The belt scale transmits the material weight signal and belt running speed signal to the field integrator through the front channel weighing device and the back channel weighing device installed on the belt conveyor. In the field integrator, the weight signal is converted into a digital quantity after AD, and the weight value is scaled by the built-in monolithic computer. The speed pulse is scaled by the built-in monolithic computer to the speed value and multiplied by the weight value to obtain the instantaneous flow rate. The two channels simultaneously accumulate the instantaneous flow rate to obtain the accumulated material amount of the two channels respectively. Stored in internal non-volatile memory. When the two channels are normal, the remote display adopts the average value of the cumulative amount of the two channels. If one party is faulty, the normal party is displayed.
020-34563445The belt scale adopts the system structure with 8031 single chip microcomputer as the control core, and constitutes the belt scale controller BWF. The hardware part mainly consists of 8031 MCU, A/D converter (ADC0809) ROMD/A converter (DAC0832) keyboard scanning circuit, display circuit, weighing module, amplifier circuit, latch and so on. Dosing is to control the feed amount of raw materials by adjusting the speed of the belt conveyor to complete the ratio of various raw materials. The belt scale is a real-time controller used to measure and control the speed and material flow of the belt conveyor. There is a hopper above the belt structure, and the material is transported with the belt when the belt moves. The conveyor belt is driven by the slip motor M(electromagnetic speed regulating asynchronous motor), the frequency of the output signal of the velocity sensor SR is proportional to the speed of the belt, the conveyor belt is equipped with a weighing module, the output voltage signal is proportional to the material on the belt, and the belt proportioning scale controller BWF receives the speed signal and the weight signal of SR. The instantaneous flow rate of the material on the belt is calculated and displayed, and the actual flow value is compared with the set value of the flow, and the output current control signal is adjusted by PID through the preamplifier and power amplifier Q to control the on-angle of the thyristor VT, so as to adjust the speed of the slip motor M, so that the material flow is stable at the expected set value.
Before the belt conveyor is put into operation, the set value of the material flow on the conveyor belt is set by the operator on the keyboard. After the system is put into normal operation, the MCU samples the belt load signal (converted by ADC0809) and the speed signal (T method), and multiplicates the belt speed signal with the instantaneous weight of the belt unit length to calculate the instantaneous flow F(t) of the material on the belt. The instantaneous flow rate can be displayed through six seven-segment nixie tubes to provide process data reference for operators. The 8031 system then compares the actual flow value with its set value, and calculates the control quantity Vi through DAC0832 to convert the current output signal (4~20mA) after the incremental PID adjustment operation, and then magnates to control the on-angle of the thyristor to achieve the function of adjusting the electromagnetic clutch excitation current of the slip motor. Thus adjust the speed of the actuator slip motor, so that the material flow on the conveyor belt as stable as possible near the set value, and has good static indicators and dynamic performance.
