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Industrial control characteristics

Industrial control computers, in simple terms, are computers designed specifically for industrial sites, which typically have strong vibrations, high levels of dust, and high electromagnetic field interference. Additionally, factories typically operate continuously, meaning they do not rest for a year

Therefore, compared to ordinary computers, industrial control computers must have the following characteristics:

1) The chassis adopts a steel structure, which has high anti magnetic, dustproof, and anti impact capabilities.

2) There is a dedicated backplane inside the chassis, with PCI and ISA slots on the backplane.

3) There is a dedicated power supply inside the chassis, which has strong anti-interference ability.

4) Require the ability to work continuously for long periods of time.

5) Generally, standard enclosures that are easy to install are used (4U standard enclosures are more common). Note: Except for the above characteristics, the rest are basically the same. In addition, due to the above professional characteristics, industrial control computers at the same level are more expensive than ordinary computers in terms of price, but generally not much different.

The disadvantages of industrial control computers Although they have unique advantages compared to ordinary commercial computers, their disadvantages are also very obvious – poor data processing capabilities, as follows:

1) Configure a small hard disk capacity;

2) Low data security;

3) Low storage selectivity.

4) The price is relatively high.

2.1 Development History of PLC

In 1968, General Motors of the United States proposed the requirement to replace relay control devices. The following year, Digital Corporation of the United States developed the first generation programmable controller, which met the requirements of GM’s assembly line.

With the development of integrated circuit technology and computer technology, there are already fifth generation PLC products.

In the manufacturing industry characterized by changing geometric shapes and mechanical properties, as well as in the process industry characterized by converting raw materials into products through physical and chemical changes, in addition to feedback control mainly based on continuous quantities, there are a large number of open loop sequential control mainly based on switching quantities in the manufacturing industry, which operates sequentially according to logical conditions;

In addition, there are controls for interlocking protection actions that are independent of sequence and timing and follow logical relationships; And a large number of state variables such as switch quantity, pulse quantity, timing, counter, analog quantity exceeding limit alarm, etc. – discrete quantity data collection and monitoring. Due to these control and monitoring requirements, PLC has developed into a product that mainly replaces relay circuits and performs sequential control. Over the years of production practice, a tripartite balance has gradually emerged between PLC, DCS, and IPC, as shown in Table 1. Other single circuit intelligent regulators also account for a certain percentage in the market.