Rejuvenate an old Tinius Olsen machine with computer data acquisition using its existing hardware and LabVIEW

Computer data acquisition is more and more widely used in today’s undergraduate laboratory courses. To meet this trend, it is necessary to bring computer data acquisition to old laboratory equipment, such as a Tinius Olsen machine. One solution is to go to the equipment’s original manufacturer or other vendors for a retrofitting package with computer data acquisition, that usually costs thousands of dollars. The other solution is to achieve computer data acquisition by utilizing the equipment’s existing hardware, together with the computer data acquisition hardware and software. This later approach represents zero cost spent specially on the Tinius Olsen machine. This paper presents the procedures to bring computer data acquisition to an old Tinius Olsen machine using its own existing hardware and National Instruments data acquisition hardware and LabVIEW software. A potentiometer that is geared to the dial servo gives the signal for load applied, while an LVDT based extensometer provides the signal for elongation of the specimen. The potentiometer output and the extensometer output were first calibrated against the load and elongation, respectively. These two signals were then hooked up directly to the data acquisition hardware. A LabVIEW program was written to acquire the signals and then generate the stress-strain curve in real time using the built-in calibration equations for load and elongation. Introduction Computer data acquisition is more and more widely used in today’s undergraduate laboratory courses. While the newly acquired laboratory equipment likely will have the computer data acquisition built into it, it is the old equipment that presents a challenge to institutions of how to modernize it with computer data acquisition. Going back to the equipment’s original manufacturer or other vendors for a retrofitting package with computer data acquisition is one possible solution, which usually costs thousands of dollars. For budget constrained institutions, a better solution is to look at the equipment itself and try to rejuvenate it with the computer data acquisition. Among the commercially available computer data acquisition systems, the hardware and LabVIEW software by National Instruments are widely used. Some educators presented efforts to modernize their equipment with computer data acquisition and LabVIEW for some individual experiments [1, 2, 3], while others implemented it for the whole laboratory course [4, 5, 6]. At the Department of Engineering at Indiana University-Purdue University Fort Wayne, the Tinius Olsen universal testing machine, which was purchased about 30 years ago and is shown in Figure 1, is used in the tension test and strain hardening labs in the laboratory course ME 304 Mechanics and Materials Laboratory. These two experiments were the two most time consuming Proceedings of the 2005 American Society for Engineering Education Annual Conference & Exposition Copyright c © 2005, American Society for Engineering Education