With the rapid growth of the economy and the continuous improvement of the living standards of the people, the demand for the filling machine is getting greater, and the extensive application technology is used in the production fields of oil, chemicals, drinks, and medical care. It is also getting higher and higher. Some materials are very expensive. The normal filling machine is slow, the accuracy is not high, and the dynamic accuracy is difficult to control stable. Therefore, the application of the high -precision weighing system in the filling machine is an inevitable trend.
Second, system summary
The system is mainly composed of feeding devices, weighing systems, conveying systems, execution agencies, and electrical control systems. The filling speed and packaging weight of the filling machine can be adjusted. According to the process requirements, the filling machine uses PLC to automatically control, and intelligently handles and display the various work conditions of the system.
Third, the composition of weighing system
Because this system requires that three different strokes can be filled with different filling buckets, the materials are expensive. In order to meet the accuracy requirements under different scale, this system uses a high -precision scale platform and weighing instrument. The connection of PLC has become a complete weighing system. The components in the system are introduced below.
(1) High -precision scale platform and sensor
The high -precision scale uses an electromagnetic sensor. This sensor has high accuracy, long service life, and stable performance, which can be used for both static and dynamic measurement. The high -precision sensor adopts the principle of electromagnetic compensation to achieve high -precision weighing and decentralized body.
The zero position changes. In order to compensate the downward amount of offset, the coil cuts the magnetic line to form a reaction force to lift the scale upward, and finally maintain the zero position of the scale. The sensor does not require elastic formation. Each time the same role is loaded, the output signal is consistent, repetitive, linear, corner difference and other parameters are more excellent, suitable for large -scale small scale applications.
(2) Weighing instrument and remote I/O module
The system selects the imported weight instrument IND560. This instrument has 366Hz extremely fast A / D conversion rate, digital filtering technology, and 50Hz input / output point refresh rate. It can achieve precise measurement from milligrams to ton. In the process of packaging and ingredients, manual, semi -automatic, and automatic automatic ways can be achieved, and the material is fast, accurate, and measurement control. ARM100 is a remote I /O module output with 4 in /6 relay output. The working voltage is 24VDC, the input point is active input, provided by external devices. Weighing controllers can connect up to 3 remote I/O modules to control the digital input point and 18 -bit digital output point of 12 -bit. You can complete the fixed value without PLC or other external I/O devices. All control. In this system, signals such as fast, slow, refined, zero -zone, and super -poor signal given by the weight instrument are controlled by remote I/O modules with PLC, and the symmetry weight process is controlled. The automatic zero tracking of the instrument is used to compensate for the slight changes near zero point near the zero point, keeping the instrument displayed in the zero heart. When the weight of the scale is within the scope of zero tracking and is in a steady state, zero tracking plays a role. When the weight exceeds the range, the instrument no longer tracks zero. The weighing instrument will directly send the digital signals transmitted by the high -precision sensor directly into the control processor that is called the heavy instrument. On the one hand, the number of weighing reads to the instantaneous number is sent to the display circuit to display instantaneous weight.
On the other hand, the weight controller is judged based on the setting value and measurement value. The comparison of the internal target value of the heavier instrument is 50 times/s. It can improve system work efficiency. The measuring values and the given value are different and the calculation is performed, the switching the actuator, and the controlling flow rate of the material can be divided into three stages, which can be divided into three stages, which are fast, slow, and integrated.