The USB interface has revolutionised data acquisition as it has so many other PC applications. It's given rise to a whole slew of ever-smaller, ever-neater I/O devices that you just plug and play – no more opening up your computer, no more fiddling around with IRQ settings and whatever. Comparatively simple applications like logging temperature data certainly benefit from the convenience that the USB has brought. But the problem with using a USB data logger is that you don't always want to have your PC in the same location as the temperatures you want to measure - especially if you have other work to do on it! In any event, there are many remote or stand-alone applications requiring temperature measurement where the use of a dedicated PC or laptop is simply not feasible
Measurement Computing (whose products are available in the UK from Adept Scientific) has come up with a very neat and inexpensive solution – a stand-alone data logger that's highly accurate, and that logs data from thermocouples, RTDs, thermistors, and semiconductor temperature sensors - all at the same time if that's what you need!
The 8-channel USB-5203 (click http://www.adeptscience.co.uk/go?pg=CA090), and its companion product, the USB-5201 (click http://www.adeptscience.co.uk/go?pg=CA092) which records only thermocouple data but is otherwise identical, ship with a 64 MB CompactFlash® (CF) card which can store approximately 2.35 million time-stamped temperature values from a single channel (if you need more, the unit supports CF cards up to 2 GB). To transfer the data to your PC for processing and analysis, either connect the device using a standard USB cable, or place the removable CF card into a standard CF card reader.
Both of these devices provide user configurable temperature alarms for control of eight digital output lines, and come with TracerDAQ software for data management and analysis. This converts and saves temperature and alarm data to standard, comma-delimited CSV or text files. TracerDAQ also plots and analyses real-time data or historical temperature files. Also included is InstaCal, an all-in-one installation, logger setup, calibration, and test application that makes setting up and retrieving data from the logger as simple as a few quick mouse clicks; and language interfaces for users who want to write programs in any of the most popular programming languages, including LabVIEW™.
But these are not the only new data logging offerings from Measurement Computing. You'd be hard pressed to find devices as small, and as inexpensive, as the USB-501 and USB-502. If you don't need the capacity of the CF card devices, or you're on the move a lot and need to take measurements in the field where no power supply is handy, these devices are a real boon.
These convenient little units are about the size of your thumb. They're battery-powered and include software to configure the loggers, program alarm thresholds, logging rates, start times, and measurement units. When the loggers are retrieved from the field and plugged straight into a USB port, the software provides simple one-click access to download, display and export your data.
Both the USB-501 (click http://www.adeptscience.co.uk/go?pg=AC093) and USB-502 (click http://www.adeptscience.co.uk/go?pg=CA094) log up to 16,382 temperature measurements in the -35 to +80 ºC (-31 to +176 ºF) range. The USB-502 additionally supports up to16,382 additional relative humidity measurements over the full 0 to 100 percent range. Rates for both data loggers can be set from 10-second to 12-hour intervals.
But we've saved the best until last: the prices of the USB-501 and USB-502 are, at the time of writing and excluding VAT, just £35 and £49 respectively!