Facts & Figures Book - KPI-JCI

Washin g/Classifyin gSPEC-SELECT CONTROLLERSPurpose: Spec-SelectControllers are utilized inconjunction with a classifyingtank to control the blendingof the various sand fractionsinto one or two specificationproducts plus an excessproduct. Spec-SelectControllers are also a valuablesource of information when troubleshooting or simplymonitoring the activity occurring within a classifying tank.Design: Spec-Select Controllers consist of an industrial-quality,solid-state PLC (Programmable LogicController) housed in the NEMA 4 junction box/controlenclosure located on the bridge of the classifying tankand a desktop PC (Personal Computer) HMI (humanmachineinterface). An optional industrial PC HMI withcolor touchscreen housed in a NEMA 4 enclosure is alsoavailable for outdoor installation in lieu of the desktop PC.Simple, Windows-based controls are used on all systems,allowing the operator to proportion the amount ofmaterial discharging from each station to the appropriatecollecting/blending flume for transport to the dewateringdevice. EEPROM memory in the PLC and the hard driveof the PC provide permanent storage PLC logic, operatingparameters, recipes and the screens displayed on theHMI, which are used to create a user-friendly interface tothe PLC, which actually controls the classifying tank.Application: Two modes of controlling the tank dischargeare utilized in conventional classifying tanks. The Spec-Select I (SSI) mode of operation is the simplest methodto operate a classifying tank and is the same in theory asthe manual splitter box type classifying tanks. It is an independentcontrol of each station by a percentage methodto determine the amount of material discharged to eachof the three product flumes. The system operates on a10-second cycle that is repeated over and over from product“A” to “B” to “C”. The mode of operation works bestin a fairly consistent pit, where the feed gradation doesnot vary too much. Monitoring of the product gradationsinforms the operator of variances in the feed. Changes124