Hollysys PLC - Introduction to the 4 basic concepts of PLC signals

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.

(1) Overhaul projects DCS system overhaul is carried out in the random group of main equipment overhaul, and the overhaul project includes the following: 1) Conduct a comprehensive inspection of the control equipment and make a record. 2) Copy the configuration of all modules, and verify the marks and addresses of the modules. 3) Qing ...

Recently, the signing ceremony of the strategic cooperation between Bureau Veritas and Hollysys and the functional safety certification ceremony of Hollysys valves were held in the Hangzhou base of Hollysys. Mr. Ye Jiong, General Manager of Bureau Veritas Technology Center, Mr. Zhong Aimin, Director of Product Certification Center, Mr. Yang Yang, Sales Director of Eastern Region, and Mr. Yang Yang, Director of Functional Safety ...

LK is a programmable controller (PLC) product launched by Hollysys for medium and high-performance control fields. It fully integrates the advantages of DCS and PLC, adopts high-performance analog processing technology, miniaturized structural design, open industry standards, and a universal system platform, so that ...

(1) When the PLC and the host computer (or touch screen) form a monitoring system, there are many times when there are "manual", "automatic" and other control modes on the screen (generally when there is only one multiple). You can use the "MOV" command in the program. For example, when "manual" is selected, the constant 1 MO ...

2. Interference in the control system and its sources On-site electromagnetic interference is one of the most common factors in PLC control system and most likely to affect the reliability of the system. It is therefore essential to know the source of on-site disturbances ...

1. Preliminary preparations Engineering configuration is operated at the engineer station, and before engineering configuration, it is necessary to have the necessary tools and information, specifically: Tools: refers to the hardware environment and software environment used in engineering configuration, usually refers to the ...

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. 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...

On October 15, 2022, the scientific and technological achievement of "SCADA system development and refined oil pipeline application based on independent chips and operating systems" jointly completed by South China Branch of National Petroleum Pipeline Network Group Co., Ltd. and Hangzhou Hollysys Automation Co., Ltd. successfully passed the China Petroleum and Chemical Industry Co., Ltd.

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 ...

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 ...

Hangzhou Hollysys Automation Co., Ltd. (hereinafter referred to as Hanghe) and Jinan Iron and Steel Group International Engineering Technology Co., Ltd. (hereinafter referred to as Jinan Iron and Steel International) signed a strategic cooperation agreement in Jinan. Luan Yuandi, Deputy General Manager of Jinan Iron and Steel International, Sun Jiaying, Director of the Automation Division, and Liu Xinjie, Director of the Automation Office...

Facing China's "double carbon" strategic goals, the Beijing Economic and Technological Development Zone is guiding a large number of enterprises to explore the implementation plan of "carbon peak" and "carbon neutrality", and strive to build a number of green factories, green products and green supply chains. Recently, enterprises in the zone and Lisi Group signed a contract for the first time in China to use CO (dioxide...

On March 15, the 2023 China Petroleum and Chemical Industry Digital Transformation and Intelligent Development Conference was held in Tai'an, Shandong. The conference aims to strengthen the construction of "intelligent oil and gas fields, intelligent petrochemicals, intelligent chemicals and intelligent oil and gas pipeline networks", and lead China's petroleum and chemical industry to achieve intelligent transformation.

3. Main anti-interference measures (1) Reasonable treatment of power supply to suppress the interference introduced by the power grid For grid disturbances introduced by the power supply, an isolation transformer with a shielded ratio of 1:1 can be installed to reduce the interference between the equipment and the ground.

There are many new developments in the field of DCS-related, which are mainly manifested in the following aspects. (1) The system function is developing in the direction of openness. The structure of traditional DCS is closed, and it is difficult to be compatible with DCSs from different manufacturers. The open DCS will allow users to set a larger system ...

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 ...

Various brands of PLCs have a self-diagnosis function, but the trick of PLC repair is to make full use of this function to analyze and then pinpoint the problem. Sorted out the 8 common types of errors that PLC repairmen need to know when the PLC presents abnormal alarms. 1. CPU abnormality ...