PLC understands the interrupt function in this way, when understanding the interrupt, we must first understand the PLC operation cycle or the scanning cycle, it is necessary to say that the PLC sequential control cycle execution process, which is the premise of understanding the interrupt, must be mastered, divided into three parts, input processing, program processing, output ...

1. Correctness (low debugging cost) First of all, the PLC program must be able to work correctly to meet the requirements of the actual control process. This is the essence of the PLC program, and if you don't do that, nothing else makes sense. 2. Reliability (low maintenance cost) Not only to ...

1. The switching signal of PLC controls the inverter The output point and COM point of the PLC (MR type or MT type) are directly connected to the STF (forward start), RH (high speed), RM (medium speed), RL (low speed), and SG input ports of the inverter. PLC can control the frequency conversion through the program ...

1. What is serial communication? Serial is a very versatile protocol for device communication on a computer (not to be confused with Universal Serial Bus or USB). Most computers contain two serial ports based on RS232. The serial port is also an instrument ...

1. Check the circuit according to the drawing (without power transmission) The drawings of the general PLC system include two parts: the drawings in the cabinet and the drawings outside the cabinet; The drawing in the cabinet refers to the wiring diagram inside the cabinet; The out-of-cabinet drawings are the wiring diagrams of all electrical cabinets that are connected out. This part needs to be checked for; 1. Drawings ...

Serial communication is done using 3 wires: (1) ground, (2) sending, and (3) receiving. Since serial communication is asynchronous, ports are capable of sending data on one wire and receiving data on the other. Other threads are used for handshakes, but are not required. Serial communication is the heaviest ...

(1) Computing function The computing functions of a simple PLC include logic operation, timing and counting functions; The operation functions of ordinary PLC also include data shift, comparison and other calculation functions; More complex arithmetic functions include algebraic operations, data transmission, etc.; There are also analog PIDs in large PLCs.

1. The switching quantity is also called the logical quantity, which means that there are only two values, 0 or 1, ON or OFF. It is the most commonly used control, and controlling it is the advantage of PLC, and it is also the most basic application of PLC. The purpose of switching control is to follow the current input combination with the historical input according to the switching quantity.

1、-10—10V。 When the voltage of -10V-10V is converted to F448-0BB8Hex (-3000-3000) at 6000 resolution; At 12000 resolution, it is converted to E890—1770Hex (-6000—6000). 2、0—10V。 At a voltage of 0-10V, at a resolution of 12000 ...

The control of pulse amount is mostly used for angle control, distance control, position control and so on of stepper motor and servo motor. The following is an example of a stepper motor to illustrate each control mode. 1. Angle control of stepper motor. First of all, it is necessary to clarify the number of subdivisions of the stepper motor, and then determine the stepper ...

According to the structural form of PLC, PLC can be divided into two categories: integral type and modular type. (1) Integral PLC The integral PLC is a centralized power, CPU, I/O interface and other components in a chassis, which has the characteristics of compact structure, small size and low price. Small PLC ...

According to the different functions of PLC, PLC can be divided into three categories: low-grade, mid-range and high-end. (1) Low-grade PLC Low-grade PLC has basic functions such as logic operation, timing, counting, shifting, self-diagnosis, monitoring, etc., and can also have a small amount of analog input/output, arithmetic operation, math...

1. Grounding problems The grounding requirements of the PLC system are relatively strict, and it is best to have an independent dedicated grounding system, and it should also be noted that other equipment related to PLC should also be reliably grounded. When multiple circuit grounding points are connected together, unexpected currents can be generated, resulting in logic errors or ...

1. Peripheral circuit component failure This type of failure often occurs in the failure of the PLC after a certain period of work. In the PLC control loop, if there is a component damage fault, the PLC control system will immediately and automatically stop working. The input circuit is a PLC that accepts switching quantities, analog ...

When the PLC understands the interrupt function, it needs to understand the PLC's operating cycle or scan cycle. It is necessary to talk about the process of PLC sequential control loop execution, which is a prerequisite for understanding interruptions and must be mastered. It is divided into three parts, input processing, program processing, and output processing. 1、 ...

(1) The PLC adopts the working mode of centralized sampling and centralized output, which reduces the influence of external interference. (2) The working process of PLC is the process of cyclic scanning, and the length of cyclic scanning time depends on the speed of instruction execution, the length of the user program and other factors. (3) Output ...

1. The role is different A PLC (Programmable Logic Controller) is an electronic system designed for digital operations in an industrial environment. The inverter is the application of frequency conversion technology and microelectronics technology to control the AC motor by changing the frequency of the motor working power supply.

1. DCS is a "distributed control system", while PLC (programmable controller) is just a control "device", which is the difference between the two. The system can realize the function and coordination of any equipment, and the PLC equipment only realizes the function of this unit. 2. In terms of networking, the DCS network is ...

In general, PLCs are extremely reliable devices with a very low failure rate. The probability of hardware damage such as the CPU of the PLC or software running errors is almost zero; If the PLC input point is not caused by strong current intrusion, it will hardly be damaged; The normally open point of the PLC output relay, if it is not a short circuit of the peripheral load ...

1. Relay output circuit This type of output circuit form can be either DC or AC. The output circuit form of PLC relay allows the load to be generally below AC250V/50V, the load current can reach 2A, and the capacity can reach 80-100VA (voltage × current), so ...

1. Circuit isolation The isolation of analog circuits is more complex, mainly depends on the accuracy requirements of the transmission channel, the higher the accuracy requirements, the higher the cost of the channel; However, when the performance requirements rise to the main contradiction, the isolation components should be selected based on performance, and the ...