1. Step The basic idea of PLC Sequential control design method is to divide a working cycle of the system into several sequential connected stages. These stages are called steps, which can be represented by programming elements (such as auxiliary relay m and sequential control relay s). Step is divided according to the state change […]
Category: Industrial Control
Logic methods and steps of PLC programming
Logic method: it is to apply logic algebra to design programs in the method and form of logical combination. The theoretical basis of logic method is logic function, which is the logical combination of logic operation and, or and non. Therefore, in essence, PLC ladder program is the logical combination of and, or and non, […]
Empirical design method of PLC ladder diagram
The empirical design method uses the method of designing relay circuit diagram to design the ladder diagram of relatively simple switching value control system, that is, on the basis of some typical circuits, the ladder diagram is constantly modified and improved according to the specific requirements of the controlled object for the control system. Sometimes […]
Common programming methods in PLC programming
Graphic method is to design PLC program by drawing. The common methods are ladder diagram method, logic flow chart method, sequence flow chart method and step sequence control method. A ladder diagram method: ladder diagram method uses ladder diagram language to compile PLC program. This is a programming method that imitates the relay control system. […]
Description of PLC control principle and characteristics of water tower
1. Question raised: the function of the water tower is to pump the groundwater into the water tower at the top of the tower for storage through the water pump, so as to ensure that the water supply system has a certain pressure. As shown in Figure 1-1. 2. Solution to the problem: the […]
Contents of each part in PLC instruction format
The contents of each part in PLC instruction format are described as follows: (1) Control conditions The number and meaning of control conditions vary with different functional instructions. The control conditions are stored in the stack register, and their order is fixed. (2) Instruction See table 5-4 for the types of functional instructions Three […]
SFC programming method of PLC
When compiling user program with SFC, sometimes the program needs to jump or repeat, the out instruction is used instead of the set instruction. (1) Partially repetitive programming method In some cases, it is necessary to return to a certain state and execute a program repeatedly, and the partially repeated programming method can be adopted, […]
Transplantation design method of PLC programming
1. Analyze the working principle of the original system Understand the process and mechanical action of the controlled equipment, analyze and master the working principle of the control system according to the relay circuit diagram. 2. I / O distribution of PLC Determine the input and output equipment of the system, allocate the I / […]
What are the forms of PLC signal address table
There are four kinds of address table and signal address table (take fs-om as an example). 1) MT → PLC address table. This table is also called “input signal address table”. It consists of 8-bit 15 byte addresses (i.e. X00, X02, X04, X06, X08, X10, X12, x14, x16, x17 － X22). Each byte corresponds to […]
LED color lamp PLC programming wiring and ladder diagram
1、 Equipment, tools and materials required for the project See Table 1. 2、 Training content: 1. Project description An artistic lantern modeling demonstration board is shown in Figure 6. In the figure, a, B, C, D, e, F, G and H are eight lanterns in a circular distribution. The control requirements are as follows (the […]