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Data Acquisition Idea Exchange

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Problem: When creating large numbers of virtual channels, the calibraton of these channels can be very time consuming and cumbersome. In large applications there can be literally hundreds of channels requiring days to calibrate.

Calibration equipment these days can be purchased with programmable capability or remote communication. Having low level functions available in Labview to calibrate MAX virtual channels programmatically would greatly reduce the time needed for calibration and reduce the potential errors of calibrating each point individually. It would also be useful to view the calibration data and scaling data from MAX in the Labview environment.

I'm not sure who reads this, but I'm not seeing any feedback in the forum so I thought I'd post up here. This may seem like a simple thing, but hopefully my pain will be someone else gain. I messed with this off and on for two months before I finally figured it out. It's probably obvious to those who work with this equipment every day and have EE degrees, but not so much to those of us who do not.

Please see http://forums.ni.com/t5/Multifunction-DAQ/Measuring-220VAC-with-CompactDAQ/td-p/1145956 for a description of the issues I was having.

Some will tell me to "search"... well, I did. ...and everywhere I looked all I found was that I needed to measure from the power leg to ground. All of the examples either were only measuring 120 which is fine since what you have is one power leg and neutral... which is basically ground! So those numbers come out fine. Or they were for 3 phase, which I don't use currently. BUT when you try and measure anything with two power legs (basically anything between 208VAC to 240 VAC) the numbers don't work out right if you try to measure between each power leg to ground and then try to recombine them and plug them into the Power VI's. Not one place that I looked did it tell me that I need to measure both power legs across a single channel. I only finally tried it because I'd done pretty much everything else. I know this is pretty basic stuff, but when all you give me says one thing... that's what we do. Just trying to help others.

Thanks,

Chad

I would really like to see a user configurable hardware front panel that integrates with LabVIEW. The panel would connect to a computer via USB. National Instruments could sell different hardware controls such as pushbuttons, LED's, switches, LCD panels for graphs, rotory encoded switches, slide switches and potentiometers, LCD indicators for text and numbers, etc.

LabVIEW would discover which panels are connected and which hardware controls are available in those panels. The user could then drop them as terminals on the block diagram and use them as normal.

Another option for the panel could be an embedded computer running LabVIEW so that the whole thing can be stand alone.

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As a user of the SCXI 1000 with a 1302 board, I had a lot of difficulty finding information on the pinout of my board. The 1302 is a direct link to the 6220 DAQ card on my computer. When I first looked for the 1302, I could find very little information on it. By adding a few windows and commands to the M&AE, I probably would have been able to solve my problem in minutes instead of days.

Solution

A. Being able to add boards which link to pinouts of the computer's DAQ and treat them as a board.

B. Have a list of pinout boards which can link to the DAQ. Since I was dealing with a 1302 which has 34 pins instead of 64 (or something close to that) I had difficulty finding the information on the pinouts. It was far easier to find the pinout of the 6220.

It could be I was a little annoyed at the amount of time that I spent on finding information on the 1302, but it took me far longer to find the information than it should have. This data should be built in.

As far as I know, the DAQ-mx has provicion to generate the COUNTER output or to read digital input triggered by the change detection event.

It would be nice if one is capable of generating the DIGITAL output on accurance of change detection event.(i.e. it can be triggered):smileytongue:

Also digital output must be allowed to generate the waveforms which are triggered by any of the digital input lines.

If possible then COUNTER counts should be available to user in LABVIEW after triggering, to synchronise the various digital input/output to counter state/count.Since some of the actions are COUNT dependent.

R&D , LABVIEW,

NATIONAL INSTRUMENTS.

FROM

Mithun Raj .T,

Pranavam, Kalluvilla , Kariyam,

Sreekaryam P.O, Trivandrum- 17,

Kerala, India.

We are a group of B.tech project students from SIST , Kerala ,India. We are doing a project on ICU using LABVIEW in Indian Space Research Organisation.

While we doing our project we found the nessecity of following :

> A functions that provides range or specification of the addressed device so that the programmer has an overall knowledge of the addressed device & its range of operation.

> A suggestion window at the top left when some error occurs.

So if our suggestions are good please kindly provide us a good idea certificate from NATIONAL INSTRUMENTS,that will help us a lot. So kindly consider our request.

Your's affectionatly,

Ahammed Shiraz A.R

Anish .S

Dileesh .S

Mithun Raj .T

Proposal : If left unwired, the DAQmx Create Channel Minimum and Maximum Value inputs would default to the maximum value for whatever physical channel was wired. Currently for example, AO Voltage defaults to +/- 10 V. Some devices such as the USB 6008 are limited to 0 to +5 V. For programs that allow for different daq devices to be used and changed at run time, one does not know ahead of time what the allowable input limits will be and cannot be assigned. Is it possible to use the DAQmx Device property I/O Type:Analog Output:Voltage:Ranges to obtain the limits and then wire that result however this involves extra coding to make use of them. If the DAQmx Create Channel is used at many places in a vi it becomes cumbersome to have to extract the property for every instance of use. i.e. even if DAQmx Create Channel is done once, another call to it does not retain the values previously set. A solution would be for DAQmx Create Channel to simply obtain the minimum and maximum values based on whatever physical channel was wired to it and use them.