Hollysys PLC - Six Fault Types of PLC and Troubleshooting Methods (1-3)

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.

On November 13, 2022, Zhong'an United Coal Chemical Branch came with exciting news that the 20,000 tons/year butene-1 plant produced qualified butene-1 products at 22 o'clock on the same day, and the one-time start-up was successful. The control system of the device adopts the innovative technology product "OCS Industrial Optical Bus Control ...

1. Budget for input and output (I/O) points When budgeting I/O points, the appropriate margin should be considered, usually based on the calculated number of input and output points, and then add 10%-20% of the expandable, and after the margin, it will be used as the budget data of input and output points. When ordering in practice, it is also necessary to rely on the manufacturer's ...

1. Power supply: The power supply is used to convert the alternating current into the direct current required inside the PLC, and most of the PLCs are powered by switching regulated power supply. 2. Central processing unit: The central processing unit (CPU) is the control center of the PLC, and it is also the core component of the PLC.

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.

The bottom layer, the field control layer, that is, the field instrument and signal transmission, is mainly the collection of signals and the transmission of control signals. From field devices to control CPUs. The middle layer, the system management layer, that is, the internal network layer of the DCS system, including the control station, the operation station, the historical server...

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. 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) There are three forms of programmable controller: relay output, thyristor output, and transistor output. (2) The wiring of the output terminal is divided into independent output and common output. When the output relay or thyristor of the PLC is activated, the two output terminals of the same number are turned on. In different groups, you can ...

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 ...

Simplicity Make the PLC program as simple as possible. Simplicity means using a standardized procedural framework as much as possible and using simple instructions as much as possible. If you want the program to be simple, in a big way, you should optimize the program structure, simplify the program with process control instructions, and ...

Recently, Hangzhou Hollysys Automation Co., Ltd. (hereinafter referred to as Hollysys Company) successfully signed a contract with PetroChina Liaoyang Petrochemical Branch (hereinafter referred to as PetroChina Liaoyang Petrochemical) to construct and rectify 16 sets of control system projects during the planned overhaul in 2023 - 9 ...

(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. 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) Select the appropriate PLC model and I/O points, and select the special function module when there are special function requirements. (2) Familiar with the selected PLC programming instructions and compilation software. (3) Carry out soft component planning, including internal relays, holding relays, data registers, ...

(1) The ambient temperature exceeds the range of 0-50 °C; (2) The relative humidity exceeds 85% or there is dew condensation (caused by sudden temperature changes or other factors); (3) direct sunlight; (4) There are corrosive and flammable gases, such as hydrogen chloride, ...

1. Logic control of switching quantity This is the most basic and most extensive application field of PLC, which replaces the traditional relay circuit to achieve logic control and sequence control, which can be used for the control of a single device, as well as for multi-machine group control and automatic assembly line. Such as injection molding machines, printing machines, ...

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.

1. Configuration of the control loop The configuration of the control loop is essentially to use the various basic functional modules provided by the system to form a variety of actual control systems. At present, the configuration methods provided by various DCSs are different, and they can be summarized as having a specific computing module connected ...

On August 16, 2021, the Tarim Oilfield Natural Gas Ethane Recovery Project, the largest natural gas deep processing base in Xinjiang (1), a key project of PetroChina, was successfully completed and put into operation, with stable operation and the production of qualified ethane products. Tarim Oilfield Natural Gas Ethane Recovery Project ...