Measuring the magnetic field of a rare earth magnet using LabView

[mkemnetz]

I would like to start out by saying I am definately a greenhorn when it comes to LabView and its hardware so if this is the wrong place for this question I apologize.  I am looking to introduce LabView and the hardware National Instruments offers into my research.  The end result I am looking for is to measure the magnetic field of a rare earth magnet using LabView capable instrumentation, hardware, and software.  I can't quite wrap my head around the hardware NI offers and I was wondering if you all could shed some light.  

Right now what looks the most intriguing is the CompactDAQ system.  I think I might be able to adapt it to my needs but even though I have done plenty of searching I cannot find how or what equipment it is used with.  I might be completely off track here so if I am please let me know.  I want to eventually interface a Gauss/Tesla meter with labView to automatic meaurements and analyze/plot the appropriate data. 

I was thinking I could acquire an appropriate Gauss/Tesla meter that outputs a voltage or current and use the CompactDAQ system to enable LabView to analyze the data.  

Am I on the right track?  Can you provide some suggestions?

[Dennis_Knutson]

Or simply locate a meter with an RS-232 connection. Then all you would need at most is a USB-RS232 converter. If you found a meter with an Ethernet connection, you might not have to spend a thing.

Even if you wanted to use a meter that only had an analog output, a cDAQ system sounds like extreme overkill for a single output.

Typically, some one starts by selecting an appropriate sensor/instrument first. You are doing it the opposite way.

[mkemnetz]

Every instrument I look at seems to ship with their proprietary software.  I am concerned with interfacing LabView with the instrument.  Do you have any experience or tips that you can share about selecting a proper instrument?

[Albert.Geven]

You could look at the Instrument Driver Network to see if a NI supported driver exists for a specific instrument.

http://www.ni.com/downloads/idnet/

[mkemnetz]

I have done that many times.  The only issue is that the only Gauss meters that seem to have drivers are way out of my budget.  

[Dennis_Knutson]

As long as you have documentation on the programming interface, writing the LabVIEW code for controlling the instrument is really not that difficult. Up to you whether you write custom code for a data acquisition device or the direct instrument connection.

[JÞB]

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@mkemnetz wrote:

I have done that many times.  The only issue is that the only Gauss meters that seem to have drivers are way out of my budget.  

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In what manner?  to me it seems you have three choices?

1. buy the meter with the driver look at the examples and code your experiment.
2. Buy a meter without a driver, study the manual, learn how to code a instrument driver, code a instrument driver code your experiment-  Whats your time worth?
3. Buy a meter without a driver, hire a consultant to read the manual and code an instrument driver look at the examples and code your experiment.

What's your total budget in time and materials?

[mkemnetz]

I have a budget of about $1200.  Do you have experience with buying instruments and making drivers? is that a common thing to do?

[JÞB]

Well, yes

This is why I asked about you budget in terms of time and money.  I do not have the bandwidth to take on other tasks but you are going to spend either time or pay for time invested.  A large investment would be involved in either (For simple 1 measurement drivers the going rate is in the range of X.x-Y.yK$ per communications bus with a bonus for certification as PnP(proj)style)  Asume a Certified LabVIEW Developer will spend 8 man hours learning coding documenting and submitting a project at normal billing rates.

[mkemnetz]

Well I want to learn ow to do it myself, which is why I came here.  I am a developer myself, just not in LabView and I am trying to pick up the "language".  Do you know of any good places to start learning how to write custom instrument drivers?