According to one study, over 70% of engineers use Microsoft
Excel to manipulate their data and produce data acquisition reports.
And why not? With Excel you can enter, edit and sort data; create
formulae to calculate values; apply a variety of statistical, mathematical,
trigonometric, logical and other functions; and graph your data
in a variety of chart formats. The Analysis ToolPak, which comes
with recent versions of Excel but isn't installed by default (enable
it from the Tools...Add-Ins menu), provides some extra engineering
functions including Bessel, conversions, logarithms and more.
Excel's Tools menu also lets you add in additional functions from
third-party developers. Various data acquisition add-ins are available
that let you feed measurement data directly into your spreadsheet,
control your data acquisition source and perform a broad range
of data manipulation, analysis and graphing tasks without having
to write programs or learn how to use specialist software.
One solution that's caught our eye recently is a hardware/software
bundle from Measurement Computing that must be one of the simplest – and
cheapest – ways to get into data acquisition. The hardware
part of the offering is a neat little unit called a Personal Measurement
Device (PMD) which offers analogue and digital data I/O through
a USB port. USB is a very convenient route as you don't have to
spend time opening up your PC, juggling with IRQs or going through
complex configuration routines.
For less than £200, you can get one of these devices capable
of monitoring 4 differential or 8 single-ended voltages at up to
1.2KS/sec, together with an Excel add-in called DAS-Wizard which
places your measurements into your spreadsheet. A simple dialogue
box lets you configure the PMD and set the appropriate range of
cells.
You can get details of this combo from Measurement Computing's
UK partner Adept Scientific (www.data-acq.co.uk/pmd-1208ls.html).
IOtech (www.iotech.com) offers an Excel add-in based on their
DaqView software. DaqViewXL puts a floating toolbar into Excel
that contains all the controls required to set up and execute data
acquisition tasks from within the spreadsheet, so you can display
and analyse your data immediately.
DaqViewXL is compatible with IOtech's parallel port-based DaqBook,
plug-in DaqBoard and Daq PCMCIA card data acquisition products,
as well as Adept Scientific's DataShuttle devices (www.datashuttle.co.uk)
which includes a USB model.
National Instruments (www.ni.com) supplies another set of Excel
add-ins, called Measure, which again let you control instruments,
read in data and configure measurement tasks through simple dialogues.
There are many others around too.
If you're a programmer, you're probably able to set up your application
to communicate with Excel through ActiveX, OLE, DDE or whatever.
If you use an off-the-shelf package, you'll probably find it has
some sort of Excel compatibility built in. National Instruments'
popular LabVIEW (www.labview.com/labview), for example, uses ActiveX
automation to communicate with Excel.
To integrate Excel objects with your LabVIEW VIs, the basic procedure
is to open a reference to Excel from LabVIEW, then invoke the methods
and get/set properties you need. Excel then acts as a server to
your client LabVIEW application.
Another popular solution, DASYLab (www.dasylab.co.uk), which we
looked at in last December's Dr Know column, uses DDE to populate
your spreadsheet.
Talk to your data acquisition supplier: they're bound to have
a recommended solution for getting measurement data into Excel
through whichever type of hardware you're using or plan to use.
Finally, however, there are some types of data acquisition application
where you don't actually need a hardware device to interface measurement
instruments to your PC. Many lab instruments, such as balances
and pH meters, have serial (RS232) outputs and can be plugged straight
into your PC's serial port. If you need to collect serial data,
WinWedge (www.adeptscience.co.uk/softwarewedge) might be just the
software you're looking for. It collects and feeds data into just
about any Windows application, including Excel. Communication is
two-way so you can control the devices as well, and it can handle
multiple serial instruments simultaneously.
Next month we'll depart from the Excel theme, and take a look
at the recently launched Data Analysis Extension Pack for Mathcad.
Dr Know's recommended download is the PMD12008LS & DAS-Wizard datasheet - download yours today.