Working Principle and Daily Operation and Maintenance of Belt Scales

   I. Composition of Belt Scales Generally, they consist four major components: weighing frame, load cell, speed sensor, and display meter. 

  II. Control Principle of Belt Scales 

1. The scale is used for continuous feeding of bulk during the quantitative feeding process. The feeder transports materials from the user's storage bin or other feeding equipment through the weighing bridge for weight detection, while the speed sensor mounted on the pulley detects the belt speed. The measured weight signal and speed signal are sent to the ZT3206 integrator for differential processing and display of the instantaneous flow rate in tons per hour for. Based on the deviation, it outputs a corresponding signal value (PID signal) to change the motor speed via a frequency converter to adjust the feeding amount, keeping it consistent with the set value thereby completing the control of a constant feeding flow rate.

   2. Control Principle of Belt Scales

   During the feeding process, the feeder transports materials from the user's storage bin or feeding equipment through the weighing bridge for weight detection, while the speed sensor mounted on the tail pulley detects the belt speed. The measured weight signal and speed signal are sent to theT3206 integrator for differential processing and display of the instantaneous flow rate in tons per hour for comparison. Based on the deviation, it outputs a corresponding signal value (PID signal to change the motor speed via a frequency converter to adjust the feeding amount, keeping it consistent with the set value, thereby completing the control of a constant feeding flow rate. From the weighing, it can be seen that the instantaneous flow rate of the material measured by the electronic belt scale depends on two parameters: the instantaneous flow rate is the product of the material load value q(kgm) measured by the load cell and the belt speed value v(m/s) measured by the speed sensor, i.e., w(t)=qv. It is that the measurement accuracy and stability of the speed sensor are as important as those of the load cell. Currently, the accuracy of load cells has generally improved to a few ten-thousand, while the accuracy of speed sensors is mostly at a few thousandths. Therefore, improving the accuracy of the speed sensor is one of the effective ways to improve the accuracy of the belt scale system.

   III. Parameter Setting and Calibration of the Weighing Feeder

   1. Calibration of Meter Parameters: After the belt has run for a period and stabilized the ZT3206 meter parameters can be set, such as the decimal point position, scale units, capacity, sensor capacity and sensitivity, belt circumference, etc. Original need to be entered for the first use, and generally do not need to be changed randomly during normal operation.

   2. Calibration of the Weighing Feeder: First, the test cycle, then perform zero-point calibration. Once the zero point is stable, interval calibration can be performed. Interval calibration methods include physical calibration, chain code calibration, tag calibration. Using the AUTO-MAT (Automatic Material Calibration) software specifically for Ramsey, the interval value of the belt scale can be automatically corrected. After N calibrations to reach the weighing metering standard, it can be put into normal weighing, metering, and accumulation.