Liquid filling machine consists of S7-200PLC and weighing instrument ICS241 and filling solenoid valve. PLC uses RS232C communication port to connect with the weighing instrument to collect and process the weight data through communication, as well as send tare signal to make the instrument tare. In the quantitative filling mode, PLC as the main controller receives the data from the weighing instrument, processes the data and sends out a series of signals to control the action of the filling machine, so that the filling machine completes the quantitative filling. the PLC communicates with the weighing instrument through RS232C, and the communication between the two is a protocol-free communication. the parameters of the serial communication between the PLC and the weighing instrument need to be set up in the same way. The PLC communicates with the weighing instrument through RS232C, the parameters of serial communication between PLC and weighing instrument should be set in the same way. The filling system adopts PID filtering algorithm to remove the interference signal, so as to improve the stability and accuracy of the filling system, according to different filling ranges to adjust the weight of the target set value and then complete the filling. It mainly includes the front weighing module, double weighing system, LMC series motion controller, LXM series servo drive and servo motor, and the upper computer monitoring system. The servo motor is used to realize the rotor pump stroke control, and then realize the filling volume control. Before filling, the front weighing module obtains the weight of empty barrel, after filling, the rear metering module obtains the weight of filling and transmits it to the weighing instrument, which will externalize the filling data in real time to get the weight deviation, and the filling algorithm calculates the control volume of large materials, the weighing system will send the control volume to the servo driver, which will drive the secondary rotor pump to execute the early closing of the small amount of small material before controlling the small material filling valve, and the upper computer will read out the filling volume in real time through the Ethernet network. The upper computer is connected to the weighing instrument via Ethernet to read the filling data in real time, and the process parameters can be set to monitor the operation of the production line. After filling and capping, drive the gripping manipulator to accurately position to the designated unit, and grab the filling barrel on the material table to transport to the designated place and then put down. Through the discussion of servo motor drive robot, the use of high-speed pulse output function of PLC, through the PTO programming to achieve accurate stacking control of the robot.

PLC selected SIEMENS S7-200 series PLC, due to the need for high-speed pulse output to drive the servo motor, PLC transistor output type. S7-200-226 DC/DC/DC type PLC is selected. servo driver adopts Panasonic MADDT1207003 full digital AC permanent magnet synchronous servo drive. The gripping manipulator device is mounted on the sliding skateboard of the linear motion transmission assembly, and the whole device makes linear reciprocating motion driven by the transmission assembly, which is set up to the material table of other work units, and then completes the function of gripping and putting down the filling barrel.

The rotor inside the servo motor is a permanent magnet, the driver controls the U/V/W three-phase power to form an electromagnetic field, the rotor rotates under the action of this magnetic field, while the encoder of the motor comes with a feedback signal to the driver, the driver compares the feedback value with the target value and adjusts the angle of rotation of the rotor. The accuracy of the servo motor is determined by the number of lines of the encoder.

AC permanent magnet synchronous servo drive is mainly composed of servo control unit, power drive unit, communication interface unit, servo motor and corresponding feedback detection devices. In the conveying unit of the filling production line, the servo motor is used for positioning control, so the position control mode is selected, that is, through the input pulse string to make the motor positioning operation pulse string frequency determines the movement speed of the manipulator. The number of pulses determines the rotational displacement of the motor, that is, the linear displacement of the robot. The parameters of the servo drive can be set on the panel of the drive using the automatic gain adjustment mode.

The main function of the weighing and filling system is to fill the liquid medium into the packaging container to realize the functions of filling, sealing, weighing and stacking. Using sequence control, motion control, communication, data management microprocessor technology and communication technology, the input signal filtering, judgment and storage, etc., the form of output signals transmitted to the filling system's actuators to complete the filling command, the real-time control of the barrel position in the online container, the pressure control on the filling barrel pre-pressure, the speed of the conveyor chain to regulate the speed of the conveyor link when the conveyor chain containers stacked blocked, but also need to coordinate the Coordination of the feeding speed of each drag point of the whole production line. Coordination signal is to other conveyor chain drag in the production line, the control system also empty / full barrels in place, pile of blockage, under the lid, open / close the filling valve for real-time pick up and control. The use of PLC signals to drive motors and other transmission mechanisms to drive the manipulator to move, while driving the motor comes with the encoder feedback bit (pulse) to the drive driver to compare the two kinds of pulses and determine the deviation, according to a certain control law algorithm obtained after the correction signal as a servo drive in the speed controller is given and then by the current regulation and power amplification, so that the grabbing manipulator towards the elimination of deviation