Pneumatic control system and electric control system, what are the advantages and disadvantages of each?

Pneumatic drive and control is one of the most effective means of automation and mechanization of the production process, but its working medium (compressed air) high manufacturing costs, energy efficiency and quite low. Improve the economy of use of pneumatic systems, has become the current should pay attention to the problem.

Pneumatic technology and other transmission and control methods (such as mechanical, electrical, electronic, hydraulic) compared to the following advantages:

1, pneumatic device structure is simple, lightweight, simple installation and maintenance. The pressure level is low, so the use of safety.

2, the working medium is inexhaustible air, air itself does not cost money. Exhaust treatment is simple, does not pollute the environment, low cost.

3, the output force and working speed adjustment is very easy. The action speed of the cylinder is generally 50~500mm/s, which is faster than that of the hydraulic and electrical methods.

4, high reliability and long service life. The effective number of movements of electrical components is about a million times, while SMC's general solenoid valves have a life of more than 30 million times, and small valves more than 200 million times.

5, the use of air compression, can store energy to achieve centralized air supply. Energy can be released for a short time to obtain high-speed response in intermittent motion. Can realize buffering. Strong adaptability to shock load and overload. Under certain conditions, the pneumatic device can be made to have self-holding ability.

6, full pneumatic control has the ability of fire, explosion and moisture resistance. Compared with the hydraulic method, the pneumatic method can be used in high temperature occasions.

7, due to the small air flow loss, compressed air can be centralized supply, long-distance delivery.

Disadvantages are:

(1) air compressibility, load changes, the transfer of movement is not smooth and uniform;

(2) the working pressure can not be too high, transmission efficiency is low, it is not easy to get a lot of force or torque;

(3) there is a large exhaust noise.

Electric control system (electric regulator) is a unified current signal (such as 4-20mA) to do the transmission of the control system, fast regulation, high precision, will be able to computer interface, commonly used in various types of industrial control Yanghe to do regulation and control.

? Advantages:

AC motor structure is simple, easy to routine maintenance;

AC motor rugged, light weight, the need for dynamic response to high occasions (precision, high-speed control) when the advantages are significant;

High power factor, harmonic wave is small;

Motor efficiency, energy-saving effect is good (compared with the DC integrated power saving rate of 15-25%).

? Although the AC speed drive has advantages, but it also has the following shortcomings to be improved:

The line is complex, the control is difficult;

The initial investment cost of the AC frequency conversion speed control device is slightly higher.