1. Configuration of the system and controller
The configuration of systems and controllers focuses on reliability and load factor (including redundancy). The communication load rate must be controlled within a reasonable range, and the load rate of the controller must be balanced as much as possible to avoid the occurrence of "high load" problems.
2. System control logic allocation
The distribution of system control logic should not be overly concentrated on a certain controller, and the main controller should adopt redundant configuration.
3. Power supply design
The power supply design must be reasonable and reliable. Pay attention to the load rate of the power supply design and the redundant configuration of the power supply to ensure that the two independent power supplies are ensured.
4. DCS system interface
Pay attention to the reliability of the DCS system interface, and pay attention to the interface mode and redundancy of important interfaces.
5. DCS system grounding
The grounding of the DCS system is carried out according to the requirements of the manufacturer to avoid large-scale system failures caused by grounding problems. Attention should be paid to the anti-interference measures of the system, and the I/O channels should emphasize isolation measures. Pay attention to cable quality and shielding, and use computer special communication shielded cables for important signals and control.
6. Equipment configuration
According to the operation characteristics of the equipment and the requirements of the unit to deal with emergency faults under various working conditions, the operator station and backup manual operation device are configured. The emergency shutdown button configuration should be separate from the DCS.
7. Protection system
For the protection system, the multiplexing signal acquisition method is used. Rational use of blocking conditions, so that the signal loop has the ability to make logical judgments.
8. Equipment commissioning
During the commissioning period, all logic, loops and working conditions are tested according to the debugging outline and method to ensure that the parameters are set correctly and reasonably.
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Hollysys PLC - What are the selection methods of PLC?
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 ...
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Hollysys DCS - the development trend of DCS
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 ...
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Hollysys DCS - How to deal with DCS system failure?
1. View the data on the monitoring screen
When the following situations occur, it means that there is a problem with the control system, and the microcomputer maintenance personnel should be notified immediately for maintenance, and the operator should go to the site to deal with it.
(1) Frequently changing data does not change for a long time, and several or all data do not ...
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Hollysys delivered a keynote speech at CAIMRS 2023 and won a number of awards
The "2023 China Automation + Digital Industry Annual Conference", "The 19th CAIMRS and Digital Leaders Forum" and the "Annual Award Ceremony" were successfully held in Suzhou. The theme of this summit is "Powerful Digital Intelligence, Junfa New Industry", combined with post-epidemic recovery, digital intelligence, and new industrialization.
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Hollysys DCS - Introduction to the hardware architecture of DCS distributed control system
DCS usually adopts a hierarchical and progressive structure, each level is composed of several subsystems, and each subsystem achieves a number of specific finite goals, forming a pyramid structure. Examining the hierarchical structure of DCS, DCS level and control management level are the two most basic links that make up DCS.
Process control...
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Hollysys DCS - Introduction to I/O in DCS control system
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 ...
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HollySys PLC - the usage and principle of PLC programming interrupts
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、 ...
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Hollysys successfully signed 16 sets of control system projects for 10 million tons of oil refining enterprises
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 ...
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Hollysys released a new 100% localized system
On the morning of October 20, 2021, at the Epec Industrial Products Exhibition, Hollysys released a new 100% localized system - 'HOLLiAS MACS IC fully autonomous and controllable DCS system'.
The system integrates the controller microkernel architecture independently developed by Lisi, embedded ...
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Hollysys PLC - what are the anti-interference countermeasures of PLC and touch screen?
In order to improve the anti-interference ability of the PLC system, we should start from the design. In the anti-interference design of specific projects, products with strong anti-interference ability can be selected to improve the anti-interference of equipment and systems by suppressing interference sources, cutting off or attenuating the transmission path of electromagnetic interference, and using software means.
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Hollysys PLC – How to calculate the analog quantity in PLC
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 ...
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Hollysys DCS——What should I pay attention to when cleaning the DCS system?
1. Power off
2. Cleaning the ash can not only clean the surface, but also clean the internal card key of the controller
3. If there is a supporting UPS, open the UPS and clean the ashes
4. After cleaning the ash, check whether the card and relay are loose, and tighten them if they are loose
5. The relays with frequent actions should be cleaned regularly.
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Hollysys PLC - Introduction to the 4 basic concepts of PLC signals
Analog signal: refers to a continuous current signal or voltage signal, and analog signal can be divided into standard signal and non-standard signal.
Switching signal: It can be divided into active signal and passive signal, which is basically an on-off signal, and can be measured on and off with a multimeter ohm.
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Hollysys PLC - common causes and treatment methods of PLC failures in operation
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 ...
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Hollysys PLC - Introduction to the functions and application fields of PLC
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.
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Hollysys helped China's first 20,000-ton green electricity to green hydrogen demonstration project be fully put into operation
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Hollysys DCS - a common fault of DCS
1. Field instrument equipment failure:
Field instrumentation equipment includes various transmitters, various switches, actuators, loads and components of various temperatures that are directly connected with the production process. If the field instrument fails, it directly affects the control function of the DCS system and the operator's ...
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Hollysys PLC – PLC programming advice
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HollySys PLC - What places should be avoided when installing PLC?
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(2) The relative humidity exceeds 85% or there is dew condensation (caused by sudden temperature changes or other factors);
(3) direct sunlight;
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