Labview VI is reading the data wrong - Agilent 34972A

[hugomeshg]

Hi guys, 

I did a simple VI to read a external instrument Agilent 34972A  using the USB port. The VI looks that it works, but I noted that the temperature datas are diferent comparing when I use the Bench Link Software (Original program to aquisit from Agilent). 

The VI is getting temperature 3,5 degrees high and when de temperature down the diference is getting high something like 5 degrees, it is not linear, I tried adjust an offset but it did not work. 

A attached the VI, the temperature readed by VI and the temperature readed by software by Bench Link

What am I doing wrong? 

I configured the VI to read Thermocouple type E, with the scan list 201:206,301:302,305:310. 

[hugomeshg]

Hi, I need your help to show me where I am not seeing.

I did a simple VI to read data temperatura of Thermocouple type E from Agilent 34972A. I noted that the temperature readed is 2,5 degrees high, comparing the temperature adquired by Benchlink Data Logger ( Original Software to Adquire Agilent). I tried to adjust an offset, but it did not work , because when the temperature down the diference is high something like 3,8 degrees. 

I though that I doing a simple VI it would read the real data, but it is not happining 

A attached the VI, the temperature readed by VI and the temperature readed by software by Bench Link

[altenbach]

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@hugomeshg wrote:

A attached the VI, the temperature readed by VI and the temperature readed by software by Bench Link

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You did not attach any VI, just pictures. Do you have the help pages of the driver VIs? Are you sure all inputs are correct?

(On a side note, if you want array elements in order, you don't need to wire indices to "index array". personally, I would probably use an array indicator resized horizontally)

[Kyle97330]

In my experience this sort of thing is usually caused by the manufacturer's software sending different commands than you are sending.

Your goal should be to find out what those commands are and then determine the difference between what LabVIEW sends and what the manufacturer's software sends.

Once you determine the difference, you can see if the difference is good or bad, i.e. either you didn't known to send a command you needed, or the manufacturer's software is sending commands that you don't want it to send.

I would recommend either:

1. Contact the manufacturer to ask what their software does different compared to you

or 

2. Change your connection method to LXI so it's over Ethernet, then use an Ethernet monitoring tool such as Wireshark to check the communications and see the commands yourself.

[RTSLVU]

Don't use the EZ Temperature vi because it clears all the other channel settings (CJC reference, Etc) 

Configure all your channels

Build a "scan list"

Trigger a "scan" when you require a measurement

I have written several posts on how to properly configure and use this instrument for various measurements, search the board.