Position: A batch weighing method in which a feeder having a fast and a slow feed rate feeds a hopper being weighed by a weighing means producing a signal indicative of the weight of the hopper. The output signal of the weighing means is first checked to determine whether or not it is within a zero tolerance band before the feeder is turned on. The hopper is then filled at the fast feed rate by the feeder until the hopper is within a predetermined weight of the set point or desired weight. When this weight is reached, called the primary cutoff, the feeder is changed to the slow feed rate. The feeder continues to feed material into the hopper at the slow feed rate until a weight is reached which is a second predetermined weight below the set point weight. At this weight, the feeder is shut off and the material falling from the feeder will bring the weight of the hopper up to set point weight. The weight of the hopper may then be checked to determine whether it is within a predetermined weight of the final set point weight, called a cutoff tolerance. In one embodiment of apparatus, a digital weight signal and a digital signal proportional to the difference between the weight signal and the set point value are generated. The weight signal is checked prior to initiation of the feeder to determine if the hopper is within the zero tolerance limits. The error or difference signal is monitored to detect when the weight is at first and second predetermined weights from the set point weight, that is to detect the primary cutoff and final cutoff points. The error signal results are monitored to determine whether the final weight is within the cutoff tolerance band.
Products Category
Batching Controllers
Belt Scale Controllers
Packaging Controllers
Batching Systems
Weighing Transmitters
