ABB PFXA401F TCP/IP communication, RS-232 control unit

Description

Millmate Controller 400 PFVA401 (PFXA 401 with PFVI 401)
Dimensions (H x W xD), two pieces 2) 380 x 235 x 90 mm each
Weight 2) 5 kg + 8 kg
Protection class 1) IP 20
Main voltage 85 to 264 V, 100 (–15 %) to 240 V (+10 %)
Power consumption 650 VA (140 VA for QGPR 104/102 installation)
Excitation current 2 A
Operating temperature 0 to +70 °C
Storage temperature –40 to +70 °C
Analog intputs Load cell connection, 2 or 4
Analog outputs Voltage 0 to ±10 V
Current 0 to ±20 mA, 4 to 20 mA (insulated as group)
Step response 1 ms (0 to 90 %), 5 ms for QGPR 104/102
Digital inputs 0/+24 V insulated 4 + 4
Digital outputs 0/+24 V insulated 4 + 4

Problems in the Application of DCS in Small Thermal Power Plants
① There is a significant gap between the manufacturing process and level of domestic DCS hardware and the international level, with a high failure rate of hardware;

② Due to the lack of practical and feasible testing methods and means. Some DCS performance indicators cannot be assessed and accepted. Many performance indicators have not met the standard requirements;

③ Due to fierce competition in the DCS market, prices have been kept very low. DCS suppliers cannot have significant investment in engineering design and application software development. The decentralized control principle of DCS is often not reflected in hardware configuration. Especially in small systems. This phenomenon is particularly evident;

④ The level of engineering design and application software development is also not high. Advanced control software and control strategies cannot be promoted and applied. Not conducive to the economic and safe operation of power plants;

⑤ The reliability and accuracy of domestic detection components and actuators often cannot meet the requirements of DCS control systems. Increased the difficulty of system automatic adjustment investment. The advantages of DCS cannot be fully utilized, affecting the economic operation of the unit;

⑥ Due to the non-standard nature of small units. Some auxiliary equipment comes with their own control system (box). A commonly used method is to use hard wiring to transmit the control signals of these devices to DCS and control them by DCS; The connection between various systems is the most troublesome problem in engineering. The ability to solve these problems has become the key to the long-term safe operation of the entire system;

⑦ Control strategies are generally formulated by DCS manufacturers. However, DCS manufacturers often do not have a good understanding of the details of the production process. Or rather, I am not very familiar with the changes in the main equipment. Therefore. Control strategies often have some shortcomings. It is necessary to continuously modify according to the actual situation with the help of experienced operators after production to achieve better results.

At present, domestic DCS has reached or approached the international advanced level. Domestic DCS has a high cost-effectiveness and is suitable for selection in units below 300MW. It can gradually expand its application range in units above 600MW.

The engineering capabilities of domestic DCS enterprises for large power plants need to be further improved through practical engineering exercises.

Domestic DCS enterprises should strengthen their research and development efforts, and quickly solve the engineering practice of connecting with field bus instruments such as FF and Profibus-PA in DCS, as well as the application of EDDL equipment description language technology and interoperability technology.

Strengthen the engineering practice of integrated control, electronic control, and instrument control application technology, especially the practice of strengthening the special technology of “asset management”.

Strengthen research on functional safety technologies.
In the introduction of foreign large-scale unit DCS application projects, domestic manufacturers are included as partners of the end users, drawing on advanced foreign technology and engineering management experience, and providing protection for the operation and maintenance of the unit for the end users.