Basic concept and specific application of weightless scale instrument panel
The weightlessness scale is a weighing system that interrupts the feeding and continues to feed. Because the weight loss control is carried out in the silo, it can achieve high linearity, and the structure is convenient for sealing. Therefore, it is used when handling pellets. The comparison with the spiral scale is a big improvement. It is suitable for the manipulation of fine raw materials such as concrete, quicklime powder, and pulverized coal. At this stage, the volumetric method or electronic belt scale and screw scale are used for measurement and verification in our country's rotary mixing machinery. In our country, the measurement accuracy of electronic belt scales used in the road field is generally only up to 5%, which is no different from the capacity measurement verification. The long-term reliability is weak. The basic concept of the differential signal reduction (weightless state) scale will be weighed. The hopper and the feeding organization are all scale bodies. According to the weighing display or the upper computer software, the net weight data signal of the scale body is continuously sampled, and the conversion ratio of the net weight per unit time is measured as the instantaneous total flow. The hardware and software filter is technically solved to obtain a specific total flow that can be used as a manipulation target. The acquisition of this total flow is very important, and it is the basis of whether the weightlessness scale can be accurately measured and verified. The detailed introduction in Figure 1 is a classic way. According to the PID feedback optimization algorithm, FC carries out the operation calculation close to the overall target total flow, and outputs the adjustment data signal to manipulate the control board of the vibrating feeder such as the soft starter. The application of the differential signal reduction scale (weightless scale) in the specific application can be seen from the basic principle that it will not be harmed by the transformation of the scale body and the mechanical equipment of the feeding organization. It only measures the net weight error (differential weight), which is different from the traditional dynamic The advantages of sex measurement verification methods are obvious. When the control target is the total flow rate (th, kgmin), and the transportability of raw materials is good, and the precision of the measurement verification is high, the selection of the weightless state method measurement verification can be the best plan. Matters that must be paid attention to in the design of weightless scales in the production process of weightless scales, elements that endanger the precision. It is best if the working category is 60%~70% of the rated transport capacity. If the communication and AC variable speed is selected, the corresponding variable force frequency is 35~40Hz. That ensures a wide range of adjustments, because the reliability of the system software is poor when the transportation rate is too low. The measurement range of the sensor is moderate. In other words, the sensor also uses 60%~70% of its measurement range. The range of data signal transformation is wide, which is extremely beneficial to improve the precision. The design scheme of the mechanical system should ensure that the raw materials have good circulation. In addition, ensure that the replenishment time is short, and the replenishment should not be excessively frequent. Generally, it is stipulated that the replenishment is performed every 5 to ten minutes. The transmission device of supporting facilities should ensure stable operation and good linearity. The application prospects are accompanied by the rapid development of electronic device control systems. According to the selection of new technologies, the weightlessness scale has increased from 0.3% to 0.5% to 0.1% to 0.2% in the measurement verification accuracy, and even exceeds the static data scale. The key to the new technology is the use of digital weight sensors.