A Simple Software And Hardware System Solution For Process Measurement And Control In Engineering Technology Student Design Projects

Many design projects conceived by engineering technology students involve using a computer to control some form of physical process. These hardware-in-the-loop (HIL) projects involve making measurements of some physical quantities, processing the measured data, and producing control signals based on the processed data. Choosing the appropriate measurement and control system to achieve the design objectives is often a difficult part of the design. Most projects require the measurement and control of very few parameters that does not justify the purchase of an elaborate analog and digital I/O system. Combining LabVIEWTM software with the 1-WireTM family of integrated circuit devices from Dallas-Maxim produces a measurement and control system that is an excellent match for many student design projects. LabVIEW is very popular in engineering technology programs and provides the software tools needed to easily develop the data acquisition, signal processing and control routines. The student version of LabVIEW 6i provides plenty of computing power for such applications, is very affordable, and runs on either Mac or IBM-compatible computers. For the measurement and control hardware, 1-Wire devices provide a flexible and low cost set of analog and digital input and output devices that can communicate with the computer via the serial port. Devices in the 1-Wire family include temperature sensors, A/D converters, counters, digital I/O and digital potentiometers. The 1Wire device bus scheme allows for many devices to be connected to the computer simultaneously, addressed individually, and powered directly from the bus. This paper presents and discusses the software and hardware necessary to implement HIL student design projects on both Mac and IBM-compatible computers. Examples of the LabVIEW code and sensor and actuator designs are also presented.