The hottest Siemens logo controller in the cement

Application of Siemens logo controller in cement silo pump conveying system

Abstract: This paper introduces Siemens logo controller and its application in cement silo pump conveying system. The application of logo greatly simplifies the system hardware structure, has high reliability, and is especially suitable for harsh working environment

in the process flow of cement production, in order to stabilize the quality of cement, the cement grinded by the ball mill must be stored in the cement warehouse before leaving the factory. While the cement out of the mill is stored in the warehouse, the cement factory generally adopts the silo pump transportation method for pneumatic transportation. The automatic control system of silo pump transportation developed with Siemens logo controller can automatically control cement transportation, measure the number of silos of cement transportation, estimate the cement output, and provide a reliable basis for workshop production assessment

1 Structure and principle of cement silo pump conveying system

the cement silo pump conveying system is mainly composed of pump body, feed valve, exhaust valve, air supply valve, discharge valve, tuning fork level switch and electric contact pressure gauge

when the silo pump conveying system starts to work, there is no material in the pump body. At this time, close the air supply valve and discharge valve, open the exhaust valve and feed valve, the cement enters the pump body from the cement silo above the silo pump, and the air is discharged by the exhaust valve. When the cement level reaches the preset position, close the feed valve and exhaust valve, open the air supply valve, and blow compressed air. After a slight delay, the cement in the pump begins to boil and reach the fluidization state, and the air pressure in the pump also reaches the preset value. At this time, open the discharge valve, and use the pressure of compressed air to send the cement through the pipeline to the cement silo. As the cement flows out, the air pressure in the pump gradually decreases. When it is lower than the preset value, it indicates that the cement in the pump has been blown out. Close the air supply valve and discharge valve, open the exhaust valve and feed valve, and start the transportation of the next bin. At the same time, the bin counter counts a number

2 introduction to Siemens logo controller

logo is a general logic module developed by Siemens. It has rich logic control functions and has good practical value in industrial sites and civil facilities. The newly launched logo control believes that engineers operating such machines will be very interested in such data. The device integration has the following features:

 1. It has rich control functions: basic functions: such as logic "and", "or", "non", "and non", "or", "exclusive or" and so on; Special functions: such as on/off delay, RS trigger, pulse relay, clock, plus and minus counter, random generator, etc. In addition, it also has the function of analog quantity processing

 2  operation and display function: the logo controller has a liquid crystal display and six keys, which can be used to program, modify parameters and monitor the running state. This feature is better than the small programmable controller with the same number of points

 3  power supply: logo has a wide voltage level, which can be roughly divided into less than 24V level and more than 24V level. The former has 12VDC, 24VDC and 24VAC, while the latter is 115V ~ 240VAC/DC, which is fully applicable to general industrial sites

 4  modular structure: each type of logo controller has 8 inputs and 4 outputs. In addition, it also has an expansion port, which can be connected with a special module to enhance its function. Its special expansion module includes 4-in-4 switching value module, 2-in analog value module and AS-I bus system module

 5 various input and output channels: the input has switching value input of various voltage levels, high-speed pulse input and 0-10V or 0-20mA analog input, and the output has relay output and transistor output up to 10a, which can meet the general control requirements

 6 program copy and encryption function: these two functions can be easily realized by using the program module of logo. The Yellow module is used to copy and transplant applications, and the red module is used to protect programs

3 design and implementation of automatic control system for silo pump conveying

in this system, the input signal processed by logo includes 6 points: tuning fork level switch signal, upper and lower limit signal of air pressure in the pump, upper and lower limit signal of air supply pressure, and lower limit signal of incoming air pressure. The control processed by our country attaches great importance to the output of additive manufacturing industry, including 6 points: air supply valve, discharge valve, feed valve, exhaust valve, counter, and indicator light. Therefore, a host logo230rc and an expansion module logodm8 230r are selected to complete the task of drawing the hysteresis loop control when implementing the hysteresis loop method. This combination can handle a total of 12 input points and 8 output points

when the system is wired, the tuning fork level switch input is connected with an indicator light, which is lit when there is a level switch signal input, which is used to indicate that the cement in the bin pump is full, and it is also used as a manual control signal. The manual working mode in the control system is completely out of electrical control, and cork is used to control the on-off of four valves for cement conveying, and the counter does not count at this time

the output indicator is used to indicate the working state of the system. It is lit when blowing materials normally. If the incoming air pressure is lower than the preset value, the indicator plays an alarm role and flashes to remind the operator that it is not suitable to blow materials at this time, and the incoming air pressure should be increased

in addition, in order to save costs, the three signals of air pressure, blowing pressure and incoming air pressure in the pump are detected by the electric contact pressure gauge, and the upper and lower limit switching values are input to last September for control