H2310240032X512 RELIANCE 

H2310240032X512 RELIANCE

In the late 1960s, based on the demand of the automotive market and the development of computing technology at that time, Bedford Associates in Bedford, Massachusetts, proposed to the US automotive manufacturing industry to develop a Modular Digital Controller (MODICON) to replace relay control panels. Other companies also suggest computer-based solutions. The core idea is to use software programming methods to replace the hard wiring method of relay control, and to provide interfaces for input sensors and output actuators that are widely used in production sites, in order to facilitate the process control of large-scale production lines. This is the origin of what will be called Programmable Logic Controller in the future. MODICON 084 is the world’s first PLC put into commercial production.

The 1970s was the period when PLC emerged, first gaining widespread application in the automotive industry and also beginning to be applied in other industrial sectors. In the 1980s, it matured and fully adopted microelectronics and microprocessor technology; A period of extensive promotion and application, laying an unshakable position in industrial control. At this stage, PLC sales have always grown at a double-digit percentage point rate, with a growth rate of over 35% in the first six years and stable development in the following four years, with an annual growth rate of about 12%. The 1990s marked the beginning of its third period of development. With the official issuance of the international standard IEC 61131 for PLC, it has driven new breakthroughs in PLC technology:

INDRAMAT Eco Drive Controller DKC02.3-040-7-F​​W

INDRAMAT HDS03.2-W075N-H​S56-01-FW DSS02.1M DAE02.1M

INDRAMAT AC-Servo Controller TDM-1.2-50-300-​W1

Indramat TDM 3.2-020-300 W0 Servo Controller

Indramat AC-Controller HDS03.2-W100-HS​45-01-FW NEW

In the 20th century, the establishment of automation science and technology and the development of industry gradually formed the automation instrument industry. Before the 1950s, PID regulation was already very popular, but base type instruments that integrated detection, regulation, and execution functions were still mainstream thermal instruments. Functional separation, signal transmission, and centralized display operation in the central control room are still being developed as a highly versatile automation instrument mode that can be applied to multiple industries.

In the 1960s, the DDZ-I electric unit combination instrument based on electronic tubes was replaced by the DDZ-II electric unit combination instrument based on discrete transistor components. This is a complete set of industrial automation instruments targeting industries such as petroleum, chemical, metallurgy, power, and building materials, with temperature, pressure, flow, and liquid level as the main control parameters. During this period, due to the large-scale production equipment, there was already a central control room, and the operation mode of base type instruments was gradually replaced. However, the communication signals between various unit instruments were not yet unified, and direct current signals of 0-10mA were widely used.

In the 1970s, the First Machinery Department organized the unified design of DDZ-Ill instruments. The DDZ-III model was developed on the basis of linear integrated circuit (operational amplifier) technology, international unified signal, intrinsic safety explosion-proof technology, and other technologies. At the same time, assembled instrument devices are also emerging.

In the late 1960s and early 1970s, the International Electrotechnical Commission (IEC) established an international unified signal of 4-20mA DC and 1-5V DC as auxiliary signals. This international unified signal was implemented with 4-2 (ADC) as the transmission signal and 1-5VDC as the reception signal. There was little resistance to its advanced technology and practical feasibility, and both the original manufacturers and users urgently hoped for a unified signal system.

In the overall design of the DDZ-III instrument, in order to meet the requirements of the automatic control system of a large refinery with a crude oil processing capacity of 5 million tons/year, the system requires intrinsic safety and explosion-proof, and the distance between the on-site instrument and the central control room should be considered to be relatively far (within about 500 meters). On the basis of complying with international unified signals, a scheme of 24VDC unified power supply and two wire transmitter and safety barrier is selected. At that time, the level of linear integrated circuits and transistors could achieve constant current performance by connecting the resistance of the external wire of the control room instrument in series with the internal resistance of the two wire transmitter or actuator under 24VDC power supply conditions. 4mA is designed to ensure the necessary power supply for the working point of the two-wire transmitter amplifier. In places where explosion-proof requirements are required, it can also withstand 24VDC, 20mADC or slightly higher electricity, so it can meet the above two requirements.