The loss-in-weight scale is a commonly used mechanical equipment in the machinery industry at present. The basic composition of the loss-in-weight scale can be divided into two parts: the equipment system and the control part. The equipment part is mainly composed of measuring hopper, screw feeder, unloading feeder, scale The control part is mainly composed of a load cell, a signal amplifier, an input and output interface, and a control instrument. The loss-in-weight scale is a kind of weighing equipment with intermittent feeding and continuous discharging. Because the loss-in-weight control is carried out in the hopper, it can achieve high control accuracy and the structure is easy to seal. It's a big improvement by comparison. It is suitable for controlling batching of fine materials such as cement, lime powder, coal powder, etc.

In order to improve the control accuracy of the weightless scale, the following points should be considered in the design:

　　1) Select the appropriate frequency of use, and it is best to keep the frequency of use at 35Hz~40Hz. When the frequency is too low, the stability of the system will be poor;

　　2) The selection of the sensor range is appropriate, and it is used in 60%~70% of the range, and the signal variation range is wide, which is conducive to improving the control accuracy;

　　3) The mechanical structure design should ensure that the material has good fluidity, and at the same time, ensure that the feeding time is short.

 　　4) The supporting transmission system should ensure smooth operation and good linearity.