Hollysys PLC - How to maintain the PLC control cabinet?

1. Stand-alone control system The stand-alone control system is controlled by one PLC to control one device or one simple production line, as shown in Figure 7-1. The composition of the stand-alone control system is simple, the number of I/O points required is less, the storage capacity is small, and when the model of PLC is selected, whether there is a communication network at present.

In general, DCS control systems require two types of grounding: protective ground and working ground (logical, shielded, etc.). For systems equipped with safety barrier explosion protection measures, such as those used in the chemical industry, intrinsically safe premises are also required. 2.1 Protected areas (CG, Cabinet Grounding...)

DCS is properly blacked out When the DCS needs to be powered off for maintenance due to overhaul or other reasons, we often directly power off the DCS, but sometimes this non-standard operation will bring serious consequences, such as configuration loss, PID parameter loss, etc. So there is a need for blackouts and re-on...

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) 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, ...

Since the day of the birth of PLC, it has occupied the core position of the entire automatic control system. There are also many discussions about the development direction of PLC, whether it is predicted that PAC will replace PLC from 10 years ago, or during this time, some people even say that PLC is no longer needed in the future Industry 4.0 era...

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 ...

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. 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 ...

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 ...

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. ...

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 ...

Hollysys' safe and trustworthy DCS control system uses the controller K-CU11 for the K series large-capacity trusted controller module, which adopts advanced PowerPC architecture high-performance main processor and security components based on national cryptography algorithm, and has the security functions of static trusted start and dynamic trusted measurement. ...

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 ...

1. Lack of motivation It may sound simple, but it's good to check the simple stuff first. Thoroughly inspect all power connections and cables for damage that could cause a short circuit. Make sure your power supply is functioning properly. Use a voltmeter to check if the grounding and voltage are correct. 2. Bad ...

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. 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 ...

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 ...

On September 19, 2022, the XCon2022 Security Focus Information Security Technology Summit was successfully held in Beijing. More than 10 technical experts, heads of security departments, and front-line security experts from well-known domestic network security enterprises shared in-depth topics at the meeting.