Agilent 34970A programing issues

[erock72]

I have a tester with 10 stations, I am using LabVIEW 2010 on Windows 7 platform with an Agilent 34970A  DAQ system with the followwing cards installed in slot 1 is a 34908A 40 channel single ended MUX in Slot 2 is a 34903A 20 channel Accuator. The DAQ part of the program runs a scan of the 40 channels  inserting the readings into an array and then runs through a series of VI's reading shared variables to turn on or off the power to my stations.   I am having trouble with the power switching. The scan works fine, however the power will switch on , but switch off the next time the scan runs. Also the scanner shows errors and LabVIEW shows errors

[Dennis_Knutson]

You have not provided the subVIs or the errors from the instrument and LabVIEW.

[erock72]

Thanks for the reply. I found my issue I am using the EZ Voltage .vi included with the 34970A driver . I have used the 34970A on a number of projects in the past without any problems, however I always used 20 channel MUX cards. This time I used the 40 channel mux and the buffer size in the EZ Voltage.Vi VISA read comand is to small for the 40 channel card. I increased the buffer size and it worked. I would like to see some documentation on how to calculate the buffer size for a VISA read coomand.

[Dennis_Knutson · Accepted solution]

Do you mean the byte count input? This is very instrument specific but in most cases, is not something you have to worry too much about calculating exactly. You can put some arbitrarily large number and the VISA Read will automatically terminate when the instrument has sent the entire buffer. The 500 bytes that is in the example may have been just some random number that the programmer decided to use.

[JPablov]

Hi LabView expert members!! 
I'm new with this software and I'm trying to make and interface between Labview and Agilent 34970A for measure 5 different temperatues of my heat exchanger in real time. Could you suggest me some tutorials or tips about this?? I made my program but I don't know how to control the time scan interval, how to write and save my data and obtain graphics in real time, currently I can get the measurements but I cannot control the interval scan time and the real time is not the same like the time in my computer, also the file shows different time line and one column data. I attach my program, I'm using Labview 2010. Thank you in advance

[JL@NI]

Hello JPablov,

Here is a tutorial that may help. It will point you to the examples that are installed when you use the Agilent 34970A instrument specific drivers.

Regards,