Hollysys DCS - Introduction to DCS grounding classification

1. It is used for switching control The ability of PLC to manipulate switching quantities is very strong. The number of points in and out of the control, less than a dozen points, dozens of points, more can be hundreds, thousands, or even tens of thousands of points, because it can be networked, the number of points is almost unlimited, no matter how many points can be controlled, the control ...

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 ...

The choice between a programmable logic controller (PLC) and a distributed control system (DCS) is a case-by-case analysis, as the requirements for the control system vary depending on the application. You can start from the following aspects! PLC and DCS PLC ...

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 ...

PLC is essentially a kind of computer dedicated to industrial control, and its hardware structure is basically the same as that of a microcomputer, and its basic composition is as follows: 1. Power supply The power supply of the PLC plays a very important role in the whole system. If you don't have a good, reliable power system that is ...

The control system needs to establish the input and output channels of the signals, which is called I/O. The I/O in a DCS is generally modular, with one or more I/O channels on one I/O module for connecting sensors and actuators (control valves). The control unit of the DCS: a process control station is ...

1. PLC programmable logic controller (programmable controller). 2. DCS system pays more attention to the field of process control. Such as chemical, smelting, pharmaceutical, etc. It mainly monitors and controls some field parameters, while PLC focuses on logic control. machining). Of course, the PLC's ...

1. High reliability Because DCS disperses the system control function on each computer, and the system structure adopts a fault-tolerant design, the failure of one computer will not lead to the loss of other functions of the system. In addition, due to the fact that the tasks undertaken by the various computers in the system are comparatively ...

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. The function of PLC PLC is a general industrial automatic control device with microprocessor as the core, integrating computer technology, automatic control technology and communication technology, which has high reliability, small size, strong function, simple program design, flexible and universal and maintenance methods.

1. Data backup When carrying out maintenance, we must cut off the power, data backup between power outages is an important link, for the data that needs to be archived for a long time, you can back up the historical trend data to the mobile hard disk, and then turn off the Windows-based operating system (Note...

1 Universal serial port module Based on the serial port communication module to realize the network connection, the network structure is shown in Figure 1, the form of computer link is adopted, the corresponding settings are carried out in the configuration software of the host computer, and the communication can be carried out with multiple PLCs without programming, and the FXlS of Mitsubishi ...

1. Use the analog output module of the PLC to control the analog output module of the inverter The analog output module of the PLC outputs a 0-5V voltage signal or a 4-20mA current signal, which is used as the analog input signal of the inverter to control the output frequency of the inverter. This control method is simple to wiring, but it needs to be selected and changed.

1. Data backup When carrying out maintenance, we must cut off the power, data backup between power outages is an important link, for the data that needs to be archived for a long time, you can back up the historical trend data to the mobile hard disk, and then turn off the Windows-based operating system (Note...

1. The output accuracy is as high as 0.05%, which greatly improves the operation efficiency of the system. 2. The full-scale output of the channel signal is 0-22.7mA, and the output range is wide; 3. It can be adapted to the enhanced base to achieve channel resistance to 220VAC; 4. It has a perfect channel signal diagnosis function, which can be realized.

1. Switch logic control Switching logic control is the basis of PLC. It is the first use case and the most extensive of all. Replace the previous relay circuit control and realize logic sequence control; It can be used for the control of stand-alone equipment, and can also be used for group control and ...

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. 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.

In December 2020, the equipment of Sinopec Qingdao Petrochemical Co., Ltd. (hereinafter referred to as Qingdao Petrochemical) 5 million tons/year oil refining integration project, which was upgraded and transformed by Hollysys, was successfully operated, marking the successful completion of the DCS equipment upgrading task. This upgrade is a major development for Sinopec Industrial Holdings.

DCS is the English abbreviation of distributed control system (Distributed Control System), distributed control system is referred to as DCS, which can also be literally translated as "distributed control system" or "distributed computer control system". The decentralized control system is based on the microprocessor, and the control function is decentralized.