In recent years the rapid development of the beverage industry, carbonated beverages, fruit juice drinks, vegetable juice drinks, dairy drinks, bottled drinking water, tea drinks and other varieties continue to enrich the output of the red, making the demand for filling equipment is also a bull market.

With the increasing level of industrial automation, the traditional relay weighing filling system combined with computer technology, in recent years in industrial automation, mechatronics, transformation of traditional industries and other aspects of the common application. As a general-purpose industrial control computer, it realizes the leap from wiring logic to storage logic in the field of industrial control, and plays an increasingly important role in the world's industrial control. The beverage dispensing metering used in this filling system is determined by time and flow rate per unit of time, and the metering accuracy is determined by PLC control. the PLC control has simple programming and practical touch screen integrating the host, input and output filling system, which is suitable to be used in the malignant industrial environments. The filling device mainly consists of two parts: constant pressure liquid storage tank filling and counting part. In the constant pressure liquid storage tank filling liquid is not sealed, there is an upper limit level and lower line level module, the liquid level is lower than the lower line level when the constant pressure liquid storage tank is empty. Through the inlet solenoid valve into the constant pressure reservoir, the liquid level reaches the upper limit level when the inlet solenoid valve power off, so that the liquid level remains constant.

Weighing and filling machine to overcome the mechanical contacts in the relay contact wiring complexity, low reliability, high power consumption, versatility and flexibility of the shortcomings of the poor, making full use of the advantages of the microprocessor, but also to take care of the field of electrical operation and maintenance of personnel skills and habits, in particular, the PLC programming, do not require specialized knowledge of computer programming language, but a set of relay ladder diagrams based on a set of simple instructions Instead, it adopts a set of simple instructions based on relay ladder diagram, which makes the user's programming image, intuitive, convenient and easy to learn; debugging and error checking are also very convenient. Users in the purchase of the required PLC liquid filling machine, only according to the instructions of the prompts, do a small amount of wiring and simple user programming work, you can flexibly and conveniently apply the PLC liquid filling machine in production practice.

According to the requirements of the filling system on the PLC system, motor, weighing module and other external systems selection, design filling production line can achieve the following purposes:

(1) The filling system is set to automatic operation mode by a switch, once it is started, the drive motor of the conveyor is started and kept until the stop switch is actuated or the bottles to be filled are transferred under the filling system and stopped; after the bottles are filled with beverages and capped, the drive motor of the conveyor belt must be started automatically and kept until the next bottles to be filled are transferred under the filling system or the stop switch is actuated;

(2) When the bottle is positioned under the filling system, pause for 1s, the filling system starts to work, for large bottles to be filled for 8 seconds, and for small bottles to be filled for 5 seconds, until the filling process is completed and then the beverage bottles are capped, and the capping time is 2 seconds. The entire filling and capping process should have an alarm display, to be capped after the completion of the alarm is no longer displayed; alarm mode for the red light flashes at 0.5s intervals;

(3) Packaging, for small bottles: 40 bottles for a large package, 30 bottles for a medium package, 20 bottles for a small package; for large bottles: 20 bottles for a large package, 15 bottles for a medium package 10 bottles for a small package;

(4) can realize the production of products for automatic counting and can manually clear the counter to zero.

Analysis of automatic filling machine

Filling system design is based on the S7-300 series PLC as the processing core, with trip switches, weighing modules will be the production process signals (such as the location of the run of empty bottles, beverage bottle size, etc.) processed and sent to the PLC processor, by the PLC for the operation of the data, and then the output of the drive signals (such as the liquid filling machine contactors, solenoid valves, etc.) to complete the beverage canning production process of liquid Filling machine operation.

The general idea of the filling system: this metering filling machine is fully automatic control, once the power is on, the PLC will automatically control the filling machine through the software, through the output relay to control the stopping of the conveyor belt and the control of the filling of beverage bottles, to achieve the display of the state of the filling system, and through the PLC internal counters for the production of the product counting.

Metering Filling Machine Program Design

The beverage filling machine brings together a filling device as well as a capping device to make the filling of beverages stable and efficient. The difference for the size of the beverage bottle is realized by the work of the reflective photoelectric module, and the positive level triggering of the counter by using the auxiliary relay to realize the counting of the produced products.

Once the filling system is powered on, the conveyor belt drives the motor to run, and when the empty bottles reach the travel switch, the travel switch closes and the motor stops, the filling system controls the time of filling through the closing of valves and the motor resumes rotating when the process of filling beverages is completed, and so on to realize the automatic control on the filling machine. The differentiation of the size of the bottles on the conveyor is realized by the work of the reflective light weight module at the location.

Filling software program design

Software design program

(1) Ladder diagram design method

Ladder diagram design method is a more extensive method. There is no universal law to follow in this method, it is very tentative very arbitrary, and the final result is not unique. The core of the method is the output coil. The following are the basic steps of the liquid filling machine design method:

1) Understand and familiarize with the process of the controlled filling system and the action of the machinery.

2)Determine the input signals and output loads of the PLC and draw the external wiring diagram of the PLC.

3)Determine the component numbers of the auxiliary relay (M) and timer (T) in the ladder diagram corresponding to the intermediate relay of the relay circuit diagram, and the time relay.

4) Draw the ladder diagram based on the previous correspondences.

(2) Logic design method

The theoretical basis of the logic design method is logic algebra. And the essence of relays is logic circuits. Look at an electrical control circuit will find that the line connection and disconnection, are through the relay and other components of the contacts to achieve, so the control line of the various functions must depend on the contacts of the open, close the two states. Therefore, the electrical control circuit is essentially a logic circuit, in line with the basic laws of logic operations. The number of points of I/O signals required by the I/O filling system statistics, and whether or not to support the expansion of the rack CPU are selected.

Selection of weighing module

The weighing module is utilized in the filling system to differentiate the size and capacity of beverage bottles, and the reflective photoelectric module is selected according to the design needs.

Circuit realization

The filling system is divided into the main circuit, control circuit and auxiliary circuit, the control circuit controls the main circuit, and the auxiliary electric circuit plays the role of auxiliary signal display.

Main circuit design

The conveyor belt is operated by motor M1, and contactor KM1 controls the operation and stopping of the motor. Overload protection is realized by thermal relay FR1. Circuit breakers QF1, QF2 and QF3 bring in the three-phase power supply, while QF1, QF2 and QF3 provide short-circuit protection for the circuit.

Design of Control Circuit

There are 9 input signals for the PLC system and they are all switches. Among them, there are 6 various single-operation pushbutton switches, respectively SB0 start button, SB1 stop button, SB4 large package, SB5 medium package, SB6 small package, SB7 bulk, SB10 manual reset button. There are 1 travel switch and 1 module switch.

There are 10 output signals for the filling system, 1 for the contactor KM1 to drive the conveyor motor, 3 solenoid valves for capping large and small bottles and canning beverages respectively, and 6 for the status display on the filling machine. Design of operation panel

The operation panel is designed in the spirit of simple operation, intuitive and clear, every step of the beverage can filling machine can be accurately displayed to facilitate the work of the staff as a principle.

The buttons in the panel are stop, start and manual reset buttons, as well as buttons for selecting large pack, medium pack, small pack and bulk. There are display lights for large, medium, small and bulk packages, as well as a power-up display and a filling process display.

The filling system is also set up with two filling modes, i.e., large bottle and small bottle filling, and four packaging modes, i.e., large, medium and small packages of large bottles and bulk and small bottles of large, medium and small packages and bulk. This facilitates the needs of different levels.

Design of the program

Set to automatic operation mode by switch, once started, the drive motor of the conveyor belt starts and keeps until the stop switch action or the weighing module under the filling system detects a bottle and stops; after the bottle is full of drinks, the drive motor of the conveyor belt must be started automatically and keep until another bottle is detected or the stop switch action. When the bottle is positioned under the filling system, pause for 1s, the filling system starts to work, the filling process for small bottles 5s clock, large bottles 8s clock, and then are on the cap for 2 seconds, filling and capping process should be alarmed display, the cap process stops and no longer show the alarm; the alarm mode for the red light flashes at 0.5s intervals. At the same time on the production of beverages for packaging and counting, for small bottles: 40 bottles for a large package, 30 bottles for a medium package, 20 bottles for a small package; for large bottles: 20 bottles for a large package, 15 bottles for a medium package, 10 bottles for a small package. Each counter can be manually zeroed during production. The filling system sends the recorded data to the designated memory every 8 hours and then zeroes the counter. Pressing the stop button when the motor is running, the filling system will stop working immediately: while pressing the stop button when the filling system is filling and capping, the filling system will not stop working immediately, and the filling system will finally stop working after the capping work is completed.

Main control program

The filling system is set to automatic operation mode by a switch, once it is started, the driving motor of the conveyor belt will start and keep on working until the stop switch is activated or the weighing module under the filling system detects a bottle and stops it; after the bottles are filled and capped, the driving motor of the conveyor belt must be started automatically and keep on working until another bottle is detected or the stop switch is activated; when the bottles are positioned under the filling system, it will be stopped for 1s When the bottle is positioned under the filling system, pause for 1s, the filling system starts to work, filling for 8s for large bottles and 5s for small bottles, and then capping the beverage bottles when the filling process is finished, the capping time is 2s. When the filling system is running to fill the cans, press the stop button, the filling system will not stop running immediately, until the end of the capping work, the filling system finally stop running.

Summarize

Based on Siemens S7-300PLC filling system design, can be transported to the empty bottle, filling, filling volume can be set according to the size of the empty bottle; full bottle delivery and counting, counting values including cumulative counting, unit package counting, unit package counting volume can be set according to the size of the package; the use of PLC good automatic control performance. Realize the unmanned control of the beverage canning production process. PLC-based liquid filling machine weighing and filling system for beverage production provides great convenience, liquid filling machine operation production also has a fairly broad prospect.