With the rapid development of urbanization, the demand for bricks is increasing. In the construction of very basic facilities, brick plays a decisive role. Good quality bricks are not only hard and not easily broken, but also do not pollute the environment during production. Based on PLC control of the brick block machine not only has the advantages of large output, stable work, high efficiency, but also can produce high-quality bricks, brick machine through PLC control, stable work, strong anti-interference ability. brick making machine controlled by the frequency of vibration frequency and density of different specifications of brick production, design is the use of Siemens S7-200 series PLC, using the Siemens MM440 inverter based on the design of automatic control of the brick making machine, PLC has good maneuverability and stability, and use of frequency converter of high speed adjusting production of different specifications of the brick, using configuration software can realize the scene monitoring and pump power monitoring data.
During the 19th century, dc and AC motors were used in industry. At that time has become the main drive machinery. But because the technology is not mature, in a very long time, most of the industrial machinery equipment for speed control still use dc motor. Because of the converter, the maintenance cost of dc motor is very high, and the maximum speed of motor and single capacity cannot be increased. Therefore, people want to replace dc motor with ac motor that can adjust the speed. Therefore, people began to study a lot of AC speed regulation system. In the early 20th century, ac motor with adjustable speed was developed rapidly in special industry. The miniaturization, networking, multifunction and pollution-free development of frequency converter. Frequency converter has excellent performance in AC speed regulating system and plays an important role in industrial application. The main disadvantages of the inverter are the influence of the output current and voltage harmonics of the inverter on the motor, the fluctuation of the power grid and the harmonic pollution of the power grid. In the use of the converter, the power loss of the converter should also be taken into account. The model of inverter used in the control system of brick machine is Siemens MM440. The Siemens MM440 inverter is used to control the speed of three-phase ac motor. Main characteristics of Siemens MM440 inverter:
(1)  Easy to install and debug
(2)  Convenient cable connection
(3)  Solid EMC design
(4)  Fast response speed
(5)  Vector control function
(6)  The slope characteristics of variable frequency acceleration/deceleration, as well as the smooth arc starting and binding stage, can be adjusted.
(7)  Convenient setting of parameters and wide setting of values