In its most basic form, data logging is the task of measuring and recording physical or electrical parameters over a period of time. A wide range of devices can measure and log data – from basic, single measurement devices to complex systems with built-in analysis functions and displays. When selecting a data logger, take into account the following considerations.
Data loggers can measure different types of signals and sensors including the following:
Some applications require only a single measurement, while others may require multiple channels and multiple types of measurements. Data loggers are available with various channel configurations: single-channel devices, multichannel devices, and modular devices with a mixture of measurement types.
Single-Channel Data Loggers
Multichannel Data Loggers
Modular Data-Logging System
Traditional data loggers are stand-alone box instruments that measure signals, convert them to digital data, and store the data to internal memory. Data must be physically transferred to a PC for visualization, analysis, and permanent storage.
PC-based data loggers, on the other hand, are a combination of a data acquisition device and a PC. Because the PC is actually a part of the system, the data logger can take advantage of the ever-increasing performance of the PC processor, hard drive, display, and I/O bus. This presents the following advantages over traditional stand-alone data loggers:
A data logger connects to a PC through the PC’s peripheral bus. To select the right data logger, it is important to understand the different types of buses.
USB - USB was originally designed to connect peripheral devices such as keyboards and mice, however, it has proven useful for other applications including connecting to measurement devices. USB is easier to use than many other PC buses because computers automatically detect the devices.
Ethernet - Ethernet is the backbone of almost every corporate network and, therefore, is widely available. Although Ethernet requires more configuration and networking knowledge than USB, it provides longer-distance measurements up to 100 m, or further if used with a hub, switch, or repeater.
Wireless - Wireless technology extends measurement capabilities to applications where cables are inconvenient or impractical. It can also dramatically reduce costs by eliminating cables and installation time.