Program memory capacity: 8k.
Input / output points: maximum 256 points.
A scan cycle of PLC must pass through three stages: input sampling, program execution and output refresh.
PLC in the input sampling phase: first of all, in order to scan the sequence of all existing input latches in the input terminal of the state or input data read,
And write it into the corresponding input status register,
Refresh the input, then close the input port, enter the program execution stage A970GOT-LBA-EU Operating Manual A970GOT-LBA-EU Input and output points: 2048 points.
Input / output data points: 8192 points.
Program capacity: 30K.
Basic command processing speed (LD command) s:0.15.
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 A970GOT-LBA-EU Operating Manual.
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 A970GOT-LBA-EU Operating Manual.
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.
User program storage capacity: it is a measurre of how much the user application can store the number of indicators A970GOT-LBA-EU Manual.
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 A970GOT-LBA-EU Manual. Timer / counter,
Shift instruction accounted for 2 words. Data operation instructions for 2~4.