted for 2 words. Data operation instructions for 2~4.