Automated food drying system using labview as controller and user-interface platform.

Date

10-2010

Degree

Bachelor of Science in Applied Physics

College

College of Arts and Sciences (CAS)

Adviser/Committee Chair

Nelio C. Altoveros

Abstract

An automated food drying system was designed, created and analyzed. LabVIEW* graphical programming environment was used to as a user interface with controls and indicators to manipulate the dryer temperature and servo motor-driven air exhaust and intake vent openings. NI USB-6218 Multifunction Data Acquisition Hub was the device in charge to gather data and control the system The system involved digital and analog sensing as well as external light indicators that indicates processing status for monitoring from a distant point. Wet bulb and dry bulb temperatures inside the dryer were measured and utilized to determine the relative humidity inside the dryer through computation using steam table and psychrometric chart for checking. The sensor calibration showed 5.56°C and 5.35°C offset value for dry bulb and wet bulb thermometers respectively. The warm-up responses of the dryer were evaluated by getting the slope of the cooling curve at different vent configurations and it was observed that the most efficient way to warm up the dryer was to close all vents with average slopes of 0.0103°C/s for heater 1, 0.0334°C/s for heater 2 and 0.0621°C/s for both heaters. It was determined that loading the chamber with sample takes a longer time to warm up. Unshielded long thermocouple wires, grounding and uneven blow of air introduced small errors in temperature measurements which were ignored since the precision of data is not crucial for the current application. System evaluation showed offset values of 0.1°C/s in the temperature measurements. Temperature data collected were based on real time measurements from two sensors. One temperature data was based from the average of 300 data points at a rate of 300 samples per measure. Tests showed that the thermostat can maintain temperature with ±0.4365°C stability which qualified the ±4°C requirement. Vent opening angles were set from 0 degree (fully closed) to 96 degrees (fully open). Solid state relays and wire performance for the fan and heaters were stable after hours of operation. The vent motors and controller were observed to have 30 seconds (max) response time per motor when the opening angle was changed which causes a maximum of ±3.6°C instability in the temperature. The functions of the workstation's input devices, such as the mouse and numeric pad were maximized by utilizing them in changing knob, slide and digital control values.

Language

English

Location

UPLB Main Library Special Collections Section (USCS)

Call Number

Thesis

Document Type

Thesis

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