PLC based Automatic Liquid Filling System

Industry automation becomes a spacious field in manufacturing which had important role in an extensive range of industries beyond manufacturing. Nowadays the rapid development of manufacturing and technology has led to an increase in production level.. Where the production managers are faced challenged to reduce the cost of the product with maintaining product quality within a time framework and due to the increased demand for on consumer products so competition among manufacturing companies has become dependent on cost, accuracy, time, and quality for that the key to such a problem is the use of integrated processes in the industry. Programmable logic controller(PLC) is extensively used in industrial automation and it act as a brain in industry application. PLCs in the industrial field are utilized to control a certain process in order to get better performance and higher accuracy to give more production in an efficient manner.

1. Description of Conveyor System 

 Nowadays with many industrial applications, a conveyor system is used to move object from one location to another in effective way to reduce losing time and effort and it is very useful in packaging process. A conveyor system has several forms but in this paper, a Flat belt type is used to move the bottles as shown in Fig.(1). Conveyors are especially useful in applications which including the transportation of heavy or large materials. A Flat belt conveyer has a dimensions of (120*70*30)cm the belt is made from elastic material. Six pulleys a distributed along the belt, the first one rotates with the rotation of motor shaft and it usually called drive pulley and the other five pulley called idler pulley. The Flat belt is fitted with aluminum plate between the pulleys to support the belt.

Fig : 1

2. Describe Water Filling Machine

Hardware System 

One of the important applications of PLC is the water filling machine. In this article, several bottles were filled in short time and the filling process became flexible to use any shape or kind of bottle by simply change the program of PLC. Implementing this whole process manually will take a long time and the process will not be accurate with less productivity.

The hardware system contains on three main components; the moving part which is the conveyor move by DC motor, water filling and control equipment using PLC. The system therefore have conveyor belt, PLC, DC motor, electrical valve, sensor. Also there are tank, plastic tube, relay.

Proposed Software System 

System Working:

The water filling machine starts when the push button switch is pressed and this caused working the DC motor hence the conveyor belt is moving. The bottles move on the conveyor belt until the first bottle reaches under the solenoid valve where the laser is cut by the bottle, hence the photoelectric sensor is sensing the bottle and gives a control signal to the PLC through the relay(24v). This leads to stopping the DC motor and hence the conveyer belt stops and the solenoid valve operates and the bottle starts filling the water (using timer in PLC to time this process).when the bottle is fully filled with water, the solenoid valve is closed and the motor is working to move the conveyor belt again to carry the bottle away from the solenoid valve. If another bottle is detected under the valve, the process will be repeated and when the stop button is pressed, the whole process will be stopped. The block diagram for water filling machine is shown in Fig.(2) while the overall automatic process is shown in flow chart in Fig.(3).  

Fig : 2

Fig : 3

Program description :

First step: Through the first step, push button is switched hence the motor run and the conveyor belt is moving and carrying the bottle towards the valve. The normally closed contact (valve) is placed to ensure that when valve ON(in step2) the motor is OFF. 

Second step: When the bottle reaches under the solenoid valve, the normally open contact (sensor) will be ON and make the valve ON and the motor OFF (conveyor stop). 

Third step: When valve ON, the PLC timer (ON-Delay timer) become active hence the valve is filling the bottle at time (5 sec) by the timer. When the timer finishes, the valve will be OFF and motor is ON again and hence the conveyor belt carrying the bottle away from the valve and the whole process will repeat again. 

Fourth step: Up counter (by PLC ) is connected to the valve to count the number of bottles filled which means that every time the valve the counter will be count.

Fig : 4

3. Conclusion 

 An automatic water filling machine system for different sized bottles by using PLC has been developed and implemented. The PLC is used in this system to get more productivity with less time high reliability for and flexible in work. The system is designed to working with different sized bottles by simply change the program. The ladder diagram language is used in this paper because this language is very useful and has a lot of functions so that most of the industrial application uses this language.