Acquire simmultanneously and geting time stamp from GPIB ?

[Nok]

Hi..everybody..

I have two questions about GPIB.

1. I want to acquire the data stream from 2 instrument simmultaneously!!!

Anybody has an idea about it. that I did now,is just can make the acquisition relatively.. eg. acquire instruemnt1 and then acquire instrument2 ... and so on.

2. I need to make the power spectrum from FFT function in LabVIEW express 7. I used the array of the data stream got from GPIB inputs to the FFT function (I convert this array to dynamic array before). The result just looks correct because the spectrum shift when I shift the frequency but the problem is "I have no idea how the frequency axis output come out and the number is not correct" So..does anyway exist for gettin
g the time stamp from the GPIB acquisition ??


Thanks for any kind help... I stuck with this for long time.!!!!

[Dennis_Knutson]

1. If the instruments have a trigger mode, you should be able to have the instruments acquire simultaneously and then you will read sequentially. Your instrument manuals should have a description of what (if any) triggering modes they support.

2. In order for the FFT to determine frequency, you need to provide the sampling rate. If you create a waveform data type, you should be adding this info from either parameters you set in the program or from a setting in the instrument that you can read back and use.