Customer SolutionsDevelopment of an Energy Consumption Measurement System Using NI LabVIEW 7.1 and DAQ
Author(s):M. Eltoukhy, Department of Industrial Engineering, College of Engineering, University of Miami; S. Asfour, Department of Industrial Engineering, College of Engineering, University of Miami
Industry:University/Education
Product:Data Acquisition, LabVIEW
The Challenge:Developing an integrated, simple data acquisition system for different energy consumption measurement applications, which is a main goal of the University of Miami Industrial Assessment Center (MIIAC).
The Solution:Using National Instruments LabVIEW software, NI data acquisition (DAQ) hardware, and our existing current transducers to build the required system.
The Need for a Flexible Measurement System Our data-logging session strategy consists of the field installation of anywhere from 18 to 540 energy data loggers. We preset each data logger to capture electrical demand inputs with sampling rates from as low as one second to as high as every 15 minutes when concentrating on demand. Hence, the retrieved energy data may be as low as 453,600 points (when 18 data loggers are installed) or as high as 13,680,000 data points (when 540 data loggers are installed). Each data logger has a capacity of 10,000 data points. Due to the memory limitation on these loggers, we are forced to return to the field multiple times to retrieve saved data and to reset the loggers for additional logging sessions. This results in additional expenses that make the measurement and verification process economically infeasible. To address this issue, we used NI LabVIEW 7.1, DAQ, and the above mentioned hardware components to develop a flexible data acquisition and current measurement system for supervised and unsupervised energy consumption measurement. The system is composed of the following:
Supervised and Unsupervised Assessment We can use our measurement system for supervised energy assessment, which requires the presence of a user on site to react to the system’s feedback. We also can use the system for unsupervised measurement, during which the SMTP-based system can instantaneously send an e-mail to the user in charge of the energy assessment process. This e-mail contains a summary of the energy assessment session and an attachment including the collected current and power data. The system also can instantaneously send an e-mail to alert the user if the condition (event) that the user previously specified took place. With LabVIEW and DAQ, we designed the entire system using a single laptop (that we can interchange with a Pocket PC), to which we attach the current transducers. The system converts the signal obtained from the current transducers into voltage using the current transducer’s calibration curve and transfers the voltage to the connector block through efficient use of shielded wiring. This secures data transfer between the sensor and the NI DAQCard-6036E (for PCMCIA) in the laptop. The system then instantaneously converts the data into current values and saves them in Microsoft Excel format for further analysis. Using our measurement system, with which we can achieve high sampling rates, we can save the data continuously for any period of time or recall the data at any time. We also can directly acquire the energy consumption data in an Excel format without the need for other hardware components, called Hobo, which include a data-collecting board that can save only 10,000 data points. Previously, with the Hobo hardware, we had to download the data and then convert it to Excel format using Hobo software. But now, with our new measurement system, we can directly generate complete reports of our collected data and necessary analysis. Results and Benefits We developed a cost-effective, stand-alone, and flexible current measurement data acquisition system for energy consumption measurement applications. We achieved high programming efficiency, high performance, and cost savings using National Instruments DAQ hardware and LabVIEW software to build our system. With simple components, we now can monitor, measure, and control the energy for any system while saving money and data-logging time. For more information, please contact: Shihab Asfour, Ph.D. |
