0 Introduction

Liquid filling machine in the workshop liquid metering control can be independently completed liquid loading and unloading truck metering, workshop gross oil and finished oil process metering, continuous filling vat filling metering, reaction kettle dosage quantitative control, etc., but also can be networked with the upper computer, composed of a decentralized computer monitoring and management. In the workshop liquid metering control can be widely used in vegetable oil, lubricating oil, petroleum, chemicals, paints, resins, beverages, alcohol and other industries of quantitative measurement control.

The automatic filling machine consists of a set of weighing instrument, touch screen, filling head, actuating cylinder, conveyor and electronic scale. It adopts programmable control, servo system, photoelectric sensing, pneumatic execution in integrated filling equipment. The filling method is realized by using fixed pressure block, fixed flow to parameters and controlling the filling time. Easy to operate, high efficiency, can be suitable for all kinds of liquid filling without gas.

The automatic filling machine is connected to the computer through 485 communication to form a network, which provides a convenient platform for the unified management of the company. It reads the on-site filling information and data through the configuration software to provide conditions for realizing the automation management, connects the weighing instrument and industrial control computer to the network for data exchange communication, performs the data parameter setting and control operation, process dynamics, filling data display, alarm display, etc. for the whole process, and connects the on-site material level signals, valve position signals and alarm signals to the input module. Valve open/close, feeder open/close and alarm signals are connected to the output module, the central processor module reads the data from the modulus module, and the whole process of filling is automatically controlled through programming.

1 filling machine

Liquid filling machine on the complexity of the process according to the principle of advanced and reliable comparison of various scenarios, and decided to use QUANTUM PLC automation platform. Programming software used CONCEPT 2.6, a WINDOWS 2000-based programming tool that provides a specialized multi-language development environment for programming. There is a function to create standard export function blocks or DFB libraries that can be called repeatedly in the application program. These DFB blocks can be written to ladder, function block diagrams, structure text or command table language. Liquid Filling Machine Frequency controlled in two ways: PLC output and weighing module.PLC can be switched to the weighing module output to ensure production continuity in the event of a failure in the specified automatic layout system.PLC output is controlled in three ways by the on-site frequency converter through the specified ratios, material designation and frequency. The operator selects the ratio on the work metering display and simply enters the total material of the material and the ratio of each quartile, tracking the adjustment according to this quartile. Weighing module: can be installed in the pipeline on the electronic scales, storage irrigation on the weighing module or load cell, etc., which is the basis of the control, directly affecting the effect of control, so the basic requirement is the measurement accuracy of the load cell is as high as possible, there is a signal output function. At the same time, the filling machine power supply DC24V or AC220V optional, flow-breaking equipment have control box internal direct power supply. And can output 4-20mA, RS485 and other signals to other control equipment, but also can be added to the print function.

2 process

Liquid filling machine self-filling method belongs to gravity filling, liquid tanks and measuring devices in high position, the packaging container is placed below. Under atmospheric pressure, the liquid automatically flows into the packaging container through its own weight, and the entire filling system works in an open state.

When the man-machine interface inputs the filling barrels to the filling conveyor table, the clamping plate stepping motor automatically sets the width of the clamping plate, and the conveyor belt works and starts to feed the barrels. At the beginning of the conveyor, there is a counting sensor to count the number of pails to be fed. When the number of barrels reaches the specified barrels, the clamp locks at both ends of the conveyor automatically track the position of the barrels, and the clamp locks are closed to fix the barrels. Then the signal is fed back to the main controller, which adjusts the position of the filling needle through the stepping motor, and when the ideal position is reached, the filling starts. When the pail filling is completed, the clamp lock controlling the pail is opened and the conveyor belt starts to operate to send the filled pail out and then proceed to the next filling cycle.

The automatic filling machine adopts liquid surface filling method, which is suitable for filling liquid materials without foam or light foam. The specially designed gun is easy to operate and the filling is fast and accurate. The invention can maximize the leakage of residual liquid. The gas collection cover can effectively protect the operator from harmful gases. During operation, the operator simply aligns the gun with the mouth of the drum directly below the nozzle, presses the "start" button, and the empty drum is automatically stripped and then filled at a precise two-speed. After the filling is completed, the gun automatically lifts the barrel away from the barrel, and the full barrel is taken out to complete the filling.

3Servo driver

The servo motor must have a servo drive to rotate, and the purpose of the servo drive, mainly according to the servo controller to send out the instructions (P, V, T) work. Synchronous motor is not completely synchronized with the rotating magnetic field, the driver must be corrected to work, so that the motor works steadily without losing step. So the drive motor correctly follow the control instruction work is the servo drive to complete the main task.

The liquid level of the conveying tank can be automatically controlled by PCC. When it is lower than the set lower limit, the lye pump will automatically start supplying from the lye storage tank. The storage tank is a carbon steel resin metering tank and the reaction tank is equipped with a temperature detection element, a secondary thermometer and a steam shut-off valve to control the temperature with the PCC.

In this intermediate weighing and filling machine, since the positioning module FM354 outputs an analog signal of -10 to +10V, the servo motor driver is used to adopt VCommand (position servo's control method).

Position servo drive internal including: position control unit, speed control unit and drive unit. The position control unit in this weighing and filling machine, that is, the positioning module FM354. encoder position servo motor traveled position signals to the FM354, closed-loop adjustment of the filling tank in the position of the pneumatic axis.

4 Introduction to the positioning module FM354

The central processor of the automatic filling machine adopts the industrial weighing instrument as the core component, which is stable and reliable, and can realize all kinds of automatic control according to the needs. Display units such as kilograms, cubic meters, liters or others can be selected as required. No need for complex processes such as peeling, weighing, loading and unloading of packaging drums, it can be directly loaded into drums. Adopting 7-inch touch screen display, the display can show various parameters as needed. Direct input through the touch screen is convenient and intuitive, easy to operate, without manpower training. Selected according to the characteristics of the measuring medium, durable. Can be equipped with a miniature thermal or needle printer, timed and manual printing of any content you want to save. Save the daily total, total total, daily fill count, fill time and fill volume of the document, which can be queried or automatically transferred to a USB flash drive or printed.

Filling system can be equipped with timed dosage start function and weighing upper and lower limit alarm function. It can be equipped with intermittent bucket function. The number of batch barrels, interval time and filling quantity can be input directly on the screen. It can be customized to calculate the price of filling quantity automatically according to the set unit price and display the printed weight and total price. With remote control function, remote computer monitoring, operation function, wireless monitoring function and so on. Improve production efficiency and realize dust-free operation.

The FM354 is a module that realizes various positioning tasks (positional closed loop) in high-speed mechanical equipment by means of servo motors. It is used for simple point-to-point positioning or complex motion patterns where response, accuracy, and speed are required. Ideal solution for positioning tasks in high-speed machinery. The FM354 positioning module for controlling servo motors can be used to position e.g. feed axes, adjustment axes, setting axes and conveyorized axes (linear, rotary).

The FM354 handles the time-based positioning of the axes and controls the drives with an analog drive interface (-10V to +10V). An encoder (SSI or incremental) reports the current position of the axis and the FM354 uses this information to correct the output voltage.

Positioning functions include: Manual Adjustment (move the servo axis with a point-and-click key), Incremental (servo control the axis along a predefined path), MDI (manual data entry), Running MDI (servo positioning at any desired, assignable position, at any time), and Auto/Single-Ended Control (for servo positioning of complex paths, continuous/periodic feeds, forward/backward).

With the integrated digital inputs of the module FM354 there are also special functions available: length measurement, starting and stopping of positioning movements by means of fast inputs of the FM354, finding of reference points, setting of actual values during the movement etc. In the industrial filling production process, the universal nitro lacquer paint dosing and filling machine should be able to realize fully automatic, semi-automatic and manual filling and to switch between different operating modes. Filling control must have high reliability to ensure continuous normal operation, timely alarms in case of failure, emergency shutdown to prevent weighing and filling machine accidents. The upper computer in the production process is not only directly on the scene to display production data, but also need to historical data, the corresponding data report, fill management and other functions of the processing function.

5 Working principle of pneumatic shaft positioning module

Usually a positioning command requires the parts on the shaft to move to another position, the positioning module FM354 first calculates a theoretical actual speed map. Then control the drive shaft with this time speed map, so that it finally reaches the specified position. the shaft positioning module is first accelerated uniformly with the acceleration set by the user, if it is in the JOG operation mode, it reaches the set JOG operation speed and then starts to move uniformly, and after a certain period of time, it then decelerates uniformly with the acceleration set by the user until the speed changes to 0. When the speed goes to 0, the shaft moves the distance exactly to the The distance moved by the axis when the speed reaches 0 is exactly the set value of the command.

6 Sensor Module

A weighing module is installed at the low end of the conveyor belt to detect and control the whole filling machine. It can be considered as the eye of the whole filling machine for controlling and monitoring the whole filling machine.

The weighing module is a detection tool that converts the mass signal into an electrical signal and uses a module with a range of 50g and a full bias voltage of 12V. The output voltage of the weighing module is compared with the threshold voltage set by the voltage comparator to output a valid detection signal. The empty bucket detection threshold voltage is set to 10g, which is converted into a corresponding voltage signal of 2.4V. i.e. when the voltage output from the weighing module is detected to be greater than the empty bucket threshold voltage, a valid signal is output, and when the output signal from the weighing module is less than the empty bucket threshold voltage, it is determined that no bucket has passed through.

7 Summarize

In the filling capacity of the precise positioning of the problem, stepper motor positioning has not been able to meet the requirements, so the use of servo motors to carry out accurate positioning. Siemens control module FM354 has a high degree of integration of control parameters, if the parameters are set reasonably coupled with PLC filling program control can achieve accurate positioning. Reasonable parameter settings also need to be on-site debugging several times to achieve the most ideal results.