Weigh feeder is a system specially designed for controlled feeding or custom feeding in very accurate measures. The feed control is achieved by controlling the speed of the conveying belt. Pulses from encoder and the weight signal from load cell are the main inputs of PLC. Set point is the value we are entering through HMI or sends through remote station to the PLC system as required TPH. From the inputs, PLC generates an exact TPH which is actually flowing. By comparing this Exact TPH (F/B) and set point TPH, a control value is generated inside the PLC by means of a PID algorithm. A 4-20ma signal is generated in the PLC according to this control value. PID always tries to match the process value and set point by generating a control value accordingly. The control value (4-20ma) decides the motor (conveyor drive) speed via VFD. Thus we get a controlled or custom feed flow by varying or controlled conveyor speed.
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