PLC APPLIED HIGH PRECISION WEIGHING FOR FEEDINGBULK STUFF

摘要

The cumulated weighing of feeding bulk stuff is implementedby the parallel hopper weighing system that is composedmainly of PLC and mechanical apparatus, of which theweighing precision is 0.1% up overmatched the OIML R 107provision of 0.2%.The parallel two hoppers are the basic components (hopper Iand hopper II) of this weighing system and automaticweighing mechanism and relieving mechanism are equippedfor each hopper. The stuff shunting mechanism is over head.This weighing system is placed in the middle of two conveyorbelts which are different in height.Bulk stuff is firstly fed into the hopper I by the upperconveyor belt via the stuff shunting mechanism, and thenbulk stuff will start to feed into the hopper II only after thestuff shunting mechanism turned in action in accordance tosystem command in the condition that weight of bulk stuff inthe hopper I had met the pre-setup value. After that, thehopper I will be in static and precision weight value will beavailable by selective smoothing program, and then series ofsystem commands including bulk stuff release and dischargedoor closing will follow. The lower conveyor belt carriesaway the weighed bulk stuff. The actual weight is equal to theD-value between the original and residue. Bulk stuff is fedinto the hopper II ceaselessly before the actual weight in thehopper I worked out. Subsequently, the same process will betaken place to the hopper II. All the weight values both fromthe hopper I and the hopper II will be added up together. So,high precision weighing for feeding bulk stuff is accomplished in static going round and round.In the mass, the bulk stuff is going through the weighing unitin dynamic, but the weighing is processing and high precisionweight value is worked out in static. Thus, the weighingprecision is 0.1% up and able to fulfill the requirement intrade balance.