PID control on a loss-in-weight feeder is stable
A plastic pelletizing plant in Guangdong used a loss-in-weight feeder to control feed rate. Flow fluctuated by ±5%. Product quality was unstable. They changed to our weight scale controller. It uses PID to adjust the feeder speed. Fluctuation dropped to ±1%. The process engineer said: "This controller tunes better than a human."
Parameters and I/O (table format)
|
Parameter |
Value |
|
Capacity range |
0 – 100 tons |
|
Control accuracy |
0.2% FS |
|
Sampling speed |
200 times/second |
|
Enclosure |
Metal, DIN rail or panel mount |
|
Display |
7-inch touchscreen, 800×480 resolution, shows recipe name, target, actual, flow curve |
|
Inputs |
Up to 4 sensors (mV or digital), 8 digital inputs (opto-isolated) |
|
Outputs |
8 relays (5A/250VAC, direct control of feeders, valves), 2 4-20mA (VFD speed control), 1 RS485 (Modbus), 1 Ethernet |
|
Power supply |
24 VDC |
Self-learning drop compensation: gets more accurate over time
The weight scale controller has self-learning drop compensation. It automatically records the actual overrun at the end of each batch. Then it dynamically adjusts the early cut-off value. After 3-5 batches, the error stabilizes within ±0.2%. It stores 100 recipes and 10,000 batch logs. Each batch record shows actual material used, time, and out-of-tolerance status. Data can be exported via USB or uploaded to MES/ERP. We also have a loss-in-weight feeder version with PID to maintain constant flow. A common question: "Can your weight scale controller handle a very fast feeding cycle?" Yes, the 200 samples/second and relay outputs are very fast. Yixing Silvanus Electric Manufacture Co., Ltd. has been making process controllers since 2007. Choosing us makes your batching system more accurate over time.
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