Peripherals And Software Packages Aid In Data Collection

Data are the heart and soul of science, as well as the backbone, the skeleton, and a wide assortment of vital organs and appendages. The ability of computers to process data quickly has been an important factor contributing to the increase in scientific productivity over the last few years. But "processing" data isn't as easy as it sounds. Many scientists, when presented with a new microcomputer, naively believe that they simply will be able to put all their data into the machine and come up with an analysis -- akin to unscrewing the lid of a blender, pouring in ingredients, and flipping the switch to make a milkshake. The reality is a little bit different. Computers require data entry, by keyboard or direct acquisition through analog/digital (A/D) data acquisition devices, and then specialized software capable of conducting the necessary types of data manipulation and analysis. Historically, data were collected by hand. Scientists wrote down their observations, then made calculations with pencil and paper (later with an electronic calculator). When microcomputers became more commonly available, the calculations went faster, but scientists often continued to collect data by hand, with an observer writing down data points -- or, at best, recording them with an electronic event recorder. In either case, researchers then typed the observations into a computer via a keyboard, or fed them to a mainframe via punched cards. In today's research environment, with computer technology playing a more prominent role, there has been a corresponding increase in the number and sophistication of peripheral devices available for computerized research. Data acquisition peripherals have been one of the more important developments within the last five years. Peripherals are the hardware part of data acquisition -- the actual electronic machinery through which signals pass into the computer. The corresponding software for these units accepts data directly from the devices and then conducts standard types of analysis, negating the necessary intervening -- and time-consuming -- step of data entry. Such software includes special programs through which the computer can control the setup and operation of the peripherals and deal with the incoming data signals. Simply stated, a data acquisition device (commonly known as a data acquisition board, though there are other types, such as digitizers, scanners, and data loggers) is an electronic device capable of translating analog, or "real-time," data into digital data that a computer can use. A data acquisition peripheral (also known as an A/D conversion device) provides the interface between an automated laboratory setup and the computer that will be analyzing the data collected from the setup. There are various types of data acquisition devices. Stand-alone devices attach to a microcomputer by means of a cable; boards insert into one of the expansion slots inside the computer; and small, hand-held devices, which can be used to collect data at a remote site, plug into a computer port to upload the data. Depending on the complexity of the device, there may commonly be from one to 16 channels available for the transfer of data. A channel is an electronic pathway, from the point of data acquisition (an electrode or transducer, for example) to the computer. The more channels there are, the greater the number of observations can be recorded simultaneously. There are at least 20 companies in the United States and Europe that manufacture data acquisition devices. Analog Devices, Omega, and Strawberry Tree are three large representative companies; others can be found under the "Electronics" or "Computer Peripherals" listings in local telephone books, or advertised in newspapers or computer magazines. Setting up a data acquisition device and its corresponding software is a task whose complexity falls somewhere between installing a VCR and building one's own TV set from a kit, but tending toward the former. It doesn't require extensive electronics experience, but it helps if you understand the basics. As with other computer hardware, a data acquisition device requires software to make it operate. Most data acquisition software packages will provide some instructions on setup, but most of these instructions assume that the hardware end of things has already been handled, and are concerned more with setting the parameters that control the device. A complete electronics novice may feel insecure about tackling installation alone; scientists who find themselves baffled would do well to hire a technician. Several software packages on the market are designed to work in conjunction with data acquisition devices. ASYST and LabTech Notebook, programs that have been on the market for several years, both have good reputations for power, flexibility, and reliability. There are several more recently developed packages on the market as well (see box). Since Macintosh computers are more recent additions to laboratories, there's not as much data acquisition software available for Macs as there is for IBM PCs and their clones. There is a version of LabTech Notebook for Macintosh, however, and LabVIEW 2 is also a good multipurpose Mac package. What does data acquisition software do? Two main things: It lets researchers control the functions of their data acquisition device, and it collects and analyzes the incoming data. The "analysis" section of a program may consist of statistical calculations, file editing, or graphical presentations; ASYST and LabTech Notebook both also include some report-generating capabilities. Data acquisition software allows researchers to do things like view the pattern of collected data in a variety of graphical or tabular forms, including a "real-time" view. This feature, instead of storing the data for later analysis, lets the user see the data being plotted as they are collected. Both ASYST and LabTech Notebook also provide a wide variety of statistical procedures and good graphics capabilities. For example, these packages allow users to edit, combine, or otherwise process files of collected data before or during analysis; also, researchers can compare two data sets collected from different channels, or at different times. In addition to the general-purpose data acquisition software packages (there are several on the market), there are more specialized packages. These programs are intended to control the functions of more specific data acquisition devices, or to perform special analytic routines on collected data. Quality control (QC) software, for example, is a subclass of statistical software that provides the specialized charts that the manufacturing industry requires for quality control, such as n-charts, p-charts, other attribute control charts, and Pareto diagrams. Most QC software is analytic only, and does not provide data acquisition features. One exception is Quality Analyst, by Northwest Analytical, which lets users interface directly with a variety of electronic units, including electronic scales, balances, and other data collection devices. Quality Analyst also is capable of interfacing with one of the more general-purpose packages, like LabTech Notebook, to provide access to a wider variety of statistical functions. In addition to its utility in quality control applications, automated data acquisition is used to good effect by many scientific disciplines. Chemistry laboratories are perhaps the heaviest users of data acquisition devices, but biomedical, physics, and even geology laboratories make good use of boards, digitizers, and scanners. Not all laboratories or experimental situations are suitable for this type of automation, and setting up data acquisition and analysis hardware and software takes some time and effort. For laboratories in which computerized data acquisition is suitable, however, the effort involved in setup is well worth it in terms of improved efficiency and accuracy. Diana J. Gabaldon is assistant research professor at the Center for Environmental Studies, Arizona State University, and editor of Science Software.

Peripherals And Software Packages Aid In Data Collection

Interested in reading more?

Become a Member of