Instrument Control (GPIB, Serial, VISA, IVI)

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How to read thermocouple data from USB

Hi guys,

 

I am trying to use LABVIEW8.6 to write a data acquisition system to measue Seebeck Coefficient, which is Voltage over Temperature difference. Now I almost have finished the part for Voltage collection, however I am stuck now when trying to read temperaure data from DICKSON SM325(which is connected with two external K type thermocouple) using USB port. I will appreciate anyone who can give me some advice or help me to figure this part out.  Pls see my attachment which is the original program I wrote before. Thank you so much.

 

Kun,

 

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Message 1 of 7
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What you have done makes no sense. Why would you wire the control pipe in to the control pipe out and then the VISA resource to Fract/Exp String to Number. It looks like just a random set of VIs. In order to use the VISA functions, For the pipe functions, You need to use the VISA Wizard to create a driver and you need detailed information on USB RAW from the vendor in order to first write (pipe out) and read the data back (pipe in). Do you have that? What type of USB drver does the vendor originally provide? Why can't you use that?

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Oh, I do not have such informations, cause I have no idea about how to write it using Labview. This is my first time using labview. By all, thank you for  your advice, I will talk with the vendor for the details you mentioned here. Thank you so much.

 

Kun

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Message 3 of 7
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By the way, How to write a driver using VISA Wizard? What kind of information I need to have ? Thank you.

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http://www.dicksondata.com/product/model_SM325.php This is the website where I bought the data logger.

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Message 5 of 7
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There is nothing useful that I could find on the website. Before you do anything with the VISA wizard, ask if they have an api fot their driver. Tell them you want to control the logger with an external program - not the program they provide.

 

The VISA wizard should be your last option to consider and if they say the cannot provide a high level api, then I doubt you'll get the low level information you need for VISA communication.

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OK. I see. By the way, for the attachment below. I want to collect the data every 10 seconds, so would you mind telling me how to make it, or help me to modify it? Thank you so much.

 

Kun,

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